Lexington, KY 40546
Online at: www.uky.edu/KPN
Number 1365
January 14, 2014
ANNOUNCEMENTS -UK Soybean Cyst Nematode Analysis Services Suspended Indefinitely
SHADE & FOREST TREES -Nature’s Impact on Invasive and Native Insects
-Upcoming IPM Training
POLLINATORS -New Pollinator Protections on Admire Pro Label
GRAINS -National Survey on Wheat and Barley Fusarium Head Blight FRUIT -Spotted Wing Drosophila Management in 2014
ANNOUNCEMENTS UK Soybean Cyst Nematode Analysis Services Suspended Indefinitely Don Hershman, Extension Plant Pathologist Due to imminent personnel changes in the UK Soybean Cyst Nematode (SCN) Laboratory, SCN analysis services have been suspended, indefinitely, effective immediately. Services may resume at a later late, but this has yet to be determined. In the meantime, all Kentucky growers who desire to have soil tested for SCN are encouraged to use the services of the University of Missouri Plant Nematology Laboratory. I have great respect for this lab: I trust the results they generate, they are accustomed to receiving out-of-state soil samples, and they are very easy to work with. The cost per sample for an SCN egg count is $20. That lab also offers HG (race) testing services, if needed, for an additional fee. Below is the website for the University of Missouri Plant Nematology Laboratory. Please note it will be necessary to use their sample submission form, which is available via a link on the Laboratory’s website. http://soilplantlab.missouri.edu/nematode/
LIVESTOCK -Lice: An Additional Potential Stress on Livestock -Maggots Are Sign of Wet Hay
Upcoming IPM Training 2014 IPM Training will be held on March 5 at the UKREC in Princeton. CEU’s for CCA and pesticide education hours will be requested. Watch Kentucky Pest News for more details. A complete program will be available soon on the IPM web site at http://www.uky.edu/Ag/IPM/ipm.htm.
GRAINS National Survey on Wheat and Barley Fusarium Head Blight Don Hershman, Extension Plant Pathologist This spring, about 16,500 wheat and barley growers in 17 states will receive a questionnaire on Fusarium head blight (FHB or head scab) from the National Agricultural Statistics Service (NASS). FHB is a fungal disease that infects the heads of small grain plants. It can be severely damaging almost anywhere in the U.S. where there is wet, mild weather before flowering or as the crop flowers. Some Kentucky wheat fields are damaged by FHB every year and significant outbreaks occur about one year in five. The FHB survey is being carried out on behalf of the U.S. Wheat and Barley Scab Initiative (USWBSI).
The USWBSI is made up of stakeholders in the cereal industry: growers, fungicide companies, millers, brewers, feed producers, scientists, and Extension workers. Its mission is to help reduce economic losses due to yield damage and vomitoxin (i.e., DON) caused by the FHB fungus, Fusarium graminearum. The USWBSI provides science-based information on the best FHB management practices. The survey is key to helping the USWBSI understand how widely FHB management practices are currently understood and applied by growers. Knowing more about the barriers to FHB management will help the USWBSI provide better support to growers and crop advisors in reducing losses. Survey data will also help to direct future research and outreach efforts. “We hope growers who receive the questionnaire will take a little time to respond,” said Art Brandli, co-chair of the USWBSI and a small-grain grower in Minnesota. “Their information will be a big contribution to helping us fight this damaging disease more effectively, both in their state and at the national level.” (Article adapted from a press release)
FRUIT
trapped for SWD, and then initiated weekly sprays after SWD was first detected on their farm, were able to get satisfactory control.
Figure 1. All small fruit growers should monitor for SWD in 2014 and be prepared to spray if it is detected on their farm.
Several ‘susceptible’ crops escaped problems in 2013, including strawberries, black raspberries, and early maturing blueberries. We don’t know if this was because the flies didn’t become active in time to attack these crops (we did experience a very cool spring) or if the flies were not widely distributed in the state early in the season. We may get those answers in 2014; at this time we cannot say what the risk will be to those small fruit crops that were not attacked in 2013. Blackberries, raspberries and some grapes that were not protected from SWD were severely damaged.
Spotted Wing Drosophila Management in 2014 Ric Bessin, Extension Entomologist The spotted wing drosophila (SWD) caused widespread problems across the Commonwealth last year in blackberries, blueberries, raspberries, and some grape varieties. In 2013, fruit infestations by the larvae in blackberries and raspberries approached 100 percent late in the season when not managed properly. While we did detect this fruit fly in SWD traps in Warren and Daviess counties in 2012, there were only a couple reports of infested fruit across the Commonwealth. SWD populations progressed rapidly in 2013. The first detection occurred in mid-June in Bourbon County, but by mid-July traps across Kentucky were detecting the flies in increasing numbers. By early August, high levels of infestations were being reported in susceptible small fruit crops. One commercial grower even resorted to mowing the blackberries down. On a positive note, growers who
Figure 2. SWD traps should be placed in the interior part of the plant canopy.
All commercial growers are encouraged to use weekly fruit sampling to monitor for larvae in the harvested fruit. To do this, select 30 to 40 apparently undamaged berries and place them in a one gallon sealable bag with two cups of sugar water (½ cup
sugar in one quart of water), seal the bags, and thoroughly mash the berries. Let the pulp settle and look for the light-colored larvae floating to the surface.
Figure 3. SWD larvae floating in mashed blackberries.
The traps we used last year were effective in detecting SWD on farms prior to detecting fruit infestations in commercial plantings. However, in southeastern states, where they have had to battle this pest for several years, growers have found the traps unable to detect flies prior to fruit infestations in raspberries and blackberries. In these late summer crops, sprays are timed based on fruit ripening rather than trap catches. Growers of these crops will begin SWD sprays one week before harvest and spray on a weekly basis through the end of harvest. What researchers have found is that by the time blackberries and raspberries ripen, SWD populations are large enough to warrant controls. Damage to strawberries and blueberries in the Southeast has been light to moderate. We still recommend growers use traps in conjunction with the larvae sampling of fruit. Traps are placed 2 to 3 weeks before the start of harvest. The traps are placed in a dense part of the canopy of the crop as the female SWD prefer to rest during the day in dark, dense locations. The trap is made of a one-quart deli container with about one inch of a sugar-yeast bait to which one drop of dish soap has been added (otherwise the SWD may be able to walk on the surface of the bait). The bait is made by mixing 2 tablespoons yeast, 4 tablespoons sugar, and 1 quart water. Last year we used an apple cider vinegar baited trap, but recent research has demonstrated that this trap generally begins to catch SWD adults 1 to 2 weeks after traps that use other recommended baits.
Sixteen Ÿ-inch holes are punched below the rim to allow the SWD to enter the traps. Alternatively, two 3½ by 1½ inch windows can be cut into the containers and 1/8 inch screen glued over the opening. Use two traps on each farm; they can be in the same crop or in different crops. It is possible to move the traps between different fields as the season progresses; for example from strawberries to blackberries to grapes. Traps need to be checked weekly and the bait is changed weekly. Be sure to dispose of the bait outside of the planting. See Entfact 229, Spotted wing Drosophila Biology, Identification, and Monitoring for more information (http://www2.ca.uky.edu/entomology/entfacts/ef229. asp). This fact sheet was updated in January of 2014. We will be using trapping in strategic strawberry and blueberry plantings across the state in 2014; results of any SWD captures will be announced via the strawberry, blueberry, blackberry, and grape alert listservs. At this time I recommend that blackberry and raspberry growers apply SWD insecticides based on fruit ripeness rather than trap catches. With grape plantings, some producers have noted high levels of fruit flies and have begun to manage them during the harvest period, but there may be large differences in varietal susceptibility. If no SWD is detected in traps located in blueberry/strawberry fields before or during the harvest period and no warning is issued for the area, no SWD insecticide sprays are needed. However, if SWD is captured in a trap or an alert has been issued, then weekly sprays during the harvest period should be initiated. See Entfact 230, Spotted wing Drosophila Management for a list of recommended small fruit insecticides (http://www2.ca.uky.edu/entomology/entfacts/ef230. asp). This fact sheet was updated in January of 2014. Dr. Rufus Issacs (Michigan State University) compiled a list of risk factors that contributed to control failures in Michigan. These include 1) intervals too long between SWD sprays, 2) dense wooded borders adjacent to commercial plantings, 3) dense plant canopies which provide refuge for SWD and limit spray penetration, 4) gallonage of sprays per acre too low to provide adequate coverage, 5) not reapplying sprays after a rain, 6) using rates that were too low, 7) intervals too long between harvests, and 8) using insecticides that are ineffective against SWD. Other practices to help manage SWD include:
immediate refrigeration of fruit after harvest, picking and proper disposal of damaged berries, and pruning of plants to provide an open canopy. Using insecticides weekly during the harvest period creates some safety concerns. The first concern is with insecticide residues on fruit. Producers will need to carefully follow mandatory preharvest intervals (PHI). The PHI is the minimum amount of time between the last application and when it is safe to harvest the crop. Due to PHIs, some effective SWD insecticides with PHIs of a week or longer may not be practical. The other concern is with pollinator safety, particularly on raspberries where harvest and bloom can be occurring at the same time. Care must be taken to avoid harming pollinators, often spraying late in the day after pollination has ceased will help to avoid harming pollinators.
SHADE & FOREST TREES Nature’s Impact on Invasive and Native Insects Lee Townsend, Extension Entomologist The recent polar vortex sent temperatures plummeting and may have some significant impacts on arthropod populations for 2014. The hemlock woolly adelgid is one invasive species that seems susceptible because temperatures in the range of -4F to -5F can be lethal. We saw those readings over much of Kentucky, which is encouraging; however, the reproductive capability of survivors can allow populations to recover relatively quickly. The mercury has to drop substantially more to impact the emerald ash borer. A temperature of -10F kills about 33% of exposed larvae; mortality at -20F is almost 80%. Additional things to remember: temperatures where the insects are spending the winter are not the same as the surrounding air temperature. Snow cover and exposure aspect of host trees can provide insulation and warming. Also, survival of beneficial insects is affected.
Figure 4. Bloom and harvest overlap in strawberries, blackberries, and raspberries creating a potential hazard for pollinators when insecticides are used during the harvest period.
There is also a fact sheet to help home gardeners with SWD, Entfact 231 Spotted Wing Drosophila and Backyard Small Fruit Production (http://www2.ca.uky.edu/entomology/entfacts/ef231. asp). This is a new pest and there is a lot of ongoing research in several states. As such, our monitoring and management recommendations will change as new information becomes available. Updates will be distributed through KPN, small fruit listservs, and fact sheets updated accordingly.
Natural enemies begin to exert some influence. Woodpeckers are significant predators of emerald ash borer larvae. In fact, increased woodpecker interest in ash trees is one of the early signs that the insect may be present in an area. Research (2008) in the Detroit, Michigan area indicates that woodpecker predation in study sites was keeping EAB density at low to moderate densities. Woodlot owners and forest managers can promote woodpecker populations by leaving potential nesting trees, snags, and dead limbs on live trees when practical. Volunteers with Project FeederWatch in the same general area noted increases in relative numbers of the red-bellied woodpecker and the white-breasted nuthatch between 2002 (first detection of EAB) and 2011. Numbers of the downy and hairy woodpecker fluctuated during that time but may be trending upward. The ranges of these four species include Kentucky.
POLLINATORS New Pollinator Protections on Admire Pro Label Ric Bessin, Extension Entomologist Few things have received as much attention in agriculture recently as the losses of honey bee colonies due to Colony Collapse Disorder. There have been numerous studies conducted and various reports as to the potential causes of this mysterious problem, including a comprehensive report from the EPA and USDA that stated there are multiple factors that may be causing the decline in honey bee numbers. The potential causes include: parasites (namely Varroa mite), diseases, poor genetic diversity of honey bees, poor nutrition, and pesticides. According to the report, it appears that a complex set of stressors and pathogens may play a role in these losses.
label discusses how bees and other pollinators can become exposed to the pesticide and steps that can be taken to minimize this exposure when using this insecticide. Colored honey bee icons on the label are used to highlight these new restrictions. Some of the important restrictions include: not using this insecticide while bees are foraging and not until flowering is complete (all of petals have fallen). Depending on whether growers have contracted for pollination services or not, there are some conditions that may allow them to use this insecticide when the above conditions are not met. With contracted pollination services, if an application must be made when bees are at the treatment site, the beekeeper providing the services must be notified no less than 48 hours prior to the time of the planned application so that appropriate actions may be taken to prevent exposure to the insecticide. In cases where there are no contract pollination services, there are several conditions that may allow for application of this insecticide. These include: the application is made to the target site after sunset, the application is made to the target site at temperatures below 55F, or beekeepers are notified, as outlined on the label. As always, read and follow all instructions on the pesticide label, before using these products.
LIVESTOCK Figure 5. Honey bee services to agricultural are valued at over $14 billion.
While the report notes that “Varroa destructor mite remains the single most detrimental pest of honey bees and is closely associated with overwintering colony declines,” it also notes that “acute and sub lethal effects of pesticides on honey bees have been increasingly documented, and are a primary concern.” A recent study published in Proceedings of the National Academy of Science (PNAS) implicated two neonicotinoids as impairing the honey bee immune system and researchers were able to demonstrate the mechanism by which this can occur. The new Admire Pro Systemic Protectant insecticide label posted on the Crop Data Management Systems (CDMS) Web site (November 2013) now contains some new information on pollinator protection in the Environmental Hazards portion of the label. The
Lice: An Additional Potential Stress on Livestock Lee Townsend, Extension Entomologist The most obvious symptoms of lice include excessive rubbing and loss of hair clumps. However, there are some other possible causes (ringworm, dietary deficiencies, mange, etc.). A careful examination of animals will let you identify the problem or combination of problems correctly. Typically, there are raw spots from constant attempts to groom or scratch areas where lice are abundant. More specifically, you should find lice and eggs (nits). Lice are small, flat-bodied insects that are uniquely adapted to live as external parasites on animals. They are generally host-specific insects that cannot survive off their host for more than a few days. Sucking lice, with their narrow, pointed heads, are blood feeders. Biting lice with wide triangular heads feed by scraping material from the dermis and
base of the hairs. Females of both types glue their eggs (or nits) to hairs so the coat may have a matted appearance.
Figure 6. Biting louse with a wide, triangular head. Many species have dark stripes across their body
The energy that lice “steal,� coupled with other factors, can have a severe impact on animal health. Infestations of biting and sucking lice have been associated with reduced weight gains and general unthriftiness. In most cases, it has been difficult to attribute direct losses specifically to sucking or biting lice. However; moderate to heavy infestations of these species add to the impact of cold weather, shipping stress, inadequate nutrition, or loads imposed by internal parasites or disease. Also, a synergism between low levels of both lice and intestinal nematodes can reduce weight gains. Other manifestations can include anemia, slow recovery from diseases, poor gain performance, or general unthriftiness.
Monitoring louse numbers Confirm lice by examining heavily rubbed areas on the animals. Most lice species have preferred feeding sites where they are most likely to be found when numbers are low to moderate. In severe infestations, they must spread more widely over the animal. Sucking lice tend to be densely packed, creating characteristic quarter-sized black or blue-brown spots. Also, they are less likely to move or to be disturbed when the hair is parted during examinations. Biting lice tend to occur in groups but not tightly packed clusters. They are active and move quickly if disturbed. Short-term louse control Depending on the situation, dewormers or insecticides provide quick knockdown of active infestations. Longer term practices ultimately can be incorporated into an integrated louse control program. A single application of any one of many systemic dewormers, such as doramectin, eprinomectin, ivomectin, or moxidectin, provides long-term louse control for cattle. However, a winter application may trigger an adverse host- parasite reaction if the animals were not treated in the fall to control cattle grubs. A variety of contact (non-systemic) insecticides with active ingredients such as cyhalothrin, cyfluthrin, or permethrin provide good control of lice. They are sold in a variety of formulations (pour-on, spot-on, or dusts) that can be applied during cold weather. Dust bags or back rubbers may be used to dispense these products, as well.
Figure 6. Nits glued to hairs
Lice, most abundant during the winter, are easily transferred by direct contact. Crowding or bunching provides many chances for lice to move throughout the herd. Reduced light intensity is thought to play a significant role in population dynamics of these insects, but nutrition, general health, reduced immune system response, and cold weather are important factors, too.
Even if insecticide coverage on the animal is not thorough, there should be sufficient to knock down heavy infestations to reduce stress on the animals. Contact insecticides do not kill nits so a follow-up treatment is needed to control lice that emerge from eggs after the residual effect of the insecticide is lost. The insecticide label will tell you how long to wait before applying the second treatment. Any animals that are not treated will rekindle the infestation. Long-term integrated management of lice includes combinations of the following methods as practical: Culling reservoirs or carriers: Lice persist over the summer months on a small number of chronically infested reservoir animals. The parasites are
Figure 7. Black soldier fly maggots in balage (Photo by B. Sears)
transferred to other animals in fall and winter. It is difficult to detect reservoir animals, but they may be older, have compromised immune systems, or reduced ability to groom. General physical attributes can come into play. For example, the longer, thicker hair and massive neck and shoulders of bulls makes self-grooming, which can reduce louse numbers, difficult. Nutrition: A high-energy ration seems to modify the effects of lice on weight gains, perhaps because lice populations decline on better-fed animals. Therefore, a sound feeding program and high energy ration serves as the foundation of a louse control program. Premises sanitation: Live louse and nit transfer could occur from hair left on fences, truck rails, or bedding. Sucking lice usually die after just a few hours off the host, but biting lice can survive for several days under ideal conditions. A clean-up and insecticide application to facilities used by infested animals or a 10 day interval before introducing new stock will minimize the chances of carryover. Quarantine: In enterprises where animals move in and out of the inventory on a regular basis, it is best to assume that all incoming animals are infested. They should be isolated until their full course of treatment is completed. Repair fencing: Cross-fence contact can be sufficient for spread of these insects, especially during the winter when louse burdens are greatest.
Figure 8. Black soldier fly larva
Black soldier fly maggots can develop in most any accumulation of moist, decaying organic matter. Females lay batches several hundred eggs so lots of maggots can develop where breeding matter is accessible. Figure 9. Black soldier fly adult (about 3/8 inch long)
Effective biting fly control program: Lice on reservoir animals may be suppressed during the summer by treatments applied to protect animals from biting flies and ticks. Maggots Are Sign of Wet Hay Lee Townsend, Extension Entomologist Large numbers of black soldier fly maggots were found recently in wrapped alfalfa/orchardgrass/clover balage from a first cutting taken last year. They were throughout a line of bales, rather than just on the exposed ends. This suggests that the infestation began on wet hay that had lain on the ground for some time before being baled and wrapped. These insects are not likely to be a problem in hay cut under favorable conditions and wrapped within hours of baling.
Development from egg to adult normally takes about 3 weeks but can be require several months if larval densities are high and/or food quality is low. Mature larvae leave the breeding site and pupate in the soil. Black soldier fly larvae, like typical maggots, are legless but darker, flattened, and have a peg-like protruding head. They are very efficient recyclers of organic matter. Meal made from dried, ground larvae has been evaluated as food for fish and other animals.
Ingested calcium is converted to calcium carbonate and deposited in the outer covering of maggots. This allows them to survive harsh environments, such as an animal’s digestive system. Ingestion of many maggots with infested hay may at least cause discomfort to animals. Heavily infested hay may be unpalatable. The adult resembles a wasp and has a buzzing flight but cannot sting or bite. It is rarely seen, even when larvae are abundant in an area.
Note: Trade names are used to simplify the information presented in this newsletter. No endorsement by the Cooperative Extension Service is intended, nor is criticism implied of similar products that are not named.