Survey Of Main Corn Pest Species And Their Control In Anhui Province

Maize is a major food crop in China.Anhui Province is one of the major maize production areas in China,and maize pests continue to damage the quality of maize,so it is urgent to develop new pesticide compound formulations and formulate new integrated management strategies for maize pests.In this study,we conducted a regional survey and analysis of the major maize pests in Anhui Province,and initially identified the species and occurrence patterns of the major maize pests in various regions of Anhui Province.The new pesticides tetrazolomide,chlorfenvinphos-methyl and abamectin were used as the targets of the study.Indoor toxicity measurements and field control tests were conducted to investigate the synergistic effects of the new pesticides and to provide a theoretical basis for the rational use of chemical pesticides for the scientific control of the grass moth.We also studied the predation function and pest control ability of natural enemies on major maize pests under field and indoor conditions,explored biological control techniques to slow down the development of resistance of maize pests,and developed integrated control strategies for maize pests according to local conditions.1.Survey of maize pest species and damage in Anhui ProvinceIn Anhui Province,three regions were selected,namely,South,Central and North Anhui,and several plots were set up in each region to investigate the data by random census.The preliminary survey data of maize pests in Anhui Province showed that there were 32 species of maize pests belonging to 3 orders,6 families and 16 families.Among them,the meadow borer,Asian corn borer,stick insect,small ground tiger,single-spined mayfly,oriental mayfly,corn aphid,cereal overflow aphid,dark gill golden turtle,ditch golden needle,and homozygous bar snail are frequent pests.Most of the pests occurred in a wide area and were distributed throughout the province.The number of pest species between regions is Northern Anhui > Central Anhui > Southern Anhui.From the viewpoint of damage,the number of Lepidoptera pests is high and the damage is heavy.The most serious damage was caused by the grass moth,followed by the stick insect and Asian corn borer.Therefore,lepidopteran pests are the top priority for corn pest management in Anhui Province.2.Indoor virulence measurement of tetrazolomide and other chemicals against major lepidopteran maize pestsThe lethal effects of tetrazolamide,avermectin and chlorfenvinphos and their combinations on the second instar larvae of the meadow corm,stickleback and Asian corn borer were investigated,and the results showed that the LC50 of 18% tetrazolamide against the three major maize pests were 18.828 mg/L,18.200 mg/L and 17.515 mg/L,respectively,and the LC50 of 20% chlorfenvinphos against the three major maize pests were 18.828 mg/L,18.200 mg/L and 17.515 mg/L,respectively.The LC50 s for the three major corn pests were 22.526 mg/L,19.246 mg/L and 19.836 mg/L,respectively,and the LC50 s for the three major corn pests were 6.573 mg/L,5.834 mg/L and 5.369 mg/L for 18%tetrazoconazole combined with 20 mg/L abamectin,respectively,and 20% chlorothalonil combined with 20 mg/L abamectin,respectively.The LC50 of 20% chlorothalonil combined with 20 mg/L abamectin for the three major maize pests were 7.537 mg/L,5.254mg/L and 5.109 mg/L,respectively.The results showed that the three pesticides and their compound formulations met the control requirements of the three major maize pests,among which 18% tetrazolomide and 5% abamectin were the most effective.3.Field efficacy tests of the three chemicals and their combinations against the major lepidopteran maize pestsThe results showed that 18% tetrazolamide 15 mL/667m2+5% abamectin50 mL/667m2 had the best overall efficacy against the three major maize pests.18%tetrazolamide and 20% chlorfenvinphos-methyl alone could be used at reasonable recommended dosage use,both could achieve the basic standard of control of major maize pests with about 80% control rate.The combination of the two chemical insecticides and 5%abamectin for field control is more effective than their single agent control,with a control rate of about 90%.4.Study on the effect of natural enemies on the control of aphids and grassland mothsThe predation response,search effect and predation selectivity of adult and 4th instar larvae of ladybird beetle were tested under field and indoor conditions against 2nd instar larvae of meadow bug and 2nd instar worm of grain constrictor aphid,respectively.The results showed that the predation responses of adult and 4th instar larvae of the heterochromatic ladybird beetle were in accordance with the Hollingll-type model equation.The predation control efficiency of adult heterochromatic lady beetle on grain constrictor aphid and grassland codling moth was 343.01 and 221.88,respectively;and the predation control efficiency of adult heterochromatic lady beetle and 4th instar larvae on two prey species of grain constrictor aphid and grassland codling moth was 210.93 and 140.88,respectively,when the two prey species of grain constrictor aphid and grassland codling moth were present in the same test space in indoor and field environments.The predation efficiency was 210.93 and 140.88,respectively.The adult and 4th instar larvae of the heterochromatic ladybird beetle showed positive preference for the grain constrictor aphid,and the predation selectivity of the heterochromatic ladybug beetle on the grain constrictor aphid was stronger than that of the meadow bollworm,and the heterochromatic ladybug beetle continued to feed on the meadow bollworm even after the grain constrictor aphid had been consumed.The experimental results showed that the adult and 4th instar larvae of the lady beetle were good at preventing and controlling both the grassland moth and the cereal constrictor aphid,but in the field environment,they would preferentially feed on the cereal constrictor aphid.