Biology and control of eucalyptus gall wasp Leptoscybe invasa Fisher & La Salle

Abstract

The Eucalyptus gall wasp Leptoscybe invasa Fisher & La Salle causes galls
on leaf midrib, petiole and stems of new shoots of eucalypt seedlings in
nursery and in plantations under two years of age. It has a four- stage life
cycle and goes through complete metamorphosis: adult, egg, larvae and
pupae. Rairing gall wasp in laboratory at an average room temperature of
28.9
o
C and humidity 78.5%, mean developmental time from egg laying to
adult stage was 131.5 days (ranges from 123 to 140 days). The time of adult
eucalyptus gall wasp emeges in year, there are three overlapping
generations per year, generation 1 from mid April to early
June, generation 2 from mid August to mid October, generation 3 from late
November to at the end of December. Control of gall wasp by yellow sticky
traps are most effective (128.1 wasps/trap), the red sticky traps are lowest
(24.8 wasp/trap), the remaining sticky traps with green, blue and white
color ranges from 24.8 wasps/trap to 54.3 wasps/trap; using chemical
prevent eucalyptus gall wasp after four spraying times compare with control
(distill water), the result shown that Actara 25WG chemical is most
effective (0.8 wasps), followed by effect of Confidor 100SL chemical (2.0
wasps); Penalty chemical (2.3 wasps) and control is 14.2 wasps alive