Corn borer
Corn borer, commonly known as arrow rod worm, corn drill heartworm, etc., belongs to the lepidoptera borer family. Corn borer is a major pest in the world, with more than 150 species of host species, of which corn is the most harmful. It can cause a loss of 5 to 15% of production per year.
Hazard characteristics
Adults: Adults of the corn borer are 13 to 15 mm long, with a yellow body (female) or yellow-brown (male) forewings with dark brown ripples on the inner transverse line and dark brown serrated outer transverse lines.
Eggs: Corn borer egg blocks are arranged irregularly by 20 to 60 eggs in an irregular fish scale, the single eggs are oval and flattened, the milky white (like wax droplets) gradually turns yellowish when they are produced, and there are black spots in the center before the eggs hatch (commonly known as black-headed eggs).
Larvae: Corn borer larvae hatch with a black 1.5 mm head shell and a milky white translucent body, and the mature larvae are 20-30 mm head shell brownish black, the body stain is white, and the dorsal hair patch is obvious.
Pupae : Corn borer pupae 15 to 19 mm, spindle-shaped, yellow-brown, dense back of the body is densely covered with small wavy horizontal wrinkles, black-brown buttocks, with 5 to 8 upwardly curved spines at the ends.
Prevention and control strategies
Before the feathering of overwintering larvae, the treatment of the stalks of overwintering hosts such as corn, sorghum and cotton is an effective measure to eliminate overwintering larvae and lower the source base of overwintering insects. In the area of 3 generations, try to expand the sown area of summer maize, compress the spring sowing area of host crops such as corn, sorghum and millet, and reduce the feeding sources and breeding sites of the 1st generation of maize borers, so as to control the occurrence of the 2nd and 3rd generations and reduce the harm to summer maize.
Using the habit of female moths to lay eggs on tall, dense and vigorously growing host plants, select plots adjacent to wintering sites about one month before normal sowing of spring maize to plant small areas of enticing belts and enticing fields, or strengthen fertilizer and water management for a small number of early-sown spring maize plots to promote their early onset and induce insects to lay eggs.
Planting borer-resistant varieties is an economical, effective and safe measure to control borers. Combined with the field management measures of some crops, especially the inter-seedling, fixed seedling and cotton whole branches, beating, topping and other measures can directly remove insects and eggs, and the control of corn borer is more closely related. For example, the first generation of corn borers is harmful at the cotton seedling stage, which can be combined with inter-seedlings and fixed seedlings to remove insect plants; the 2nd generation of corn borer young larvae are first infested in the young head and petiole of cotton, and then the stem is mothed, which can be combined with the whole branch, the top to remove the petiole, young tip and branch, and brought out of the field for centralized treatment, which can significantly reduce the damage of corn borer to cotton.
Physical control: use high-pressure mercury lamps to induce insects, specifically: in the overwintering generation of adult feathering period, 200W or 400W high-pressure mercury lamps are installed in a more open area of the village, with a light distance of 150m (200m with 400W bulbs). The bulb should be installed on the waterproof lamp head, fixed with iron wire, and a circular pool with a diameter of lm under the lamp, brick structure and cement structure can be repaired; you can also dig a pit of the same size under the lamp, and the pit is paved with plastic sheet, but it is subject to no leakage. Put water in the pool 6cm deep, add about 100g of washing powder, mix well. Generally, change the water once every 3 days and add laundry detergent. If the water change time is not up and the water in the pool is insufficient, it can be added at any time. It is advisable to hang the bulb in the center of the pool 15 cm from the water surface. From the beginning to the end of the feathering of the overwintering adults, the lights are turned on at 20:30 a.m. and turned off at 4:00 a.m. the next morning. Since the amount of moths is usually very large, the moths in the pond are fished out and buried deep every morning.
Biological control: From mid-April to early May each year, before the overwintering larvae pupate, the remaining host crop straw and root stubble are sprayed and sealed with white zombie spore powder, and the amount of bacterial powder is 100g/m³, and the stack surface is sprayed with 1 point per square meter, and the bacterial powder can be seen on the stack surface. Or in the middle of the heart leaf, the white zombie spore powder with a bacterial content of 10 billion to 50 billion / g is mixed with skg sieved cinder and mixed well to make 1:10 white zombie granules, and applied to the corn heart leaf according to 2g per plant. 8000IU/mg Thuringiensis wettable powder 3kg/mu, mixed with 10kg fine sand to make granules, applied in the middle of the corn heart leaf, the control effect is better. Summer maize is used as mung beans to increase the population of natural borer eggs such as red-eyed bees and other borer eggs to control the occurrence of borer infestation. Or breed in large numbers to release parasitic bees to cure borers. In addition, the sexual pheromones of the corn borer can be used to trap male insects or release a large number of sexual pheromones, making it difficult for males to find female insects and unable to cross the tail. The optimal time for the control of corn borer is the end of the heart leaf, that is, the large horn mouth stage, which is the critical period for the control of corn borer.
Pharmaceutical control:
In the 2-3 instar larval stage, the following agents can be used:
25% cypermethrin octiophos emulsion 80-100ml/mu;
20% octylthion emulsion 200-250ml/mu;
30% methamidophosphate acetate emulsion 125-230ml/mu;
48% chlorpyrifos emulsion 70-90ml/mu;
80% dichlorvos can be solution 80-100ml/mu;
40% methyl octylthion emulsion 50-100ml/mu;
40% hydroamine thiophos emulsion 75-150ml/mu;
40% triazolium emulsion 60-100ml/mu;
25% quetiphos emulsion 120-150ml/mu;
20% pyridazine thiophos emulsion 75-l00ml/mu;
50% diazinphos emulsion 80-120ml/mu;
20% iminothiophos emulsion 250-300ml/mu;
10% acarburide wettable powder 100-200g/mu;
50% methylpyrimidine phosphorus emulsion 80-100ml/mu;
30% chlorinin phosphorus emulsion 160-200ml/mu;
40% pyrimidine phosphorus oxide emulsion 150-300ml/mu;
20% butyl sulk Budweiser emulsion 200-250ml/mu;
75% sulfur sunway wettable powder 60-70g/mu;
25% sedentine butter 200-250ml/mu;
50% borer soluble powder 70-100g/mu;
25% menaphthene wettable powder 200-300g/mu;
2.5% cypermethrin emulsion 25-50ml/mu;
2.5% cypermethrin emulsion 20-30ml/mu;
5.7% cypermethrin emulsion 30-40ml/mu;
20% zootylhydrazide suspension 25-35ml/mu;
24% methoxychlorhydrazide suspension 20-30ml/mu;
1% methylaminoavermectin benzoate emulsion 5-10ml/mu:
8000IU/ml Thuringiensis wettable powder 100-200g/mu to water 40-50kg evenly sprayed.
At the height of young larval age, there is no harm in using a pack of fixed (8.2% mevin carbohydrazide) emulsion oil, 20 ml of water and 15 kg of spray mixed with corn field herbicide.
At the end of the corn heart leaf, the following agents can be used: 5% octanthio and triophos granules 150-250g/mu; 10% diazine phosphorus granules 0.4-0.6kg/mu; 1.5% octylthiophos granules 0.5-0.75kg/mu; 40% anti-borer phosphorus emulsion 150-250ml/mu; 3% cadavec granules 2-3kg/mu; 5% propyl-sulfur BACT granules 2-3kg/mu, mixed with fine soil 15-20kg perfusion.
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