Liquid vs. Crystal Thimet for Fast Insect Control in Pine Seed Orchards

Many pine seed orchard managers in the South regularly use the systemic poison Thimet (0,0diethyl S-methyl phosphorodithioate) for insect control. Usually the chemical is applied in crystal form, either broadcast on the soil or deposited in holes around individual trees. Either treatment is effective if applied early in the spring and if sufficient soil moisture is available to dissolve the crystals. Depositing the chemical in holes avoids the possibility of surface runoff, carrying the poison away with it. But, occasionally, the best time for application passes before an orchard manager can get the job done. When this happens, the Nantucket tip moth (Rhyacionia frustrana) can do considerable damage before control is effected. Even if DDT foliar sprays are used in the interim between Thimet application and its dispersion into the tree, some moths will escape and reproduce. Such a situation arose in a young shortleaf pine seed orchard in north Alabama. In this orchard, liquid Thimet was applied early in the season in combination with liquid fertilizer. The correct dosage per tree was prescribed, but the material was spread over the entire orchard area, rather than locally around each tree.

Download this file:

Download this file

Details

Author(s): Donovan C. Forbes

Publication: Tree Planters' Notes - Volume 21, Number 1 (1970)

Volume: 21

Number: 1