Two insect growth regulators (IGR) ZR-512 (Ethyl 3,7,1l-trimethyldodeca-2,4-dienoate) and ZR-515 (Isopropyl 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate) were evaluated for their control of the pear psylla,Psylla pyricolaFörster, and for their effect on nontarget pear pests and predators. Under laboratory conditions, adult psylla exposed to residues of IGR's failed to lay viable eggs, though the number laid and the general appearance of eggs seemed normal. Adult psylla from late-instar nymphs which were exposed to ZR-515 failed to lay viable eggs. In field tests no direct reduction in adult psylla levels was observed following application with IGR's, but 3 weeks post treatment the ratio of psylla eggs per nymphs was much greater in these plots. The effect of IGR's was minimal on other pest species, and no significant decrease in predator species was noted.