Investigation On Natural Enemy Insect Resources Of Hyphantria Cunea (Drury)in Shandong And Biology Of Exorista Japonica Townsend

The Hyphantria cunea (Drury) is one of the major serious insect pests to the forestry in the northern China. The parasitoids played an important role on the host. Exorista japonica Townsend. is a taehinid parasitoid of the Hlyphantria cunea (Drury) and other lepidopterous insects . It can effectively control the damages of Hlyphantria cunea (Drury), In order to use the natural enemyinsects to control the Hlyphantria cunea (Drury) effectively,In DongYing,Taian and Binzhou we have carried out a thorough investigation on the natural enemy insect resources and biology of Exorista japonica Townsend was studied. The preliminary result as follows:The Enemy Insect Resources of Hyphantria cunea.The parasitoids of Hyphantria cunea (Drury) mainly includes parasitic wasps and tachinid flies. Five of which belong to Exorista Meigen of Tachinidae,such as Exorista japonica Townsend,Exorista fasciata Fallen, Exorista sorbillans Wied,Blepharipa zebina,matsukarehae. There are 16 kinds of parasitoid wasps,seven of them belong to Icheneumonidae,such as Coccygomimus diparis Viereck,Gotra octocinctus (Ashmead), Coccygomimus luctuosus (Smith),Gregopimpla kuwanae (Viereck), Coccygomimus parnasae Viereck,Vulgichneumon leucaniae Uchida, undetermined species of Icheneumonidae.six of them belong to Chalcididae,such as Brachymeria lasus Walker, Chouioia cunea Yang,Tetrastichus nigricoxae Yang, Tetrastichus septentrionalis Yang, Tetrastichus septentrionalis Yang;one of them belong to Trichogrammatidae, such as Trichogramma dendrolimi Matsumura; two of them belong to Braconidae, such as Dolichogenidea ingularis Yang et You, Cotesiagregalis Yang et Wei; one of them belong to Pteromalidae, such as Dibrachys cavus (Walker). Besides, found six Predatory, such as Chrysoperla sinica Tjeder,Coccinella septempunctata,Leis axyridis,Dolichoderinae,Pica pica Linnaeus,Radix pulsatillae Chinensis?Temperatures range between 18℃~30℃,the durations of different stages of Gastrolina depressa shortened as temperature rising. The developmental threshold temperatures of egg,larvae , pupa and pre~oviposition stages were 10.12℃, 8.86℃, 7.81℃and 9.88℃, respedivety and the effective accumulated temperatures were 58.89, 100.2, 189.47 and 20.43 degree~day,respectively. The developmental threshold temperature was 8.15℃and the effective accumulatetive temperature was 383.25degree-day for the whole generation. Parasitic behavior of Exorista japonica Townsend was observed in present study. Results indicated that the tachinid preferred to oviposit on thorax of Bombyx mori L., second on head and the least on abdomen. Egg production on the three parts was significantly different. The most favorite host was the larvae of B. mori with parasitism rate of 62.79%, then was the larvae of Spilarctia subcarnea (Walker) and Hyphantria cunea (Drury), with parasitism rate of 26.15% and 12.33%, respectively. The number of eggs deposited on the larvae of B. mori, S. subcarnea and H. cunea was 5.63 4.05 and 1.85, respectively. Parasitism on the 5th, 4th and 3rd instar larvae of B. mori was 44.38%, 34.67% and 21.05%, respectively, and the number of eggs was 9.58, 7.95 and 4.45, respectively. Parasitism on the 7th, 6th larvae and 5th of H. cunea was 53.33%, 27.02% and 19.67%, respectively, and the number of eggs was 7.27, 3.17 and 1.33, respectively. As the numbers laid on larvae increased, the death rate of host increased. When egg number was 1, pupation was 52% and host mortality was 58.33%. When egg number was 2, pupation was 69.16% and host mortality was 71.67%. When 4 eggs were laid on host, pupation was 76.83% and host mortality reached 100%. When egg numbers was over 4, pupation reduced.Investigated on the effects of 2 kinds of suger (10% honey water, 10% sucrose water) solution and pure water on longevity and fecundity of Exorista japonica Townsend,results raise the egg?laying?amount?and?longevity?of?imago.Set up 2 experimental treatment,the pupae of Exorista japonica Townsend and the pupae of Hyphantria cunea (Drury), the pupae of Exorista japonica Townsend and the pupae of Bombyx mori Linaeus, we made Chouioia cunea yang to parasitism, the pupae of Exorista japonica Townsend was 53.33%.