Investigation On The Damage And The Chemical Control Of Spodoptera Frugiperda (J.E.Smith) In Shenze County,Hebei Province

Spodoptera frugiperda(J.E.Smith),which invaded China in early 2019,at present mainly damages corn fields in our country.It has the characteristics of wide host range,strong reproductive ability,fast migration and spread,sudden damage and difficult to control.According to the previous field investigation and experiment on Spodoptera frugiperda(J.E.Smith)in our laboratory,the research contents of this paper are as follows:(1)From September 17,2020 to October 24,2020,the checkerboard five-point survey method was used to investigate the damage regularity of Spodoptera frugiperda(J.E.Smith)in corn fields at different growth periods in Qiaotou Township,Shenze County,Shijiazhuang City,Hebei Province.The results showed that,the young larvae of Spodoptera frugiperda(J.E.Smith)prefer to damage the three-leaf and one-hearted corn plants,and the 3～4 instar larvae prefer to damage the seven-leaf one-hearted corn plants.In the severely damaged plots,the population of 100 insects was 50 per 100 plants,and the damage rate of 100 plants reached 70%.(2)From May 29,2019 to June 1,2019,the effectiveness of 5 insecticides against Spodoptera frugiperda(J.E.Smith)was tested in Aqi Township,Liangshan Yi Autonomous Prefecture,Sichuan Province.The results showed that,72 hours after the treatment,the 20%chlorantraniliprole suspension 10 g/667m 2 and the 10%tetrachlorantraniliprole suspension 20 g/667 m2 have better control effects which were 93.2%and 94.2%,respectively.The insecticidal activity of 4 insecticidal active ingredients with different formulations against the 3rd instar larvae of Spodoptera frugiperda(J.E.Smith)was determined by indoor immersion method.The insecticidal activity of different formulations of chlorantraniliprole against the 3rd instar larvae of Spodoptera frugiperda(J.E.Smith)was ranked as follows:suspending agent>water dispersible granules;The insecticidal activity of amido abamectin benzoate against the 3rd instar larvae of Spodoptera frugiperda(J.E.Smith)ranked as follows:microemulsion>water emulsion>emulsifiable concentrate;The insecticidal activity of different formulations of formamidoavermectin benzoate·indoxacarb against the 3rd instar larvae of Spodoptera frugiperda(J.E.Smith)was racked as follows:Suspension agent>Water emulsion;the insecticidal activity of different formulations of formamidoabamectin benzoate·termanil against the 3rd instar larvae of Spodoptera frugiperda(J.E.Smith)was racked as follows:suspension agent>water dispersible granules.(3)The insecticidal activity of the seed coating of tetracloran and chlorantraniliprole against the first instar larvae of Spodoptera frugiperda(J.E.Smith)was tested by indoor feeding method and indoor pot inoculation method.15 days after sowing,the indoor feeding test showed that 4 g/kg and 2 g/kg of tetraclofenac coating had 100%and 98.8%control effects on the first instar larvae of Spodoptera frugiperda(J.E.Smith);15 days after sowing,the first instar larvae of Spodoptera frugiperda(J.E.Smith)were used to inoculate potted maize plants.The results showed that the control effect of the coating dose of 4 g/kg and 2 g/kg on the first instar larvae of Spodoptera frugiperda(J.E.Smith)was 96.6%and 79.3%,respectively.20 days after sowing,the control effect of corn plants coated with brassin lactone seeds with chlorantraniliprole increased by more than 20%,and the control effect of corn plants with chlorantraniliprole added with brassinolide seed coatings was increased by more than 10%.30 days after sowing,the control effect of corn plants coated with tetracloran,chlorantraniliprole,and bromoyl thiamethoxam with brassinolide was increased by about 10%.(4)The maize plant height,stem thickness,single leaf leaf area,and root dry weight were measured at the maize seedling stage,large bell mouth stage,and filling stage to evaluate the safety of seed coating on different growth periods of corn.The results showed that the seed coating of chlorantraniliprole,chlorantraniliprole,and 40%bromoyl·thiamethoxam seed treatment suspension agent could promote the growth and development of corn plants at the seedling stage and the bell mouth stage,and the addition of brassinolide further promotes the growth and development of corn plants.