| Orius similis Zheng(Hemiptera:Anthocoridae ) is an important predator in agroecosystems of South China.A lot of literatures were reported on the characteristics of biology,ecology and taxology of O.similis,O.sauteri and O.minitus.However,the technology of their mass rearing and field release were comparatively less studied.Thus, the key technologies of mass rearing of O.similis was systematically studied in this paper. In addition,the controlling effect of O.similis to one of the main cotton plant pest Tetranychus cinnabarinus was studied.Also,the release of O.similis in the field to control T.cinnabarinus and Frankliniella intonsa(Trybom) was studied.The main results were as following:Eggs laid on nine oviposition plants were checked and the plants that eggs laid from high to low are Capsicum frutescens,Vigna unguiculata,Kalanchoe blossfeldiana, Jasminum nudirlorum,Vitex negundo,Echeveria peacockii,Gossypium hirsutum,Vigna radiate,Portulaca grandiflora,and Gossypium hirsutum,respectively.As far as the number of eggs laid which account for 23.4%of the all,Orius similis likes to oviposit on the twig of the C.frutescens best.And the eggs laid in the twigs of the J.nudirlorum were highest in hatching rate,which was over 80%.The twigs of C.frutescens and J. nudirlorum had comparatively higher propagation coefficient,which was 7.6 and 12.8, respectively.In addition,the study of conservation condition of eggs showed that the highest cold-resistance was observed on eggs,followed by adult,and the best conservation condition was keeping the eggs at 8℃for nine days,and 80%of the survival would be guaranteed.To evaluate the artificial liquid diet we made for O.similis Zheng,the nymph and adult of O.similis were fed on the artificial diet for two generations continuously using cotton aphids as the control,and their developmental and reproductive indexes at different stages were investigated.The results showed that the durations(22-23 days) of the two consecutive generations of O.similis were not significantly different from that of the control(21 days),which suggested that the diet could well meet the nutritional need of the nymph of O.similis for growth and development.However,the obtainable rate of the adult of O.similis fed on the cotton aphids could achieve 63%,which was prominently greater than those of the two consecutive generations of O.similis fed on the artificial liquid diet,which were 45%and 43%,respectively.There were no significant differences in the period of pre-oviposition,the fecundity and longevity of the adult of O.similis between the treatments and the control.But the significant difference was observed in the period of oviposition between the treatments and the control,which are about 13-16 days for the treatments and 20 days for the control,respectively.These results suggested that the artificial liquid diet could also well meet the nutritional need of adult O.similis for reproduction.Also,the use of other prey item,such as Tyrophagus putretcentiae to feed O.similis was studied in the lab.There were no significantly differences in the survival of each instar of the three generations of nymphs fed on T.putretcentiae.The survival increased as the instar stages increased,and declined from the first to the third generation. Developmental periods of each instar increased with an increasing of generation. Moreover,there were no significant differences in the pre-reproductive period, reproductive period and the male adult longevity,however,the longevity of female adult and its fecundity of the third generation were significantly different from those of the first and the second generations.Developmental characteristics of the predatory bug O.similis on T.cinnabarinus were investigated at three constant temperatures 25,28 and 31℃under laboratory conditions(75±5%RH,and an 14 L:10 D photoperiod).The survival of nymphs were highest at 28℃(75.57%),also,the longest oviposition period(21.1 d),the greatest fecundity(40.3 eggs) and intrinsic rate of increase(0.108 d-1) of female adults were observed at 28℃.These results suggested that O.similis can keep greater population in the field in July and August.In addition,the functional response showed that O.similis has highest attacking rate(1.04) and greatest maximum prey capacity(30.7 spider mites per bug in 24h) at 28℃.This work can provide useful information in the evaluation of best time for releasing O.similis to control T.cinnabarinu in field.The release of O.similis that reared in the lab to control of T.cinnabarinus and F. intonsa was also studied,the results showed that the best time to release O.similis in the field to control them is in August,which in accordance with the results that got from the lab.The key technology system of artificial mass rearing and the ecological basement of O. similis were founded,and the foundation of biological control of pests in the field using O. similis was well established in this study.
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