Treatment of Bare Root Spruce Seedlings with Permethrin against Pine Weevil before Lifting
The possibility of applying permethrin on coniferous bare root seedlings to protect them against pine weevil (Hylobius abietis L.) in the transplant lines may avoid or diminish problems connected with dipping or spraying plant bundles with the insecticide after lifting. Spraying 0.5 or 1% permethrin solution on bare root spruce seedlings in the transplant lines resulted in initial amounts of about 0.35 and 0.74 g permethrin mm-2 bark on the lower part of the plant stem. This amount diminished during the first month to a level that remained stable for a period of at least 1.5 yrs. The permethrin that reached the soil was degraded with a half-life of 3-4 months. The trans isomer was degraded more rapidly than the cis isomer.