Borers are borer moth pests, completely metamorphosed insects, from the egg → larvae → pupae → adults (moths) into a generation. Mainly including the dinatural borer, three borer, large borer, Taiwan rice borer, brown edge borer, etc., is the most common and harmful type of pest of rice in China, commonly known as "drill heartworm" or "borer heartworm".
Symptoms of hazards of dimorphic borers: the hatching larvae of rice at the seedling stage and the tillering stage first cluster in the leaf sheath, causing damage to the dead sheath; the larvae that grow to 2 or 3 years old disperse into the stem and harm into the dry heart; the rice gestation stage and the ear extraction stage, the larvae moth into the hazard, resulting in dead pregnant ears and white spikes; the harm caused by insect injuries during the milk ripening stage, which seriously threatens rice production. Ants hatched on the same egg block harm nearby rice plants, and dry hearts or white spikes often appear in clumps, resulting in "dry heart clusters" or "white spike groups" in the field.
Nihua: 1?Female adult 2?Male adult 3?Larva
The appropriate period for the control of dimorph borer is during the incubation period of the young borer. First, agricultural control is adopted, mainly to eliminate the source of wintering insects, irrigation to kill pupae and the selection of insect-resistant varieties. Second, the adoption of physical control, the installation of frequency vibration insecticidal lamps to trap adult insects, rice field ducks, protection of frogs, etc. have a good control effect, which can effectively reduce the source of insects in the next generation. Third, pharmaceutical control: when 5 to 7 days after the peak of incubation in the tillering stage, there are 100 "dry sheaths" per mu or a dry sheath rate of 1%to 1.5%; or when the fracture period, the plant damage rate reaches 0.1%, pharmaceutical control should be carried out. Per acre with 200 to 250 ml of 25% insecticidal dihydrate, or 100 ml of 20% triazolium emulsion, or 40 ml of 5% fipronil suspension agent, 50 to 60 kg of spray on water or 200 kg of water. It can also be used to make 80% insecticidal single powder 35 to 40 grams, or 5% insecticidal double granules 1 to 1.5 kilograms mixed with wet fine dry soil 20 kilograms to make medicinal soil for sprinkling. When applying the drug, it is necessary to pay attention to the amount of water required, spray the fine mist evenly, leaving no blank space; after the drug, the field maintains a water layer of 3 to 6 cm for 3 to 5 days. It is necessary to pay attention to the rotation of agents to delay the development of drug resistance.
Symptoms of sanhua borer hazard: the larvae eat rice stalks, suffer in the tillering stage, and the heart leaves are longitudinally rolled into a false dry heart to cause dry heart seedlings; the damage at the gestational panicle stage causes the dead pregnant panicle; the white panicle is caused by the damage during the broken ear extraction stage; and the insect injury plant is caused by the damage after filling. The appropriate period for the prevention and control of sanhua borer heart seedlings is more than 50 to 60 "hazard groups" per mu or the hazard rate of the cluster is 2% to 3%. Prevent the appropriate period of white panicles in the egg mass more than 100 ~ 120 blocks / mu, prevention and control at the fracture stage, if the amount of occurrence is large, the panicle stage is prevented again. When agricultural control is taken, the following is mainly to eliminate the overwintering larvae in winter; in the peak period of spring pupal pupae, irrigation floods the rice roots for 3 days to kill the overwintering insect pupae in the rice stubble. Pharmaceutical control and precautions are the same as dicarbonate borers.