DEGRADATION OF ALTOSID(R) XR BRIQUETS UNDER FIELD CONDITIONS IN MINNESOTA

Incomplete degradation of control products and subsequent carryover of active ingredient to the next year are operational concerns for contr ol agencies. Altosid(R) XR briquets were weighed before and after 6-18 months of exposure in temporary wetlands to determine the rate of phy sical degradation of the briquets. Degradation rate was influenced mai nly by the number of days a briquet remained under water. The average briquet degraded to 19% of its weight within 150 days of immersion and was completely degraded after 1.5 yr under water. The active ingredie nt (methoprene) content of briquets declined faster among those expose d to air and more slowly among those that were immersed.