American spotted diving fly belongs to the diptera submersible family, commonly known as "little white dragon", which is a quarantine pest introduced to China in recent years.
<h1 class= "pgc-h-arrow-right" >1, hazard characteristics</h1>
The diet is more heterogeneous, and the host is known to involve more than 60 species of plants in 13 families. Among them, cucurbitaceae, solanaceous and leguminous crops are the most seriously affected, and can also harm chrysanthemums, dry lotuses, Dali flowers and other flowers. Among vegetables, melon crops are the most affected. The larvae are dominated by mesophyll cells between the epidermis on the moth-eating leaves, often forming curved snake-shaped tunnels on the leaves. The front end of the tunnel is thinner, growing with the larvae, and the back end tunnel is thicker. Adult feeding and spawning also cause harm, affecting photosynthesis and nutrient transport, and transmitting the virus.
<h1 class = "pgc-h-arrow-right" >2, morphological characteristics</h1>
Adults are 1.3 to 2.8 mm long, pale yellowish brown, the dorsal plate of the middle thorax is bright black, the ventral surface of the body is yellow, the antennae and forehead are bright yellow, the forefoots are brownish yellow, the hind feet are brownish black, and the abdomen is mostly black, but the dorsal edges are yellow. Eggs 0.2 to 0.3 mm, beige, slightly translucent. The larvae are headless maggot-like, colorless at the beginning of incubation, gradually turning into pale orange-yellow, and later orange-yellow, about 3 mm long, a total of 3 years old, and mostly pupate outside the leaves after aging. The pupa is oval in shape, the ventral surface is slightly flattened, orange-yellow.
<h1 class = "pgc-h-arrow-right" >3, prevention and control methods</h1>
(1) Agricultural control
There are many agricultural control measures, mainly including removing the leaves of the insects that are seriously harmful, thoroughly cleaning the countryside after the harvest of vegetables every season, and completely removing the residue of the vegetable plants, concentrating on fertilizer or burning. Strengthen fertilizer water management, and short-term irrigation can be used to kill pupae during the peak period of spotted fly pupae. The use of vegetables with peculiar odors such as garlic and beans and melons that are preferred by spotted divers can reduce the harm.
(2) Physical prevention and control
In view of the yellowing habit of adult insects, at the peak of adult insects, trap adult insects by planting yellow plates or hanging yellow strips inside and outside the greenhouse vegetables and around the open vegetables or in the field. The yellow board can be used to use rectangular wooden boards, plastic boards, the front and back are coated with yellow paint, and then coated with a layer of motor oil or sticky shellac on the outside of the paint, and inserted around the vegetable field with bamboo sticks as support.
(3) Biological control
The natural enemies of the American spotted fly are the submarine fly cocoon bee, the green wasp, the double eagle wasp, etc., and the use of natural enemies can reduce the insect infestation. Foreign countries have carried out the control of spotted fly cocoon bees through indoor rearing and field release, and the control of American spotted fly on greenhouse vegetables and flowers has been carried out. At this stage in China, for most vegetable areas, the focus is to select some biological pesticides and plant pesticides that are largely killer and less harmful to natural enemies, and protect natural enemies by changing the application method and reducing the number and area of application to protect natural enemies and give full play to the natural control role of natural enemies. The antibiotic biopesticide avermectin has recently been widely used in the control of american spotted fly populations and has excellent control effects.
(4) Pharmaceutical prevention and control
Generally, when the leaf damage rate reaches more than 10%, or the number of louvers is more than 30, the drug control is started. At 8 to 10 a.m. and at the peak of egg hatching, spray the liquid evenly against the front of the leaf, once every 5 to 7 days, and spray 2 to 3 times continuously, with good results. Spray the following agents 8 to 10 days after the peak pupal pupal period of larval pupae: 48% Lesben Emulsion 1000 times liquid, 1.8% Efudine Emulsion 1000 times liquid, 10% Nicotine Emulsion 1000 times liquid, Jingyebao I. 1500 times liquid.
The application of biopesticides to control american spotted diving flies has achieved good results in recent years. The first biopesticides selected are 0.2% avirade clear emulsion 1500 times liquid and 25% urea urea no. 3 suspension 1000 times liquid, and the insect control effect of the two agents can reach more than 95%. The appropriate period for control is in the larval stage, spraying every 7 days, 2 to 4 times in a row. The above two agents can be applied separately or alternately. Spraying should be careful, it is best to add 1000 times the pesticide synergist Tolipine in the liquid to increase the permeability, spread and adhesion of the agent, so that the efficacy is higher and longer lasting
<h1 class= "pgc-h-arrow-right" > [Conclusion].</h1>
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