EFFECTS OF AN INSECT GROWTH-REGULATOR, FE NOXYCARB, ON THE DIAPAUSE OF THE PEAR PSYLLA, CACOPSYLLA-PYRI

Effects of an insect growth regulator fenoxycarb, on the diapause of t he pear psylla, Cacopsylla pyri Under natural conditions, winter-form females undergo a reproductive diapause. Topical application on adults and treatment of young pear foliage with fenoxycarb show that this mi mic of juvenile hormone (JH) accelerates ovarian maturation of winter- form females, leading to a rapid breakdown of diapause. Treatment of m ales increases the mating rate of non-treated females. The physiologic ally mature winter-form males exhibit a behavioural arrest which can b e eliminated by this insect growth regulator. Mating thus depends more on the 'maturity of sexual behaviour' of males than on the physiologi cal maturity of females.