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
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
There is a long list of insects that can damage field pepper fruit in Ontario. Many cause significant damage on their own, but they also provide a means of entry for rot organisms. For more on pepper rots, see Pepper fruit rots.
European corn borer
Continue reading Insect pests of pepper fruit
Darren Robinson, University of Guelph, Ridgetown Campus; Janice LeBoeuf, OMAFRA, Ridgetown
Herbicides are useful tools for the management of weeds. The herbicides registered for use in tomatoes are selective in their activity, injuring or killing weeds while being safe to use on the crop. Crop injury may occur, generally when a crop is stressed beyond its ability to adequately deal with a herbicide application. Injury due to herbicides can arise as a result of several factors, including weather-related stress, soil factors such as light soil texture and low soil organic matter, shallow planting and sensitive crop varieties. The pages in this section contain information on herbicide injury for several products registered on tomatoes in Canada. Continue reading Herbicide injury symptoms in tomatoes
Kristen Obeid, OMAFRA Weed Specialist – Horticulture
Weedinfo.ca: If you are trying to identify a weed, find the newest information on herbicide resistance and other emerging issues in weed management you need to visit weedinfo.ca.
Provincial Weed Page: http://www.omafra.gov.on.ca/english/crops/insects/weeds.html
Ontario Crop IPM: Know how and why it is important to scout and identify weeds, as well as diagnose herbicide injury. Continue reading Resources on weed management
Field peppers are susceptible to a number of pests and disorders that can lead to fruit rots. This can make managing rots quite difficult. This article outlines some key points to understand about the variety of pests, disorders, and contributing factors that lead to fruit rots. Continue reading Pepper fruit rots