| Leptocybe invasa Fisher&La Sallethe most important pests of Eucalyptus,make much of Eucalyptus planting areas damaged in our country.In order to provide a scientific basis to the biological control work of L.invasa,the first time discovered an obligate parasitic natural enemy of L.invasa recently in China,which is Quadrastichus mendeli Kim&La Salle(Hymenoptera:Eulophidae),and now the bee biological characteristics,ecological characteristics and common pesticide safety evaluation to its content has carried on the thorough research.The main results were as follows:1.The morphological observation of Q.Mendeli:it's eggs is long elliptic,slender egg pedicle,and the egg body enlargement;the larvae in spindle,and its intestine obviously shows bright yellow,there are 13 section metamere;the pupa is exarate,parts of thepronotum close to the head each has a black spot.The female adult body color is yellow,dorsal of ventral with three to four transverse dark brown stripes.2.Q.mendeli lays eggs in L.invasa surface,and this phenomenon belongs ectoparasites,the bee feathering time to focus on 10:00—12:00,the adult female parthenogenesis,and phototaxis strong,more active.In the natural environment,the ratio of female to male strobile of the Q.mendeli is 1-0,not collected the male bees.3.The parasitism efficiency of early instar larvae of the Q.mendeli for the L.invasa was significantly higher than mature larvae and pupae,their parasitism rate was 86.33%,58.72%and 6.58%respectively.One of the Q.Mendeli female once produced an egg,and a single gall;can be produced eggs for many times(because there is a lot of L.invasa infestation in one gall),while found no repeat hyperparasitism.Single-head mature of Q.Mendeli female medium fecundity was 63.68.4.The adult longevity of Q.mendeli is significantly affected by temperature and nutrient conditions.Maintained at a temperature between 18-33 ? as the temperature rises,the bee's life of Q.Mendeli gradually shortened.At the same temperature conditions,respectively,a:honey solution(1:5 solution in distilled water);b:young healthy foliage of E.exserta;c:combination of treatements a and b;d:galled foliage and twigs of E.expertise;combination of treatments d and a.e:water;f:no food for the control group.Honey solution feeding group of the Q.mendeli longest life expectancy with an average life of 14.8 d,no food supplement group of the bees shortest life expectancy of about 3.8 d.5.The experiment showed that:the development and reproduction of Q.mendeli significantly affected by temperature.The Q.mendeli eggs,larvae and pupae developmental threshold temperature is 11.99 ?,12.11 ? and 13.19 ?,their effective cumulative temperature are 53.60,199.32 and 135.91 degree days;its development from egg to the early stage of the feather needs temperature are 13.19 ? and the need for the effective accumulated temperature at least 353.11 d ?,each state insect developmental duration prediction formula:Eggs N = 53.60 ± 0.20/[T-(11.99 ± 1.12)]d;larvae N= 199.32 ± 0.58/[T-(12.11 ± 1.10)]d;pupa N= 135.91 ± 0.25/[T-(13.91±1.01)]d;egg-pupal N=353.11±0.21/[T-(13.17±1.01)]d.6.In the test of bioassay in lab of eight kinds of pesticide to the L.Invasa and the Q.mendeli,the experimental results showed that the priesthoods pesticide had the characteristics of the risk-benefit ratio,particularly,the pesticide of beta-thermometric and beta-cyfluthrin to safety coefficient is significantly higher than other pesticides,they recommend concentration was far less than the bee in the field of the semi-lethal concentration. |
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