| Corn is the largest grain and the highest yield grain crop in China,and it is also an important industrial raw material.There are numerous types of pests and diseases,which harm the growth process of corn,among which sucking pests such as planthoppers,thrips,and aphids are the most harmful to corn,and at the seedling stage and the middle and later stages,in addition,planthoppers can spread MRDV and cause serious impact on corn yield.Seed coating agents have a small amount of roxicity for treatment,a long effective period,and a strong target,and have become the main means for sucking mouthparts pests and diseases in agricultural production.The main neonicotinoid insecticide seed coating agents for controlling sucking mouthparts pests on corn are imidacloprid,thiamethoxam and clothianidin.However,studies have shown that imidacloprid,thiamethoxam and clothianidin are effective against natural enemies and other non-nemoline insecticides.Target organisms pose a serious threat,while thiacloprid is less toxic to bees and safe to environment.However,compared with other nicotine,thiacloprid has problems such as easy decomposition and short persistence period in soil.This experiment mainly studied the effect of seed dressing treatment with thiacloprid seed coating on the germination of corn seedlings in an incubator under indoor conditions;the effects of greenhouse potting on growth and growth of maize seedlings;different film forming agents thiacloprid under field conditions.Seed dressing is safe for corn growth and effective sucking pest control.The main experimental results are as follows:1.Culture with sand in incubator: Thiacloprid seed coating treatment with a dose of 400 g a.i./ 100 kg had no adverse effect on the germination potential and germination rate of the maize seed,increased the seed vigor of the corn seed,and improved the seed Alpha-amylase activity and reduced sugar content during germination peaked on the fifth day after seed sowing,while treatment with 800 g a.i./100 kg inhibited seed germination,reduced corn seed vigor and reduced seed Alpha-amylase activity and reduced sugar content during germination.2.Effects of seedlings treated with 400 g a.i./100 kg and 500 g a.i./100 kg of thiacloprid seed coating on growth,chlorophyll content,free proline content,antioxidant enzyme activity and root vigor of maize seedlings under greenhouse potting conditions.It is best to have stong seedings and promote seeding growth.The root length,thick stem,and fresh weight of maize seedlings reached the maximum at 500 g a.i./100 kg,which was 25.93%,15.87%,respectively,and 43.7% higher than that of the control,at 400 g a.i./100 kg reached the maximum plant height.Increase by 25% over control,chlorophyll content and free proline content reached a maximum at 400 g a.i./100 kg treatment,an increase of 22.17% and 42.24% compared to the control.SOD and POD had the highest activity after treatment with 500 g a.i./100 kg,and the activities were increased by 59.93% and 56.28%,respectively.The activities of CAT and root activity were the highest at 600 g a.i./100 kg,which increased by 18.45% and 17.7%.The value of each treatment was higher than that of imidacloprid treatment,and it showed the trend of increasing first and then decreasing with the increase of the active ingredients of thiacloprid treatment.3.Under field conditions,the growth safety of corn seedlings treated with 400 g a.i./100 kg seed dressings and the control effect of three different film-forming agent seed coats on sucking pests were verified.Our results showed that the treatment of the thiacloprid seed coating agent of the film former ZY904-1 had a certain delaying effect on the emergence of corn,and can reduce the emergence rate of the corn,and the treatment of the filming agent ZY904-3 and ZY904-5 on corn seedling did no effect.The treatment with three film formers and without film formers can increase the plant height,root length,thick stem,and fresh weight of maize seedlings in different degrees,increase the content of chlorophyll and free proline,and increase the activity of antioxidant enzymes,and promote the growth of corn seedlings.The number of sucking mouthparts pests in the control treatment reached the maximum 50 days after sowing,which was 3363/100 plants.The number of sucking pests of ZY904-1,ZY904-3,ZY904-5 and non-filming agents were 1239,1302,1526 and 1802/100 plants,much lower than the blank control.The three film-former dressings treated with thiacloprid in corn leaves and soil had a longer time than the control without film-forming agent,and the residual time of ZY904-1 and ZY904-3 thiacloprid in the leaves was prolonged.The remaining time in the leaves was extended by 30 days and the soil was extended for 50 days,the ZY904-5 thiacloprid extended 20 days both in leaves and soil. |
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