Research On The Occurrence And Green Control Of The Asian Corn Borer In The Semi-arid Area Of ??western Heilongjiang Province

Asian corn borer is one of the most harmful and serious pests in maize crop planting regions.Which will result in reducing crop yield about 10% in common years,more than 30% production reduction in serious happening years.Due to the change of global climate and local environmental conditions,the occurrence and damage law of Asian corn borer has also changed in varying degrees,which brings new challenges to the biological control of this kind of pests.Therefore,in this study,on the one hand,the rules of occurrence and damage of Asian corn borer in the semi-arid area locating the western of Heilongjiang Province were investigated,and the representative experimental plots were selected from Daqing city.The growth and decline dynamics of the pests living in maize plants in different conditions,including the cultivation methods,corn varieties,different fertilizer rates and fertilizer depth,were analyzed by using the method both sex trapping and trapping lamp in the field.On the other hand,combined with the occurrence law of corn borer in the field,the combined biocontrol system was established,which involved in the application Trichogramma thuringiensis controlling the pest eggs and Bacillus thuringiensis controlling the pest larvae based on UAV method.It provides theoretical guidance and technical support for the construction of green insect control system of corn.Based on the investigation of corn leaf damage rate,drilling rate,stem folding rate,female panicle damage rate and male folding rate in Daqing Gaoxin region and Zhaozhou County in 2017 and 2018,the occurrence and damage of corn borer in different cultivation methods were revealed.In 2017,the average damage rate of corn was the highest in Gaoxin region,and the lowest was ridge culture(dense sparse and dense).There were significant differences in the female panicle damage among the tested cultivation methods.More than 30%,including flat cropping(dense sparse and dense)and double row,and there was no significant difference among the eight different cultivation models.Among the five farming methods tested,the damage of corn borer was generally serious,and the leaf damage rate,the stem folding rate and the female panicle damage rate were higher.In the region of Zhaozhou experimental area in 2018,the highest average damage rate of the corn is the ridge cultivation,the lowest is the no-tillage with the narrow and narrow straw,and the difference of the female ear is not significant in the four tillage methods,and the yield of the no-tillage method are almost all lower than that of the ridge.The above results showed that compared with ridge cultivation,the damage of corn borer in plain cultivation and no-tillage cultivation in Gaoxin region was more serious,while no-tillage cultivation in Zhaozhou County was lighter.At the same time,the occurrence and damage of Asian corn borer under different fertilizer methods in corn field were investigated.Among the four fertilizer treatments tested in Zhaozhou experimental area,the occurrence of corn borer in high fertilizer and organic fertilizer field was lighter,and the damage caused by low fertilizer application of corn borer was generally more serious.The five killing indexes were significantly higher than those in the high fertilizer area,and the leaf damage rate(16%)and drill string rate(4.89%)were significantly higher than those in the control.The effect of fertilizer and top dressing on the corn field in Daqing urban area is not obvious,but the damage rate of the leaves is significantly lower than that of the non-fertilization control,Folding male is significant difference between PU2 and PU3.The application of nitrogen fertilizer in different depths can reduce the male folding and stem folding of corn.The results showed that the cdamage of the corn borer were obviously affected by no fertilizer and low fertilizer area based on the both Experimental areas.On the other hand,the pupation and emergence of overwintering Asian corn borer and the laying of eggs in the field showed that the Asian corn borer in Gaoxin region(the second accumulation temperate zone)and Zhaozhou County(the first accumulation temperate zone)were both complete second generation areas.However,the amount base of overwintering corn borer in Zhaozhou was large,the number of 100-worm was 50,and the number of 100-rod live worm was 40.Among them,the peak period of pupation of corn borer in Gaoxin was June 2,and the peak period of emergence was from June 6 to June 14.The peak period of pupation in Zhaozhou was from June 1 to June 5,and the peak of emergence was from June 8 to June 19.The peak period of laying eggs of the first generation corn borer in Gaoxin was June 10,and the peak period of the second generation of corn borer was August 11.The first generation of eggs in Zhaozhou was on June 13,and the second generation of the second generation was on August 14.In 2018,releasing Trichogramma and spraying Bt were used to control Asian corn borer in Zhaozhou County Experimental area.The parasitic rate of pests eggs was more than 80%,and the comprehensive control effect was more than 70%.The combined biocontrol of insect and bacteria can reduce the loss of corn yield by 50 kg per mu.Based on the above research results,it is helpful to construct a green control system of Asian corn borer,which is dominated by biological control of eggs and larvae(UAV release bacteria and insects)and Monitoring the physical control of adults(light and sex inducer trapping),supplemented by agricultural measures and chemical control.