Growth Adaptability Of Hyphantria Cunea Larvae To 8 Host Young Trees

Hyphantria cunea is a quarantine pest of agriculture and forestry in China.It has a wide host range,strong fecundity,fast transmission speed,strong resistance and adaptability,and poses a great threat to the trees mainly distributed in Heilongjiang Province.In order to explore the adaptability of Hyphantria cunea to different host young trees,this experiment took 8 kinds of trees widely distributed and planted in Northeast China as the experimental objects,raised indoors and measured the growth and development,nutritional effect indexes,detoxification enzyme,digestive enzyme activity,secondary biomass and nutrient content of Hyphantria cunea larvae after eating the leaves of different host young trees.The main results are as follows:1.Different host young trees have significant effects on the growth and development of Hyphantria cunea larvae.The higher survival rates of 3rd-6th instar larvae were Ulmus pumila and Juglans mandshurica,followed by Fraxinus mandshurica,Salix matsudana and Tilia amurensis;the lower survival rates were Larix olgensis and Albizia kalkora,followed by Betula platyphylla.Larval development duration is longer for Larix olgensis and Albizia kalkora,shorter for Ulmus pumila,Juglans mandshurica;Ulmus pumila,Juglans mandshurica and Fraxinus mandshurica have higher pupation rate and emergence rate,while Larix olgensis and Albizia kalkora have lower rate;The higher weight,body length and head shell width of the 4th-6th instar larvae were Ulmus pumila and Juglans mandshurica,followed by Tilia amurensis,Fraxinus mandshurica and Salix mandshurica,and the lower were Betula platyphylla and Albizia kalkora.2.Different host young trees had significant effects on the nutritional effects of Hyphantria cunea larvae.In addition to the 4th instar larvae,the 5th-6th instars were Ulmus pumila,Juglans mandshurica and Fraxinus mandshurica,which eat more,followed by Salix mandshurica and Tilia amurensis,and Betula platyphylla and Albizia kalkora were the less;The food utilization rate of 4th-6th instar larvae feeding on Ulmus pumila and Juglans mandshurica was higher,followed by Fraxinus mandshurica,Tilia amurensis and Salix mandshurica.The lower food utilization rates were Betula platyphylla and Albizia kalkora;The result of food conversion rate is directly proportional to food utilization rate,and the result of food consumption rate is inversely proportional to food utilization rate.3.The contents of secondary metabolites and nutrients in different host young trees were significantly different.Albizia kalkora and Betula platyphylla had higher Tannin content,while Larix olgensis and Ulmus pumila had lower Tannin content;Larix olgensis and Albizia kalkora have higher Lignin content,while Fraxinus mandshurica,Juglans mandshurica and Ulmus pumila have lower Lignin content;The contents of Total phenols and Flavonoids in Ulmus pumila,Juglans mandshurica,Tilia amurensis and Fraxinus mandshurica were higher,while the contents of Betula platyphylla,Albizia kalkora and Larix olgensis were lower;The contents of amino acid and soluble sugar of Ulmus pumila and Juglans mandshurica were higher,while those of Larix olgensis and Albizia kalkora were lower.4.The activities of detoxification enzymes and digestive enzymes in larvae fed on different host young trees were significantly different.Except for GSTs of 5th instar larvae,the higher activities of the three detoxification enzymes were Ulmus pumila and Juglans mandshurica,followed by Tilia amurensis and Salix mandshurica,and the lower activities were Betula platyphylla and Albizia kalkora;The higher activity of GSTs of 5th instar larvae was Tilia amurensis and Salix mandshurica,and the lowest was Albizia kalkora;In general,the trypsin activity of larvae fed on Ulmus pumila and Juglans mandshurica was higher,while that of Betula platyphylla and Albizia kalkora was lower;The same is true for amylase activity of4 th instar larvae and lipase activity of 5th-6th instar larvae;The activities of amylase and lipase in 5th-6th instar larvae and 4th instar larvae fed on Ulmus pumila and Juglans mandshurica were lower.5.Correlation analysis found,flavonoids,total phenols,soluble sugars and amino acids were significantly positively correlated with the growth,development and nutritional effects of the 4th instar larvae of Hyphantria cunea,while tannins were significantly negatively correlated;Flavonoids and total phenols were significantly positively correlated with detoxification enzyme activity of 4th instar larvae,while lignin and tannin were significantly negatively correlated;Soluble sugar was positively correlated with trypsin activity of 4th instar larvae,and amino acid was positively correlated with trypsin and amylase activity of 4th instar larvae;The activities of amylase,GSTs,ache and trypsin in the 4th instar larvae were significantly positively correlated with their growth and development indexes,and the activities of ache,care,trypsin and lipase in the 5th instar larvae were basically significantly positively correlated with their growth and development indexes.In conclusion,Ulmus pumila and Juglans mandshurica are more suitable hosts,with high nutrient content and relatively high detoxification and digestive enzyme activities in larvae;Larix olgensis and Albizia kalkora are unsuitable hosts for the Hyphantria cunea,their nutrient content is low,and the activities of detoxification enzymes and digestive enzymes in larvae are relatively low.Tannin and lignin can inhibit the growth of Hyphantria cunea,and soluble sugar and amino acids can promote its growth,development and nutritional effects;Secondary substances and nutrients can induce the increase of ache,care and trypsin activities in the 4th and 5th instar larvae and promote their growth and development.This study clarified the adaptability of Hyphantria cunea to different hosts,and provided a theoretical basis for scientifically building mixed forests,protecting target tree species and effectively controlling Hyphantria cunea.