Ovicidal and larvicidal effectiveness of several insect growth inhibitors and regulators on the codling moth Cydia pomonella L. (Lep., Tortricidae)

Several insect growth inhibitors (IGIs) and regulators (IGRs) were tested i n the laboratory for their ovicidal and larvicidal properties on the codlin g moth C. pomonella, by dipping apples in solutions of them. The IGIs which block chitin synthesis diflubenzuron, hexaflumuron and teflubenzuron - wer e noticeably more effective against eggs than on newborn larvae with preven tive ovicidal 50% lethality concentrations (LC50) values of approximately 0 .6, 1.3 and 15 p.p.m., respectively, and larvicidal LC50 values of 104, 120 8 and 204 p.p.m. Flufenoxuron, on the other hand, is almost as effective on larvae (LCS50 : 9.9 p.p.m.) as on eggs (LC50 : 5.4 p.p.m.). Fenoxycarb. an IGR juvenile hormone analogue, acts as an excellent ovicidal product with an LC50 value of 0.05 p.p.m. Tebufenozide, an IGR ecdyson (moulting hormone ) agonist, is exclusively larvicidal with an LC50 at 0.4 p.p.m. Methoxyfeno zide, an IGR of the same family and currently being developed, acts as effe ctively on eggs as on larvae with ovicidal and larvicidal LC50 values Of ab out 0.6 and 0.8 p.p.m., respectively. When ovicidal products are applied as a curative treatment on eggs less than 24 h old, their effectiveness is mu ch lower than that obtained from preventive application.