Studies On The Bioactivity And Action Mechanism Of Plant Extracts To Vegetable Insect Pests

In order to meet the need of the no-pollution-agriculture , it is important to find new biological pesticide. Botanical pesticide has many modes of function against insect pests , and it's safe to senior animal and natural enemy. Their resistance won't easily occurred . It's also friendly to environment. Because of these advantages, botanical pesticide is to be the substitute of chemical pesticide. Some poisonous substance of poisonous plants and Chinese traditional medicines were extracted . Bioactivities and action mechanism of the extracts against vegetable insect pests were researched. The main results were as following :1. Poisonous plants and Chinese traditional medicines in Jiangsu province were investigated preliminary in this paper. 82 kinds of poisonous plants and 45 kinds of poisonous Chinese traditional medicines were found .2. Bioactivities and functional modes of plant extracts against insect pests were systematically studied in this paper. Results indicated that in toxicity measurement , the extract from Cortex periplocae was found to have good poisonous activity against Pieris rapae and Phaedon brassicae . The adjusted mortality of 89.66% and 96.55% were observed respectively after 72 hours of treatment. The extract from Areca catechu was found to show strong poisonous activities against Spodoptera litura, Spodoptera exigua, Bemisia tabaci and Henosepilachna vigintiocto punctata . The adjusted mortality of these insect pests was above 90% after 72 hours of treatment. The adjusted mortality of Myzus persicae treated by the extract from Acoras Calamus was 100% after 72 hours. The extract from Acoras Calamus was found to have strong antifeedant effects against Spodoptera litura, Spodoptera exigua and Myzus persicae. The antifeedant rate of Spodoptera exigua reached 77.04 % after 24 hours. The growth inhibitor experiments indicated that the inhibitor rates of the larvae of Spodoptera litura and Spodoptera exigua treated by the extract from Acoras Calamus were higher than the other plant extracts. The reduce rate of the weight of Spodoptera litura and Spodoptera exigua respectively...