Effects Of Feeding On Tea Leaves On The Development And Stress Resistance Of Helicoverpa Armigera

Helicoverpa armigera belongs to Lepidoptera Noctuidae.Because of its wide host range and strong adaptability,it has caused great economic losses to global agricultural production.In recent years,our team found the harm of Helicoverpa armigera in tea gardens in different areas of Shandong Province.In order to clarify its harm and adaptability to tea trees,this study used the theory of Two-Sex life table to clarify the influence of tea on the growth and development of Helicoverpa armigera and population parameters.At the same time,somatotype measurement and stress-resistant enzyme activity detection were carried out to clarify the adaptability potential of Helicoverpa armigera on tea trees.This study laid a theoretical foundation for clarifying the adaptation mechanism of Helicoverpa armigera in tea garden,and provided a reference for guiding the green prevention and control of Helicoverpa armigera in tea garden.The specific results are as follows:1.The growth,development and population parameters of Helicoverpa armigera feeding on corn and tea were analyzed by using Two-Sex life table software.When eating corn and tea,the average life span is 31.85d and 18.68 d respectively;The average number of eggs laid by a single female is 237.5 grains/female,and it is 5.33 grains/female when eating tea.The longevity and egg production of corn were significantly higher than those of Helicoverpa armigera that ate tea.The net multiplication rate（R₀）of Helicoverpa armigera fed on corn and tea was 33.0958 and 0.1678 offspring,respectively.The intrinsic growth rate（r）is 0.0691d^-1and-0.0423d^-1,respectively;Finite rate of increase（λ）is 1.0716d^-1and 0.9587d^-1,respectively;The average generation period（T）is 48.908d and 6.398d.2.The body length,body width and weight of Helicoverpa armigera fed on two kinds of food were obtained by measuring and analyzing the scales according to the proportion after taking photos under the stereoscope.The body length,body width and weight of Helicoverpa armigera larvae fed on corn were significantly higher than those fed on tea larvae.3.The changes of enzyme activities of five enzymes,namely superoxide dismutase（SOD）,catalase（CAT）,glutathione S-transferase（GSTs）,acid phosphatase（ACP）and alkaline phosphatase（AKP）,in Helicoverpa armigera larvae fed on two kinds of food were determined.The activities of SOD and CAT in the larvae of Helicoverpa armigera fed on tea were higher than those fed on corn,and the SOD activity in the 5th instar larvae was the highest,which was significantly higher than that fed on corn.The activity of CAT enzyme in the 6th instar larvae of Helicoverpa armigera fed on tea was the highest,which was significantly higher than that fed on corn.However,the activities of GSTs,ACP and AKP were obviously inhibited after Helicoverpa armigera fed on tea,and the activities of GSTs in the 4th instar larvae were significantly lower than those in corn,and there was an upward trend with the growth of the instar.The activities of ACP and AKP enzymes in the larvae feeding on tea showed an upward-downward-upward trend with the increase of age,and were significantly lower than those feeding on corn at all ages.The above results showed that the developmental period,adult longevity,fecundity and female to female population ratio of Helicoverpa armigera were prolonged,mortality was significantly higher,fecundity was significantly lower,body size was significantly smaller than that of maize,and the activity of protection enzymes related to stress resistance in the body was enhanced but detoxification enzymes activity was significantly lower when feeding on tea leaves.