Regulation of seasonal egg hatch by plant phenology in Stethoconus japonicus (Heteroptera: Miridae), a specialist predator of Stephanitis pyrioides (Heteroptera: Tingidae)
1992
Neal, J.W. Jr | Haldemann, R.L.
Stethoconus japonicus Schumacher altered its oviposition site on azalea, Rhododendron spp., plants as the summer progressed. During June, eggs were deposited mostly in the midrib on the new growth. As leaves aged, the oviposition site shifted to current year's stems and the leaf sears of year-old growth. The shift in oviposition site was coincidental with a decline in leaf moisture of approximately 9% and an increase in leaf age. Eggs deposited in the leaf midrib changed shape significantly and increased in weight by 60% from day 3 to day 10; the sigmoidal curve fit a change in weight. As eggs aged from 2 to 10 d, they showed a significant increase in breadth, no change in length, and a significant reduction in width. Eggs of S. japonicus began to hatch in the field in late June when early instars of the second generation of its prey, the azalea lace bug, Stephanitis pyrioides (Scott), were present. The late hatch of this specialist predator resulted in synchrony with the second generation of its prey. Asynchrony and late hatch of overwintered eggs makes S. japonicus a suitable candidate for IPM programs because the predator may escape the effects of pesticides directed at the first generation of azalea lace bug nymphs.
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