THE INFLUENCE OF CARRIER OIL VISCOSITY ON THE TRANSFER OF BIFENTHRIN FROM COTTON TO TOBACCO BUDWORM LARVAE HELIOTHIS-VIRESCENS(F) (LEPIDOPTERA, NOCTUIDAE)

The transfer of bifenthrin/carrier combinations from glass, wax, and c otton leaves to tobacco budworm, Heliothis virescens, larvae was deter mined. Persistence of bifenthrin/oil combinations on the cotton leaf w as also determined. Results indicated that the amount of bifenthrin/ca rrier transferred from glass to sixth-instar tobacco budworm was influ enced by viscosity; however, transfer from wax to larvae was not affec ted. In spray table tests, amounts of bifenthrin bound to leaf surface s over time were influenced by carrier viscosity. Oils transferred sig nificantly greater (up to 50%) amounts of bifenthrin from cotton leave s to tobacco budworm than water. The transfer of bifenthrin using vege table and hydrocarbon based oils from cotton leaves to larvae was affe cted by carrier viscosity; however, there was no relationship between transfer and viscosity when silicone fluid was included in the compari son. Silicone fluid was twice as viscous as soybean oil, yet bifenthri n transfer to tobacco budworm was greatest when mixed in soybean oil. Larval mortality in the bioassay substantiated the amount of bifenthri n detected on larvae in the transfer test.