The effects of pyrethroids fenvalerate and permethrin were studies upon isolated abdominal nerve cords from the susceptible (HD-S) and resistant (HJ-R) strains of Helicoverpa armigera (Htibner). 10^-5 mol/L fenvalerate and 10^-5 mol/L permethrin induced increases in spontaneous firing frequency primarily and then led to cessation in both strains; 10^-4 mol/L permethrin blocked the neural activity directly without producing repetitive discharges. On the basis of the time of excitation or cessation, there was a consistent pattern showing that the nervous system of HJ-R is 2- 3 times more resistant to pyrethroid actionshan that of HD-S. This experiment implied that there is a resistant mechanism of decreased nervous sensitity to pyrethroids in the field strain of Heliothis armigera in China and the mechanism conferred resistance to type I or II pyrethroids.

nduction of glutathione S-transferases (GSTs) by insecticides and plant allelo chemicals, and metabolism of insecticides by GSTs were investigated during 1992-1995 in cotton bollworms, Helicoverpa armigera (Htibner). GSTs of the midguts from cotton bollworms metabolized parathion-methyl and methomyl more quickly than diethylmaleate, o, odiethyl-phenyl phosphorothioate (SV₁) and mixtures of parathion-methyl and methomyl.At 24 h or 48 h after treatment with LD₅₀ of parathion or methomyl, the GSTs activity of cotton bollworms did not increase. Selection of LD₅₀ of parathion made GSTs activity increase 15% while selection of LD₅₀ of methomyl had no effect on GSTs activity. Midgut GSTs activity in cotton bollworm larvae was induced up to 18-fold by feeding on the artificial diet containing 0.01% of quercitrin compared with activity in larvae only fed with artificial diet and up to 4-fold compared with activity in larvae fed with the diet containing 2tridecanone or rutin. Toxicity of parathion-methyl to larvae of cotton bollworms reduced about 50% due to feeding on the diet with quercitrin. But the 0.01% of rutin, quercitrin and 2-tridecanone in diet had no effects on toxicities of methomyl and deltamethrin to larvae of cotton bollworms.

Acetylcholinesterase insensitivity is an important mechanism of resistance of diamondback moth (Plutella xylostella (L.)) to organophosphorus and carbamate insecticides, which has been widely recognized and documented. A dot-blot on nitrocellulose membranes technique for identification of insensitive AChE in single insect provides the opportunity for early detection and subsequent monitoring of resistance in field population. The technique is simple, sensitive and inexpensive. The percentages of inhibition of AChE activi ties in resistant strain (GBR) and field population (DG) were 50.97% and 43.96 % respec tively in the presence of propoxur and were 63.76% and 35.87% respectively in the presence of paraoxon. The results showed the GBR and DC, had a higher degree of AChE insensitivity to OP and carbamate than did the susceptible strain.

Coccobius azumai Tachikawa which was introduced from Okinawa, Japan, was first released and successfully established in Huidong County, Guangdong Province in 1989.Since then systematic observation and investigation were made. The result showed that a year later the parasitism rate of C. Azumai on Hemiberlesia itysophila reached as high as 55.8%-64, 2% within 50m from the released site and the density of female H. pitysophila was reduced from 3.41 to 0.64 per needle. Two years later the effective control radius hadincreased to about 300m. The parasitism rate ranged from 20.8% to 32.9%. The density of female H. pitysophila became as low as 0.6 per needle. Both C. azumai and H. pitysophila were in a balanced state of Iow density, whereas in the areas where no C. azumai was released, the density of female H. pitysophila had increased from 3.4 to 4.22 per needle, 6.10 times higher than that in the released area. Judging from the spreading speed ,competitive ability and the number-stabilizing level of C. azumai, it is concluded that Marietta carnesi(Howard) had only a hyperparasitism rate of 3.1%45.3% so that it had no influence on the control efficiency of C. Azumai.

Searching behavior of the larvae of Harrnonia axyridis (Pallas) was studied with Nakamuta apparatus (1982), under two illumination conditions. The results show: 1.Feeding stimulus can induce a switchover of searching behavior from area-dissipated type toarea-concentrated type; 2. The longer the feeding time, the higher the giving-up time (GUT) value; 3. The GUT is determined by the size of prey at the final feeding; 4. Light illumination has influence on searching behavior and 5. The degree of starvation has certain in-fluences on GUT.

The absorption and utilization of nitrogen and sugar in diet by the Asian corn borer (O, trinia furnacalis) larvae reared on artificial diets with different levels of nitrogen and sugar were s.tudied. The results showed that the absorption of nitrogen decreased hile that of sugar increased with larval development from the third to fifth instar. In the fifth instar larvae the absorption of sugar increased with the increase of nitrogen conte.nt in the diet.In the fifth instar larvae the consumption rates of nitrogen and sugar increased but the nitrogen utilization rate and the nitrogen content decreased when fed on the diet with higher sugar content. The nitrogen content in larvae decreased significantly from the third to fifth instar when theywere red on the diet with 3.01% nitrogen content, due to the decrease in nitrogen utilization rate. These results indicated that the nitrogen and sugar contents in diets influence their absorption and utilization by the larvae, and sugar is more important than nitrogen for older larvae.

The sex-pheromone-gland extracts of female oriental armyworm Mythirnnaseparata Walker at calling period were individually analyzed with capillary GC and GC-Mstechniques. The suitable solvent was selected. Both extracting and detecting methods weredeveloped. The components, content and ratio in one gland extract were etermined. The individual variation of each component in the extracts was also discussed.

According to the fluctuation of population of Citellus dauricus and the index for body flea in Wuningbatu Sumu,Zhengxiangbai Banner, Inner Mongolia Autonomous Region during 1981-1993, the authors have found that there are ten flea species, with Citellophilustesquorum mongolicus (72.38%) as the dominant species and Frontopsylla luculenta (18.03 % ) comes second, the common species are Neopsylla abagaitui and N. bidentatiformis,and the other species are very few. The host population and the flea index increase exponen tially during this period and the correlation between them is very significant (P<0.0001),I. E. , host population=exp (-0.6206+0.1989t), flea index= 1.6109+0.8997 (host popu lation). The diversity and evenness of flea are influenced significantly by the proportion of C. t. mongolicus in the flea population and the relation between host density and flea infection rate is positively correlated (P〈0.10).

Results of enzyme-linked immunosorbent assay (ELISA) showed that therewere significant differences among the predatory effects of different predatory arthropods on whitebacked rice planthopper Sogatella furcifera (Horvath) and brown planthopper Nilaparvata lugens Stal in rice field. In these results, the predation effects of predominant spiders Urnrneliata insecticeps (Boes. Et Str. ) and Pirata subpiraticus Boes. Et Str. , werr thebest, their positive reaction rates were closely correlated with the population density of the planthoppers, and high positive reaction rates occurred even under low rice planthopper density.

The morphological character, biology, and natural enemies of Pseudopha copteron caharium were studied. In the meantime, chemical control was carried out against the pest. It has 7-9 overlapping generations in a year, the first generation adults appeared in late April, and there are three adult peaks during early July to early September. In addition, experiments showed that the best chemical to control this pest was Meothrin, it could result in 96. SM control effect in the next day after spraying, the second was Fenvalerata,93. 8% the next day, and the rest-2.5% Decis, 40% Omethoate and 80% Dichlorvos was all between 81%-90%. Many kinds of natural enemies played important roles in sup pression of the population development of the pest. There were beetles,chrysopas, cheroidea,spiders and predatory mites, of which beetles were dominant. The entomogenous fungus Metarhizium was also first introduced to control this pest.

In this paper, a new species of Prosentoria from Yunnan Province is described.The type specimen is deposited in the Institute of Zoology, Academia Sinica. All measurements in descriptions are in mm.

In the present paper,a new species is described. Type is preserved in the Institute of Zoology, Academia Sinica.

This paper described a new species of the genus Carinata Li et Wang 1992, collected from Vietnam. The type specimens are deposited in the Guizhou Agricultural College.

Four species of Berosus Leach were recorded in China. In this paper, four newspecies are reported. All type specimens are deposited in Research Institute of Entomology,School of Life Sciences, Zhongshan University.

This paper deals with two new species of the genus Oscyporus Fabricius (1775)from Sichuan and Yunnan Provinces, China. The types of new species are deposited in theDepartment of Biology, Sichuan Teachers College.

In the present paper two new species of the genus Hepialus collected from the Baima Snow Mountain of Yunnan are described. All types are deposited in Kunming Institute of Zoology, Academia Sinica, Kunming, China.

The present paper contains a brief historical account of investigations on Chinese Halictus and an annotated list of 16 species. The following new taxa are described:Halictus (Monilapis) yunnanicus sp. Nov. and Halictus (Protohalictus ) hedini hebeiensis sub sp. Nov. Synonymies H. takuiricus Bluthgen, 1936= H. pseudotakuiricus Fan, 1990= H.Zadaensis Fan, 1990 and Halictus palustris Morawitz, 1876= H. frostus Fan, 1990 are ascertained. Halictus maculatus Smith and Halictus compressus (Walkenaer) are new recordsfor China. Holotypes and most of the paratypes are deposited in the Institue of Zoology, Academia Sinica, Beijing; a few paratypes-in the Zoological Institute, Russian Academy of Sciences, St. Petersburg. The diagnostic characters of the new taxa are given as follows:

In this paper a new species of the genus Trioxys Haliday from Shanxi Province,China is described. Type specimens are deposited in the Natural Enemy Collection of the Entomology Institute of Shanxi Agricultural University.

A new species of genus Cosmoconus Foerster, 1868 is described in this paper. Type specimens are deposited in General Station of Forest Pest Management, Ministry of Forestry.

Plant protease inhibitors are considered to be protective agents in plants against herbivorous insects. It was shown that damage to the leaves of certain plant species by insect feeding induced the synthesis of protease inhibitors. Plants can now be genetically manipulated with protease inhibitor genes to express the inhibitor proteins in relatively high level resistant to insect pests. Studies on interactions of protease inhibitors with insect digestive enzymes may further elucidate the physiological role in natural plant defense and the potential usefulness in resistant crop breeding against insect pests of agriculture.