Story Posted: July 07, 2010
Insect Monitoring Update, July 07, 2010
Greetings! A busy week for all so it's a shorter update this time around. This week's insect update includes: Bertha armyworm, Grasshoppers, Wheat Midge, Cabbage seedpod weevil, and a few other happenings.
Bertha armyworm (Mamestra configurata)
The degree-day accumulations for the predicted emergence of Bertha armyworm adults in 2010 are shown below. The prairies have accumulated 90-100% of the heat requirements necessary for adults to emerge from pupae in the soil.
Grasshoppers (Orthoptera: Acrididae)
As of July 6, the model predicted that 20.5% of the eggs had not yet hatched. Approximately 68.6% of the population is predicted to be between first and third instar stages. The model predicts that 9.2% of the population should be at the fourth instar and 1.0% of the population should be at the fifth instar stage.
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| Prov |
Location |
Average of % at Egg stage |
Average of % at First-Third instar stages |
Average of % at 4th instar stage |
Average of % at 5th instar stage |
Average of % at Adult stage |
| MB |
Brandon |
1.0 |
88.9 |
10.1 |
0.0 |
0.0 |
| MB |
Carman |
0.0 |
28.9 |
54.5 |
16.6 |
0.0 |
| MB |
Dauphin |
0.4 |
69.1 |
26.4 |
4.1 |
0.0 |
| MB |
Melita |
0.9 |
91.6 |
5.7 |
1.8 |
0.0 |
| MB |
Swan River |
12.4 |
73.0 |
14.6 |
0.0 |
0.0 |
| SK |
Estevan |
1.6 |
77.3 |
21.1 |
0.0 |
0.0 |
| SK |
Kindersley |
40.4 |
44.7 |
14.9 |
0.0 |
0.0 |
| SK |
Maple Creek |
23.6 |
76.4 |
0.0 |
0.0 |
0.0 |
| SK |
Melfort |
10.6 |
85.8 |
3.6 |
0.0 |
0.0 |
| SK |
Prince Albert |
5.6 |
85.4 |
9.0 |
0.0 |
0.0 |
| SK |
Regina |
11.4 |
81.9 |
6.7 |
0.0 |
0.0 |
| SK |
Rosetown |
3.8 |
89.9 |
6.3 |
0.0 |
0.0 |
| SK |
Saskatoon |
3.3 |
86.0 |
10.7 |
0.0 |
0.0 |
| SK |
Scott |
9.7 |
66.2 |
4.9 |
0.0 |
0.0 |
| SK |
Swift Current |
64.9 |
35.1 |
0.0 |
0.0 |
0.0 |
| SK |
Val-Marie |
10.6 |
84.6 |
4.7 |
0.0 |
0.0 |
| AB |
Calgary |
77.6 |
22.4 |
0.0 |
0.0 |
0.0 |
| AB |
Edmonton |
41.7 |
58.3 |
0.0 |
0.0 |
0.0 |
| AB |
Fairview |
11.6 |
85.4 |
3.0 |
0.0 |
0.0 |
| AB |
Fort Vermilion |
0.2 |
71.5 |
24.1 |
4.2 |
0.0 |
| AB |
Grande Prairie |
26.3 |
73.7 |
0.0 |
0.0 |
0.0 |
| AB |
Halkirk |
79.4 |
20.6 |
0.0 |
0.0 |
0.0 |
| AB |
High Level |
15.5 |
84.5 |
0.0 |
0.0 |
0.0 |
| AB |
Lethbridge |
5.1 |
79.2 |
15.7 |
0.0 |
0.0 |
| AB |
Manning |
15.7 |
78.4 |
5.9 |
0.0 |
0.0 |
| AB |
Medicine Hat |
4.8 |
89.4 |
5.7 |
0.0 |
0.0 |
| AB |
Red Deer |
75.4 |
24.6 |
0.0 |
0.0 |
0.0 |
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Average |
20.5 |
68.6 |
9.2 |
1.0 |
0.0 |
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Wheat Midge (Sitodiplosis mosellana)
Keep in mind that 10%, 50% and 90% emergence of adult wheat midge should occur after 693, 784 and 874 degree-days (base 5oC), respectively. It is important that producers monitor their fields during heading and anthesis for the presence of adult wheat midge. Bob Elliott noted this week that they have started to monitor for adults, however, none have appeared yet.
Keep in mind that degree-day requirements for the emergence of adult wheat midge are based on air temperatures. Dry conditions advance the emergence of adults since the soil will warm more quickly whereas moist conditions delay emergence because the soil warms less quickly. Expect wheat midge emergence to be delayed in regions where precipitation has been above-average.
Cabbage seedpod weevil (Ceutorhynchus obstrictus)
Annual surveys for Cabbage seedpod weevil have begun now that canola has started to flower. Sample in several areas of the field (including the perimeter and interior of the field) in order to determine if control is warranted. A description of Cabbage seedpod weevil monitoring methods is located on the westernforum.org website. Click here to download the PDF.
Populations exceeding an average of three-four weevils per sweep are recommended for control with the ideal insecticide application timed for 10-20% flowering (to protect pods from egg laying) and are best applied late in the day to protect beneficial insects.
Other happenings this week...
- Central Manitoba: "Green cloverworm have been found in dry beans, soybeans, and alfalfa. Green cloverworm will loop when they walk, so it is easy to mistake them for alfalfa looper. One difference though is that green cloverworm will rapidly wiggle when disturbed." – John Gavloski.
- Morris, Winkler and Carman Manitoba: "A few reports of true armyworm (Pseudaletia unipuncta) in cereal crops" have been received. - John Gavloski.
- Dauphin, Manitoba: "Slugs were noted feeding on wheat in about a 35 acre patch in a field. It appears they may have moved in from the ditch area. Slugs do need moisture, so this is something that may be more common in wet years such as this." – John Gavloski.
- Near Aberdeen, Saskatchewan: "Heavy wireworm damage was observed in about 80 acres of borage." Several specimens were collected and species identifications will be confirmed. – Julie Soroka.
- West central to Lloydminster area of Saskatchewan: "Several inquiries about "black worms" and cutworms in fields (mostly canola)." Suspect that the "black worms" might be scarab larvae and possibly June beetles. – Scott Hartley.
- Moose Jaw, Saskatchewan: "An average of 52 alfalfa weevil larvae per 10 sweeps were counted in sweep-net samples collected in alfalfa and the majority of larvae were at least 3rd instars." – Julie Soroka.
- Brooks, Alberta: "High numbers of 1st-2nd instar larvae of Alfalfa weevil were observed in alfalfa grown both for hay and seed". – Scott Meers.
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