Pest Watch 2018

The cold temperatures we have been experiencing so far, this winter are helping to lessen the threat of insect pests that have been able to overwinter in Ontario during the mild winters the last couple years, but inevitably there will be insect pests affect our 2018 corn and soybean crops during the growing season. Entomologists predict that the main pests to watch for in 2018 are: seed corn maggot and bean leaf beetle in soybean fields and western bean cutworm in corn fields.

Soybean Pests:

Seed Corn Maggot are generally more of a problem during cool wet springs. They are attracted to things that “stink” such as freshly tilled soil, manure, and decaying vegetation.  So, if your field “stinks” more than neighbouring fields you have a greater chance of seed corn maggot problems.

Bean Leaf Beetles are attracted to early planted fields. So, if you are the first to plant in your area they will be attracted to your field before the neighbours. Bean leaf beetles defoliate the soybean plants, but generally any yield reduction caused by this pest is due to them infecting the soybeans with the Bean Pod Mottle Virus and not due to defoliation.

Corn Pest:

Western Bean Cutworm (WBC) begin to move into our area from the United States in June most seasons. Females prefer to lay their eggs in corn fields that have the tassel in the whorl or just emerging. Optimum egg laying is 1 week after peak flight is reached in the trap network. The peak flight varies by region but is generally in late July in southwestern Ontario. Threshold for WBC is 5% of plants with egg masses over a 2-3-week period, use cumulative counts. You want to spray when fresh silks are present and target the ear, so ground application is best.