Arthropod Communities In Macleaya Cordata Fields And Effection On Spodoptera Litura(Fabricius) By Macleaya Cordata

Research were design to confirm the arthropod communities and their growth and decline trends in two different kinds of Macleaya cordata field. And characteristic index of these communities were calculated. The results would help to ascertain the categories of main pests and natural enemies, so as to provide some theoretical basis for the pests control in Macleaya cordata planting. At the same time, it also researches on the effect of Macleaya cordata for the growth of Spodoptera litura (Fabricius), the main pests in the field, measures and analyzes the activity of glutathione S-transferase and acetylcholinesterase. The main research results are as follows:In the planting area of two-year-old Macleaya cordata, there is no farmland maintenance measures as weed control and pests elimination. Among them, the categories and quantity of arthropod are enriched including 36 species of arthropod with 11 herbivorous pests,7 natural enemies and 8 species of spiders being involved. In the planting area of one-year-old Macleaya cordata where chemicals are used to eliminate pests, the categories and quantity of arthropod are relatively in smaller number and the proportion and quantity of herbivorous insects and their natural enemies arthropod are similar.In the preliminary period of planting area of Macleaya cordata (March to May), the dominant pest is Myzus persicae (Sulzer), in the medium and later period (June to October), the dominant pest is Spodoptera litura (Fabricius). In the two kinds of planting conditions, the common dominant natural enemies are Hylyphantes graminicola, Tetragnatha squamata Karsch and Coleosoma octomaculatum (Boes. et Str).The research finds out that Macleaya cordata has some disadvantageous effect on the growth of Spodoptera litura (Fabricius) with the main shows being that larval duration is prolong; the egg hatching rate, pupation rate and eclosion rate are reduced; the amount of oviposition by the single female is reduced and the pupa body is becoming smaller. With the increasing of Macleaya cordata in feed, the population number tendency index and relative fitness of Spodoptera litura (Fabricius) species is gradually reduced.It is found out in the experiment of activity of detoxification enzyme that Spodoptera litura (Fabricius) has some certain degree of metabolic capacity for the insecticidal active alkaloids of Macleaya cordata. Feeding on the Macleaya cordata will activate the glutathione-S-transferase and acetylcholinesterase in the larval of Spodoptera litura (Fabricius). But the higher-countertraded Macleaya cordata will be able to restraint the activity of acetylcholinesterase of Spodoptera litura (Fabricius) to some extent.