Population Dynamics Of The Main Pests And Natural Enemies And The Pests Control In Organic Peach Orchard

In this experiment, the author investigated the main pests and natural enemies in the organic peach orchard and the conventional peach orchard, in Pinggu region of Beijing. The author studied the population dynamics of the three main pests (Grapholitha molesta Busck, Adoxophyes orana Fischer von Roslerstamm and Lyonetia clerkella Linnaeus)and the five main natural enemies(Propylaea japonica (Thunbery), Leis axyridis Pallas, Coccinella septempunctta, Orius and Chrysopidae ) with ecological method, and comparatively studied the population dynamics and amount of the main pests and their natural enemies in the organic peach orchard and the conventional peach orchard, the influences of the organic management on the population of the main pests and their natural enemies were discussed. The author also studied the effect of some pesticides for the severe pest (Lyonetia clerkella Linnaeus), and selected some good pesticides. The results of this experiment may provide some theoretical and practical bases for the integrated pest management in organic peach orchard. The main results were as follows:1) There were 4 generations of G. molesta, 3 generations of A. orana, and 6 generations of L. clerkella a year in the organic peach orchard. For the main natural enemies, the highest population density was Orius, the following were P. japonica, L. axyridis, C. septempunctta and Chrysopidae. The population density of P. japonica and L. axyridis was more than the others during the early stages, but during the late stages , the population density the Orius was most;2) The population dynamics of the pest and natural enemies in different plots were consistent. The population density of the pests in the organic management peach orchard was lower than that of the conventional management peach orchard. In the organic management peach orchard, the pest population density in the area where the ground cover (alfalfa) was grown was lower than that without the mulching material, and the pest population density in the central area of the peach orchard was lower than that in the periphery. In organic management peach orchard, the population density of natural enemies in the periphery was higher during the earlier stages, but during the late and middle stages the population density of natural enemies in the central area was higher, and the living of the natural enemies in the central area were longer than the other area;3) The effects of Natural Pyrethrum for L. clerkella was the best, and the effect of the compounding of 1500 times' Natural Pyrethrum and 300 times' bamboo vinegar was the best compared with the other insecticides, the density reduce rates of the that increased continually and reached the peak value (73.2%) after 15 days. The effect of potash soap took second place, the reduce rates of 300 times' potash soap reached the peak value (63.2%) after 15 days. Bamboo vinegar, potash soap and suspending agent of sulfur could increase the effect of Natural Pyrethrum, Baicao I and Kingbo for L. clerkella. We suggested you use Natural Pyrethrum (the compounding of 1500 times' Natural Pyrethrum and 300 times' bamboo vinegar) or 300 times' potash soap to control Lyonetia clerkella Linnaeus in organic management peach orchard.