INSECT SURVEY RESULTS – 2024 – CARDSTON
2024 Summary
Thank you, Rod for all your support of the insect monitoring program, including the important grasshopper survey.
In 2024, I sampled both dryland and irrigation for wheat midge. I didn’t find any midge in any of the fields I sampled, even in irrigated fields. Midge needs rains in May and June to complete its lifecycle. This insect can spend several years in the soil, waiting for ideal conditions to finish its lifecycle. Wheat midge does not pose a significant risk in Cardston.
Of the none of the bertha armyworm sites in Cardston County none were above the first warning level of 300 moths, not even breaking 100 moths. It is important to keep monitoring, so we can catch the first warnings of possible population build up to an outbreak as well as for in season predictions.
It is not a surprise that wheat stem sawfly was an issue in the municipality in 2024 again. It will continue to be an issue in 2025. Dry Augusts, with early harvests, negatively affect the parasitoid Bracon cephi by hindering the second generation (overwintering generation) which is key to breaking the wheat stem sawfly lifecycle.
Pea leaf weevil damage was low in in the survey we conducted in late May – early June, with the exception of that one field. This trend of lower damage numbers in the southern region continues.
Cabbage seedpod weevil numbers were generally low. Maybe it was because I missed the fields with lots of weevil while out surveying. Cabbage seedpod weevil is a perennial problem and those early flowering canola fields still need to be scouted.
I did hear of some army cutworm issues in the County, producers need to be aware that they need to be vigilant when it comes to scouting for cutworms in the spring.
BERTHA ARMYWORM (BAW)
Bertha armyworm is very cyclical. In order to catch outbreaks and help producers minimize losses it is necessary to maintain a good monitoring system using pheromone traps. The number of moths caught in the traps informs us of the risk of damaging populations with a 3 to 5 week lead time. These numbers are generated from paired pheromone traps in individual fields, except in the Peace River region where only 1 trap is used to reduce impact on native pollinators.
LLD TRAP AVERAGE
SE-11-5-23-W4 2.5
SW-25-6-22-W4 3
SW-4-2-24-W4 7
NE-31-3-24-W4 1
Shaded cells were managed by County
Sampling period June 16 - July 27, 2024
CABBAGE SEEDPOD WEEVIL (CSPW)
In southern Alberta, including all counties south of and touching Highway 1, the earliest flowering canola crops will be at the highest risk from cabbage seedpod weevil and should be monitored very closely.
Cabbage seedpod weevil overwinters as an adult so the risk of infestation is further indicated by the adult population of the preceding fall. Winter condition also appear to have an impact on populations with mild winter favoring build-up of populations and expansion of their range.
We track the population of other insects in these sweeps as well. These go into long term data sets that will help us research their population trends over time from individual fields.
LEGAL LAND DESCRIPTION CSPW IN 25 SWEEPS LYGUS ADULT LYGUS NYMPH LEAFHOPPER FLEA BEETLE RED TURNIP BEETLE DBM ADULT DBM LARVA WASP <5 MM
WASP >5MM HONEY BEE BEE BUT NOT HONEY CATERPILLAR
e 25 6 22 4 39 3 0 0 0 0 0 0 0 2 0 0 0
sw 29 2 21 4 33 1 0 0 0 76 0 0 0 0 0 0 0
se 34 2 25 4 31 0 0 0 0 0 0 0 8 0 0 0 0
Samples done with standard sweep net. (15” diameter & 3 foot handle). 25-180 degree sweeps.
Sampling done by Alberta Agriculture and Irrigation, Plant and Bee Health Surveillance Section staff
PEA LEAF WEEVIL (PLW)
Experience has shown us that high numbers of pea leaf weevil adults in fall will likely mean significant infestation levels in the following spring. The timing and intensity of spring damage is strongly related to the onset of warm conditions (>20oC) for more than a few days in April or May. The earlier the weevils arrive in fields the higher yield loss potential. Extended cool weather delays weevil movement into the field. Yield impact is lower if the crop advan past the 6 node stage before the weevils arrive. The numbers represented here are generated from assessing feeding damage on 10 plants in 5 locations in a field.
LEGAL LAND DESCRIPTION AVERAGE NODE STAGE TOTAL NOTCHES AVERAGE NOTCHES/PLANT
SE-17-6-25-W4 4.28 49 0.98
N-27-5-25-W4 4.64 369 7.38
SW-25-3-28-W4 4.86 4 0.08
NE-14-6-22-W4 4.26 176 3.52
Sampling done by Alberta Agriculture and Irrigation, Plant and Bee Health Surveillance Section staff
WHEAT MIDGE (WM)
Wheat midge is an insect that increases in numbers in wet years. Numbers can vary drastically from field to field and we try to sample wheat adjacent to the previous years’ wheat in order to pick up populations if they are present. There is no definitive way to know exactly the risk in any given field so field scouting when the wheat comes into head is critical. The numbers shown here give a general trend of midge populations. Individual fields will have a different risk.
These numbers are generated by taking soil samples from wheat fields after harvest using a standardized soil probe.
The risk level as shown on our maps is as follows:
• 0 midge will be displayed as light grey (No infestation)
• 2 or less midge will be shown as dark grey (<600/m2)
• 3 to 5 will be shown as yellow (600 to 1200/ m2)
• 6 to 8 will be shown as orange (1200 to 1800/ m2)
• 9 or more will be shown as red. (>1800/ m2)
LEGAL LAND DESCRIPTION TOTAL MIDGE PARASITOID
27 2 21 4 0 0
n 31 6 31 4 0 0
27 2 21 4 0 0
se 6 6 25 4 0 0
nw 16 5 27 4 0 0
Sampling done by Alberta Agriculture and Irrigation, Plant and Bee Health Surveillance Section staff.
WHEAT STEM SAWFLY (WSS)
The percent of stems cut by sawfly gives an indication of the number of reproductive adult sawflies that will emerge in late June through early July. Winter conditions have very little impact on sawfly populations and a high proportion of wheat stems cut in the fall will produce adults. It is possible that population hot spots still exist in areas of lower risk, individual producers need to be aware of the potential risks in their own fields.
LEGAL LAND DESCRIPTION PERCENTAGE CUT
27-2-21-4 18
10-5-24-4 10
n-31-6-23 4
nw-16-5-22-4 1
Sampling done by Alberta Agriculture and Irrigation, Plant and Bee Health Surveillance Section staff.
DIAMONDBACK MOTH (DBM)
It is generally accepted that diamondback moth adults don’t overwinter in the prairies and that most infestations occur when adult moths arrive on wind currents in the spring from the southern or western United States or northern Mexico. In mild winters there is suspicion that diamondback moth do overwinter in Alberta. To assess the population, a network of 43 monitoring sites has been established across the province. This network is meant to act as part of an early warning system for diamondback moth and should be used in conjunction with crop scouting.
LLD TRAP AVERAGE
SE-12-2-21-W4 7
SE-36-11-6-W4 2.5
Sampling period May 5 – June 16, 2024
CUTWORM
Although we don’t actively monitor for cutworms, we do have an online reporting tool. This tool relies on the volunteer reporting of cutworm finds in Alberta.
LLD Crop 2022 Crop Species Acres Affected Spray Required
SE-25-6-25-W4 Canola Wheat Army 150 No
WHEN DOING FIELD VISITS WE:
• never drive into the field
• sanitize our equipment between fields with bleach solution
• wear boot covers