If chemical control is required, an insecticide registered for LBAM must be used. There are several new insecticides available that are 'softer' and specifically target caterpillar pests and have a negligible or minimal effect on non-target species. Spraying is most effective after eggs have hatched, but before caterpillars reach 3 to 5 mm and build feeding shelters. Caterpillars within rolled leaves and bunches are difficult to control because spray coverage in these concealed places is poor. Biological insecticides containing the bacterium Bacillus thuringiensis (Bt) specifically kill only caterpillars and not thei