| Sphaerolecanium prunastri(Boyer de Fonscolomber)is a invasive new pest found on the wild apricot Armeniaca vulgaris Lamarck in the wild fruit forest of Tianshan Mountains in Xinjiang in recent years.It causes serious damage to wild apricot forest,which leads to the stress on the ornamental value,economic value,ecological value of wild apricot forest and the genetic resources of wild apricot.In this paper,the species of the parasitoid wasp was collected and identified.To investigate the effects on the control of ants against the natural predator Heteroptera axyridis.The toxicity of six chemicals to S.prunastri was determined indoors and the effect of adding different adjuvants on the physico-chemical properties of the insecticides.At the same time,artificial ground spraying and unmanned air vehicle(UVA)flight control tests were carried out in the field to provide scientific basis and technical support for the rational development of biological control and chemical control measures of S.prunastri.The main findings are as follows:(1)Between 2020 and 2021,a total of 5 species of parasitoids were found,namely Coccophagus sp.,Microterys breviventris Xu,Blastothrix longipennis Howard,Blastothrix sp.and Coccophagus yoshidae Nakayama.Among them,the dominant species were Coccophagus sp.,Microterys breviventris Xu,Blastothrix longipennis Howard.The peak emergence period of the parasitoid wasp was in late May and early June.In 2020,the parasitic wasp rates of S.prunastri in Jiaotuohai and Baiyinggou were relatively high,57.95% and 57.08%,respectively.In 2021,the parasitism rates of the parasitoid wasps in all plots were less than 15 %.(2)In order to explore the interaction between predators H.axyridis,ants and S.prunastri,the effects of ants on H.axyridis’ s control of S.prunastri were studied by field bagging.Under the influence of ants,the survival rate of overwintering 2nd instar and 1st instar nymphs of S.prunastri was higher than that under the influence of no ants.That is,ants have significant effects on control of H.axyridis to S.prunastri.Under field conditions,the control effect of releasing H.axyridis adults + egg cards on the overwintering 2nd instar nymphs and 1st nymphs of S.prunastri was higher than that of releasing adults and hanging egg cards,but the control effect was lower than 40 %.(3)The toxicity of 6 kinds of medicaments to S.prunastri at different ages was determined indoors,and several insecticides with higher toxicity were selected for field test.Matrine 1.3% AS had the highest toxicity to the overwintering 2nd instar of nymphs of S.prunastri,and azadirachtin 0.3% EC had the highest toxicity to the 1st instar of nymphs.Field experiments showed that matrine 1.3% AS(500×)had the best control effect on the overwintering 2nd instar nymphs of S.prunastri at 14 days after spraying,which was 95.4%.The control effect of azadirachtin 0.3% EC(500×)on the 1st instar nymphs of S.prunastri was the best,80.9% at 14 d after spraying.matrine 1.3% AS and azadirachtin 0.3% EC could be used as the green and efficient insecticides for the control of S.prunastri.(4)The effects of 6 kinds of adjuvants on the surface tension,spreading area and maximum retention of different pesticides were determined under indoor conditions,and the UVA flight control tests on S.prunastri after adding self-formulated adjuvants was carried out.d-limonene had the greatest effect on the surface tension,spread area and maximum retention of the six agents.The field experiments showed that matrine 1.3% AS had the best control effect on the overwintering 2nd instar nymphs of S.prunastri after 14 days,and the synergistic ratio was 21.33% ~ 28.97%.azadirachtin 0.3% EC had the best control effect on the 1st nymphs of S.prunastri,and the synergism ratio ranged from 18.12% to 23.69% after adding 2000mg·L-1 self-made adjuvant*.To sum up,the addition of adjuvants has obvious synergistic effect on the control of S.prunastri,and it should be popularized and applied in production practice. |
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