EFFICACY AND PERSISTENCE OF INSECTICIDE RESIDUES ON FRUIT OF KIWIFRUIT TO PREVENT GREEDY SCALE (HEMIPTERA, DIASPIDIDAE) CRAWLER SETTLEMENT

Insecticides were applied to kiwifruit (Actinidia deliciosa) in Februa ry and April 1992 and April 1993. A bioassay technique was used to mea sure levels of greedy scale, Hemiberlesia rapax (Comstock), crawler se ttlement on fruit at various times after insecticide application. Orga nophosphate and pyrethroid residues remaining on the fruit were measur ed but not the mineral oil residues. The February and April 1992 trial s showed that diazinon, chlorpyrifos, and diazinon/permethrin gave sho rt-lived protection compared to phosmet, mineral oil, and pirimiphos-m ethyl/permethrin. The residual times for 50% of fruit to be settled by scale in the April 1993 trial were: pirimiphos-methyl/permethrin, hal f rate <8 days; 1% Citrole mineral oil, 8 days; pirimiphos-methyl/perm ethrin, full rate 16 days; 1% Sunspray Ultra-Fine mineral oil, 19 days ; 2% Citrole, 21 days; and 2% Ultra-Fine, 24 days. Estimates of residu e levels at which 50% of fruit were settled by scale were generally be low or similar to the maximum residue levels set by the Coder Alimenta rius Commission. The potential for reducing residues at harvest is dis cussed.