Screening And Safety Evaluation Of Insecticides Against Scale Insects In Jujube Orchard

Jujube is the main economic forest fruit in Xinjiang.The planting area accounts for about 30 % of the total area of the country,and the yield accounts for more than 50 %.Scale insect is one of the main pests on jujube.In recent years,the scale shell insects in southern Xinjiang showed an increasing trend year by year,especially wax scale and pear scale.In the prevention and control of scale shell insects,pesticides are mainly used,and screening efficient pesticides has become an urgent need for production.In this study,we investigated the occurrence of two major scale insects,carried out the field pesticide screening test,and carried out the residue detection and environmental safety evaluation of the screened pesticides,which provided the basis for the prevention and control of scale insects.The main results are as follows :(1)C.jujuba had one generation a year in Alar reclamation area,and the 2nd instar nymphs entered the overwintering dormancy period from mid-late October to late March of the next year.The damage began in early April of the next year,and the 1st instar nymphs appeared in mid-May.P.pyritica occurred for two generations a year in Alal,and the period of emergence was basically consistent with the germination period of jujube.The first generation nymph began to appear in early June,and the second generation nymph appeared in late July.(2)Six different types of insecticides,i.e.,thiamethoxam,spirotetramat,thiamethoxam,abamectin,lambda-cyhalothrin,mineral oil and matrine,were selected to be used in the bloom stage of C.jujuba.The results showed that the three insecticides were not very effective in the control of C.jujuba,but the control effects were more than 80 % after 15 days of spraying,showing good persistence.Among them,the control effect of 25 % thiamethoxam water dispersible granules at 1250 times on the adult stage of C.jujuba reached91.71 %.Thiamethoxam,spirotetramat and mineral oil were mixed in pairs to control C.jujuba,and the control effect reached more than 80 %.Abamectin,lambda-cyhalothrin and matrine were used to control nymphs of C.jujuba.The control effects were all over 90 % 15 days after spraying,and the control effects of matrine at various concentrations reached 100 %.(3)Four insecticides,thiamethoxam,spirodiclofen,thiamethoxam and matrine,were used to control the first generation nymphs of pear scale,and the quick effect and persistence were not ideal.The best control was 1250 times liquid of thiamethoxam,reaching 73.24 %.(4)The residues of several pesticides in jujube fruit were detected two months after application.The results showed that matrine residue was much higher than 0.55 mg / kg,and no pesticide residue was detected in jujube fruit.(5)Final detection of pesticide safety to tree environment.The investigation showed that the growth of jujube leaves in each treatment area was normal,and several test agents sprayed were safe and harmless to jujube trees under the set test concentration.The toxicity of three pesticides to Apis mellifera ligustica was determined by spray tower spraying.The results showed that thiamethoxam had the highest toxicity,followed by spirodiclofen and thiamethoxam.