A STUDY ON HIPPOTA DORSALIS (STL) I.BIOLOGY

Hippota dorsalis (Stal) belongs to the family Pentatomidae,which is a main pest of bamboo discovered recently and caused severe damage in bamboo grove.In Zhejiang Province,its infested area was only 13 ha in 1984,but enlarged to 12.9 thousand ha in 1987.The mortality of infested bamboo could be as high as 76%,and the brow-height circumference of new culm in next year would have a reduction from 13.18% to 54.78%.It has one generation a year.2-4 instar nymphs overwinter under the litter,among which 4 instar ones reach around 95%.In the following year,in early and mid-April when the mean day temperature is above 10℃,the nymphs will climb up to bamboo culm and feed in aggregation.There is a close relationshop between the number of nymphs climbing to bamboo culms and the relative humidity,which is a linear regression as Y=75.89-0.77x.If the temperature decreases or it is windy and rainy,the nymphs will climb down from the bamboo culms and try to hide themselves.Adults appear from the end of May to the beginning of June.Both the overwintered nymphs and the adults feed the old culms at the same time,and they have a habit of feigned death.After feeding for 15-35 days,the adults start to mate.The female may couple with the male for several times and then oviposit eggs on the back of the new culm's leaves in 30-45 days.A female may lay 30-60 eggs.The starting temperature and day accumulative temperature for the egg's development are 20.3℃ and 39.2℃ day-1 respectively,1-instar nymph does not feed.There are 5 instars in the nymphal stage.The life span of the female is around 70 days.The nymph dropped down to the ground and overwinter under the litter.