Downy mildew of brassicas (Hyaloperonospora parasitica syn. Peronospora parasitica) is a fungal-like oomycete that can be devastating in cooler, wet weather. While the ideal temperature for downy mildew development is 8-16˚C it can infect in temperatures outside that range. Prolonged leaf wetness due to fog, dew, or evening irrigation can create ideal conditions for the pathogen to develop.
Downy mildew is most devastating on Continue reading Downy mildew of brassica vegetables
We are currently conducting a clubroot survey for Brassica vegetables in Southwestern Ontario. To date we have identified or collected samples within eight counties and are looking to obtain samples from as many different counties as possible this field season.
Onion thrips (Thrips tabaci) feed on more than just onions; they also feed on cabbage, leaf lettuce, a variety of other vegetables and fruits, field crops, and many weed species. Thrips are unique from other insects as they have rasping-sucking mouthparts that allow them to scratch the cell walls of leaves, suck up the cell contents including the chlorophyll, and leave behind a shiny, translucent trail on the leaf. A single female can produce Continue reading Scouting for onion thrips
Stemphylium leaf blight (Stemphylium vesicarium) of onion starts as yellow-tan, water-soaked lesions developing into elongated spots. As these spots cover the entire leaves, onions prematurely defoliate thereby reducing the yield and causing the crop to be more susceptible to other pathogens. Stemphylium was first identified in Ontario in 2008 and has since spread throughout the Holland Marsh and other onion growing areas in southwestern Ontario.
Stemphylium leaf blight can sometimes be misdiagnosed as Continue reading Stemphylium is the new Botrytis
By Cheryl Trueman, University of Guelph – Ridgetown Campus
Scouting for downy mildew in pickling cucumber fields in Norfolk County began on June 13 (3 of 5 sites) and will begin in Kent County on June 19.
You can track sightings of downy mildew in North America on the IPMpipe Cucurbit Downy Mildew website.
More information:
2017 Downy Mildew Control Strategy for Cucumber Crops
2016 Fungicide efficacy and fungicide program results.
The cabbage maggot (Delia radicum) is the larvae stage of the cabbage root fly which can cause severe damage to all Brassica crops. The adult cabbage maggot is a fly that is about half the size of a house fly and is grey in colour.
In the early spring, cabbage maggot flies emerge from the soil and the females lay small, white eggs ~2-10 cm below the soil line. Depending upon the temperature, eggs hatch 3-7 days later as larvae that immediately start boring Continue reading Cabbage Maggot; An old pest with limited options
Adapted from ONfloriculture by Sarah Jandricic, Greenhouse Floriculture IPM Specialist, OMAFRA
This article was originally written for the floriculture industry, but I have adapted it, with permission, as an awareness article for vegetable growers. — Janice
At this point, most field vegetable growers are focussed on getting the crops in and juggling early season field activities. If you’re thinking about caterpillars right now, it would probably be black cutworm. But recent alerts put out by the United States Department of Agriculture (USDA), bring a new emphasis to caterpillar control. Read on to understand what’s happening, and — for those with US customers — how to control occasional pests like cabbage looper, and avoid potential issues at the border. Continue reading Lassoing Loopers: why you NEED to care about caterpillar control
