Written by | Chen Huachun
Students of the third advanced training class of passion fruit industry provided photos of their own orchards
What are the characteristics and hazards of red fire ants?
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The fire red ant is an invasive ant species, bright brownish red in the sun, with a body length of 3-9 mm, a slightly square head, a significant depression in the center of the posterior head, a well-developed palate, and 4 distinct small teeth on the inner edge. The dorsal plate of the abdomen is dark brown, the anterior thorax dorsal plate is raised at the front, and there are two ventral stalk knots at the thoracic-ventral junction, the first nodule is inverted "v" shaped, and the second nodule is conical. The abdomen is ovoid in shape with a chelated needle protruding at the end. The anthills are 10–30 cm tall and 30–50 cm in diameter, and the internal structure is honeycomb-shaped.
Due to the lack of natural predators and other constraints, flaming red ants are extremely prone to large population outbreaks. Red fire ants eat seeds, stems, roots, fruits, etc. of a variety of crops, which harm seedlings and cause crop yields to decline; and even damage irrigation systems, reduce work efficiency, and cause agricultural losses. In addition, the fire red ant has active aggression, its chelate is poisonous, the human body is stung by the red fire ant after the pain like fire burns, followed by burn-like blisters, endangering human health.
*Be especially careful when moving in areas where red fire ants are infested, it is best to wear long rubber shoes and apply talcum powder to the outer wall. If you are accidentally bitten, you can wash it with soapy water, and if you are seriously ill, you need to see a doctor in time.
Physical control mainly includes boiling water treatment, nest digging, flooding, liquid nitrogen treatment and mechanical nest breaking method. Due to its high cost, time-consuming and laborious effort, it has been gradually abandoned.
Chemical control mainly uses poisonous bait traps and drug spraying. Years of research and control practice have shown that poison bait is the best way to control red fire ants. Fluosulfamide bait is currently a better insecticide for the control of red fire ants in China. After 10-15 days of continuous use, the mortality rate of red fire ant worker ants can reach 100%. 35 days after the drug, the mortality rate of the nest reached 100%. The dosage is about 10-25 g of the agent / nest.
The "two-stage treatment method" in chemical control is the most commonly used red fire ant agent treatment method. The specific operating procedures are as follows: in the season when the surface temperature is 21-38 ºc, the bait is spread in the dry area around the nest during the foraging stage of the red fire ant, and then directly poisoned with contact insecticides such as liquids, powders or granules after 7-10 days. The "two-stage treatment method" can be treated 2-4 times a year to achieve the effect of completely eradicating red fire ants. Commonly used baits include fenpni, shinoki, meshepin, and ememeson. At the same time, dry and high temperature weather is the use of fluorosulfonamide bait is the guarantee of better control results. Contact-type agents include indochlorvos, bromoniatrile, diazine farmers, etc.
Biological control is a hot issue in the control of red fire ants, which is to control the target pest population at a low level through biological control factors, restore the advantages of native species, and finally achieve continuous control of red fire ants. Biological factors that can control red fire ants have been identified include predatory insects such as flea bees, ant wasps, and aphid cocoon bees; parasitic nematodes such as Stis nematodes and Xenophoria nematodes; predatory mites such as lice-like puppers; and pathogenic microorganisms such as fire ant microsporidium and coccidioides albiosis. Although the law is harmless to humans and livestock and does not cause secondary pollution, it has a limited degree of commodification.
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