| Longitarsus bimaculatus Baly was one of the most important leaf-eating insects on Fraxinus americanna. In this thesis, Morphology of Longitarsus bimaculatus Baly was described, rearing method and biology of Longitarsus bimaculatus Baly were studied. And the olfactory response of Longitarsus bimaculatus Baly to odor volatiles from 6 species of trees (Fraxinus americanna, Fraxinus velutina Torr, Fraxinus mandshurica Rupr, Fontanesia fortunei Carr, Chionanthus retusus Lindl. Et Paxt. and Ligustrum lucidum Ait) were researched using"Y"-shaped olfactometer, wind tunnel and net cage. The results are as followings:1 Morphology of Longitarsus bimaculatus BalyBody brown, small. There is a markings on elytra, markings brown to black, when elytra folds, the two markings forms a transverse band. Marks on male elytra are smaller and lighter than those on female. Female are a little biger than male. Protarsuaâ… of male are dilated and pyriform; Protarsuaâ… of female are lanky.2 Rearing method and biology of Longitarsus bimaculatus Baly2.1 Rearing methodBy analysing average mortality, average longevity, average eggs per female and hatching rate of the three rearing methods, the effect of mask flask test was the best, the next was net cage feeding, the effect of reared in wide-mouth bottle was the poorest. However, if we can find the better egg collecting method and good overshadow, net cage feeding can have the same or even better effect as rearing in the mask flask.2.2 Biology of Longitarsus bimaculatus Baly2.2.1 AdultFeeding habit of Longitarsus bimaculatus Baly was special, but when host was in a bad condition, it fed Fraxinus velutina Torr and Fraxinus mandshurica Rupr. Majority adult fed all day long and mostly damage in the lower parts of the crown, the degree of young trees damaged is severer than aged trees.Majority adult copulated and oviposited after 4 p.m., a little of adults copulated before 11a.m.. Mating time varies from 20min to 3h, some were even longer. Mating process included preparation stage, mating and completion.The preoviposition period of adult was 5~10 days. Adults deposited eggs in the soil surface after 4 p.m.. The fecundity of the most female was 3-15 eggs, most 21 eggs during its lifetime.In addition, the adults had phototaxis, yellowtaxis, falsedeath and liked moving up, and be good at jumping, and can fly over 3 m.2.2.2 LarvaeThe larvae are inactive and feed cortex on the secondary rootlets in soil.3 The odor responses of adult Longitarsus bimaculatus Baly to different plants'volatiles3.1"Y"olfactometerIn the process of adult of Longitarsus bimaculatus Baly searching host plants, it can be attracted by the volatiles of plants. Different plants attribute their own degrees, and actions of Fraxinus americanna, Fraxinus velutina Torr are the biggest, at 76.7%and 65.0% respectively.3.2 The wind tunnelLongitarsus bimaculatus Baly shew the greatest tendency to Fraxinus americanna, the next was Fraxinus velutina Torr and Fraxinus mandshurica Rupr, at 73.3%, 63.3% and 63.3% respectively, while shew lower tendency to other plants, which were all less than 55%. This result was basically the same as"Y"olfactometer.3.3 Net cageAdult of Longitarsus bimaculatus Baly shew great preference to Fraxinus americanna and Fraxinus velutina Torr, with an average rate of 22.2% and 15.7%, respectively. However, the rate of choices were low to Fraxinus mandshurica Rupr, Fontanesia fortunei Carr, Chionanthus retusus Lindl. Et Paxt. and Ligustrum lucidum Ait , respectively, 14.5%, 13.3%, 11.1% and 4.4%. This result corresponded with"Y"olfactometer and the wind tunnel.
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