Study On The Starvation Endurance Ability Of Wooly Apple Aphid

Woolly apple aphid, Eriosoma lanigerum (Hausmarm), is an significant quarantine pestall over the world, which have a seriously damages to the apple trees, resulted in tremendouseconomic loss to apple production area. In order to clarify the viability and the influence ofenvironmental factors on the starvation endurance ability of woolly apple aphid understarvation conditions, this paper studied the following three topics under controllingconditions in the laboratory: The first, the ability of woolly apple aphid to endure starvation inthree treatments providing leaf, branch (serving leaves and branches, with no moisturizationor change), nothing (totally starved, with no food served). The second, the influence ofdifferent temperature and humidity on the starvation endurance ability of woolly apple aphid.The third, the influence of starvation on the fecundity. The results are as following:1. Under starvation conditions, the order of the starvation endurance ability of woollyapple aphid from strong to weak is4nd instar, adult female,3rd instar,2nd instar,1st instar;the starvation endurance ability of woolly apple aphid in three treatments is branch> leaf>nothing. The optimum living areas of woolly apple aphid was branch.2. During the experiment, the escape phenomenon existed in the younger age of woollyapple aphid, indicating their activity ability are stronger, the activity ability of3rd,4th instarand adult female were weaker; The total amount of the escape of1st instar was4.1times thesize of2nd instar. Results showed that1st instar and2nd instar were the chief spread instarsand the quantity of1st instar wrer more; The period from1st instar to2nd instar is the bestspreading periods, the other periods have no diffusivity. In addition, host appeal to the woollyapple aphid, the appeal of branch is stronger than beaf.3. The negative correlation was found between the starvation endurance ability of woollyapple aphid and the temperatures ranged from15to31degrees, the higher the temperaturewas, the weaker the starvation endurance ability was. When the relative humidity ranged from40%to80%, the lower the relative humidity was, the weaker the starvation endurance abilitywas.4. The survival rate of woolly apple aphid decreased as the starvation period extended,and the descending trends all appeared slow in the early stage, faster in the mid stage, then became slow again in the late stage under starvation conditions. On the whole，the fastestreduction of the survival rate happened in the time during24to64hours after starvation,which was the peak of death.5. Woolly apple aphid propagate largely at the early stage of starvation under theinfluence of starvation conditions, while the fecundity was declined sharply later. Woollyapple aphid had three peak and two trough periods of laying aphids within a day, and thefecundity in daylight was more than in night. The fecundity of aphids in starvation conditionswas far less than in rearing conditions.6. Here we found that the starvation endurance ability of4th instar was stronger, they hadbetter tolerance to the severe environment, so they had potential risks to spread and transfer toother areas.