Key Technology Of Mass Rearing Of Orius Similis And Its Ecological Basement Of Field Release

Orius similis Zheng(Hemiptera:Anthocoridae) is an.important predator in agroecosys-tems 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,nevertheless,the technology of their mass rearing and field release were comparatively less studied.Herein, the key technologies of mass rearing of O.similis and the ecological basement of its field release were systematically studied in this research.The main results were as following:1.The key technologies of mass rearing of O.similisThe optimal temperature for development,the major factors influencing predation,the artificial fodder and host,the oviposition host-plant and the optimal condition for eggs conservation were studied in this section.The effects of temperatures on the development of O.similis were measured at five constant temperatures(20,25,28,31 and 34℃).The results showed that the developmental durations of eggs and nymphs decreased with an increasing of temperature, however,the developmental rates increased and the mortality increased with an increasing of temperatures.The longevity of female adult was longer than that of male adult under each temperature,and the longevities of female and male adult decreased with an increasing of temperatures.Besides,the fecundity was greater at 28℃and 31℃,but oviposition was not observed at 34℃.The developmental zero was estimated at 10.7℃and 7.1℃for the development of eggs and nymphs,respectively.The predation of O.similis on Aphis gossypii was measured under different temperatures and photoperiods.The results showed that temperature was the main influencing factor on predation,and the predatory capacity of adult was the highest at 35℃(24.7 aphids per 10 adults).The acquired rate of adult O.similis fed on the selected liquid artificial fodder ranged from 25%to 40%,but less fecundity than those of adults fed on aphids.The selected solid fodder,which provided enough nutrition for the development of O.similes, was rich in fat,protein,mineral material and amino acid,eight essential amino acids and several microelements.There were no significantly differences in the survival of each instar of the three generations of nymphs fed on Tyrophagus 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.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.Besides,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.2.The ecological basement of field releasing O.similisThe extraction and analysis of the information materials in the processes of food searching,the effect of these information materials on predation,the functional responses of O.similis on A.gossypii,Myzus persicae,Bemisia tabaci,Tetranychus cinnabarinus and Frankliniella occidentalis were studied in this section.Moreover,the evaluation of the controlling effect of O.similis on F.occidentalis was also made under the controlled field conditions.The prey searching behaviors were significantly affected among the materials rinsed from the body of A.gossypii by different organic solvents.Among the rinsed materials, those rinsed by the 95%ethanol could greatly affect the predatory behaviors of O.similis. The behavioral effects of O.similis to the materials extracted from the body of A.gossypii indicated that the activation was highest when the ethanol was used.With behavioral bioassay on n-hexane rinses from cotton aphid body surface,it was found that there had obviously attractive activity to O.similis.GC-MS analyses showed that the main components in the n-hexane rinses were methyl acrylate,Hexanoic acid,methyl ester, 2-methyl-pentane,undecane,n-Hexane-1,1-dioldiacetate,Dimethyl phthalate,Hexanoic acid,2-propenyl ester and eicosane.The results of predatory functional response of O.similis against several preys under different constant temperatures(25,28 and 31℃),indicated that O.similis had the highest predatory capacity under 28-31℃,and the greatest single theoretically predatory capacities of nymph and adult were 67.2 and 116.6 aphids and each nymph could prey 87 spider mites at most per day theoretically.Under 28℃,each adult and high instar nymph could prey 68.7 and 57.8 M.persicae per day,and 102.0 and 85.5 B-type B.tabaci per day,respectively.The searching effects of O.similis to A.gossypii,T.cinnabarinus,M. persicae and B-type B tabaci declined with the prey densities increasing,and the searching effects of adults were higher than those of nymphs.All the third,fourth and fifth instar of O.similis had strong predatory abilities against F.occidentalis under laboratory conditions,and could prey 68.4,72.9,86.2 and 130.6 nymphal thrips and 16.7, 39.3,51.2 and 49.3 adult thrips per day per individual,respectively.The researching effects of nymphs of O.similis against nymphal and adult thrips increased as its instar stage increased.The results of O.similis against F.occidentalis under the condition which covered the twig and individual plant showed that the predatory capacity was higher when the twig was covered than the individual plant was covered,and the predatory capacity of adult was higher than that of nymph,which showed that it is more effective to release adult than to release nymph in the field for controlling the F.occidentalis.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.