| Bombyx mori is an insect that is very susceptible to disease.The occurrence and spreading of various diseases have always been a thorny problem in sericulture production,which bring huge economic losses every year.Mulberry leaves are the most important food source for silkworms.If it is contaminated by pesticides or carries pathogenic bacteria,it will bring great harm to sericulture.Therefore,whether the mulberry leaves are clean or not is the first step to prevent silkworm infection.Traditional foliar disinfectants,such as Xiaoteling,chlorine dioxide,and kesporin,can kill pathogenic bacteria and reduce the harm of silkworm infectious disease.But there are more or less disadvantages.Looking for a new type of disinfectant,which can replace the traditional foliar disinfectant and is environmentally friendly,is the key to prevent the disease of silkworm.It has important practical significance for the sustainable,healthy and stable development of sericulture.As a new type of disinfectant,slightly acidic electrolyzed water is widely used in food disinfection and preservation,medical disinfection,animal husbandry and agriculture because of its advantages,such as convenient preparation,low cost,high efficiency,no pollution,no residue,and so on.In this study,the degradation effect of slightly acidic electrolyzed water on hexaflumuron pesticides was systematically studied by high performance liquid chromatography and bioassay,the effect of slightly acidic electrolyzed water on mulberry leaf quality and silkworm rearing performance were also investigated.The main findings are as follows:1.The degradation effect of slightly acidic electrolyzed water on hexaflumuron in the solution system was determined by high performance liquid chromatography(HPLC).The results showed that the degradation rate of treating 30 min was the highest when the slightly acidic electrolytic water stored for 8 hours,the degradation rate reached 79.07%.Biological experiments were used to identify the removal effect of slightly acidic electrolytic water on hexaflumuron residues of mulberry leaves.The results showed that the mulberry leaves were soaked in the mixture of slightly acidic electrolytic water and hexaflumuron solution and fed to silkworms,the hexaflumuron poisoning symptoms of silkworm were alleviated,and the body weight,cocoon formation rate and dead cage rate of silkworm were increased,but the higher the concentration of hexaflumuron was,the worse the detoxification effect was.The isolated mulberry leaves were sprayed with hexaflumuron and then soaked in slightly acidic electrolytic water to feed the silkworm.It was found that the growth rate of silkworms,the weight of mature silkworm,the weight of whole cocoon,and the rate of cocoon formation increased significantly with the extension of soaking time,while the rate of dead silkworm decreased.Similar experimental results were obtained when silkworms were fed mulberry leaves sprayed with slightly acidic electrolytic water after spraying hexaflumuron.The above results showed that the slightly acidic electrolyzed water could degrade the residual hexaflumuron in mulberry leaves to a certain extent,and reduce the residual amount of hexaflumuron in mulberry leaves.2.The moisture content of mulberry leaves before and after treatment with slightly acidic electrolyzed water was determined by timing and quantitative determination.It was found that when the treated mulberry leaves were preserved for 24 hours,the moisture content of mulberry leaves decreased by 2-3% in the slightly acidic electrolytic water group and water group.The moisture content of leaves in the blank control group decreased by about 3%;and the moisture content of leaves in the treatment group decreased by 5%.Kjeldahl method and anthrone colorimetric method were used to detect the effect of slightly acidic electrolyzed water on the contents of crude protein and soluble sugar in mulberry leaves.The results showed that with the extension of preservation time,the contents of crude protein and soluble sugar in mulberry leaves decreased in slightly acidic electrolytic water group and Xiaoduling group,and the longer the treatment time was,the less crude protein and soluble sugar content was.However,the decrease in slightly acidic electrolytic water treatment group was significantly lower than that in Xiaoduling treatment group.The above results showed that the treatment of slightly acidic electrolyzed water had no effect on the quality of mulberry leaves.And it was found that slightly acidic electrolyzed water had a good killing effect on mulberry pathogens,which was obviously better than that of traditional disinfectant Xiaoduling.3.The effect of feeding silkworm with mulberry leaves disinfected by slightly acidic electrolyzed water from hatching to maturing on silkworm rearing was detected.The results showed that the body weight of silkworm fed with mulberry treated by slightly acidic electrolytic water was significantly higher than that of water group(P<0.05),and the body weight of big silkworm was significantly higher than that of Xiaoduling group(P<0.05).There was no significant difference in cocoon shell rate among different treatments,and there was no significant difference in dead cage rate,dead silkworm rate and cocoon formation rate between slightly acidic electrolyzed water groups and water group(P<0.05).However,the dead cage rate and dead silkworm rate in slightly acidic electrolytic water group were significantly lower than those in Xiaoduling group,while the cocoon formation rate in slightly acidic electrolytic water group was significantly higher than that in Xiaoduling group(P<0.05).The results showed that the mulberry leaves impregnated and disinfected with slightly acidic electrolytic water had no adverse effect on the growth and development of silkworm,and the effect of foliar disinfection was better than that of Xiaoduling.4.The effect of feeding silkworm with mulberry leaves disinfected by slightly acidic electrolyzed water from hatching to maturing on silkworm egg production was detected.From the point of view of the oviposition performance of silkworm moth,the fecundity of silkworm moth in the slightly acidic electrolyzed water group was not significantly different from that in water group,the silkworm eggs were full and flat,and the number of silkworm eggs in Xiaoduling group was significantly lower than that in the former two groups.From the perspective of silkworm egg quality,the hatching rates of silkworm egg in slightly acidic electrolytic water group,water group and Xiaoduling group were 96.16%,97.35% and 76.46%,respectively.The results showed that there was no significant difference between slightly acidic electrolyzed water group and water group(P<0.05).There was significant difference between the Xiaoduling group and water group(P<0.05),and the effect was negative.The results showed that the slightly acidic electrolyzed water had no adverse effect on fecundity and quality of silkworm eggs,and the effect was far better than that of Xiaoduling.All of the above,slightly acidic electrolyzed water can be used as a mulberry leaf disinfectant with both detoxification and germicidal efficacy in sericulture production. |
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