Yellow-orange coloured lesions of strip rust are small, round, blister-like lesions that merge to form stripes.

Winter wheat crops quickly advance, alfalfa weevil seen active

OMAFRA Field Crop Report for the week of May 16

Ontario’s crop season continues to be advanced of normal, which is especially evident in perennial and over-winter crop development. Crop heat units (CHU) and growing degree days (GDD) are significantly above the 10-year average, especially in southern Ontario. Progress for field work, particularly on heavier-textured soils has been limited due to frequent patchy rain, cool […] Read more

In a four-year crop plan, the best advice is to plant wheat to break the cycle of corn rootworm numbers.

By the numbers – corn rootworm in 2023

Populations were lower but intensity in some regions was higher

Concerns about corn rootworm have increased in the past two years as numbers continue to rise across the province, particularly in areas where corn is a feed source for livestock. Two years ago, Tracey Baute, field crops entomologist with the Ontario agriculture department, noted that resistance to Bt Cry proteins had become an issue, where […] Read more

Growers need to familiarize themselves again with signs of damage by European corn borer, including insect frass in the whorl.

Old pest for corn growers returns with new threat

Corn Guide: ECB is showing resistance to Bt hybrids, but not in Ontario yet

Bt corn hybrids have been the story of success in transgenic innovation, a gold standard of biotech pest management, first with European corn borer (ECB) and then corn rootworm (CRW). Now comes a case from Truro, N.S., where a resistant corn borer population confirmed in 2018 also appears resistant to another protein. Why it matters: […] Read more

Two-spotted spider mites covering the underside of a bean leaf.

Spider mites bugging your soybeans?

OMAFRA Field Crop Report for the week of July 3

Dimethoate resistant two-spotted spider mite populations in Ontario soybeans Results from bioassays conducted on two-spotted spider mite (TSSM) populations collected in soybean fields across Ontario show the prevalence of dimethoate (Cygon or Lagon) resistance is high in some areas. Through a collaborative project with Dr. Vojislava Grbic, Professor at Western University, Dr. Ian Scott at […] Read more

It is recommended growers better understand the pest and scout appropriately.

Fall armyworm poses risk for Ontario growers

Warmer fall allows for longer grazing season for the pest in fall crops

Parts of southwestern Ontario have higher than normal levels of fall armyworm.  Traps placed south of London, particularly within Essex County, have seen multitudes of moths this fall. “Similar to last year, we are seeing – when I say ‘we’, Ontario, the Great Lakes area, Ohio, New York, Quebec even – reasonably high levels of […] Read more


Corn genetic heritage the strongest driver of chemical defenses against insect munchers

Corn genetic heritage the strongest driver of chemical defenses against insect munchers

Science Notes: The plant, microbes and soil all play an important role

Plants release chemical distress signals when under attack from chewing insects. These “911 calls,” as entomologist Esther Ngumbi calls them, alert other bugs that dinner or a nice place to lay their eggs is available nearby.  If predatory or parasitic insects detect the right signal, they swoop in to make a meal out of – […] Read more

Just rotating pyramids of Bt traits won’t help as most of them are similar, say OMAFRA experts.

Lessons learned from U.S. struggle against corn rootworm resistance

Producers growing corn-on-corn encouraged to find new sources of feed

Specialists from the Ontario Ministry of Agriculture, Food and Rural Affairs recently urged the province’s corn-growing livestock producers to take the issue of corn rootworm resistance to Bt traits seriously. They said efforts in the United States to slow the growth of resistance in corn rootworm to Bt-based control traits have not been effective. Why […] Read more

An adult western corn rootworm.

The challenge with Bt

Insects are developing resistance to the formerly bulletproof building block of corn hybrid traits

The United States Environmental Protection Agency (EPA) is considering a ban on some Bacillus thuringiensis (Bt) corn and cotton hybrid traits in an effort to slow the proliferation of resistant pests. In Canada, where the number of control options is limited, this move might be a cause for concern. Why it matters: Tools to control […] Read more


VIDEO: Armyworm a growing concern in wheat

VIDEO: Armyworm a growing concern in wheat

Field Talk with Johanna Lindeboom: How to scout for this crop pest

Cool and wet April weather along with thunderstorms are ideal for armyworm, a hay and wheat pest, to migrate north to Ontario. There are minimal options for dealing with armyworm, so proper scouting is a must as this crop pest has been quickly appearing in Ontario fields. In this edition of Field Talk, Farmtario reporter […] Read more

A Cornell researcher is testing a novel approach to control diamondback moths, a major pest of brassica crops including cabbage and broccoli.

Genetically engineered moth could help control pest populations

Science Notes: The diamondback moth damages brassica crops such as cabbage and broccoli

A newly published study reports a first-ever open-field release of a self-limiting, genetically engineered diamondback moth, stating that it paves the way for an effective and sustainable approach to pest control. The diamondback moth, also known as Plutella xylostella, is highly damaging to brassica crops such as cabbage, broccoli, cauliflower and canola. This new strain […] Read more