Corn growers should pay attention to: corn aphids and other diseases and insect pests enter the peak period, look at these control methods!

A few days ago, the National Agricultural Technology Center held a corn disease and insect conference chamber of commerce, at which technicians and experts analyzed and predicted that aphids and other diseases and insect pests were the peak period from the end of July to the end of August this year. So the following prevention and control methods, corn growers must take a look, do not let diseases and insect pests lead to the loss of your corn production ah!

I. the general situation of diseases and insect pests in the early stage of corn

Corn borer, armyworm, Helicoverpa armigera, Helicoverpa armigera, Spodoptera litura, underground pest, thrips and sheath blight were the main diseases and pests in the early stage of corn, which occurred in the first generation of corn borer, armyworm, cotton bollworm, armyworm, armyworm,

Second, the occurrence trend of diseases and insect pests in the middle and later stage of maize.

It is estimated that the diseases and insect pests of maize in the middle and later stage of the whole country

Occurred 869 million times per mu.

Pest 592 million mu, disease 277 million mu

It is estimated that the occurrence of diseases and insect pests is more serious in the middle and later period of this year, and the occurrence degree is more serious than that of last year, and the peak period of various diseases and insect pests is from the end of July to the end of August. Corn borer, cotton bollworm, aphids, leaf spot, small spot and brown spot were common and serious in the middle and later stages of maize. Leaf mites, double-spotted long tarsal firefly, Curvularia leaf spot, head smut, smut, sheath blight, stem rot, gray spot and so on occurred in some areas.

The first generation of borer occurred heavily in the northeast of Heilongjiang and Inner Mongolia, the second generation occurred more seriously in the middle and west of Liaoning and Jilin, the west of Xinjiang and the east of Inner Mongolia, and the third generation occurred more seriously in Henan and Anhui and light to medium in other areas. The third and fourth generations of cotton bollworm occurred more frequently in Huang-Huai-Hai and northwest regions, while the damage of peach borer and big borer became more serious in some areas.

The third generation armyworm of leaf-eating pests occurred slightly in Northeast, North China, Huang-Huai, Southwest and Northwest, and moderately occurred in Liaoning, Jilin, Heilongjiang, Inner Mongolia, Shandong, Shaanxi, Shanxi, Henan and Yunnan. among them, some areas with high moth number and suitable climate have the possibility of high-density fields, while double-spotted long-tarsal leaf beetles occur heavily in the northeast and western part of the northwest, and moderate in most other areas.

The occurrence of prickly sucking pest aphids occurred moderately in Northeast, North China, Northwest and Huang-Huai, with more emphasis on drought in Northeast, North China and Northwest China, and moderate occurrence of leaf mites in most areas of Northwest China, especially in Ningxia, Gansu and the central and western parts of Inner Mongolia.

The occurrence of large leaf spot is more serious in the east of northeast, moderate in the central and western part of northeast and northern North China, moderate in most parts of Huang-Huai and southwest, and light in other areas. Curvularia leaf spot and brown spot occur lightly in most of Huang-Huai-Hai; gray spot occurs moderately in southwest mountainous areas and eastern northeast; sheath blight occurs more seriously in most parts of southwest There is a high risk of stem rot in Huang-Huai-Hai. In addition, diseases such as powdery mildew and ear rot will also cause damage in some areas. (detailed data of corn diseases and insect pests in the early and middle and later stages can be found in the data table at the end of the article, which is clearer.)

Practical problems

Maize varieties and planting system are beneficial to the occurrence of many kinds of diseases and insect pests.

There are few varieties resistant to diseases and insect pests in China, and the continuous planting mode of corn in the north is conducive to the occurrence of diseases and insect pests in a large area. Some of the plots with extensive management are conducive to the concentrated occurrence of armyworm. At the same time, in the later stage of maize growth, the plant is tall and the field is closed, so it is difficult to prevent and control corn diseases and insect pests.

Future prediction

The future meteorological conditions are beneficial to the occurrence of maize diseases and insect pests in most areas.

According to the forecast of the National Climate Center, there was more precipitation in the eastern part of Northeast China, the south of southwest China, northern Xinjiang and Jiangnan in August, which was beneficial to the occurrence of humid diseases and pests such as corn borer, armyworm, leaf spot, leaf spot, brown spot and Curvularia leaf spot in the above areas. The precipitation in central Inner Mongolia, most of North China and the north of Huang-Huai is 20-50% less, which is beneficial to the occurrence of drought-loving pests such as cotton bollworm, aphids, leaf mites and double-spotted long-tarsed firefly beetles in these areas. It is expected that one or two tropical cyclones will make landfall or affect China in August, which will be conducive to the spread of southern rust in the south of Huang-Huai.

III. Methods for prevention and control of key diseases and insect pests

Corn borer was crushed and returned to the field to reduce the number of insect sources; Beauveria bassiana was sealed and stacked 15 days before pupation in spring to prevent and control overwintering larvae; insecticidal lamps combined with traps were used in the emergence period of overwintering adults; Trichogramma eggs were released in the early stage of adult oviposition. Spraying the preparation of Bacillus thuringiensis (Bt) at the end of the heart leaf, or spraying chlorobenzamide, thiazide and methamidone reasonably to improve the control effect and control pests such as aphids and red spiders.

Corn stalk rot was treated with suspension seed coating agents such as fipronil, fine nail frost or difenoconazole and tebuconazole to control head smut and root rot. After the corn is harvested, the diseased body of corn in the diseased field should be cleared in time.

Disease-resistant varieties were selected for maize leaf spot diseases and reasonable close planting. Topdressing at the right time to improve plant disease resistance. At the end of corn heart and leaf (8-10 leaf stage of corn), difenoconazole, diniconazole, pyrazolyl carbendazim and Jinggangmycin A were sprayed again every 7 to 10 days according to the incidence. When mixed with brassinolide, it can improve the control effect and reduce the dosage.

Resistant and resistant varieties were selected for maize sheath blight. In the early stage of the disease, the leaf sheath at the base of the stem can be removed, combined with spraying biological pesticides such as Jinggangmycin A, or Sclerotinol, Diniconazole, mancozeb and other pesticides have better control effect, and they can be sprayed again every 7 to 10 days depending on the disease.

Corn aphids were sprayed with thiazide, imidacloprid, acetamiprid and imidacloprid at the initial stage of occurrence and outbreak of corn aphids.

Corn leaf mite cleared the weeds on the edge of the field in time to eliminate the habitat of early leaf mite. When the spot piece occurs, choose the spray or reasonable mixed spraying of daben, thiaben, propargite and avermectin, focusing on the back of the middle and lower leaves of the corn plant around the field, and the weeds on the edge of the field should also be sprayed together; the addition of urea water and spreading agent can restore leaves and improve control effect.

In the early stage of spawning, cotton bollworm released Trichogramma to kill eggs, or sprayed with Bacillus thuringiensis (Bt) and methylvitamin salt at the peak of egg hatching.

The moth ploughed the winter fallow field deeply, killed or cleared the stubble before sowing, and removed the mulch on the corn sowing ditch. Chloramphenicol benzamide, cypermethrin and carbaryl salt can be used for chemical control, and spray, bait and soil can be used for chemical control.

According to the occurrence of leaf spot and corn borer, cotton bollworm, aphids and other pests in the middle and later stage, mixed spraying insecticides and fungicides, popularize the use of high-stem crop sprayer and aircraft spray control technology, and improve the ability of prevention and control in the middle and later stage.