| The soybean aphid migratory, dispersion and overwintering habits were studied. Understanding the species of winter host of the soybean aphids, the biology and the ecology habits of the Sexual morphs, zygote, fundatrix, fundatrigenia, The result was a addition to the soybean aphids researching and there was a certain guiding significance to the soybean aphid prediction and control.The main results of the test were as follows:①The species of winter hosts and the life history on winter hostsSix buckthorns were found in Harbin through investigation, only one specie of buckthorn was not soybean aphids'winter host, three of the other five buckthorns were the main winter hosts.Oviparae migrated to winter hosts in the end of the September and died after birthing. Sexual morphs mated in the early-October, Ovipar egged in 1 to 3 days after mating, zygote overwintered on winter host from the beginning of the November to the end of April, zygote started hatching in the end of April, in the early May fundatrixes reproducted fundatrigenias through parthenogenesis, then the population increased rapidly, a large number of alate aphid appeared in the end of May, emigrated winter host.②Soybean aphids′natural enemy species were invested on winter hostsThere were 4 orders, 4 families, 7 species natural enemies through investigation in 2006～2007。③Sexual aphid inductionIndoor treatments of certain temperature and photoperiod combinations had successfully induced the alate aphids, gynoparae male, gynoparae female. But gynoparae female can't product oviparae in the soybean plant, when it was transferred to buckthorns leaves, it begin to product oviparae in 1 to 2 days. The general conditions for producing alate aphis were≤22℃of temperature combined with 8-12 hours of light per day. Under 19℃, gynoparae female appeared combined with 10 hours of light per day, the highest ratio of gynoparae female was induced by 16℃and 8 hours of light for one generation, under 16℃, gynoparae male appeared combined with 12 hours of light per day, the highest ratio of gynoparae male was induced by 16℃and 10 hours of light for one generation.④Effective accumulated temperature and developmental threshold temperature of different soybean aphid morphs.This experiment based on effective accumulated temperature rule and effective temperature calculation formula,measured the development threshold temperature and effective accumulated temperature of ovipara, zygote, fundatrix and fundatrigenia. ovipara's development threshold temperature was (-2.16±1.32)℃, effective accumulated temperature was (216±12.50), zygote's development threshold temperature was (-3.6±2.04)℃, effective accumulated temperature was (186±19.66), fundatrix's development threshold temperature was (1.69±1.14)℃, effective accumulated temperature was (210±18.75), fundatrigenia's development threshold temperature was (0.26±0.059)℃, effective accumulated temperature was (204.84±1.76).⑤The spatial distribution of ovipara and zygoteThe results indicated that ovipara and zygote of aphids were gathered distribution on any parties of winter hosts. Ovipara and zygote spatial distribution of the basic ingredient was the individual groups,individuals attracted together and gathered distribution.⑥Soybean aphids dispersion and migration habits in soybean fieldsSoybean seedling stage in early June, the soybean aphids moved into the soybean fieldwere scattered, very universal,during mid-July to mid-August the aphids maintained at the rate of 100%,soybean aphids happened widespreadly in the soybean fields. After mid-August,the number of soybean aphids dropped, Aphid strain rates have been reduced,in late September started to emigration out soybean fields.It showed that population number peak of alate aphid occurred respectively in early June, mid July, early August and during late August to early September. Soybean aphid began to emigrate into soybean in early June, but only occurred sporadically. Soybean aphid number was large in mid-July and in early August, which influenced the subsequent population. The aphids emigrated in search of Rhamnus during late August to early September.
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