Expectations are that corn flea beetle populations may be very large this spring (see article on pages 55-56). This insect can physically damage seedling corn by chewing long lesions in the leaves. These feeding lesions run parallel to the leaf veins and they first appear as thin, silvery or white streaks. Heavily injured leaves turn brown and wilt. The insect also can transmit Stewart's wilt, also called Stewart's disease. This disease can be controlled on susceptible corn by controlling the corn flea beetle with an insecticide. Use the following thresholds: in field corn prior to stage V5, 50 percent of plants with severe feeding injury and 5 or more beetles per plant; in seed corn on susceptible inbreds, 10 percent of the plants with severe feeding injury and 2 or more beetles per plant. There are a number of insecticides registered for flea beetles. A new systemic insecticide, formulated as the seed treatment Gaucho, also has been shown to reduce flea beetle feeding and Stewart's disease. See the table for insecticides and the manufacturer's recommended labeled rates.
|||Corn flea beetle, carrier of Stewart's disease in corn.|
Insecticides labeled for corn flea beetle.
|Asana XL||5.8-9.6 oz/acre|
|Furadan 4F||1 qt/acre|
|Gaucho 600F||6.4-12.8 oz/cwt of seed|
|Lannate LV||12-24 oz/acre|
|Lorsban 4E||1-2 pt/acre|
|Pounce 3.2EC||4-8 oz/acre|
|Sevin XLR Plus||1-2 qt/acre|
This article originally appeared on page 57 of the IC-484 (7) -- May 1, 2000 issue.