Seed Treatment: An option for Seed and Soil Borne A. K. Singh 22 25 Disease Management in Crops

3. Eradication—eliminates, destroy, or inactivate the inoculum. 4. Protection—prevents infection by means of a toxicant or some other barrier to infection. 5. Resistance—utilizes cultivars that are resistant to or tolerant of infection. 6. Therapy—cure plants that are already infected

Advantages of Integrated Disease Management

Integrated approach integrates preventive and corrective measures to keep pathogen from causing significant problems, with minimum risk or hazard to human and desirable

components of their environment. Some of the benefits of an integrated approach are as follows:

 Promotes sound structures and healthy plants  Promotes the sustainable bio based

disease management alternatives.  Reduces the environmental risk

associated with management by encouraging the adoption of more ecologically benign control tactics  Reduces the potential for air and ground water contamination

 Protects the non-target species through reduced impact of plant disease management activities.  Reduces the need for pesticides and fungicides by using several management methods

 Reduces or eliminates issues related to

pesticide residue  Reduces or eliminates re-entry interval restrictions

 Decreases workers, tenants and public exposure to chemicals  Alleviates concern of the public about pest & pesticide related practices.  Maintains or increases the cost-

effectiveness of disease management

programs

Components of Integrated Disease Management

The major components of disease management are host-plant resistance, cultural practices, biological control and chemical control. Even though these components will be dealt with individually, it should be mentioned that often the different

components are complementary to each other with strong interaction among and between them and the environment. The major components of Integrated Disease Management are -

Cultural practices

Cultural practices such as cultivation techniques, mulching, intercropping, plant density, planting date, crop rotation, strip farming, timing of harvest, barrier crops, crop mixtures, roguing, healthy planting material, soil solarization, soil amendments, fertilizer management, and water management have been used singly and in combination as tools for disease

management. Cultural control methods not only serve in promoting the healthy growth

of the crop, but are also effective in directly reducing inoculum potential and in enhancing the biological activities of antagonists in the soil. Crop rotation is a very important practice, especially for soil borne disease control. For many soil borne diseases, at least a 3-year-rotation using a non-host crop reduces pathogen populations. This practice is beneficial for Phytophthora blight of pepper and Fusarium wilt of watermelon. Vegetable fields should be located as far as away as possible from inoculum and insect vector sources. Weed

control is important for the management of viral diseases. Weeds may be alternate hosts for several important vegetable viruses and their vectors. Elimination of weeds might reduce primary inoculum. Cover crops help to reduce weed populations that may harbor pathogens between seasons. For this purpose use cover crops that grow fast and provide maximum biomass. Excessive handling of plants such as thinning, pruning and tying may be involved in spread of pathogens, particularly bacteria. Because some pathogens can only enter the host through wounds, situations which promote plant injury should be avoided. During pruning process and harvest, workers should periodically clean their hands and tools with a disinfectant, such as isopropyl alcohol. If applicable, plants can be staked and tied for improved air movement in the foliar canopy. A more open canopy results in less wetness, discouraging growth of most pathogens. Soil aeration and drying can be enhanced through incorporation of composted organic amendments in the soil. Build up of inoculum can be reduced by removing all plant materials (infected and apparently healthy) after harvest. Between-row cover crops reduce plant injury from blowing sand. Polyethylene mulch can be used as a physical barrier between soil and above-ground parts of plants. This is an important practice for fruit rot control in the field. Highly UVreflective (metalized) mulches repel some insects. It is beneficial to use metalized

mulch during certain times of the year when insect vectors of some viral diseases are

prevalent. Tomato spotted wilt virus (TSWV) incidence and associated vector thrips populations have been demonstrated to be effectively reduced by using metalized mulches on tomatoes. Plant nutrition and soil

pH can also impact some diseases. Fertilizers with a higher proportion of nitrate nitrogen (NO3) than ammoniacal nitrogen (NH4) will help to reduce the incidence of Fusarium wilt on tomato. Increasing soil pH by liming is a good management strategy to reduce Fusarium wilt incidence as well as Botryis gray mold severity. Optimum calcium nutrition and higher soil pH may reduce the incidence of bacterial wilt in the field.

Adequate calcium is necessary to minimize blossom end rot and to provide for overall healthy growth. Avoiding excessive nitrogen

leads to less dense canopies, thus improving air movement in the canopy. High soil moisture enhances the development of soil borne pathogens including Phytophthora, Pythium and the bacterial wilt pathogen. Excess water damages roots by depriving them of oxygen and creates conditions that favor infection by certain soil borne pathogens. Irrigation management, based on plant needs, will help to create an environment unfavorable for pathogen survival and disease development.

Chemical control

For many decades fungicides played an important role in disease control. In the1960s, systemic fungicides started gradually to replace the older non-systemic chemicals with more effectiveness and

specificity in disease control. Very quickly, triazole fungicides gained 24% of the total fungicides market (Hewitt, 1998). However, the non-systemic fungicides such as mancozeb and chlorothalonil plus copper and sulpher-based products continued to have a good share of the market, especially in developing countries because of their lower cost.

Biological control

Success in using microorganisms against plant pathogens started with the control of crown gall with Agrobacterium radiobacter K84 (Kerr, 1980), and that of seedling blights caused by Pythium and Rhizoctonia with Trichoderma harizanum (Harman and Bjorkman, 1998), Gliocaladium virens (Lumsden and Walter, 1995) and Streptomyces griseus (Cook et al., 1996). However, the use of naturally occurring biocontrol agents (antagonists) of plant pathogens can be traced back to many centuries through the traditional practice of crop rotations that primarily permit the reduction of pathogens’ inoculum potential in the soil below injury level. This approach is still the most important single component, in both developed and developing countries used to manage root pathogens. This process is often accelerated by adding composts or manures, which enrich the soil with antagonistic microflora (Baker and Cook, 1974).

Host-plant resistance

Host plant resistance is an important tool to control diseases of major food crops in developing countries, especially wheat, rice, potato, cassava, chickpea, peanuts and cowpea. The use of resistant varieties is very much welcomed by resource poor farmers because it does not require additional cost and it is environment-friendly. Rice varieties resistant to rice blast, bacterial blight, rice tungro and brown spot are widely used. Rusts have been known to cause serious disease on

wheat since its domestication. The use of

genetic resistance is still the most economic and feasible mode of disease control.

Conclusion

Integrated disease management (IDM) is a disease control approach that uses all available management strategies to maintain disease pressures below an economic injury threshold. It does not advocate a routine

chemical application program to prevent disease, but promotes the integration of cultural, physical, biological and chemical control strategies.

Infected Potato Plants with Potato leaf

roll virus in the field

Serological testing for PLRV in various test samples by ELISA (Antibody based assay) Infected Tomato samples with Tomato leaf curl virus

Whitefly (Bemisia tabaci) induced Tomato leaf curl virus

2

Integrated Pest management in Field and Horticultural Crops in Rabi season

Uma Shankar and Amit Kumar Singh Division of Entomology, Faculty of Agriculture, SKUAST-Jammu

Introduction

India is bestowed with a diverse kind of

agroclimatic conditions which is congenial for varieties of field and horticultural crops in rabi season. Rabi season popularly reflects the phonological growth of crops in winter season in India. A large magnitude of field crops such as wheat, chickpea, Garden pea, faba bean, mustard and horticultural crops like cole crops, tomato, capsicum, onion, peach, pear and plum are grown and successfully attains the reproductive growth. Apart from these, mango also bears inflorescence and new groeth and development starts on guava and pomegranates with the onset of spring season. Although our country has attained the self sufficiency in food grain production, we are still lagging behind in terms of nutritional security. With the diversification and innovative

interventions in agriculture with horticultural crops, we can ameliorate the nutritional security problems. Further, the climatic aberration and the insect pests attack may become major constraints in successful cultivation of

these crops which may be addressed in right time through the use of Integrated Pest Management (IPM) to mitigate the problems and save our crops to enhance the production and safeguards our ecosystem and environment.

Insect pests of field crops Insect pests of Wheat Wheat Aphids (Sitobion avenae)

Among the insect pest attacking wheat crop in India, cereal aphids has assumed economic importance during past three decades and have become regular pests in

all major wheat growing areas. In India, aphids are the major pest of cereal crops in the winter/spring. Aphids are soft bodied insects that can be found in wheat

during the growing season. The most common aphids found on wheat are the bird cherry oat aphid, root aphid, green bug, corn leaf aphid and English grain aphid. The first four occur mostly in the fall and winter. Only the green bug aphid causes direct feeding damage that appears speckled brown and discoloured with some leaf curling. Aphids also act as vector for viral disease named barley yellow dwarf (BYD). Wheat and barley can be severely damaged, but oats are mostly susceptible to this disease. Infection can occur from seedling emergence through heading, but yield loss is greatest when plants are infected in the fall. Yield losses of 5-15% are

common but losses can exceed 30%

during epidemics. This year, a serious aphid infestation has been recorded in Jammu region which is the indication for future outbreak of aphids.

Integrated Management

1. Growing aphid resistant varieties may be promising, if available. 2. For the management of aphids, foliar spray of imidacloprid 17.8 SL @0.2 ml per lit of water is recommended on border rows at the start of the

aphid colonization.

Wheat Aphids (Sitobion avenae) and white eggs of syrphid flies

3. A well timed application of Lamda cyhalothrin can reduce the incidence of barley yellow dwarf (BYD) and increase yields. 4. Spraying oxydemeton methyl @ 1 ml per litre of water may be beneficial in reducing the aphid infestation.

Fall army worm (Spodoptera frugiperda)

Spodoptera frugiperda (Fall Armyworm) is an invasive pest of many crops but most serious pest for wheat, maize and many vegetable crops. It is an emerging insect pests problems which have been recorded from different parts of our country on many host crops. It is migratory lepidopteran army like pest infesting more than 100 plant species in India.

Fall army worm on wheat

Integrated Management

1. Clean cultivation and balanced use of

fertilizers is recommended to avaoid

its attack.

2. Deep ploughing is advocated before sowing to expose the FAW pupae to predators. 3. Monitoring is done by installation of pheromone traps @5/acre in the current and potential area of spread in crop season and off-season. 4. Erection of bird perches @ 10/acre during early stage of the crop (up to 30 days). 5. Augmentative release of

Trichogramma pretiosum or

Telenomus remus @ 50,000 per acre at weekly intervals or based on trap catch of 3 moths trap. 6. Biopesticides: Suitable at 5% damage in seedling to early stage and 10% panicle damage with entomopathogenic fungi and bacteria. a. Entomopathogenic fungal formulations: Application of Metarhizium anisopliae talc formulation (1x108cfu/g) @ 5g/litre at 15-25 days after sowing. Another 1-2 sprays may also be given at an interval of 10 days depending on pest damage. Bacillus thuringiensis var. kurstaki

formulations @ 2g/l (or) 400 g/acre. 7. To manage 2nd and 3rd instars larvae at 10-20% damage, spray Emamectin benzoate @ 0.4 g/l of water or

Spinosad @ 0.3 ml/l of water or

Thiamethoxam 12.6% +

lambdacyhalothrin 9.5 %@ 0.5 ml/l of water or Chlorantraniliprole 18.5%

SC @ 0.4 ml/l of water.

Termites (Microtermes obesi, Odontotermes obesus)

Termites are social insects, live in colonies and build up nests on the ground to attack growing plants, timber wood, dry leaves and grasses. Due to attack of termites on crops, roots and stems are damaged which resulted into wilting and drying of plants. The

queen may lay 30,000 to 80,000 eggs/day and 15 million eggs throughout her life span of five years. A large number of

workers are involved in damaging the

crops.

Integrated Management

1. Do not use raw or undecomposed farmyard manure. 2. If possible irrigate the field when infestation is serious.

3. Treat the seed with chlorpyriphos @ 5 ml/kg of seed before sowing. 4. In the termite prone areas, (especially the northern states) seed treatment with chlorpyriphos @ 0.9g a.i /kg seed.

5. Fipronil (Regent 5FS @ 0.3 g a.i./kg seed) is also very effective. 6. In the standing crop, the broadcasting of the insecticide treated soil 15 DAS

be practiced. For this, chloropyriphos @ 3 ml mixed in 50 Kg soil be used for one hectare field.

Insect Pests of chickpea

In India, more than 80 per cent people depend upon vegetarian food wherein, pulses constitute a major component of their diet. Pulses occupy an important place in human nutrition as dietary protein and have unique characteristics in ameliorating and restoring soil fertility. Among the pulses, chickpea (Cicer arietinum L.) is an important nutritious grain legume crop of India contributed 48%, towards total pulses production. In India, Chickpea (Cicer arietinum L.) is a Rabi season food legume grown and ranked first in area 96.00 (lakh ha) and production 88.325 (lakh tones) in the world. In India, chickpea is severely affected by around 57 species of insect pests causing economic damage. It faces the attack of more than 60 insect-

pests right from germination to maturity. Among them, gram pod borer (Helicoverpa armigera) and cutworm (Agrotis ipsilon) are recognized as major pests causing an extent of 25-30 per cent crop loss in India.

Helicoverpa armigera on chickpea

Integrated management

1. At the time of land preparation, broadcast cartap hydrochloride @ 20 kg.ha is quite beneficial in reducing the damage of Helicoverpa and cut worm in chickpea.

2. Installation of pheromone traps @ 5-7 per ha for detection and mass trapping and destruction @ 12-15 per ha of male moths.

3. Erection of bird perches @ 50/ha for the insectivorous birds

4. Spray Ha-NPV 250 to 500 LE/ha (freshly prepared) 2-3 times at 10 days interval at evening hours. 5. Spraying of the following insecticides

Bacterial formulation @ 500g .ha is also promising. 6. Alternative spraying of cypermethrin @ 1 ml/lit water and Dimethoate @ 2ml/lit of water at 12 days interval.

Insect pests of Horticultural crops Tomato Fruit borer: Helicoverpa armigera

Helicoverpa is a very serious pest and has been reported on more than 200 host plants in India. In the pre-fruiting stage, the caterpillar feeds on the tender foliage including leaves, flowers and buds and the crop gives a perforated look. After fruiting, they bore large, clear, circular holes into fruits and feed on the pulp. The larvae thrusts its half of the body in to the fruits or pods and feeds the inner contents and rendering them unfit for the human consumption. It causes damage up to the tune of 30 to 40 %.

Integrated management

1. Soil solarization and seed treatment

with Trichoderma of seeds for

nursery raisings. 2. Plant one row of Agrican marigold as trap crop for every 16 rows of tomato.

3. Monitor or clipping of top 3 tender leaves for Helicoverpa eggs destruction.

4. After 45 days of transplanting give 23 sprays of NSKE 4% at 10 days interval

5. Erection of bird perches @ 50/ha for the insectivorous birds (Black drongo) especially in tomato field and installation of pheromone traps @ 5-7 per ha for detection and mass trapping and destruction @ 12-15 per ha of male moths.

Helicoverpa on tomato

6. Spray Ha-NPV 250 to 500 LE/ha (freshly prepared) 2-3 times at 10 days interval at evening hours. 7. Spraying of the following insecticides- cypermethrin @ 1 ml/lit water or Dimethoate @ 2ml/lit of water.

White-fly (Bemisia tabaci)

Both adults and nymphs suck sap from the leaves of the host plants and lower their vitality. Tiny, white flies are also responsible for transmitting the virus in tomato causing tomato leaf curl virus. Severe stunting of plant with downward rolling, crinkling of leaves and severe chlorosis of newly formed leaves takes place. Older leaves become leathery and brittle.

White-fly on tomato

Integrated Management

1. Use of Cartap hydrochloride 4G @ 1 kg a.i. per ha as soil treatment in nursery. 2. Seed treatment with Gaucho @ 3 g/ kg seed provides protection from whiteflies at nursery. 3. Rouge out and burning of the infected plants in early stages. 4. Use of delta traps also recorded effective in catching whiteflies. 5. Cover the nursery bed with Agronet or nylon net (200 gauge) or muslin cloth for 25-30 DAS to prevent entry of adults of whitefly. 6. Spray metasystox @ 1 ml or imidacloprid @ 0.3 ml per lit of water

Garden pea

Garden pea is an extensively grown vegetable as well as for seed crops in Jammu region which harbours a large magnitude of insect pests ranging from leaf feeding defoliators, miners, sucking insect pests and fruit boring insect. Pea stem fly, Ophiomyia phaseoli; pea aphids, Acyrthosiphon pisum; leaf miner, Chromatomyia horticola; green pod borer, Helicoverpa armigera and bird pest, Alexandrine parakeet were the major insect pests causing considerable damage to garden pea crop at various stages.

Integrated Management

1. Thiomethoxam 25WG was found

superior in reducing the pea leaf

miner population and damage in the field condition.

2. Soil application carbofuran 3G + alternative foliar spray of cypermethrin and imidacloprid 17.8

SL was found superior in mitigating the larval population of Helicoverpa armigera.

Pea leaf miner

Insect Pests of Mango

Mango is better known as the king of fruits and is attacked by over 500 species of insect pests wherein, only few are recorded to be economic insect pests.

Mango hoppers

Only 3 species are serious pests such as Amritodus atkinsoni, Idioscopus clypealis and Idioscopus niveosparsus in India. The mango leaf hoppers are small wedge shaped insects which continuously suck the saps from the inflorescence thereby reducing the vigour of the plants and particularly destroying the inflorescence and causing fruit drop. Heavy puncturing and continuous draining of the sap encourages development of sooty mould Maliola mangiferae and Capnodium mangiferae on leaves and inflorescence. The extent of damage depends upon the critical crop stage and hopper population. Cloudy weathers and precipitations are conducive conditions which favours the

pest population build up at the time of blooming. Temperature and relative humidity constitute important environmental factors regulating the population of the mango hoppers.

Mango hoppers

Integrated management

1. Conserve the natural enemies like

coccinellids, chrysopids and spiders as they are potential predators of nymphs of hoppers. 2. In senile orchards, dense tree canopy should be pruned heavily to have better light penetration.

3. Spray insecticides at critical crop stages, namely, bud burst stage, panicle emergence and after fruit set. First spray cypermethrin or fenvalerate (1ml per lit of water) followed by imidacloprid (0.3 ml per lit of water) at fortnightly interval at evening hours. Do not spray when trees are on full bloom to avoid

killing of pollinators.

Mango fruit fly

Fruit flies are polyphagus in nature and their extent of damage depends upon type, size and condition of fruit, availability of different hosts and population density. They have been recorded on various host crops in Jammu like mango, guava, litchi, citrus, ber, peach, phalsa etc. About a dozen species of Bactrocera dorsalis complex are considered of economic importance in Asian continent. Female lays eggs below the fruit epidermis (1-4mm) deep. On hatching, the maggots feed on fruit pulp and the infested fruit starts rotting due to further bacterial infection. Attacked fruits

usually show signs of oviposition punctures and ripe fruits with high sugar content exude a sugary liquid. Mango fruit fly The maggots come out of the affected fruit to pupate in soil. Due to climate change and adoptability of insects the unripe and immature fruits are also claimed to be damaged by the fruit fly. On the average, 36-40% fruits of mango have been observed damaged.

Integrated Management

1. Fourty five days prior to harvest, deep plough the soil around trees to expose and destroy the fallen and pupating fly populations. 2. Install sixteen methyl eugenol bottle traps (0.1%) per ha or one commercially available trap per tree. 3. One months before harvest, spray decamethrin (0.5 ml/lit) or malathion (2ml/lit) along with gur solution and sticker.

4.

C.

Mango mealy bug

Mango mealy bugs are polyphagous and serious pests from India on several host crops. Nymphs and adult female bugs are flat, oval and covered with waxy white powder which makes them hard to control. Generally eggs are laid in silken pouch in ending May to June, which hatches out during ending December to starting January. The newly hatched nymphs ascend the trees and settle on inflorescence causing flower drop and affecting fruit set.

Mango mealy bugs

Integrated Management

1. Deep ploughing of orchard immediately after harvest or during summer months to expose eggs and pupae of mealy bugs to natural enemies and sun heat.

2. Heavy irrigation of orchard in

October also helps in destruction of eggs of mealy bugs. 3. Raking of soil around the tree trunk and mixing with drench the tree basin with imidacloprid @ 0.5 ml per lit of water for controlling early instar nymphs of mealy bugs in the month of November–December.

4. Release Cryptolaemus montrouzieri at 10 beetles/plant. Mealybug destructors are observed devouring the mealybugs in Jammu conditions. 5. After mud plastering 25 cm wide, 400 gauge alkathene (polythene) sheet should be fastened to the tree trunk

about 30 cm above the ground level to prevent migration of freshly hatched nymphs of mealy bugs in the month of December-January.

Pomegranate Pomegranate Butterfly

The larvae bore into the fruit can destroy up to the 50 % of the fruits. The female butterfly lay egg singly on the calyx of flowers or small fruits. On hatching, the larvae bore inside the developing fruits and feeds on aril and seeds. The entry hole allows secondary infection of fungi and bacteria to cause rotting of the fruits and rendering them unfit for consumption. The affected fruits ultimately fall down.

Anar butterfly larva

Integrated Management

1. Removal and destruction of fallen

and affected fruits with exit hole.

2. Remove flowering weeds in and around the anar crops. 3. Release of Trichogramma chilonis @ 2.5 lakhs per ha four times at 10 days interval.

4. Spray decamethrin @ 1ml per lit of water at the time of 50 % fruit set.

Repeat after 15 days with fenvalerate 0.5 ml per lit of water during nonrainy season.

Pomegranate Thrips

Thrips are minute insects having piercing and sucking type mouth parts. They suck the sap from tender leaves and flowers causing leaf tip or margin curl and shedding of lowers. When they feed on tender fruit causing scab like symptoms and reduce the market value of fruits.

Integrated Management

1. Sparying of dimethoate @ 2ml per lit or imidacloprid @ 0.3 ml per lit of water before flowering. If incidence is high enough, Sparying of dimethoate @ 2ml per lit or imidacloprid @ 0.3 ml per lit after fruit set.

Peach

Peach crops have been found infesting by peach leaf curl aphid, peach fruit fly and peach twig borer as major insect pests in Jammu.

Peach leaf curl aphid

It is a serious pest of peach and indirectly reduces the yield and quality of produce. Nymphs and adults suck the sap from all tender parts especially leaves of the plant. Affected leaves turn pale and curl up, blossom withers and fruits do not develop and drop prematurely.

Peach leaf curl

Integrated Management

1. Conserve and encourage the coccinellids beetle to suppress the aphid populations. 2. Spray the trees with metasystox @ 1ml per lit or imidacloprid @ 0.3 ml per lit of water.

Peach fruit fly

Adult females lay eggs in small batches of 2-10 inside the ripening fruits by making punctures with their ovipositors (egg laying apparatus). On hatching, the maggots feed on the pulp and fruit becomes soft, ferments and drops. The attack is more serious on late maturing varieties. Full-grown maggots come out of the infested fruits and jump into soil for pupation.

Peach fruit fly

Integrated Management

1. Fallen fruits should be collected and

burnt to maintain sanitation in peach orchard. 2. Summer ploughing just after harvest is essential to expose the hibernating pupae to sun and for parasitisation. 3. Methyl eugenol or Bait traps should be used to suppress the fly pest population. 4. Flooding and drenching the orchard with fipronil through irrigation water is also beneficial to check the

pupating population of fruit fly.

Citrus

More than 300 species of insects and mites have been recorded on different

Citrus spp. from Asia. However, the key pests are leafminer, psylla, mealybugs, scales, blackfly, whiteflies, aphids, fruitfly, fruit sucking moths, mites and thrips. In Jammu condition, six insect pest viz., citrus psylla, leaf miner, whiteflies, mealybug, aphids and citrus caterpillar and their natural enemies have been

recorded as the major pests of citrus.

Citrus Psylla

The citrus psylla is widely distributed in A ’ y l b ng c ll Asian psyllids. Adults are grey coloured actively flying insects and while at rest, they raise their body upward. The nymphs are orange yellow in colour, flattened and circular in shape. The

damage is caused by the nymphs and adults who suck sap from buds and leaves. The affected leaves get curled and shoots become dry. The psyllid also acts as a vector of greening disease. There are no systematic data available on extent of damage, however, citrus psylla has been reported causing loss to mandarin to the tune of Rs. 40 million (about US $ 1.04 million) alone in Vidharva region of Maharashtra in India.

Citrus Psylla

Integrated Management

1. Several species of predators and syrphids have been reported feeding on eggs and nymphs of citrus psylla. 2. At the initiation of new flush, spray monocrotophos (1.5 ml per lit) or dimethoate (3ml per lit) or

Imidacloprid (0.5 ml per lit). If required, repeat the spray at 15 days interval, once or twice.

Citrus Leafminer

Leafminer adult is a tiny silvery white moth with black eyes and narrow fringed white hind wings. Eggs are minute, rounded and yellowish green. The caterpillars are legless and pale yellow in colour with brownish head. The larvae

feed on the epidermis of tender leaves making serpentine mines of silvery colour. Severely infested leaves become distorted, crumpled and finally fall off. Attack of leafminer encourages the incidence of canker during rainy season.

Citrus leaf miner

Integrated Management

1. For the effective management of citrus leafminer, clipping of infested leaves and their pruning is advised. 2. Commencement of new flushes

should be sprayed with fenvalerate (0.05%) and neem seed extract (2%), alternatively, at 10-12 days interval.

3. Release of parasitoids C. quadristriatus and T. phyllocnistoides is also recommended.

Citrus caterpillar

Two species of citrus caterpillar butterfly namely Papilio demoleus and P. Polytes have been recorded in Jammu causing complete defoliation of citrus. The pests are active throughout the year except winter months. The infestation is more

pronounced in nurseries and on young trees. Peak pest activity coincides with the new flushes in citrus. This pest has also been found defoliating the beal fruit (personnel observation).

Citrus caterpillars

Integrated Management

1. Collect and destroy the larvae which look like bird excreta in early stage. 2. Spray endosulphan @ 2ml per lit or carbaryl @ 2g per lit of water.

3

Biological Control in Rabi Crops

Vishal Gupta, S. K. Singh and R. S. Sodhi Division of Plant Pathology, Faculty of Agriculture SKUAST-Jammu

Introduction

The burgeoning human population in the developing countries like India requires increased amounts of food and fiber from

a shrinking land base. To date, modern agriculture has largely achieved these objectives by intensive and extensive cultivation of high yielding varieties coupled with chemical fertilizers and pesticides. This chemical pathway to intensify crop production has led to poisoning in human beings and animals and also polluting the environment including air, soil and water resources. The worldwide consumption of pesticides is about two million tonnes per year, out of which 45 % is used by Europe alone, 25 % is consumed in the USA, and 25 % in the rest of the world. India’s share is

just 3.75 %. The usage of pesticides in Korea and Japan is 6.6 and 12.0 kg/ha, respectively, whereas in India, it is only 0.5 kg/ha. Discussing the total consumption of pesticides in India, 80 % are in the form of insecticides, 15 % are herbicides, 2 % are fungicides, and less than 3 % are others. While comparing the worldwide consumption of pesticide, 47.5 % is the share of herbicides, 29.5 % is the share of insecticides, 17.5 % is that offungicides, and others account for 5.5 % only. On the contrary, the consumption of herbicides in India is probably low, because weed control is mainly done manually by hand. In addition to public health and agricultural use, pesticides also find their use in other sectors too.

Chemical pesticides and their residues have been detected in the food grains, vegetables, fruits, oils, feed, fodder and fiber in most parts of the country. This has given rise to the serious concerns regarding health problems and seeking alternatives to the overdependence on synthetic chemicals. Organic crop production emerged as new system which

is characterized by the absence of synthetic pesticides and fertilizers but practices that promote ecosystem health. Organic agriculture has increased its importance worldwide over the past 20 years with growth rates more than 10% in many countries. Approximately 2 million certified organic producers farmed more than 43 million hectares of certified

organic agricultural land.For plant disease suppression, bio-control agents are a class of environmentally friendly micro-organisms that are increasingly being used to manage the pests including insects, weeds and diseases. Out of different bio-control agents, Trichoderma spp., the beneficial fungi present naturally in the soil, are known to protect the crops from various soil-borne diseases and also supply nutrients which are essential for crop growth enhancement. Regular incorporation of Trichoderma spp. in high value agricultural or horticultural crops can reduce the dependence on chemical pesticides.

Advantages

 Biological control is less costly and cheaper than any other methods.  Bio-control agents give protection to the crop throughout the crop period  They are highly effective against specific plant diseases.  They do not cause toxicity to the plants  Application of bio-control agents is safer to the environment.

 They multiply easily in the soil and leave no residual problem  Bio-control agents can eliminate pathogens from the site of infection.  Bio-control agents not only control the disease but also enhance the root

and plant growth by way of encouraging the beneficial soil microflora.

 It increases the crop yield also.  It helps in the volatilization and sequestration of certain inorganic nutrients.

 Bio-control agents are very easy to handle and apply to the target.  Bio-control agents can be combined with biofertilizers.

 They are easy to manufacture.

Effective against various diseases

Trichoderma spp. is effective against various soil borne diseases like wilt, collar rot, rhizome rot, corm rot, dry root rot, stem rot, damping off, etc.,

Application methodology 1. Seed treatment

Make a paste or slurry of 4g of Trichoderma powder in 100 ml of water, to it add 1 kg of seed and mix properly to coat the seeds uniformly. Shade dry the coated seeds for 30 minutes before

sowing.

2. Soil treatment

Mix 1 kg of Trichoderma powder in 50 kg of well decomposed FYM in a pit 3' x 6' and cover it with polythene sheet. After every 3-4 days give thorough turning to the FYM and regularly sprinkle small amount of water to maintain humidity. After 15 days the mixture will be ready to apply on one acre of land. One kg of Trichoderma +FYM mixture can also be

applied to the tree basin before the onset of monsoon and after monsoon to

manage soil-borne diseases.

3. Nursery Treatment

 Bed treatment:

Prepare a suspension by adding 50 g of Trichoderma powder in 10 L of water and drench the nursery bed.  Seedling treatment Prepare suspension by adding 10 g of Trichoderma powder in 10 L of water, dip the seedling roots in it for 30 minutes before transplanting.

4. Tuber/ rhizome/corm treatment

Dip the tuber/rhizome/corm in the suspension prepare by mixing 50 g of Trichoderma powder in 10 L of water for 30 minutes before planting/ sowing.

Advantages

Trichoderma spp. offers effective management against a wide range of plant diseases. It acts on the disease causing organism in more than one ways. Being an excellent saprophyte it has high level of perpetuation in the soil thus increasing its populations and exerting long-term control over phytopathogenic fungi. It also helps to decompose organic matter, converting nutrients into available forms so that plant can easily uptake them. Due to the indirect effect on crop nutrition it stimulates crop growth because it secretes metabolites that

promote the plant development processes. Trichoderma spp. are an important enzyme producing microbe and can produce cellulases, hemicellulases, lignocellulases, chitinases, glucanases and proteases thus can degrade several complex organic substances in soil into smaller forms which can easily be consumed by plants for their growth

4

Seed Treatment: An Option for Seed and Soil Borne Disease Management in Crops

A. K. Singh, S. K. Singh, Ranbir Singh and Sachin Gupta Division of Plant Pathology, Faculty of Agriculture SKUAST-Jammu

Introduction

Seed treatments are defined as chemical

or biological substances that are applied to seeds or vegetative propagation materials to control disease organisms, insects, or other pests. Seed treatment pesticides include bactericides, fungicides, and insecticides. Most seed treatments are applied to true seeds, such as corn, wheat, or soybean, which have a seed coat surrounding an embryo. However, some seed treatments can be applied to vegetative propagation materials, such as bulbs, corms, or tubers (such as potato seed pieces). Most seed treatment products are fungicides or insecticides applied to seed before planting. Fungicides are used to control diseases of seeds and seedlings; insecticides are used to control insect

pests. Some seed treatment products are sold as combinations of fungicide and insecticide. Fungicidal seed treatments are used for three reasons: (1) to control soil-borne fungal disease organisms (pathogens) that cause seed rots, damping-off, seedling blights and root rot; (2) to control fungal pathogens that are surface-borne on the seed, such as those that cause covered smuts of barley and oats, bunt of wheat, black point of cereal grains, and seed-borne safflower rust; and (3) to control internally seedborne fungal pathogens such as the loose smut fungi of cereals. Most fungicidal seed treatments do not control bacterial

pathogens and most will not control all types of fungal diseases, so it is important

to carefully choose the treatment that provides the best control of the disease organisms present on the seed or potentially present in the soil. The degree of control will vary with product, rate, environmental conditions and disease

organisms present. Some systemic fungicidal seed treatments may also provide protection against early-season infection by leaf diseases. Fungicideinsecticide combination products or an addition of insecticide for wireworm

control should be considered if planting newly opened land or land that has had a history of wireworms.

Bactericide

Streptomycin (trade names AgStreptomycin and Agri-Mycin) is an antibiotic that kills a broad spectrum of bacteria. It can be used to control

seedborne populations of the halo blight pathogen on beans and as a potato seed piece treatment against soft rot and black leg.

Fungicides

Biological agents consist of dormant microorganisms that are applied to seeds. Under favorable conditions, these microorganisms grow and colonize the exterior of the developing seed or seedling. Biocontrol agents may reduce seed decay, seedling diseases, or root rot either by competing with pathogens or by producing antibiotics. Biocontrol organisms include the bacteria Bacillus subtilis (trade name Kodiak) and Streptomyces griseoviridis (trade names Mycostop, Subtilex, System 3), and the fungus Trichoderma harzianum (trade names T-22, Bio-Trek). Captan is a broad-spectrum, nonsystemic fungicide effective against various seed decay and damping-off fungi, such as Aspergillus, Fusarium, Penicillium, and Rhizoctonia. Carboxin (trade name Vitavax) is a systemic fungicide with good activity against smuts and fair activity against general seed rot, damping-off, and seedling blights. It is commonly used to control wheat embryo infections by the loose smut fungus. Carboxin is commonly formulated with other fungicides or insecticides to increase the pest control spectrum. Difenoconazole (trade name Dividend) is a broadspectrum, systemic fungicide that controls common bunt and loose smut of

wheat. At high label rates, it has activity against some fall-season root rots and foliar diseases (powdery mildew and rust). Fall control of root rots and leaf

diseases may or may not carry through to the following spring. Fludioxonil (trade name Maxim) is a broad-spectrum, nonsystemic fungicide effective against various seed decay and damping-off fungi, such as Aspergillus, Fusarium, Penicillium, and Rhizoctonia. In addition, it performs well against seedborne wheat scab.

Mefenoxam (trade name Apron XL) and metalaxyl (trade names Apron and Allegiance) are closely related, narrowspectrum, systemic fungicides. They are effective only against Pythium, Phytophthora, and downy mildews. These fungicides are commonly used on a wide range of crops, often in conjunction with a broad-spectrum fungicide, such as captan or fludioxonil. Tebuconazole (found in Raxil) is a broad-spectrum, systemic fungicide. It controls common bunt and loose smut of

wheat and has activity against some fall season root rots and some foliar diseases

(powdery mildew). Fall control of root rots and leaf diseases may or may not carry through to the following spring. In addition, it performs well against seedborne wheat scab. Tebuconazole is

commonly formulated with other fungicides or insecticides to increase the pest control spectrum. Thiabendazole (also called TBZ) is a broad-spectrum, systemic fungicide useful against common bunt and various seed decay and damping-off fungi, such as Fusarium and Rhizoctonia. In addition, it performs well against seedborne wheat scab. Thiabendazole is commonly formulated with other fungicides to increase the disease control spectrum. Thiram is a broad-spectrum, nonsystemic fungicide labeled for a wide range of field crops and vegetable crops, and for ornamental bulbs and tubers to

control seed, bulb, and tuber decay, and damping-off, as well as common bunt of wheat.

Triadimenol (trade name Baytan) is a broad-spectrum, systemic fungicide that controls common bunt and loose smut of

wheat. At high label rates, it has activity against some fall-season root rots and foliar diseases (powdery mildew and rust). Fall control of root rots and leaf diseases may or may not carry through to the following spring. Triadimenol may be formulated with other fungicides to increase the disease control spectrum.

Methods of Seed Treatment

Fungicide seed treatment products come in a variety of formulations and in a variety of packaging sizes and types. Some are registered for use only by commercial applicators using closed application systems, others are readily available for on-farm use as dusts, slurries, water soluble bags, or liquid ready-to-use-formulations. Whatever the formulation used or application method chosen, some precautions should be taken to assure applicator safety and appropriate seed coverage. Cautions should Follow label directions when

handling seed treatment chemicals. These products are potentially poisonous if mishandled or misused. Extreme caution

must be used when handling seed treatment chemicals: some are toxic, others may be irritating. An approved chemical respirator and goggles are recommended even if not specifically required by the fungicide label. The rate of application prescribed by the label must be used: overtreatment may injure the seed and under treatment may not provide good disease control. To apply the correct rate, it is essential to calibrate application equipment carefully and to check calibration frequently. Metering cups of commercial applicators should be cleaned daily to prevent a buildup of chemical that might result in reduced application rates. An auger which has been used to treat seed cannot be cleaned

up sufficiently for use in augering grain for food or feed. Once an auger is used for seed treatment, it should be used only for treatment or augering seed for planting. It should not be used to auger grain used for food or feed. Treated seed should not be used for food or feed, and treated grain should not contaminate grain delivered to elevators or be placed in bins or in trucks delivering to elevators. Containers should be triple rinsed with the rinse water added to the

treatment mixture.

5

Integrated Disease Management in Pulse Crops

Upma Dutta1, Sachin Gupta2, Ranbir Sodhi3 and Satish Sharma1

1

Division of Microbiology,

2

Division of Plant Pathology,

1

Faculty of Basic science,

2

Faculty of Agriculture, SKUAST-Jammu

Pulses are major source of protein for the majority of Indian population and contribute significantly to the nutritional security of the country. Also due to their uses in enriching soil with nitrogen with atmospheric n i t r o ge n , gr e e n m a nu r e a n d c o v er c r o p s i n s h o rt season cropping windows, breakfast grains and dietary p r o p e r t i e s , p u l s e s a s s u m e S i g n i f i c a n c e i n o u r a g r i c u l t u r a l s y s t e m . P u l s e s a s a c o m p l e m e n t t o cereals, make one of the best solution to protein-calorie malnutrition apart from its less requirement of water (300 mm). Though India is the largest producer of most o f t h e p u l s e s , i t s p r o d u c t i v i t y l e v e l s a r e l o w a n d t h e r e f o r e , t h e c o un t r y i m p o rt s a h u ge q u a nti t y o f pulses to cater domestic demand. In case of

lentils, arhar and peas, the productivity is lower than the world a v e r a g e l e a v i n g a m p l e s c o p e t o e n h a n c e i t w i t h available technologies. India do not figure in major technological breakthroughs in the world with countries like Canada and others achieving averages of around two tonnes per hectare in pulse productivity, hence concerted efforts are required. With over a dozen pulse crops occupying a large acreage including chickpea, pigeonpea, urdbean, mungbean, lentil, French bean, horse gram, field pea, moth bean, grasspea, grown in different part of the country, pulse production has n o t i c e d a n u p w a r d t r e n d i n t h e r e c en t p a s t a n d consistently remained over 17 mt. Production data of

GOI, indicated that area vis-a-vis production have been stagnant over the years with shift in traditional growing areas Over the years pulses cultivation in India has been p u s h e d t o m a r g i n a l l a n d s a n d r a i n f e d a r e a s n o t providing the crop to express itself fully in terms of yield. Still pulses are cultivated on more than 12 per cent of the Country’s total cultivated area and they constitute more than 4% of the output of crop sector in value terms. Pulses being grown in rain fed suffers crop failure due to wide spread drought in 2009 and resulted in sharp rise in prices of pulses prompting G o v e r n m e n t o f In d i a t o r e v i e w

t h e s t r a t e g i e s t o increase production of pulse crops to reduce gap between supply and demand. These grain legumes grown worldwide are prone to attack by a large number of plant pathogens, from fungi, bacteria, phytoplasmas, and viruses to nematodes and parasitic angiosperms, which result in severe economic losses globally. Among these, fungi and viruses are the largest and perhaps the most important groups affecting all parts of the plant at all stages of growth (Table 1). Foliar diseases such as gray mold, chocolate spot, Ascochyta blight caused by species of Botrytis and Ascochyta are of great importance to faba bean, lentil, and chickpea. The genus Stemphylium causes foliar disease in lentil and Septoria species causes leaf spots in cowpea. Around 45 viruses are reported to infect legumes worldwide. However, only few are of major economic concern with respect to specific regions. Among the more important groups are the Luteoviruses, Nanoviruses, Carlaviruses, Furoviruses and Potyviruses. The Potyviruses are the most important overall causing economically important diseases in grain legumes. Many of the viruses are seed borne in their legume hosts; some are sufficient to have enabled worldwide distribution.

Table 1: Important diseases of food legumes and their causal organisms Food legume Disease Causal organism Cool season legumes

Chickpea (Cicer arietinum L.) Ascochyta blight Ascochyta rabiei Botrytis gray Botrytis cinerea mold Stunt Bean leaf roll luteovirus

(BLRV) Lentil (Lens culinaris Medik.) Rust Uromyces viciae-fabae Ascochyta blight Ascochyta lentis Stemphylium Stemphylium botryosum blight

Faba bean (Vicia faba L.)

Ascochyta blight Ascochyta fabae leaf spot Botrytis cinerea / Botrytis fabae Rust Uromyces viciae-fabae Necrotic yellows Faba bean necrotic yellows virus Field pea (Pisum sativum L.) Powdery mildew Erysiphe polygoni Downy mildew Peronospora viciae

Warm season legumes

Pigeonpea (Cajanus cajan [L.] Millsp.) Mungbean (Vigna radiata [L.] Wilczek and black gram (Vigna mungo [L.] Hepper)

Cowpea (Vigna ungiculata [L.] Walp.) Sterility mosaic Pigeonpea sterility mosaic virus

Yellow vein mosaic Mungbean yellow mosaic virus

Cercospora leaf Cercospora cruenta, C. spot canescens Powdery mildew Erysiphe polygoni Cercospora leaf spot Cercospora canescens and Pseudocercospora cruenta

Cowpea golden mosaic Cowpea golden mosaic virus

Cowpea aphidborne mosaic Cowpea aphid-borne mosaic virus

Integrated Disease Management of foliar diseases of food legumes

The main emphasis in research and development to combat food legume diseases is on host resistance and

chemical control where ever applicable, and quite often these components of disease management were practiced in isolation to each other. Recently a shift in scientific thinking and practice in the management of grain legume diseases has been seen and greater emphasis was on identifying, evaluating, and integrating location specific components of

integrated disease management (IDM). In general IDM has followed the principles of IPM. The location specific IDM of food legumes is primarily based on host plant resistance (HPR) or genetic resistance; additionally other components of diseases management. In some environments, IDM may require a single component used alone (usually HPR) or in combination with one other component (such as fungicide seed treatment) to adequately combat diseases of food legumes. The components of IDM employed in the production of food legumes are listed as follows: Host plant resistance (HPR), Disease modeling (prediction) for avoidance of high risk or disease pressure, Chemical sprays (fungicides, pesticides), Biological control, and Cultural (agronomic) practices (sowing dates, plant population etc.)

Cool season legumes Chickpea (Cicer arietinum L.)

Major foliar diseases of potential economic importance in chickpea are ascochyta blight (AB) and botrytis grey mold (BGM). Ascochyta blight infection and disease progression occur from 50 to 25 °C with an optimum temperature of 16-20 °C, and a minimum of 6 h leaf wetness. Disease severity increases with the increase in relative humidity. Cloudiness and prolonged wet weather favour rapid development and spread of both the diseases. The pathogen survives on infected or contaminated seeds, infected chickpea debris which causes AB, produces both rain splashed conidia and windblown ascospores Infection of BGM occurs from 15-25 °C with an

optimum temperature of 20-25 °C. High moisture and high relative humidity are congenial for BGM development. Under such conditions there is abundant

sporulation of the fungus B. cinerea on dead plant parts, particularly on flowers and pods (Pande et al., 2006). The pathogen B. cinerea is reported to have extreme diversity and adaptability to a wide range of environmental conditions. Existence of 4-5 pathotypes of B. cinerea has been reported from northern India. Adoption of IDM practices is essential for economical and effective control of

AB and BGM. In several studies

conducted in different chickpea growing areas of the world, several sources of resistance to AB were identified.

Furthermore, development of AB resistant genotypes has made it possible to sow the crop during winter in the

Mediterranean region thereby doubling the chickpea production potential. On the other hand, an adequate level of genetic resistance to BGM is not available in the

cultivated genotypes and fungicides become ineffective under the high disease pressure. Hence, IDM using the available management options is essential to successfully manage the disease and mitigate yield losses. Moderate level of HPR can be combined with other cultural

practices and/or application of minimum dosage of fungicides for control of AB and BGM. A combination of a

moderately resistant variety and 2 sprays of chlorothalonil, one during the seedling stage and another at the early podding stage, provided the most economical field control of AB. The location-specific recommended IDM practices for AB include: (a) use of pathogen-free seed, (b) seed treatment with fungicides, (c) practice of crop rotation, (d) deep ploughing of chickpea fields to bury infested debris, (e) use of diseaseresistant genotypes, and (f) strategic application of foliar fungicides.

Lentil (Lens culinaris Medik.)

Ascochyta blight, rust and powdery mildew are economically important foliar diseases of lentil. Ascochyta blight is caused by A. lentis produces conidia, in a flask-shaped fruiting body (pycnidium), which are spread by rain splash. The teleomorph, Didymella lentis, produces ascospores which can be wind dispersed large distances. The pathogen is both stubble and seed borne. Progress of foliar blight is rapid and epidemic levels can be reached under cool and wet weather

conditions as a consequent of spores being disseminated by rain splashes. It survives for more than 3 years in infected pods and seeds at 4-5 °C or under shelter outdoors, and 1-5 years at the soil surface. IDM of Ascochyta blight of lentil includes use of resistant cultivars, use of disease free seed, crop rotation, seed treatment and foliar spray. Application of the fungicides benomyl, carbendazim, thiabendazole, chlorothalonil, prothioconazole and strobilurin, are useful for managing Ascochyta blight epidemics. Lentil rust is caused by Uromyces vicia-fabae (Pers.) de Bary. It is an autoecious fungus; completing its life cycle on lentil. The disease occurs during the flowering/early podding stage as aecia, which may develop into secondary aecia or uredia. The resulting aeciospores and uredospores lead to a further disease

spread in the crop season. Uredia rapidly appear a little late in the crop season followed by development of telia. The fungus survives in summer as teliospores. High humidity and cloudy weather with temperatures of 20-22 0C favor disease development. The plants give dark brown or blackish appearance visible as patches in the field. Integrated management of rust includes control of volunteer plants over the summer and removal of infected

lentil debris. It is advisable to use clean

seeds without rust contaminations, and to treat the seed with a suitable fungicide such as diclobutrazole. Preventive

fungicide sprays of mancozeb at early disease development stage have been recommended. The use of host plant resistance is the best means of rust

management Powdery mildew another important disease of lentil. The disease poses a serious problem on breeding material in plastic or glass houses in both India and Syria, and in India it is also recorded in off-season nurseries in Trans Himalayan regions but it is rarely seen in the field during the cropping season. A fine powdery, white growth of conidia and mycelium initiates as small spots and rapidly spreads to cover the entire surface of leaves, stems and pods. Later, the leaflets become dry and curled, and are shed prematurely, causing considerable reduction in yield and seed quality. The seeds from infected plants remain small and shriveled. Powdery mildew of lentil is caused by the ectoparasites Erysiphe pisi DC., and E. polygoni DC. and the endoparasite Leveillula taurica (Lév.) Arnaud. Recent evidence showed that E.

trifolii also infects lentil . The anamorph stage is responsible for spread of the disease. The teleomorph stage has been reported to occur in India and Sudan. Moderately high temperatures and moderate relative humidity favour the disease development. Many lentil genotypes are reported resistant to powdery mildew, and should be planted whenever possible. Foliar sprays with fungicides benomyl, tridemorph, aqueous sulfur, karathane (dinocap), calixin or sulfex (ferrous bisulfide) as well as certain insecticides (Quinalphos, Tnazophos, Phoxim) applied at 10-15 days interval are effective in suppressing mildew growth.

Field pea (Pisum sativum L.)

Peas are adversely affected by serious fungal, bacterial and viral diseases such as: powdery mildew (Erysiphe pisi Syd.

(syn. E. polygoni DC), Ascochyta blight or black spot (Ascochyta pisi/A. pinodes), downy mildew (Peronospora pisi), bacterial blight (Pseudomonas pisi), Pea early browning virus (PEBV), Pea enation mosaic virus (PEMV) and Pea mosaic virus. Powdery mildew occurs all over the world and can cause severe

damage in areas where pea is cultivated. Powdery mildew of pea caused by Erysiphe pisi, is a serious disease both in the field and in the greenhouse. All aboveground parts of plants are susceptible to powdery mildew. Pod infection may discolor seeds to a gray brown color. The powdery look of the disease is caused by the profuse production of conidia on the upper leaf surface. Management of powdery mildews of grain legumes is through use of resistant cultivars, especially in late sown crops, which are likely to experience high disease pressure. Resistance in pea is conditioned by two recessive genes (er-1 and er-2) along with two or more modifying genes. Resistance in cultivars homozygous for er-2 is expressed mostly in leaves and this resistance can be rendered ineffective

under high disease pressure. The disease is often less severe in areas where overhead irrigation is applied regularly because long periods of free water on host leaves reduce conidium viability and wash conidia from host tissue. Other

control measures include fungicide sprays of sulfur and/or demethylation inhibitors such as cyproconazole, fenarimol and triadimenol. Fungicide spray should be applied at least two weeks before harvest to avoid residue on

peas. Ascochyta blight or black spot is the most common and most damaging disease of field pea in southern Australia. Worldwide, the disease is recognized as being caused by any one, or combinations, of three fungi; Mycosphaerella pinodes, Phoma medicaginis var. pinodella and Ascochyta pisi. All three frequently occur together hence the disease is generally referred to as the ascochyta complex of peas. Mycosphaerella pinodes causes the most damage to pea crops in Western Australia, Washington, USA and is the principal pathogen involved in nearly all occurrences of blackspot. Mycosphaerella pinodes survives on pea stubble for more than 3 years producing viable ascospores during each growing season. Ascospores are released from pseudothecia on the stubble following

rain events of as little as 0.2 mm. The

airborne ascospores can infect crops several kilometres away. IDM includes use of moderately resistant varieties, disease free seed, crop rotation, delay in the sowing, disease forecast model that predicts the time of onset, and progression of ascospores maturity and spread of spores from the source of infection and need based foliar and in-

furrow applications of fungicides in conjunction with other agronomic practices

Warm season legumes Pigeonpea (Cajanus cajan (L.) Millsp.

Sterility mosaic disease (SMD) is the most important foliar disease of pigeonpea in India. Etiology of sterility mosaic is unknown despite of numerous attempts during the past 20 years. Tenui virus of asymmetric morphology as the cause of SM disease and retained the

name of virus as Pigeonpea sterility mosaic virus (PPSMV). PPSMV is flexous, branched filaments measuring 38nm in diameter. The SM causal agent is not transmitted through sap or seed. It is transmitted by the eriophyid mite vector. HPR is the most reliable and sustainable

method for the management of SMD. Considerable progress has been made in identifying resistance sources and developing resistant cultivars to the disease. Some attention has also been

paid to cultural and chemical control of sterility mosaic. Cultural practices include: Destroy ratooned pigeonpea, uproot and destroy infected plants at the initial stage of disease development, crop rotation to reduce inoculum levels and

vector populations, chemical control as seed treatment with 25% carbofuran or

10% aldicarb (3g kg-1 seed) and spraying acaricides or insecticides like karathane, metasystox to control the mite vector in the early stages of plant growth

Mungbean (Vigna radiata (L.) Wilczek) and blackgram (Vigna mungo (L.) Hepper

Mungbean (green gram) and urdbean (black gram) are widely cultivated in many Asian countries in different seasons. Three diseases (yellow mosaic, Cercospora leaf spot and powdery mildew) that attack both the pulses are considered economically important. Yellow mosaic caused by mungbean yellow mosaic virus (MYMV) is the most serious limiting factor in mungbean and urdbean cultivation. The pathogen is transmitted by the white fly Bemisia tabaci Genn. Cultivation of resistant

varieties, manipulation in sowing dates, inter/ mixed cropping of mungbean and urdbean with non-host crops like sorghum, pearl millet and maize and application of systemic insecticides such as aldicarb, disyston and foliar application of metasystox has been found effective in controlling the disease by reducing vector control Cercospora leaf spot caused by Cercospora cruenta and C. canescens causes severe leaf spotting and defoliation at the time of flowering and pod formation. Involvement of different species in causing cercospora leaf spot complicates characterization of species. Since there is low level of resistance to

cercospora leaf spot, the cultural practices and chemical control play an important role in its management. Cultural practices such as field sanitation, crop rotation, destruction of infected crop debris, and avoiding collateral hosts in the vicinity of the crop may help in reducing the incidence. Mancozeb, carbendazim, copper oxychloride and benomyl are reported to reduce disease incidence considerably Powdery mildew caused by Erysiphe polygoni DC, is a problem in cool dry weather. Pathogen is obligate parasite and has wide host range. Limited information is available on the etiology and biology of E. polygoni on Vigna mungo and Vigna radiata. Many resistant sources are available against powdery mildew. its incidence can be reduced by adjusting the date of sowing with wider spacing. Chemical control with fungicides karathane, calixin, bavistin, benlate, topsin M, sulfur dust etc. has been found effective to control the

disease under field conditions.

Cowpea (Vigna ungiculata (L.) Walp.) Cowpea is the most important legume vegetable grown in India. Cercospora leaf spot, cowpea golden mosaic and cowpea aphid-borne mosaic are of potential economic importance. Cercospora leaf spot caused by Cercospora canescens and Pseudocercospora cruenta have been observed in all the cowpea growing areas. Despite the fact that cercospora leaf spot develops late in the season, disease spread is often rapid and premature defoliation can be severe. The disease can

be controlled by combining resistant varieties and spray of fungicides such as benomyl and captafol post flowering. Among viral diseases, Cowpea golden mosaic virus (CPGMV) and Cowpea aphidborne mosaic (CABMV) are the

two most important diseases of cowpea. CPGMV belongs to genus of Begomovirus and is transmitted by whiteflies (Bemicia sp.) and it produces intense yellow leaves which after sometime become distorted and blistered.

CABMV is a cosmopolitan, economically significant seed-borne virus of cowpea (Bashir et al., 2002). The virus-infected seed provides the initial inoculum and aphids are responsible for the secondary spread of the disease under field conditions. The virus symptoms vary with the cowpea genotype and virus strain. Excellent sources of resistance are

available for the breeding of resistant cultivars. Either a dominant or a recessive

gene confers resistance in cowpea. Enzyme-linked immunosorbent assay (ELISA) is the most appropriate method for the detection of the virus in the seed

or plant tissue for seed certification

programmes.

Management of viral diseases of legumes

The development of an effective management package for virus diseases is dependent on the availability of basic information required to design an appropriate combination of interventions which can slow down virus disease development. The most important of these are: (i) identity of the causal agent, (ii) mode of transmission, (iii) ecology of the virus disease including that of its vector, (iv) extent and value of crop losses, (v) availability of genetic resistance, and (vi) available cropprotection methodologies and their applicability to specific farming systems and socio-economic situations. In many locations, however, such complete basic information is not yet available. Control is optimized through IDM approaches, which combine all possible measures that operate in different ways such that they complement each other and applicable in farmers’ fields. Thus, control measures can be classified as (i) those that control the virus, (ii) those that are directed towards avoidance of vectors or reducing their incidence, and (iii) those that integrate more than one method. Cultural practices such as healthy seed, rouging, alteration in sowing dates and use of early maturing cultivars are effective in minimizing virus disease incidence. Almost 50% of viruses affecting leguminous crops are seed-borne. Seedborne infections permit the introduction of primary virus inoculum into the field which facilitates secondary spread to

reach a serious level in locations where

the environmental conditions permit high vector activity. A close relationship between sowing date and the extent of subsequent virus spread is well documented for many crops. Host resistance is the most acceptable component in virus control because it is environment-friendly, practical and economically acceptable to farmers. There are many crop cultivars with adequate levels of virus resistance; in lentil against Pea seed-borne mosaic virus (PSbMV), Bean yellow mosaic virus (BYMV), Alfalfa mosaic virus (AMV), Cucumber mosaic virus (CMV), Pea enation mosaic virus (PEMV), Bean leafroll virus (BLRV), FBNYV and Soybean dwarf virus (SbDV), in chickpea against CMV, BYMV and PSbMV, in faba bean against BYMV, CMV, AMV, BLRV and PEMV, and in pea against BYMV, PEMV, PSbMV and BLRV. Another area of host resistance which is

not well exploited is resistance to vector(s). Success in reducing virus spread by chemical control of vectors is likely with persistently rather than with non-persistently transmitted viruses Each of the control measures mentioned

provides only partial control, but combining genetic resistance, cultural practices, and chemical sprays is expected to lead to improvements. The use of host resistance, and one or two well-timed sprays coupled with optimal planting date and early roguing of virusinfected plants could offer reasonable and economic control and stabilize faba bean

production. Each strategy needs to be affordable by farmers and fulfill the requirements of being environmentally and socially responsible. It must also be compatible with control measures already in use against other pests and pathogens.

6

Major Diseases of Rapeseed-Mustard and Linseed: their Management through Integrated Approach

V. B. Singh M. K. Pandey and R. S. Sodhi*

Division of Plant Breeding and Genetics *Division of Plant Pathology, Faculty of Agriculture, SKUAST-Jammu

Diseases of mustard crops are categorized into the followings- 1. Bacterial diseases

2. Fungal diseases 3. Miscellaneous diseases and disorders

4. Nematodes, parasitic 5. Viral diseases

Damping-off, Wirestem, and Brown Girdling Root Rot

Damping off – Phytophthora cactorum and/or Pythium spp.

Symptoms

The symptoms appear on stem near ground level as a water soaked spots on newly germinated plants. Ultimately topple down of the seedling takes place. Wirestem and brown girdling root rot –Rhizoctonia solani

Symptoms

The disease is characterized by gridling and rotting of roots. Ultimately, drying of the plants.

Blackleg

Pathogen: Phoma lingam, Leptosphaeria maculans and/or Leptosphaeria biglobosa

Symptoms

Watch for round to irregularly shaped dirty white lesions on the leaves and white or gray lesions with a dark border on stems or points of leaf attachment. Stem lesions may also appear as a general blackening or dry rot inside the stem base. Blackleg lesions are usually dotted with numerous tiny round specks (pycnidia).

Clubroot

Pathogen: Plasmodiophora brassicae

Symptoms

Watch for suspicious stunting, wilting, yellowing and premature ripening. Check the roots for clubroot galls. • The disease attacks on the lower

leaves as small circular brown

necrotic spots which slowly increase in size.

• Many concentric spots coalesce to cover large patches showing blightening and defoliation in

severe cases.

• Circular to linear, dark brown lesions also develop on stems and pods, which are elongated at later stage. • Infected pods produce small, discolored and shriveled seeds.

Sclerotinia White Mould

Pathogen: Sclerotinia sclerotiorum

Symptoms

Watch for soft, water-soaked white to gray lesions on leaves and stems. Plant parts above the affected area may turn pale green or yellow, wilt and die. Mature lesions will become bleached

shred easily, resulting in premature ripening and lodging. White mould may grow on rotting stems and sclerotia may be evident inside infected stems.

Downy Mildew Symptoms

Watch for a mealy growth on the underside of the leaf, corresponding to yellowing of the upper surface of the leaf.

White leaf spot

Mycosphaerellacapsellae (anamorph = Pseudocercosporellacapsellae). tan. Black rot (Xanthomonas campestris pv. Campestris)

Powdery mildew (Erysiphe poligoni) Disease symptoms

• Grayish white irregular necrotic patches develop on the lower surface of leaves.

• Later under favourable conditions

brownish white fungal growth may also be seen on the spots. • The most conspicuous and pronounced symptom is the infection of inflorescence causing hypertrophy of the peduncle of inflorescence and develop stag head structure.

White Rust

Pathogen: Albugo candida

Watch for white pustules and “staghead” deformation of flowering stems and pods.

Disease symptoms

• Both local and systemic infections are observed.

• In case of local infection, white creamy yellow raised pustules appear on the leaves which later coalesce to form patches. • In systemic infection and during humid weather, mixed infection of white rust and downy mildew cause swelling and distortion of the stem and floral parts due to hypertrophy and hyperplasia and develop “stag head” structure.

Bacterial blight/ black rot

• The leaf tissue turns yellow and chlorosis reach towards the centre

of the leaf and form V shaped area with base of V towards the midrib.

The veins show brown to black

discoloration. Dark coloured streaks

are formed on the stem from the

ground level and gradually these streaks enlarge and girdle the stem. • Stem become hollow due to internal

rotting. • Midrib cracking of lower leaves, browning of veins and withering is observed.

• In severe cases, the vesicular bundles of the stem also turn brown

and the plant collapses.

Integrated Management

 Follow crop rotation with non-host crop particularly in soil borne diseases.  Growing of resistant / moderately resistant varieties i.e. DGS-1, RH749, Girraj, PM-25 etc.  Use of bio control agent i.e.

Trichderma harzianum, T. viridae,

Bacillus subtilis for seed and soil

borne diseases along with FYM.  Balance use of fertilizes: Decrease

the nitrogenous fertilizers and increase the use potash and sulphur which is helpful for minimizing the brassica diseases.

 Follow disease forecasting and agro-metrological advisory for timely and prophylactic spray.  Destruction of disease infected plant parts for minimizing the secondary

spray. • Older fungicides used, but less effective, for white rust control include: Dithane Z-78, Blitox, wettable sulphur, fixed copper compounds, Bordeaux mixture, chlorothalonil, captofol, captan, dodine, mancozeb, metiram, maneb, and zineb.

• Foliar application of Mancozeb/

Metalaxyl+ Mancozeb/ Metalaxyl/

Chlorothalonil at 15 days interval. • Foliar application of Propiconazole 25EC/ hexaconazole 25EC/

penconazole/ difenoconazole/

dinocap/ wettable sulphur at 15 days interval. combination 300g + Copper oxychloride 1.25 Kg/ha.

• Foliar application of Streptomycin sulphate + Tetracycline

Systemic fungicides use for management of oil seed diseases

Name

Propiconazole25 EC Tebuconazole25 EC Concentration

0.10%

0.10%

Trifloxystrobin 25WG 0.10%

Pyraclostrobin 133g/L Epoxiconaxole 50g/L SE Picoxystrobin 7.05% Azoxystrobin 18.2% w/w Cyproconazole 7.3% w/w Fluxapyroxad 62.5g/L 0.10%

0.10%

0.10%

0.10%

0.10%

0.10%

Tebuconazole 50% + Trifloxystrobin 25WG 0.06%

Pyraclostrobin 133g/L + Epoxiconaxole 50g/L SE, 0.10% Picoxystrobin 7.05%+propiconazole 11.7% SC 0.10%

Azoxystrobin 18.2% w/w+ Cyproconazole 7.3% w/w 0.10% Fluxapyroxad + Epoxiconazole 62.5 0.10%

Linseed diseases

Rust (Melampsora lini)

Symptoms

Rust is readily recognized by the presence of bright orange and powdery pustules, also called uredia. Rust pustules develop mostly on leaves (Photo 8-2), but also on stems. The pustules produce numerous urediospores which are airborne and cause new cycles of infections during the season. Spread and infections are favored by high humidity during cool nights, warmer day temperatures and on plants growing vigorously. As the season progresses, the orange pustules turn black and produce overwintering telia and teliospores The black pustules are most common on stems.

Management

Complete control is achieved by the use of rust-resistant varieties. All registered Canadian varieties listed in Table 11-1

are immune to local races of rust.

Planting susceptible varieties may not only result in serious yield loss, but also affords the fungus a chance to produce new races that may attack resistant varieties. Additional safeguards include: destroying plant debris, using certified and disease-free seed of a

recommended variety, crop rotation and planting the flax crop in a field distant from that of the previous year.

Fusarium Wilt

Symptoms

Early infections may kill flax seedlings shortly after emergence (Photo 8-5), while delayed infections cause yellowing and wilting of leaves, followed by browning and death of plants (Photo 8-6). Roots of dead plants turn ashy grey. The tops of wilted plants often turn downward and form a “shepherd’s crook”. Affected plants occur more commonly in patches but may also be scattered throughout the field. The fungus persists in the soil, as mycelia and spores survive for many years in debris of flax and other organic matter in the soil. Wind-blown and

water run-off soil may spread the fungus from one field to another.

Management

The most important control measure is the use of available resistant/moderately resistant varieties. Crop rotation of at least three years between flax crops helps to maintain low levels of inoculum in the soil. Seed treatment

with recommended fungicides may protect the crop from early infection at the seedling stage and helps maintain good stands and seedling vigor.

Powdery Mildew Symptoms

The symptoms are characterized by a white powdery mass of mycelia that start as small spots and rapidly spread to cover the entire leaf surface. Heavily infected leaves dry up, wither and die. Early infections may cause complete defoliation of flax plants.

Management

The most economical control is through the use of resistant varieties, Early seeding will reduce the impact of this disease on yield loss by avoiding early infections and buildup of epidemics. Foliar application of recommended fungicides around flowering time may protect the crop from severe powdery mildew epidemics and reduce losses in yield and seed quality.

Compendium on Two Days Training Programme on

INTEGRATED DISEASE AND PEST MANAGEMENT APPROACHES IN RABI CROPS