Studies On Process For Extraction Of Camptotheca Acuminata Decne. And Bioactivity Of Extracts From Camptotheca Acuminata Against Plutella Xylostella L.

Laboratory studies were conducted to determine the efficacy of Camptotheca acuminata Decn leafs and fruits extracts against adults and larvae of Plutella xylostella with five different mothods (including: Alcohol ultrasonic extraction technology, Alcohol extraction technology, Soxhlet extraction technology, NaOH ultrasonic extraction technology, Alkali extraction technology). The main results are as follows:(1) The content of the Camptothecin in the lesfs of Camptotheca acuminata Decne was higher than it in the fruits. In spite of leafs or fruits, among the five extract methods, the Alcohol ultrasonic extraction was the best one. The optimum extracting condition was adding 14ml.g-1, amount of 60% alcohol, ultrasonic extracting for 120s and totally extracting for one time.(2) All different extracts presented strong oviposition deterent effect against the Plutella xylostella L. adults. It was apparent that extracts was more effective in the choice test than in the non-choice test. The higher their concentrations were, the stronger ovipositions deterrent effect was. The total number of eggs laid by Plutella xylostella L. decreased on plants with increase of high concentrations in non-choice test.(3) The extracts of alcohol ultrasonic had displayed high potentials of ovicidal action. The extracts of NaOH ultrasonic and Alkali extraction ether had no effect to the hatching rate and egg development duration, but they were toxic to the newly hatched larvae of Plutella ylostella. The hatching rate of eggs decreased significantly when the concentration of the leaf's extract increased. If the concentration was higher than 31.25mg/L, the extract would significantly prolonged the eggs' development durations, and reduced the survival rate of the newly hatched larvae.(4) All extracts of Camptotheca acuminata Decn had stronger antifeedant activity towards 3rd-instar larvae of Plutella xylostella. In choice test and non-choice test, the antifeedant effect after treated 24h was higher than 48h, and it indicated that the lasting time of antifeedant effect was short.All extracts of Camptotheca acuminata Decn had unapparent contact toxicity. Only the alcohol ultrasonic extract of leafs and fruit showed the contact toxicity activity. The alcohol ultrasonic extract of leafs caused 30% mortality of Plutella xylostella at concentration of 500mg/L.All extracts of Camptotheca acuminata Decn showed strong stomach toxicity towards 3rd-instar larvae of Plutella xylostella. The longer treating time, the less stomach toxicity activity. All extracts also showed growth-inhibition effect against Plutella xylostella with a time dependent inhibition. The activity was lower when the treat time was going long.