Laboratory Toxicity And Field Efficacy Of Lecanicillium Psalliotae HFLP006 Oil Formulation Against Three Aphid Species

Aphids are important agricultural pests,including Rhopalosiphum padi,Myzus persicae and Rhopalosiphum maidis,which cause serious harm to the production of wheat,maize,tobacco,cabbage.In recent years,aphids have been resistant to various types of chemical pesticides,so biological control is paid more and more attention.Lecanicillium is an entomopathogenic fungus with high toxicity to aphids,and has great application potential in aphid control.The preparation of Lecanicillium psalliotae HFLP006 oil formulation was developed in our laboratory.In this study,we investigated the control effect of HFLP006 oil formulation on Rhopalosiphum padi,Myzus persicae and Rhopalosiphum maidis under laboratory conditions,observed the symptom changes of the three aphids infected by HFLP006 oil formulation under stereoscopic microscope,and evaluated the field efficacy of HFLP006 oil formulation against three aphids.The results provide a scientific basis for further large-scale application of this formulation.The main results of this study are as follows:1.The laboratory toxicity and field efficacy of HFLP006 oil formulation on R.padiThe toxicity of HFLP006 oil formulation on R padi at different instars increased with the increase of HFLP006 oil formulation concentration,and the cumulative mortality increased gradually under laboratory conditions,among which wingless adults>nymphs of4^thinstar>nymphs of 3^rdinstar>nymphs of 2^ndinstar>nymphs of 1^stinstar.At the concentration of 100×,the corrected mortality rate of wingless adults treated with HFLP006 oil formulation for 6d was 100.00%,and LT₅₀was 2.74d.After inoculation with300×and 500×HFLP006 oil formulation,there was no significant difference in mortality rate and LT₅₀of R.padi.Among all of them,the toxicity to wingless adults was the highest,and the cumulative corrected mortality was 95.00%and 91.67%on 6th days while LT₅₀was 2.84d and 2.97d respectively.However,the cumulative corrected mortality of wingless adults treated with HFLP006 oil formulation reached 81.67%after 6 days treatment while LT₅₀was 3.16d at the concentration of 800×.The field experiments showed that the control effect of HFLP006 oil formulation one day after application on R.padi was 22.83%,which was significantly lower than that on the other three target crops while the corrected control effect was above 30.00%.After 3 days,the control effect increased rapidly to 51.35%and reached 88.33%after 7 days.HFLP006 oil formulation has high toxicity and control effect on R.padi both in laboratory and field which is worthy of popularization and application.2.The laboratory toxicity and field efficacy of HFLP006 oil formulation on M.persicaeThe toxicity of HFLP006 oil formulation on M.persicae at all stages increased with the increase of HFLP006 oil formulation concentration,and the cumulative mortality increased gradually under laboratory conditions,among which wingless adults>nymphs of 4^thinstar>nymphs of 3^rdinstar>nymphs of 1^stinstar>nymphs of 2^ndinstar.On cabbage plants,the cumulative mortality of wingless adults treated with HFLP006 oil formulation dilution of 100×for 6 days was 98.33%while LT₅₀was 2.68d.The cumulative corrected mortality of 300×and 500×HFLP006 oil formulation formulation were 93.33%and 86.67%,LT₅₀were 2.73d and 3.02d respectively.However,the cumulative corrected mortality of wingless adults treated with HFLP006 oil formulation reached 78.67%after 6days treatment while LT₅₀was 3.36d at the concentration of 800×.In tobacco crops,the cumulative mortality of wingless adults treated with HFLP006 oil formulation dilution of100×for 6 days was 100.00%,LT₅₀was 2.36d,and the cumulative mortality was 96.67%,93.37%,80.00%higher than 300×,500×,800×.Field experiments showed the corrected control effect of M.persicae on tobacco was 41.56%on the 1st day after application,and rapidly increased to 83.27%on the 5th day.The corrected control effect of M.persicae on tobacco was 90.32%on the 7th day,which was 5.58%lower than that on cabbage.HFLP006 oil formulation has good control effect on M.persicae both indoor and field.3.The laboratory toxicity and field of HFLP006 oil formulation on R.maidisThe order of virulence of HFLP006 oil formulation to R.maidis was the same as that of R.padi.At the concentration of 100×,the cumulative mortality of wingless adults treated with HFLP006 oil formulation for 6 days was 98.33%while LT₅₀was 2.47d.After inoculation of 300×,500×HFLP006 oil formulation,there was no significant difference in mortality and LT₅₀of R.maidis.Among them,the toxicity to wingless adults was the highest with cumulative mortality of 93.33%and 93.17%on the 6th day,and LT₅₀of 2.56d and 2.68d respectively.At the concentration of 800×,the cumulative mortality of HFLP006oil formulation on wingless adults reached 80.00%and LT₅₀was 3.03d.Field experiments showed that HFLP006 oil had the highest corrected control effect on R.maidis,and the control effect reached 90.08%on the 7 th day.HFLP006 oil formulation had high toxicity and control effect,which is a green and effective control method for R.maidis.In conclusion,the results of laboratory and field experiments showed that the toxicity of HFLP006 oil formulation to three aphids was more than 80%,and the control effect was good.This study provides a new idea for the biological control of three aphids,and also provides a theoretical basis for promoting the application value of HFLP006 oil formulation.