Studies On The Effects Of Temperature And Humidity Conditions On The Evelopment, Reproduction And Population Growth Of Acanthoscelides Macrophthalmus

Leucaena is an important shrub or arbor of paramount forage use that is growing on tropical areas. In addition to forage use it also has a series of applications, including being used as fertilizer chemical, core wood, building materials, water and soil conservation and breakwind, etc. Acanthoscelides macrophthalmus (Schaeffer) is one of the most important obligatory parasitism injurious insects of Leucaena. It feeds on Leucaena seeds and that the harmed seeds cannot be used as sowing seeds and only could be used as fodder, and thus the practical values have been lost dramatically.Temperature and humidity are two paramount ecological factors that affect the development, reproduction and population growth of Acanthoscelides macrophthalmus. The effects of temperature and humidity conditions on the eggs, larvae and pupae of the pest insect have been studied:including the developmental threshold temperature, effective accumulated temperature and the development rate of the pest, the wipe out percentage of a range of extreme temperatures of the eggs, larvae and pupas of the pest and the effects of humidity condition on the development, survive and reproduction of the pest. The results of the test were as follows:The developmental threshold temperature of eggs, larvae and pupas are10.50℃,9.52℃and12.79℃respectively, when being put under the condition of RH75%and six constant temperatures(20℃,25℃,28℃,32℃,36℃and40℃, respectively). The effective accumulated temperature is126.91,500.36and115.17days, respectively under the same conditions, and the developmental threshold temperature and the effective accumulated temperature of the whole life of Acanthoscelides macrophthalmus is10℃and742.44days. The population grow of the pest and the temperatures show a clear parabolic mutuality, and both high and low temperatures are not propitious to the growing development of the pest. The highest theoretically innate rate of increase reached0.02971under the30.75℃condition and the highest week limit growth rate isl.0374when the temperature is31.75℃According to the statistics collected from the extreme temperature test, the mortality rate reached100%when the eggs, larvae, pupae and imago of Acanthoscelides macrophthalmus have been put under the temperature of55℃and60℃for more than an hour, the test result was fairly well and the short time treatment also showed a great mortality rate except for the pupae. It showed that the pupae have a better endure capability under extreme temperature than the other stages of the pest. Therefore, higher temperature and longer time than the eggs, larvae and imago is needed to conserve the Leucaena seeds.The test of the effect of the humidity condition on the eggs, larvae, pupae and imago of Acanthoscelides macrophthalmus revealed that the effects were slighter than the imago stage when the effects were relatively apparent. When the humidity was RH30%, the mortality rate of the eggs has been greatly influenced, and the imago stage of the pest was relatively shorter and the egg laying amount was much lower than the pest under other humidity conditions. The egg laying amount of the imago was12.11when the humidity level was RH30%, while the number reached23.45when the humidity level was RH70%.