Application Of Insect-proof Net Shed In Vegetable Planting

As the second largest agricultural industry in Hainan Province,vegetables have broad prospects for development and opportunities.However,the suitable climate in Hainan also provides favorable conditions for the high incidence of pests and diseases.As a newly promoted plant protection technology,insect-proof net coverage can bring great economic,social and ecological benefits.However,most vegetable farmers in Hainan Province still use plastic sheds or other facilities to grow vegetables,insect-proof mesh sheds are not well promoted.The first topic is to select suitable pest control net according to pest species;Two is to study the ability of three important vegetable pests to resist hunger,in order to provide a theoretical basis for hunger;Three is to study the effect of temperature on the survival of thrips,on this basis,to study the effect of different time on field pests and yield,lay the foundation for the popularization and application of insect-proof net shed.The main results of this study are as follows:(1)Under starvation conditions,Megalurothrips usitatus(Bagnall),Aphis craccivora Koch and Phyllotreta striolata(Fabricius)were placed in artificial climate boxes under their optimum conditions,respectively.The longest starvation tolerance time of yellow striped beetles was 168 h,soybean aphids 72 h and thrips 24 h.(2)Field pest investigation and yield comparisonDifferent varieties and treatments were as follows: Cowpea and fruit cucumber were planted in summer,and the air-drying time after plowing was 10 d,5 d,1 d and 10 d(partial early sowing),respectively.In autumn,the air-drying time after plowing was 11 d,11 d(partial early sowing),2 d and 11 d(open perimeter),respectively.When cabbage and cabbage were planted in summer,the air-drying time after ploughing in summer was 7d,5 d,1 d and 7 d(partial sowing in advance),respectively.When planting in autumn,the air-drying time after ploughing was 9 d,9 d(sowing in advance),2 d and 9 d(open surrounding network),respectively.In summer,the pests of cowpea were mainly Bemisia tabaci(Gennadius)and Megalurothrips usitatus(Bagnall),Spodoptera litura(Fabricius)and L.sativae Blanchard in a small amount,and there was no Aphis craccivora Koch damage.The damage degree of pests on 10 days and 5 days of air-drying was lighter than that on 1 day and 10 days of air-drying(sowing in advance).Cercospora vignicola(Kaw.)Goto,Sphacerotheca fuliginea and Uromyces vignae Barclay、mainly occurred in the harvest period.Cowpea moasic virus continued to occur from adult stage to harvest period,and the disease index was higher and higher.There was no significant difference between different treatments.There was no significant difference in the average yield per mu among different treatments,but the average yield per mu was: dry land 5 d(772.99 kg)> dry land 10 d(639.32 kg)>dry land 1 d(594.62 kg)> dry land 10 d(early sowing)(448.70 kg).In autumn,the number of insects in the whole growth and development period of cowpea is relatively small,and the insects include Bemisia tabaci(Gennadius),Aphis craccivora Koch,Spodoptera litura(Fabricius),Aulacophora femoralis(Montschulsky),Lamprosema indicata Fabricius,Megalurothrips usitatus(Bagnall),Antoculeora ornatissima and L.sativae Blanchard.The weather becomes cold with time,and there is basically no insect in the late growth period.The occurrence degree of pests on 11 days and 2 days of air-drying was lighter than that on 11 days of air-drying(early sowing)and 11 days of air-drying(open around),but the occurrence degree of pests on 11 days of air-drying,2 days of air-drying and 11 days of air-drying(early sowing)was more serious than that on 11 days of air-drying(open around).Average yield per mu: 2 days(566.31 kg)> 9 days(424.86kg)> 9 days(392.72 kg)> 9 days(297.15 kg).After planting fruit cucumbers in insect-proof net shed,the pests on fruit cucumbers in summer were mainly Bemisia tabaci(Gennadius),with few occurrences of Diaphania indica(Saunders)and L.sativae Blanchard,and no damage of Aulacophora femoralis(Montschulsky).Sudden fall of Pythium deliense Meurs in the seedling stage,mainly in the late growth of Cucumber virus disease,c Pseudomonas syringae pv.Lachrymans angular leaf spot.The severity of pests and diseases was basically as follows: 10 d(early sowing)>1 d > 5 d > 10 d;On the average yield per mu,air-dried 10 d,air-dried 5 d,air-dried 10 d(early sowing)than air-dried 1 d increased 41 %,59.6 %,10.32 %,air-dried 5 d treatment increased the most.In autumn,the main pests of fruit cucumber in the net sheds of 11 d,11 d and 2 d were Bemisia tabaci,and the main pests of semi-open net sheds of 11 d were Bemisia tabaci(Gennadius),Aulacophora femoralis(Montschulsky)and L.sativae Blanchard.Pseudoperonospera cubensis,Sphaerotheca curbitae and Colletotruchum lagenarium did not occur at the early growth stage of fruit cucumber,and due to the cold and humid weather in the middle and late stages,the disease was serious without pesticide control.The yields of the three treatments for 11 d,11 d mixed planting and 11 d semi-open planting were significantly lower than those for 2 d,and the yields were24.98 %,30.65 % and 47.53 % lower than those for 2 d,respectively.Insect control net shed was used to continuously plant two cabbages in summer.The results of field pests and diseases showed that the main pests of the first cabbage and cabbage were Bemisia tabaci(Gennadius),Phyllotreta striolata(Fabricius),Cicadellidae,Phaedon brassicae Baly and Hellula undalis Fabricius.No disease occurred.The main pests of the second cabbage were Phyllotreta striolata(Fabricius),Phaedon brassicae Baly and Bemisia tabaci(Gennadius).Compared with the first crop,the species of pests decreased,the population base decreased and the yield increased.The diseases were mainly Alternaria brassicae(Berk.Sacc.)and Erwinia aroideae,with low disease index.Compared with the first crop,the yields of the second crop with different treatments for 7days,5 days,1 day and 7 days were increased by 55 %,127 %,88 % and 89 %,respectively.Compared with the first crop,the yield of the second crop of Chinese cabbage mixed with different treatments for one day and seven days increased by 74 % and 7 %,respectively.Compared with the first crop,the yields of 7 days and 5 days were reduced by10 % and 10 % respectively.Using insect-proof net shed planting,the field pests of cabbage and Chinese cabbage in autumn were mainly Phaedon brassicae Baly,Phyllotreta striolata(Fabricius),Pieris rapae(Linnaeus)and Spodoptera litura(Fabricius),and the population base was less,and there was no significant difference between the treatments.The main disease of cabbage was Alternaria brassicae(Berk.Sacc.)in the late stage,and Chinese cabbage was Alternaria brassicae(Berk.Sacc.)and Erwinia aroideae.There was no significant difference between different treatments.The average yield per mu of cabbage from large to small was 2 days(333.55 kg),9 days(327.64 kg),9 days(310.54 kg),and 9 days(249.98kg).The average yield per mu of Chinese cabbage from high to low was air-dried for 9days(339.69 kg),air-dried for 2 days(337.94 kg),air-dried for 9 days(297.39 kg)and air-dried for 9 days(254.66 kg).(3)Three vegetable pests of Megalurothrips usitatus(Bagnall),Aphis craccivora Koch and Phyllotreta striolata(Fabricius)were packed in different sizes of insect-proof net bags.The results showed that the smaller the number of insect-proof net meshes,the higher the penetration rate of pests.The minimum number of longitude and latitude line roots of the pest control net that the yellow strip beetle can not pass through is 29 * 29.After one-way analysis of variance on the penetration rate of F.sojae,P = 0 < 0.05,the difference between treatments was significant.The average penetration rates in different sizes of insect-proof net bags were 29 * 29(100 %),35 * 32(88.89 %)and 35 * 35(63.33 %).(4)The survival rate of different state of Megalurothrips usitatus(Bagnall)under different high temperature(26 °C,35 °C,37 °C,39 °C,41 °C,43 °C,45)decreased gradually with the extension of starvation time.When the temperature was higher than40 °C,the mortality rate could reach 100 % within 3 hours of starvation,and the starvation tolerance time of young larvae was less than that of 3rd and 4th instar larvae.At low temperature(1°C,4°C,7°C,10°C),the survival time of each insect state was prolonged.When the temperature was lower than 1 °C,the mortality rate of each insect state reached100 % within 12-24 h of starvation,and the longest starvation tolerance was at 4 °C.In conclusion,whether in summer or autumn using insect-proof net greenhouse planting,for cowpea,fruit cucumber,vegetable,Chinese cabbage crops,airing 5-7 days before sowing is more appropriate.