Living habits, harmful characteristics and control methods of corn borer, a Lepidoptera pest

Corn borer belongs to Lepidoptera, Pyralidae. Distributed in Europe, North America and Northwest Africa, the dominant species in China is Ostrinia furnacalis. European corn borer is mainly distributed in Inner Mongolia, Ningxia and Hebei. These provinces are mixed areas of European corn borer and Asian corn borer, while Changji is mainly European corn borer. The hosts of corn borer are corn, sorghum, millet, cotton, hemp, beans, sweet potato, sugar beet, tomato, pepper, wheat and so on.

1. Morphological characteristics

The adult has a wingspan of 25 mm, yellowish brown, the female moth is stout, the forewings are bright yellow, and the wing base 2 has brown stripes and a brown corrugated line in 3 places, and a yellow serrated line on the outside. The male moth is thin, the wing color is slightly darker than the female moth, the head, chest, front wings are yellowish brown, and the back of the chest is light yellowish brown. The inner horizontal line of the forewing is dark brown, corrugated, the inside is yellow-brown, the base is brown, the outer horizontal line is dark brown, serrated, the outer yellow-brown, and then outward with a brown band parallel to the outer margin, brown between the inner and outer horizontal lines, and light brown hind wings. The ventral thorn area of the spore organ is shorter than the thornless area at the front, usually with 3 thorns, sometimes with 2 large thorns or 4 thorns containing 1 small thorn, and the average number of thorns is less than that of Asian corn borer.

II. Living habits

European corn borer (Ostrinia furnacalis) produces two generations every year in Changji, overwintering with mature larvae in corn stalks, stubbles and ears. The overwintering larvae began to pupate in early May, the peak period of Eclosion was in the middle and late of May, and the spawning period was in the middle of June. The first generation of adults appeared in mid-July, the peak period of adults and eggs was from late July to early August, the peak stage of larvae was in the middle of August, and the overwintering began in late September. In Changji, corn is seriously damaged, and the rate of damaged plants is 20% to 80%.

III. Characteristics of hazards

The larvae in the heart leaf stage of corn feed on the mesophyll or the undeveloped heart leaves, resulting in "mosaic". After heading, the stalk is drilled, the development of the female ear is hindered and the yield is reduced, and the hole is easy to be reversed. The grain defect and mildew was caused by eating the female ear and tender grain at the panicle stage, and the quality decreased. Production will be reduced by 10% to 30%.

IV. Prevention and control methods

The main results are as follows: 1. The straw of the overwintering host should be treated in time after harvest before the overwintering larva pupation.

2. Trichogramma was released for 2 times from the beginning of oviposition to the peak spawning period of corn borer, with 10 ~ 20 000 heads per 667 square meters.

3. Spray 25% thiazuron No. 3 suspension 600 times or B.T. Emulsion, 200ml of emulsion containing more than 10 billion spores per gram per 667m2, can also be made into granules.

4. Spray it on the stack with 50 ~ 10 billion spores per gram of straw per square meter before pupation.

5. Use 0.5 kg of green worm fungus powder to mix 100 kg of fine soil and apply it on heart leaves, 2.5 kg to 3.5 kg of fungus soil every 667 square meters.

6. Trapping moths with black light combined with egg inspection in the field, under the condition of grasping the number of eggs, the progress of hatching and damage in the field, when the rate of flowers and leaves at the end of the heart leaf of spring corn reaches 10%, more than 20% or 100 plants with more than 30 eggs need to be prevented again. The summer corn should be controlled once at the end of the heart leaf stage, and should be controlled immediately when the ear rate reaches 10% or when there are 50 insects on 100 ear filaments. The medicament can be mixed evenly with 50% parathion EC 500 ml plus an appropriate amount of water and 25 kg of sifted cinder or sand, 1 gram of granule per plant or 0.16 g of 0.1% kungfu granule per plant. It can also be sprayed with 40% Qixingbao EC 800x solution or 40% synergistic methamphetamine EC or 5% rifampicin EC 2000 times. In addition, the retention fumigation method can be used. The most important of the above methods is to reduce the overwintering base of corn borer in order to effectively prevent the occurrence of corn borer and minimize the occurrence of insect pests.

Attachment: there are many kinds of natural enemies of corn borer, including parasitic egg Trichogramma, black egg wasp, parasitic fly, Beauveria bassiana, bacteria, virus and so on. Predatory natural enemies are ladybugs, walking insects, lacewings and so on, all of which have a certain inhibitory effect on the insect population. Corn borer is the main pest of corn. Mainly distributed in Beijing, Northeast, Hebei, Henan, Sichuan, Guangxi and other places. Corn sown in spring, summer and autumn all suffered to varying degrees, especially in summer. It can harm all parts of maize plant, make the damaged part lose function and reduce grain yield. "the corn borer is not human."