- Trail Jr., Henry
Maine Forest Service
The application of insecticide must be timed with budworm development. Insecticide should be applied early to minimize defoliation but not before the young larvae have reached a stage where they will be exposed to the chemical. Budworm behavior varies with changes in larval instar and is one factor in determining the insects susceptibility to the insecticide. Percentages of budworm in each instar can be used to plot their susceptability to spray treatment. In addition to insect development, an adequate spray target provided by the expansion of foliage is necessary. Bud development is also monitored and used in conjunction with insect development data.