Pest monitoring in the Peace Region, 2020

SARDA Ag Research will closely monitor 3 insect pests; Bertha Armyworms (Berthas), wheat midge, and diamondback moths (diamondbacks). Diamondbacks, Berthas and Wheat midge have been monitored closely for the past three years according to the protocols provided to us by Alberta Agriculture and Forestry.

Berthas, are important pests of canola in the Prairie Provinces. They belong to a group of insects known as the climbing cutworm and are native to the Peace Region. Berthas begin as small green worms but darken as they grow until they become velvety black. They are only a concern when they feed, in the larval stage. SARDA will once again set up traps in the municipalities of Big Lakes, Greenview, Northern Sunrise and Smoky River to monitor the likelihood of infestations. These traps will be checked weekly; moths counted for Berthas as the risk of infestation is high in 2020. Despite only causing damage during the larval stage, we monitor Berthas at the moth stage in order to predict the risk of infestation. The counts determine the risk levels. For example, it takes a count of about 900 – 1200 for a moderate risk level, and 1200 – 1500 for a high risk level. Even traps with low counts, anywhere from 0-300, have been reported to have damage if the larvae tend to cluster in one field. Bertha traps are green barrel shaped traps with pheromones which lure the moths in. A pesticide strip inside the trap kills the moths once they enter allowing them to easily be counted. Overall, the degree of damage that can occur from Berthas varies substantially yearly. There are elements that impact their numbers, such as cold weather as well as the levels of parasites and diseases. Last year, the conditions were ideal and many farmers had to spray in order to keep these pests under control. The trend in 2019 demonstrated a continued increase in numbers in many locations across Alberta. In particular, Alberta Agriculture and Forestry highlighted the Peace Region as an area of strong outbreak in Alberta. As a result, numbers in 2020 are being carefully monitored.

Bertha Army Worm Trap

The second type of pest monitoring that SARDA Ag Research is doing this year is for the Wheat Midge. Over the last 3 years, SARDA has set up pheromone sticky traps in three different locations across the MD of Smoky River, which are checked 2-3 times a week. These traps are used to indicate the time Wheat Midge males begin flying, which are always 3-4 days ahead of the female “egg laying” midge. Pheromone traps only catch male Midge and therefore, the traps only give us a rough estimate of when an outbreak could occur. The larvae damage the crop by feeding directly on the seeds of growing wheat kernels. Last year male counts were only 30 or less per week, whereas in the past there have been counts up to 700 in years of extreme infestation. Counts of about 70 midge have caused small losses in the past. Wheat Midge also lay eggs in the soil, which can remain dormant for a number of years, until the ideal weather conditions occur and hatch the eggs. This is why continuous monitoring is important and is also why SARDA Ag Research does fall soil sampling in addition to trap monitoring. SARDA soil samples 12 fields per year across the Peace Region. The samples collected are sent to Lacombe, where the eggs are washed from the soil and counted. Counts are used to help predict where higher populations of Wheat Midge may occur. Population estimates can be viewed on the Alberta Agriculture and Forestry Pest Monitoring website (https://www.agric.gov.ab.ca/ app68/listings/midge/midge_map.jsp).

The third kind of pest monitoring that SARDA Ag Research conducts is for Diamondback Moths. Diamondback Moth and Wheat Midge Traps only diff er in the type of pheromone lure used and where they are placed. Diamondbacks were introduced into the Peace Region about 150 years ago from Europe and now occur throughout North American wherever its host plants are grown. Diamondbacks feeds on all types of plants in the mustard family which includes Canola. They can cause millions of dollars in damage and may devour entire plants if larvae are large enough and the population is substantial. Despite the possible dangers associated with Diamondbacks, infestations are relatively rare. Diamondbacks usually die during the harsh winters in Alberta. At SARDA Ag Research, we begin setting out pheromone traps at the beginning of May and check them until mid-June to anticipate if any moths are being blown up from the United States. If high counts appear then crop scouting will be required. The tallies for 2019 showed relatively low numbers of Diamondbacks. This live map can be viewed at https://www.agric.gov.ab.ca/ app68/ listings/diamondback/diamondback_map. jsp.

Wheat Midge Trap or Diamond Back Moth Trap

Recently, attention has been drawn towards monitoring Wireworms. Wireworms are predicted to become a bigger problem heading forward. Due to new regulations on seed treatments, which eliminate specifi c active ingredients, seed may become more susceptible to both Wireworms and Cutworms damage. Despite the general notion of the imminent threat of Wireworms in the Prairies, there is currently no hard evidence to support this. Studies are being done regarding the eff ects of crop rotation on Wireworm populations. SARDA Ag Research is following the development of this research and participated by collecting samples in 2018. No new samples have since been collected.

left to right - Wire worms, cutworms (typical "c" shape)

Another insect that has made its way to the Peace Region is the Pea Leaf Weevil. The Pea Leaf Weevil feeds on the roots of plants in its larval stage, and the leaves of plants in its adult stage. Pea Leaf Weevil typically feeds on legume crops, but can also feed on canola plants as well. A notched or scalloped appearance in pea and faba bean leaf is an indication that the pest is present. This weevil is relatively new to Alberta as it was first identified in Lethbridge in 2000, and has migrated into the Peace Region over the past few years. Last year Alberta Agriculture carried out a survey during May and June that had spanned 262 fields, and 59 municipalities throughout Alberta. This survey rated the damage caused by examining the leaves of 50 plants near the field margin, and counting the number of notches per plant. Although, damage is actually caused by damage to the roots of these plants, counting the notches in the leaves is an indication of the population of the weevils. The Peace Region only saw an average notching between 0-1 on plants whereas West of Edmonton saw an average notching to be between 3 and 9 notches a leaf. Nine notches per leaf has been proven to signal that damage to plants is likely. The Pea Leaf Weevil was positively identified in the MD of Smoky River in 2018, although levels were below economic thresholds. Through this survey they were able to determine that the Pea Leaf Weevils are at a level that could cause concern in 2020. Nevertheless, the Peace Region only saw low numbers from the survey for the 2019 year.

Note the notching on the leaf margin

SARDA Ag Research would like to encourage farmers to help with the reporting of pests this year which can be easily done through the use of Alberta Agriculture’s reporting tool. Th e tool is set up for cutworms and the cabbage seed pod weevil although the most relevant pest is the cutworm in the Peace Region. The cutworm reporting tool can be found at the Alberta Agriculture & Forestry website (https:// www1.agric.gov.ab.ca/$department/pestmon.nsf/ CutwormWebSubmission).

The Peace Region is notorious for being contrary to the norm when predicting pest and disease outbreaks. The willingness of producers to report the unusual and allow inspections by local experts, Alberta Agriculture and Forestry staff, and Ag Canada staff have allowed us to identify these trends and notify others to encourage a strong agriculture industry locally. An important example of this is the identification of the local grasshopper pest known as the Bruner. This species of grasshopper, which is common in the Northern portion of Alberta, follows a lifecycle very different from the traditional grasshopper pests such as the clearwing and migratory grasshoppers and can be easily mistaken for these pests. As a result of the misidentification, the grasshopper forecast was always wrong for the Peace Region. Alberta Agriculture and Forestry is now testing its new hypothesis for forecasting grasshopper populations in the Peace Region and we should soon see accurate predictions.

Alberta Agriculture & Forestry Pest Monitoring Page: https://www.alberta.ca/alberta-insect-pestmonitoring-network.aspx

Information taken from https://www.alberta.ca/agriculture-and-forestry.

Left to right - Bruner Grasshopper, Clear-winged Grasshopper, Migratory Grasshopper