Top Crop Manager

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Swede midge and Western bean cutworm among key trouble-makers in 2014

December 19, 2014 - OMAFRA's Tracy Baute reports on what insects affect Ontario's crops the most during the 2014 growing season.

Swede midge continues to be a serious pest of canola  in Ontario. Positive efforts in the development of a trap network and delivery of timely information through the Ontario Canola Growers in 2014 have helped, but effective control options are still needed. Research will continue on improving spray timings and finding new management tools for both swede midge and flea beetles.Cereals: Cereal leaf beetle (CLB) caught some growers offguard with infestations showing up in areas not typically known to have CLB outbreaks. A good rule of thumb is to expect armyworm and/or CLB outbreaks following a cool, wet April due to the impact this has on their natural enemies.

Western bean cutworm (WBC) infestations were more prevalent and widely distributed in 2014. Ear damage was found in corn fields in many parts of Ontario beyond the typical hot spot areas of Bothwell and Tillsonburg. Ear molds are therefore a concern this harvest due to the wounds created by WBC and birds scratching to get at the larvae.

Close to 100 corn strip trials with replicated insecticide and fungicide only seed treatments were established by Ontario Soil and Crop Improvement Association members, the Ontario Corn Committee and others in 2014. This  research will continue for the next three years in corn, soybeans and wheat, helping to build our understanding of  where the key soil insect pests reside, and determining the value of insecticide seed treatments.

Dry Beans
2014 was the first year that Western bean cutworm damage was found on dry bean pods in Ontario. A
few fields between Thamesville and Parkhill experienced significant economic damage. Trap monitoring to  determine when peak flight occurs and scouting as soon as pods are developing is key. Scouting adjacent corn fields can also be helpful as it is easier to find the egg masses in corn than in dry beans.

Grubs continue to plague forage fields in Central Ontario. With lack of effective control products for this crop, rotation out of forages on infested ground and tillage are the only measures currently available against these serious soil pests.

Central and Eastern Ontario experienced significant soybean aphid infestations later in the season during the mid to late R stages of soybeans. Insecticide seed treatments do not provide protection from aphids that late in the season, resulting in both untreated and treated fields reaching threshold and requiring foliar applications of insecticides. The brown marmorated stink bug (BMSB) monitoring program has found breeding populations in the Hamilton region, London, Newboro, St. Catherines and Windsor.

We have also captured BMSB over the last few years in pheromone traps and confirmed homeowner finds in various locations across Ontario (see link below). Fortunately, no BMSB have been found in corn or soybeans during our surveys this year. Adults move indoors this time of year to overwinter.

Anyone that finds adults in their homes (other than in the Hamilton region) should contact the Agriculture Information Contact Centre at 1-877-424-1300. For more information, visit the BMSB website

For 2015
Wet fall conditions benefit slugs. Fields with a history of slug issues may see significant populations next spring. Plant next spring into conditions that help the crop grow quickly to avoid heavy slug damage and ensure seed slots are closed.

Tillage can eliminate significant crop residue, exposing slugs to dehydration and predation. Zone tillage or row sweepers can help speed up drying of the row area, thus deterring slug feeding.Though the deadline has passed for some seed corn companies, others are still accepting fungicide only seed treatment orders. Growers are encouraged to complete the “Pest Evaluation Checklists for Targeted Use of Insecticide Seed Treatment” for corn and soybeans, available at: Growers with fields at low risk of pests are encouraged to plant seed treated with only fungicides. 

A new “Guide to Early Season Field Crop Pests” is also available free of charge through GFO at:

December 19, 2014  By Top Crop Manager


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