See below for the degree days accumulated from April 1^st until June 27^th, 2013.These values are provided as guidelines only. Local environments, soil type, field history, etc. are likely to influence activity of these pests.

Onion maggot fly activity is variable and there are reports of onion maggot damage in the Holland Marsh. For the Windsor area, 2^nd generation onion maggot flies and cabbage maggot flies may start emerging in 3-5 days.  Carrot rust fly counts at the Muck Crops Research Station in the Holland Marsh are currently 0.13 flies/trap/day (treatment threshold is 0.1 and 0.2 flies/trap/day for fresh market and processing carrots, respectively). Tarnished plant bugs have likely emerged in all areas. Tarnished plant bugs have been seen in the Holland Marsh. We’ve seen tarnished plant bug on sticky traps as by-catch over the last couple weeks. Local leafhopper adults have likely started emerging in all areas. Low counts of aster leafhoppers have been reported in the Holland Marsh. We’ve also seen some active in carrots crops in the Southwest part of the province (based on a quick field walk with a sweep net). Be sure to monitor for leafhoppers in aster yellows susceptible crops.

Onion thrips have been seen on onions in the Holland Marsh and in some areas of Southwestern Ontario.  See the latest articles on onion thrips management on ONvegetables.com at https://onvegetables.com/2013/06/20/onion-thrips-management-part-i-identification-and-monitoring/ and https://onvegetables.com/2013/06/28/onion-thrips-management-part-ii-management-options/.

Based on the 2013 Leek Moth Survey, it appears that the 2nd flight of leek moth has started in the Waterloo Region. Leek moth have not been detected in any new areas so far this season.

No onion downy mildew has been reported.

Data provided by Environment Canada.

*Data provided by Muck Crops Research Station, University of Guelph.

Degree day model information for pests