Potato Leafhopper Onslaught Continues: Be Aware of Treatment Restrictions for Alfalfa

August 6, 1999
Yes, potato leafhoppers continue to wreak havoc within alfalfa fields throughout Illinois. This year will be long remembered as one of the worst leafhopper outbreaks any of us can remember. This week we've received a number of inquiries concerning spraying restrictions. Specifically, the questions have focused on how many times a field can be legally treated. Obviously one must consider the economic ramifications of repeated treatments throughout a season. You may recall that potato leafhoppers will be with us until several hard frosts have occurred. The short-term news is not good: leafhoppers will remain a challenge. Please keep in mind these spraying restrictions for the following products. Those insecticides followed by an asterisk are restricted-use products and may be applied by certified applicators only.

Ambush 2E* and Pounce 3.2 EC*--Do not apply more than 0.2 pounds of active ingredient per acre per cutting. When rates of 0.1 pound active ingredient per acre or less are used, an application may be made on the day of harvest. When rates greater than 0.1 pound of active ingredient per acre are used, do not apply within 14 days of harvest.

Baythroid 2*--Apply only once per cutting. A total of 11.2 fluid ounces per acre may be applied per crop season.

Dimethoate--For alfalfa grown for hay, apply only once per season. Do not apply within 10 days of harvest.

Imidan 70-W--Do not apply more than once per cutting. Grazing, cutting for hay restriction is equal to 7 days.

Lorsban 4E--Do not make more than four applications per year or apply more than once per cutting. Do not cut or graze within 4 days after application.

Penncap­M*--Do not apply within 15 days of harvest or grazing.

Sevin XLR Plus--Apply only once per cutting. The harvest restriction is equal to 3 days.

Warrior T* or 1E*--Do not apply more than 0.03 pound of active ingredient (0.24 pint) per acre per cutting. Do not apply more than 0.12 pound of active ingredient (0.96 pint) per acre per season. Do not apply within 1 day of harvest for forage or within 7 days of harvest for hay.

Good luck with the leafhopper battles. Please consult individual product labels for more specific instructions.--Mike Gray

Author: Mike Gray