See below for the degree days accumulated from April 1^st until June 18^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 peaked last week in the Holland Marsh (reported on 13 June 2013).  For all areas, accumulated degree days indicate emergence of first generation carrot rust fly adults, if resident populations are present. Carrot rust fly counts at the Muck Crops Research Station in the Holland Marsh reached threshold 0.2 flies/trap/day (treatment threshold is 0.1 and 0.2 flies/trap/day for fresh market and processing carrots, respectively). If resident populations are present, degree days indicate 90% oviposition by carrot weevil in all areas except Wellington. Tarnished plant bugs have likely emerged in all areas; however, the Muck Crops Research Station scouts have not seen tarnished plant bugs on celery in the Holland Marsh yet. I’ve seen tarnished plant bug on sticky traps as by-catch though. Overwintering leafhopper eggs have likely started to hatch in all areas. Local leafhopper adults will likely start emerging in Bradford/Holland Marsh, London, Thedford, Delhi and Ridgetown over the next 5 to 10 days. Very low counts of aster leafhoppers have been reported in the Holland Marsh.

Onion thrips have been seen on onions in the Holland Marsh. Be sure to scout for thrips.

Data provided by Environment Canada.

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

Degree day model information for pests