Using Nematodes to Control Root Maggots in Cole Crops (2016) - 3 pages
Root maggots (Delia radicum) represent a major problem for growers of vegetable cole crops (cabbage, cauliflower, radish, rutabaga etc.) in Saskatchewan. Feeding by the maggot stage damages the roots. In young plants, this damage may kill the seedlings – whereas in older established plants the damaged root systems are less capable of delivering the water and nutrients required for optimal growth. Affected crops are slow to mature and may not reach optimal size or quality. In crops grown for their roots (rutabaga and radish), the scars left by the feeding maggots may render the roots unmarketable. Presently, the most widely utilized approach to controlling maggots is to apply the insecticide chlorpyrifos (Lorsban) as a root drench on several occasions through the growing season. The timing of the chlorpyrifos application(s) is targeted to correspond to the development of the maggot population. Application of chlorpyrifos must cease 30 days prior to harvest. Organophosphates like chlorpyrifos have been targeted for phase-out as soon as effective reduced-risk alternatives are identified.
Parasitic nematodes have shown the potential to control a broad range of soil-inhabiting and above-ground insect pests. The nematodes can be applied as a foliar spray to reach above-ground pests or as a drench for soil-borne pests. The nematodes sense the carbon dioxide emissions of soil-borne insects and “swim” through the soil solution towards their intended host. For that reason, the soil must be kept moist for the nematodes to be effective.