This can result in either paralysis of the hind legs, in the case of the northern cattle grub, or respiratory distress, in the case of the common cattle grub. In the case of insects that are not visible during the time of treatment, such as cattle grubs, the concept of economic threshold is not a useful one. There is no way to estimate how large the grub population will be at the time that treatment must be administered. Treatment must therefore be applied prophylactically in advance of any knowledge of the size of the pest population in order to avoid losses in production. Infestations of cattle grubs can cause reductions in the quality of both meat and hides and in the quantity of milk.
Many slaughterhouses automatically downgrade cattle with five or more grubs.
Management Strategies Chemical Control Strategies . Treatment should be administered while the larvae are migrating through the connective tissue, normally July through September in West Virginia. Be certain the read the insecticide label carefully prior to the application and to comply with the treatment cut-off date. Nonchemical Control Strategies . Heel flies and bomb flies lay eggs only in the daytime and do not enter stables.