Studies On The Occurrence And Control Of Aleurocanthus Spiniferus In Tea Gardens And The Parasitic Behavior Of Eretmocerus

Aleurocanthus spiniferus has become one of the most serious pests in northern tea gardens in recent years.Due to the popularization of dense planting and dwarf cultivation technology in tea gardens,it provides a suitable environment for A.spiniferus to inhabit and reproduce.The A.spiniferus provides a good overwintering environment,which causes the occurrence of A.spiniferus to increase year by year.The purpose of this study is to clarify the occurrence regularity of A.spiniferus in tea gardens on different tea tree varieties,to screen the chemical control agents of A.spiniferus,and to find out the parasitic behavior of A.spiniferus’s natural enemy,Eretmocerus gunturiensis.It starts from each aspect,and provides scientific basis for the correct formulation of comprehensive control strategies for A.spiniferus.The main findings are as follows:1.Through the investigation on the occurrence of A.spiniferus on 7 different tea tree varieties,it was found that the high incidence period of A.spiniferus on several kinds of tea trees was in late June.Longjing 43 also had a small peak in late May.‘Zhongcha 108’and‘Zhong huang 1’had the largest incidence amount of A.spiniferus,while‘Anji bai cha’,‘bi xiang zao’and‘bai hao zao’had the highest incidence amount of A.spiniferus.2.Toxicity of four agents,spirotetramat,emamectin,tea saponin and bifenthrin were selected to test the toxicity of A.spiniferus.The LC₅₀of the lethal concentration at 24 hours after treatment was 7.92 mg·m L^-1,followed by emamectin and tea saponin.The lethal concentration LC₅₀at 24 hours after treatment were 7.346 mg·m L^-1and 0.431 mg·m L^-1,respectively,the most virulent is spirotetramat,the lethal concentration 24 h after the drug is0.065 mg·m L^-1.3.Discovery of the natural enemy of the A.spiniferuson,Eretmocerus gunturiensis.In nature,the larvae of E.gunturiensis parasitize the 2～3 instar nymphs of the A.spiniferus.Adult head,thorax,abdomen and most of the legs yellow,transparent wings.Wing base with1 hair,submarginal vein with 2 hairs,anterior chamber with 3 hairs at rear end,and marginal vein with 4 hairs at front edge.There are 7 hairs in a row between the marginal vein and the glabrous oblique zone,and there is a group of hair tumors at the rear end of the glabrous oblique zone,about 11 hairs.Below the glabrous oblique band,at the base of the mid-wing domain,there is a group of about 28 hairs pointing towards the leading edge of the wing,and about 186 hairs in the rest of the mid-wing domain pointing towards the wing tip.The tarsus of the foot has 4 segments,the end of the front tibia has an antenna cleaner,the end of the hind tibia has a wing cleaner,and the front tarsus has two small claws,with a membranous middle pad in the middle.The three monocular eyes on the head of E.gunturiensis are arranged in a triangle,which is located in the middle of a pair of compound eyes.Each segment of the bent-knee-like antenna is yellow,the stalk segment is 2.5～3 times the basal segment,the pedicle segment is 0.8～1 time the basal segment,the rod segment is not segmented,and the width is flat like an oar.Chewing mouthparts,ovipositor transparently exposed.The female bee lays eggs for about 2 minutes.After the eggs are laid,she uses her front feet to comb her antennae.4.Parasitism of E.gunturiensis affects the size of pseudopupae of the A.spiniferus.The parasitized whitefly pseudopupae were significantly shorter than the unparasitized pseudopupae.The width of the pseudopupae of the parasitized A.spiniferus was significantly shorter than that of the unparasitized ones.The parasitization rate of E.gunturiensis parasitica was different in different tea locations,and the parasitizing rate of E.gunturiensis was significantly higher in the middle leaves of the tea bush than in other parts.The parasitism rate of the positive side of the middle leaves was significantly higher than that of the shaded side of the tea bush and the middle of the tea bush,and there was no significant difference in the parasitism rate of the leaves of the rest of the leaves between different tea bush orientations.5.The sensilla on the antennae of E.gunturiensis are plate-shaped sensilla（Sensilla placodea,SP）,hair-shaped sensilla（Sensilla trichodea,ST）,altar-shaped sensilla（Sensillum ampullaceum,SA）,thorn-shaped sensilla（Sensilla chaeticum,SC）,cone-shaped sensilla（Sensilla basiconica,SB）,B（?）hm’s bristle（B（?）hm bristles,BB）;there is only one cone-shaped sensilla（SB）on the compound eye,which is born in the small compound eye.Between the eyes,the number is large and the length varies.The mouthparts are chewing and have a well-developed upper jaw.There are two types of sensilla on the mouthparts,namely the hairy sensilla（ST）and the spine-shaped sensilla（SC）.There are two types of female external genitalia,namely the squamiformic sensillum（SS）and the spine-shaped sensillum（SC）at the end of the abdomen;The tibia has a large spur（CAL）at the end of the tibia.