Effects Of Nitrogen Level On Feeding Damage And Population Proliferation Of Ostrinia Furnacalis(Guenée)

Ostrinia furnacalis(Guenée)is one of the most important pests affecting maize production in China.In recent years,it has successively erupted in major maize producing areas in Xinjiang.At present,ostrinia furnacalis has become one of the most serious pests restricting maize production in Xinjiang.However,it is not clear whether its feeding selection,field damage and population proliferation and expansion are related to the increase of food nitrogen level,especially the driving force of nitrogen nutrition.Therefore,by clarifying the impact of nitrogen level on the feeding selection and field damage of O.furnacalis(Guenée),this paper explores the impact of food nitrogen level on the individual development and population proliferation of O.furnacalis(Guenée),studies the impact of nitrogen content on the material nutrition and metabolism of O.furnacalis(Guenée),and finally reveals the impact of host nutrition of nitrogen growth on the population surge and field damage of O.furnacalis(Guenée)in Xinjiang,It provides a scientific basis for formulating accurate and efficient prevention and control strategies and comprehensive supporting measures for the key factors affecting the field feeding damage and population proliferation of corn borer in the future.(1)The effects of nitrogen level on the feeding preference and field harm of O.furnacalis(Guenée)showed that in the 48 h non selective experiment,the feeding rate of the newly hatched larvae of O.furnacalis(Guenée)at the medium nitrogen level(N3: 10.69%)was the highest,more than 60%,and the feeding rate of high nitrogen level(N4: 18.84%)was the highest at 8h,12 h,36h and 48 h,70.5%,67%,61.5% and 63.5%.In the selective experiment,the feeding rate of O.furnacalis(Guenée)larvae was higher in the treatment of medium nitrogen(N3:10.69%)and high nitrogen(N5:30.31%).The feeding rate showed an upward trend from 1h and reached the maximum at 8h.The medium nitrogen level(N3:10.69%)was76.67%,and the high nitrogen level(N5:30.31%)was 46.7%,73.37% and 43.37% higher than the low nitrogen level(N1:3.94%),The investigation on the harm of O.furnacalis(Guenée)under different nitrogen fertilization in the field also showed that the feeding and harm were more serious under high nitrogen treatment.(2)The study on the effects of nitrogen level on the individual development and population proliferation of O.furnacalis(Guenée)showed that the development duration and population proliferation parameters of O.furnacalis(Guenée)raised at high nitrogen level(N4:18.84%)were significantly higher than those of other treatments.At 25 ℃,the larval duration of O.furnacalis(Guenée)at high nitrogen level(N4:18.84%)was significantly shortened,and the intrinsic growth rate(0.13),net growth rate(66.14),weekly growth rate(1.14)and hatching rate(90.06%)were the highest,The average generation duration(30.79)and population doubling time(5.17)were the shortest,and there were significant differences with the other four nitrogen levels(P < 0.05).When the nitrogen was lower than 3.94% or higher than 30.31%,the larval growth was inhibited,and there was no significant difference between different nitrogen contents on pupal stage,adult moth development duration,pre spawning stage and spawning stage.It was speculated that the larval stage of O.furnacalis(Guenée)was sensitive to the demand of nitrogen and other nutrients,and the adult stage had no significant effect;The N content of 18.84% significantly promoted the population proliferation of corn borer compared with the control.(3)The effects of nitrogen level on nutritional metabolism and utilization of O.furnacalis(Guenée)showed that the change trends of food utilization,food conversion and approximate digestibility of 3rd ～5th instar larvae of O.furnacalis(Guenée)were the same,which increased with the increase of nitrogen content in feed,and the same age larvae in high nitrogen treatment(N4: 18.84%,N5: 30.31%)were significantly higher than those in low nitrogen treatment(N1: 3.94%,N2: 7.33%).The fifth instar food utilization rate reached the highest under N5 treatment,which was 16.65%,23.64% and 31.30%.The N utilization rate Nur was the highest at high nitrogen level(N5: 30.31%),which was 72.33%,86.09% and90.91%.The nitrogen content had a significant effect on the content of nutrients,protective enzymes and metabolic enzyme activities in the third instar larvae of O.furnacalis(Guenée)(P < 0.05).The contents of amino acids,proteins and free fatty acids were the highest when the N content was 10.69%(N3),which was 6.09 μ mol/mg prot、3.68mg/ml、0.13 μ Mol / mg prot,lipase and β-Amylase activity was the highest when the N content was 10.69%(N3),β-Amylase activity decreased with the increase of nitrogen content,and the activities of SOD,glutathione S-transferase and catalase decreased with the increase of nitrogen content in feed.When the N content was 3.94%(N1),it was the highest,which was 3.34u/g,6.42u/mg prot and 101.59u/mg prot.