| Nicotiana tabacum is one of the most important cash crops in China.It is an important part of agricultural production in China.Myzus persicae is one of the main pests damaging tobacco.It occurs to varying degrees in all tobacco-growing areas of China,which seriously reduced the quality of tobacco leaf production.At present,chemical control is still the main way to control Myzus persicae.With the long-term use of chemical pesticides,the ecosystem of tobacco fields has been seriously damaged.The problem of 3R(Residue,Resistance,Resurgence)in tobacco production is becoming more and more serious.Chemical control of Myzus persicae is becoming more and more difficult,which is not conducive to the safety of tobacco production and the sustainable development of tobacco ecosystem.In recent years,the method of ecological control through landscape layout design of flowering plants has been widely studied and applied.Its main purpose is to protect and utilize natural enemies and give full play to the natural control ability of farmland ecosystem by providing available food sources and shelters for natural enemies.In this research,landscape layout designed in Liangshan tobacco field,planted Helianthus annuus,Tagetes erecta,Ocimum basilicum,Lobularia maritima three-level buffer zones of flowering plants and placed natural enemies shelter islands to introduce food sources and shelters available to natural enemies;At the same time,further studied effects of different flowering plants on the ecological adaptability of Aphidius gifuensis indoors.The obtained results are as follows:(1)Made clear the species and quantity of pests and natural enemies in Liangshan tobacco fieldThe results of field investigation and identification showed that the Myzus persicae was the main pest in Liangshan tobacco field,with a relative abundance of 63.40%.Natural enemies were few in species and quantity of tobacco field with the long-term use of chemical pesticides,and only found two natural enemies,Aphidius gifuensis and Coccinella septempunctata,with relative abundance of 3.03% and 0.22%.(2)Made clear the influence of landscape layout of flowering plants on insect diversity in tobacco fieldThe results of field investigation and identification showed that the landscape layout design of flowering plants increased the species and quantity of natural enemies and neutral insects in tobacco field,and then significantly increased the diversity of insects in tobacco field.The relative abundance of natural enemies,neutral insects and pests in tobacco field demonstration of flowering plant landscape layout was 11.34%,6.58% and 82.08%,respectively.The relative abundance of pests in non-flowering control tobacco field reached 98.21%.The relative abundance of natural enemies was only 1.79%.The species richness,diversity index and evenness index of the tobacco field in the demonstration of flowering plantlandscape layout were significantly higher than those in the non-flowering control tobacco field(22.00>15.30,2.174>1.7786,0.7065>0.6545),and the dominance concentration index was significantly lower than those in the non-flowering control tobacco field(0.2060<0.2850).(3)Made clear the influence of landscape layout of flowering plants on the control effectiveness of Myzus persicaeThe results showed that the landscape layout of flowering plants could effectively control Myzus persicae,reduce percentage of aphid-infected plant,aphid situation index and per plant insect quantity,were better than chemical control in the persistence of control,and improves the field control effectiveness of Aphidius gifuensis.Aphidius gifuensis control effectiveness of the demonstration tobacco field as greater than non-flowering control tobacco field in statistical time,and the effectiveness was gradually obvious,reaching 45.86% in 35 days,17.22% in non-flowering control tobacco field,and the worst in chemical control tobacco field,which was only 6.23% in 35 days.Decreased rate of pest and corrected control effectiveness of the demonstration tobacco field were lower than chemical control tobacco field at early stage,but the number of aphids of chemical control tobacco field rebounded after 28 days,reaching 42.76% and 51.66% in 35 days;Decreased rate of pest and correcting control effectiveness of the demonstration tobacco field gradually increased with the change of time,reaching 40.54% and 49.79% in 35 days,which were closed to chemical control tobacco field.(4)Studied the effects of different flowering plants on parasitic rate,emergence rate,percentage of female and longevity of Aphidius gifuensisThe results showed that in the same statistical time,the parasitic rate of Aphidius gifuensis could be significantly increased by Helianthus annuus,Tagetes erecta,Ocimum basilicum,Lobularia maritima four kinds of flowering plants.The treatment of Tagetes erecta flowering plants was the most effective.After 15 days,the parasitic rate of Aphidius gifuensis by Tagetes erecta flowering plants treatment was 78.56%,followed by Helianthus annuus flowering plants treatment,which was 70.01%,Flowering plant treatments of Ocimum basilicum and Lobularia maritima were 63.68% and 57.07%,and the CK was 50.08%.The four kinds of flowering plant treatments could significantly increase the emergence rate of Aphidius gifuensis,the treatment of Ocimum basilicum flowering plants was the most effective,the emergence rate of Aphidius gifuensis was 75.62%,followed by Tagetes erecta,was 74.56%,and the CK was 67.42%.The four kinds of flowering plant treatments could significantly increase the percentage of female Aphidius gifuensis,The treatment of Tagetes erecta flowering plants was the most effective,the the percentage of female Aphidius gifuensis was 59.25%,followed by Lobularia maritima,was 58.60%,and the CK was 52.91%.The average longevity of male and female Aphidius gifuensis was prolonged by feeding on four kinds of flowering plants.The treatment of Tagetes erecta flowering plants was the most effective,the average longevity of male and female Aphidius gifuensis were significantly reached 184.53 hours and 184.73 hours,followed by feeding on Helianthus annuus flowering plants,were reached 182.27 hours and 171.60 hours.By feeding on water,the average longevity of male and female Aphidius gifuensis were reached 85.73 hours and 83.47 hours. |
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