Control of Cacopsylla (Psylla) pyri (L.) (Stenorhyncha, Psyllidae) by juvenile hormone analogues

Abstract

Juvenoids could be a useful tool for the control of psyllids. The 12 new juvenoids synthetized at the Institute of Organic Chemistry and Biochemistry in Prague were tested by dipping the feeding plants in the juvenoid solution and by indirect contact application on Cacopsylla (Psylla) pyri (L.). The tested compounds were mostly less active than the commercial juvenoid, methoprene. However, even the low doses of active juvenoids which evoked only small malformations on wings and external genitalia of the treated psyllids disabled them from flying and also from copulation. The most sensitive period for juvenoids in psyllids comprises the first 4 days of the last larval instar. Aside from this period, juvenoids failed to evoke any malformation. The investigated juvenoids were also tested on the main predator of psyllids, the pirate bug, Anthocoris nemoralis (Fabr.), using the indirect topical application. It was found that the sensitive period of these bugs to the tested juvenoids is restricted to the first 24 h of the last larval instar. Hence, the pirate bug revealed very low sensitivity to the tested juvenoids.

Silencing Abnormal Wing Disc Gene of the Asian Citrus Psyllid, Diaphorina citri Disrupts Adult Wing Development and Increases Nymph Mortality

“…Many proteins and hormones and their analogues are implicated in the development of wings and flying ability [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]. Wing discs and other imaginal discs, are cells in the larval stage of insects that remain diploid and continue to divide by normal division in order to differentiate into adult organs [6].…”

Using degree-day accumulations and host phenology for predicting larval emergence patterns of the olive psyllid, Euphyllura phillyreae

“…But the delayed timing prevents damage neither on inXorescences nor on fruit setting of olive trees. Moreover, the inaccuracy of such a traditional approach can be accounted for the reduced eYcacy of Insect Growth Regulators (IGR), such as diXubenzuron, and fenoxycarb, being safe to natural enemies, due to untimely application (Baldassari et al 1997;Dhadialla et al 1998;Medina et al 2001Medina et al , 2003. Clearly, an alternative method which should target larva emergences rather than waiting for honeydew droplets to appear is needed for timing insecticide applications.…”