Toxicity Determination Of 19 Kinds Of Insecticides To Triplax Ainonia (Coleoptera: Erotylidae), And Effects On Mycelial Growth Of Edible Fungi

The edible fungus industry has developed rapidly and its scale has been expanding in China.There are many kinds of edible fungi pests,and they are easy to burst,which is difficult to control.At present,the prevention and control measures for edible fungi pests are mainly chemical control,but the chemical control of edible fungi pests mainly has the following problems:（1）The pesticides allowed to be used on edible fungi are very limited,and there is only one pesticide,chlorofluoromethyl·emamectin benzoate.Long-term use of a single agent is easy to make pests resistant,and the tolerance of different pests to the same agent is different.Only using one agent is not conducive to the prevention and control of multiple edible fungi pests at the same time.（2）Pesticide abuse exists in the production process of edible fungi,including unreasonable preparation of pesticides,mixed pesticides,and the use of banned and restricted pesticides.Unreasonable use of pesticides may have adverse effects on the growth of edible fungi,such as inhibiting mycelial growth and causing malformation of fruiting bodies.Triplax ainonia Lewis,1877 is one of the important pests of edible fungi in China.It is easy to gather and erupt in high-temperature seasons,and it is difficult to control,which has brought great economic losses to the edible fungi industry in some areas of China.At present,there are few studies on the biology and control of T.ainonia.Based on the above problems,this paper carried out the following study:（1）The morphological characteristics,feeding habits,damage characteristics,and development process of different stages of T.ainonia were studied.Provide basic information on the biology of the pest.（2）The toxicity of 19 kinds of biological and chemical insecticides（including 9 kinds of biological insecticides,6 kinds of insect growth regulators,and other 4 kinds of chemical insecticides,among which the chlorofluoromethyl·emamectin benzoate registered on edible fungi was used as a reference）to the adults of T.ainonia was determined.The safety of these insecticides on the mycelial growth of five edible fungi,Lentinula edodes,Flammulina velutipes,Pleurotus ostreatus,Termitomyces albuminosus,and Agaricus blazei was evaluated,so as to screen out insecticides with good insecticidal effect and no adverse effect on the mycelial growth of edible fungi.The main results are as follows:1.Biology of Triplax ainonia（1）The morphological characteristics of T.ainonia were observed by optical microscope,and the morphological characteristics of each insect state and the sexual dimorphism characteristics of the pupal stage were clarified:The eggs were long oval and translucent;Larvae long strip,milky white;The pupae are oval in shape and milky white with translucent villi.There are two’eight’finger protrusions on the ventral surface of the eighth segment of the female pupa while the male pupae do not have this structure.The adult is oval,light yellow with two black spots on the pronotum,and the elytron and head are bright black.（2）The ultrastructural morphology characteristics of the stridulatory files,labial palpus,maxillary palpus,compound eyes,and antennae of the adult head of T.ainonia were observed by scanning electron microscopy.The results show that the head has two sound files,which are composed of neatly arranged and parallel thin strips.The labial palpus must be axe-shaped,with a dense columnar structure at the end;the maxillary palpus is brush-like,with a dense columnar structure at its end;the compound eyes were nearly round.The minor axis diameter,major axis diameter,arc height,number of ommatidia,number of sensilla and ommatidum diameter of male were higher than those of female.The surface of the antennae is fish-scale,and the terminal three segments have a large number of hairs,and there are many types of hairs.The length of the male antennae and the width of each segment are higher than those of the female.（3）By investigating the damage characteristics of T.ainonia,it was found that the larvae and adults of T.ainonia could damage the fresh and dried products of Pleurotus ostreatus.The adults can feed on the oyster mushroom,and the adults can eat the mushroom stick.The larvae only left yellowish-brown filaments（insect manure）after feeding on the mushroom body.In the exploration of the feeding habits of the adults of T.ainonia,six different genera of edible fungi were used to feed the adults of T.ainonia,and the adults of T.ainonia only fed on Pleurotus（Pleurotus ostreatus,Pleurotus eryngii）.Therefore,the feeding habits of adults of T.ainonia may be oligophagous.（4）In terms of pupal changes and emergence behavior of T.ainonia could be divided into three stages:（1）early pupation;（2）4–5 d after pupation;（3）7–8 d after pupation.At the beginning of emergence,there was a small fluctuation transmitted on the pupae,and the entire emergence process lasted for about 1 h.After1.5 days,the adults after emergence basically developed and matured.2.Determination of toxicity of 19 insecticides to adults Triplax ainoniaThe toxicity of 19 insecticides to T.ainonia adults was determined by the filter paper contact method.The results showed that the toxicity of spinosad to T.ainonia adults was high,and the LC₅₀ was 0.083 mg/L.The LC₅₀ of spinetoram,indoxacarb,and lambda-cyhalothrin were 0.195 mg/L,0.681 mg/L,and 0.789 mg/L,respectively.The toxicity of the above four insecticides to T.ainonia was better than that of chlorofluoromethyl·emamectin benzoate(LC₅₀=2.314 mg/L),and the toxicity of the remaining 15 insecticides was lower than that of the agent.3.Effects of 19 insecticides on mycelial growth of 5 edible fungiThe effects of 19 insecticides on the mycelial growth of 5 edible fungi were determined by the plate addition method.The results showed that the inhibitory effects of hexaflumuron,diflubenzuron,and spinosad on the mycelial growth of the five edible fungi were small and lower than that of the pesticide chlorofluoromethyl·emamectin benzoate registered on edible fungi.In addition to the inhibitory effect of cyromazine on the mycelial growth of Agaricus blazei being greater than that of chlorofluoromethyl·emamectin benzoate,the inhibitory effect of cyromazine on the mycelial growth of the other four edible fungi was lower than that of chlorofluoromethyl·emamectin benzoate,and the above four insecticides had a promoting effect on the mycelial growth of some edible fungi at low concentrations.Based on the above results,the safety factors of 19 insecticides to 5 edible fungi were analyzed,and the ratio of beneficial to harmful toxicity of these insecticides to edible fungi and T.ainonia was analyzed.The results showed that spinosad,diflubenzuron,spinetoram,and hexaflumuron performed well in the safety factor analysis.The safety factors of spinosad against the five edible fungi were higher than those of the registered insecticide chlorofluoromethyl·emamectin benzoate.The safety factor of diflubenzuron,spinetoram,and hexaflumuron to some edible fungi was higher than that of chlorofluoromethyl·emamectin benzoate.In the analysis of the ratio of beneficial and harmful toxicity,the ratio of beneficial and harmful toxicity of spinosad to 5 kinds of edible fungi was higher than that of chlorofluoromethyl·emamectin benzoate.The ratio of beneficial and harmful toxicity of spinetoram to Termitomyces albuminosus,Pleurotus ostreatus,Agaricus subrufescens and Lentinula edodes was higher than that of chlorofluoromethyl·emamectin benzoate.The toxicity of insecticides to adults and safety to edible fungi were analyzed.It was found that the microbial biopesticides spinosad and spinetoram had high toxicity to the insect and were safe to the mycelium of five edible fungi.The chemical insecticides lambda-cyhalothrin,indoxacarb,and chlorofluoromethyl·emamectin benzoate had high toxicity to the insect and low effect on the mycelium of edible fungi.Diflubenzuron,cyromazine and hexaflumuron were safe to the mycelia of five edible fungi,but had weak toxicity to the adults of T.ainonia.Spinosad and spinosad can be listed as candidate insecticides for registered insecticides.