Corn borer will affect corn yield, what are the hazards of corn borer and what are the control measu

Corn borer is the most common occurrence on corn, the most serious damage, the most difficult to control a pest, can eat corn leaves, ears, male ears, borer stems, seriously affect the growth and development of corn plants, resulting in a reduction of 10-30% of yield, every year in the control, the effect is not ideal. So how to control corn borer correctly and scientifically?

After the corn heartworm borrows the corn stalk, it causes very bad harm to the growth and development of the corn plant, and it is very easy to break in windy weather, and causes seedlings to fall, affecting the production of corn. The heartworm harms the male ear and the corn pollination, and the bee pollen is significantly reduced due to the damaged area, which harms the female ear and the seed is pollinated sufficiently, and the lack of seed grains occurs.

The larvae of the corn borer can harm the filament of the female ear, bite off the filament, will harm the pollination of corn, and will drill into the flower ear, gnaw the corn kernel, discharge the fecal sewage, pollute the flower ear, and the damaged corn kernel is moldy, resulting in a decrease in the quality of corn, a decrease in production, and the young larvae harm the young position, and the larvae above the 3 or 4 instars will drill the stem and the flower ear will be harmed.

Corn borer worm in the north and south of China corn production areas are harmful, the north and south of the country occur in the same generation, the whole year occurs 1 6 generations, the temperature in the south is high, the occurrence of analytic geometry is more, the main corn production areas in the north generally occur 1 2 generations, Shandong Province, Henan Province, Jiangsu Province generally occurs three generations a year, mainly occurs at the end of spring to the corn harvest, and there are no old mature larvae that have not been masked, hidden in the corn stalk under the condition of suitable temperature pupation mask.

Corn borer control, to grasp the corn borer of the young larvae of the application of chemical fertilizer, the third instar before the corn borer, mainly in the corn bell mouth stage to harm the heart leaves, grasp this stage to carry out control, can have the actual effect of half the effort.

There are many drugs used for corn heartworm, you can choose phosphine granules, chlorantraniliprole tablets, folk alias this tablet is called "gravel medicine", lose hearts one by one, the effect of preventing and controlling corn heartworm is very good, and the effective period is long, the only defect is time-consuming and time-consuming.

The natural enemy of the corn borer is the red-eyed bee, the red-eyed bee mainly lays eggs in the eggs of the corn borer, to reproduce the purpose of the offspring, and the use of the red-eyed bee to control the safety of the corn borer, no damage to other natural enemies.

In the early stage of corn borer, 1000 times of 5% chlorantraniliprole suspension can be used to spray the first time in the large bell mouth stage of picking corn, and then spray the second time at an interval of 7 days, and then spray the third time at an interval of 10 days, which has a very good effect on the control of corn borerworm. You can also use 500 times liquid emamectin fenapyr + 500 times liquid lice mites to carry out control, and the actual effect is also good.

The use of corn straw returning to the field, the first corn straw returning machine, the crushed corn straw is very broken, there is no feathering of the old mature larvae, in the process of returning the straw to the field is broken by the crusher, destroying the wintering place of the pest, which can greatly reduce the overwintering base of the corn borer and reduce the occurrence of corn borer in the second year.

1. Occurrence rules and hazards. The larvae only harm the heart leaves, causing "mosaic leaves", and then burrow into the male ears to feed when the corn buds, and some 4 5 instar larvae burrow the ear stalk or the female ear and the nearby stem to eat and cause breakage. It is very important to do a good job in the prevention and control of the end stage of the heart lobe to reduce the damage of borer.

2. Prevention and control time and standards. The end of the heart leaf and the peak stage of silk extraction of corn are the appropriate periods for the control of corn borer. There are two ways to determine the end of the heart lobe, one is to pinch the base of the corn horn by hand, and the front end of the male bud can be felt, but when the male ear bud is not visible from the bell mouth, it is the end of the heart lobe.

The second is to pull out the leaves that are still rolled into a cylindrical shape in the bell mouth for autopsy, such as peeling off 4 or 5 leaves to see the male panicle, that is, the middle stage of the heart leaf; After peeling off 2 3 leaves, the male spike is at the end of the heart lobe.

3. Prevention and control measures. First of all, the overwintering host straw, root stubble, cob, etc., should be treated, especially before the emergence of overwintering insects in spring. It is an effective way to reduce the occurrence of corn borer by means of burning, guillotine, dipping, and drug sealing incision to reduce the number of insect sources.

At the end of the corn heart leaf, the corn borer bites the unheart leaf, resulting in the "mosaic leaf" shape, and the general treatment is carried out when the mosaic plant rate reaches 10%.

Environmental factors: The physiological habits of corn borers determine that they like high temperature and high humidity environmental conditions, so generally 7 9 is in the high temperature and rainy season, and the disease is more serious; Even in some areas, corn borer damage occurred in June. In terms of temperature and humidity, the temperature is 22 28 ° and the relative humidity reaches about 60%, which is the most suitable for the development of corn borer.

Adult eggs and hatching are most vigorous at a relative humidity of about 90%. In the corn growing season, it can just meet the temperature and humidity conditions of corn borer; This has led to the high incidence and common occurrence of corn borer. Planting Factors:

Affected by different sowing dates, the harm of corn borer is also different. If the heart-leaf stage of corn is at the peak of adult egg laying and larval hatching; Then the severity of the damage can be expected. At the same time, the mixed planting mode is often more serious than that of monoculture. Reducing the planting area of spring sowing and expanding the planting area of summer sowing can effectively reduce the damage of summer maize.

Insect population base: The size of the overwintering insect source base is directly proportional to the number of eggs laid in the field and the number of damaged plants. The large base of insect population, the more the overwintering base, will also affect the degree of damage of corn borer in the coming year.

The occurrence period of corn borer is at the summer corn ear stage, and the plant is tall and not easy to be applied, which makes the occurrence of corn borer at the ear stage have a tendency to aggravate and aggravate the occurrence of ear rot. The control technology of corn borer has been relatively mature, through the planting of insect-resistant varieties, the use of red-eyed bee, Beauveria bassiana, BT granules and other biological control, frequency vibration insecticidal lamp light trapping and other physical control, insecticide spray or granule filling and parasitic agent irrigation can be controlled.

The effect of corn borer on corn seedling stage is relatively small.

Corn borer (corn borer) control methods

Prevention time

Corn borer can affect the entire growth period of corn, whether it is spring corn or summer corn, and can be sprayed to control young larvae at the seedling stage of bright corn.

Corn seedlings 6 leaves, and then spray again to control the heart worm. Corn grows to waist-high and is a critical period for the prevention and control of corn borer affecting male ears during the big flare stage. Corn grows to the ear stage, and it is a critical period for the prevention and control of corn borer, and the ear spraying can greatly reduce the control effect of corn borer worm with half the effort.

The control of corn borer should be mastered in the early larval stage, which can achieve twice the result with half the effort.

Prevention and control agents

In the corn seedling stage, corn borer larval occurrence stage, 8 ml of chlorantraniliprole suspension, 20 ml of lice mite urea suspension, mixed with 15 kg of water, can be sprayed on the whole corn seedlings. When corn seedlings grow to the big flare stage, it is best to use zinc sulfur granules or BT insecticide granules, and then throw the corn heart, which can concentrate on the control of corn borer larvae hiding in the heart leaves, and the effective period is very long. It can also be sprayed with 1000 times of cyhalothrin + 25 grams of emamectinethcarb suspension agent mixed with 15 kg of water at the corn flare stage, which has a good control effect on older borers.

Beauveria bassiana spore powder for the control of corn borrower, prepare 1 kg of Beauveria bassiana spore powder, and 10 kg of briquette ash after incineration, mix evenly, and throw it into the corn heart leaf at the corn horn stage, which has a good control effect on the larvae of corn borrower.

Auxiliary prevention and control methods

Corn borer adults, phototaxis, especially the trend of black light is stronger, the black stuffy only wide light hanging to two meters high, it can attract about 35 acres of corn borer adults, can be concentrated control, in addition, the selection of corn varieties with strong resistance to diseases and pests also have a certain effect on prevention.

Corn borer worm is one of the very serious pests of corn, corn borer is also called corn borer, as long as it is planted corn, basically every year, with the expansion of corn planting area, corn borer also has a tendency to aggravate the impact, corn stalk through the bite of the kernelworm, will cause corn lodging aggravation, and even affect the normal ear setting of corn, corn empty pole rate increases, after the insect infestation corn ear, the grain of corn ear is polluted, which will have a very great impact on the yield and quality of corn.

Corn heartworm mainly feeds on the leaves of the aboveground parts of corn, corn cobs, corn tassels, corn stalks, etc., which can affect the entire growth period of corn. After hatching at the seedling stage, the larvae burrow into the heart leaves to feed on the young leaves, and the damaged corn grows leaves with transverse holes, and the older larvae eat the stems, corn cobs, corn kernels, corn ears, cob filaments, etc., which will cause a lot of corn yield reduction.

Large spot disease mainly harms leaves, and can be dangerous bracts when severe, and it is a blue-gray spot at the beginning of the disease, and then gradually spreads, and the whole leaf is covered with large irregular spots, and there is black mold on the spot. Small spot disease affects leaves and stems, and oval or rectangular spots appear at the onset of the disease, and then after the vesicles rupture, rust-colored powder appears, which is the pathogen summer spores; In the later stages of development, black oval or elongated bumps appear on the leaf surface of the corn, and when they are cracked, they reveal a black-brown winter robe.

In the early stage of corn rust, the main appearance is that light yellow elongated and ovoid brown pus scars grow on both sides of the leaves, and then after the vesicles rupture, rust-colored powdery matter appears, which is the pathogen summer spores; In the later stages of development, black oval or elongated bumps will appear on the leaf surface of corn. When it is cracked, it reveals a black-brown winter robe. If the insect pest is very serious, the plot area is relatively large, it is necessary to use the method of spraying drugs, spraying can be used, 50% content of phosphine, according to a solution of 1 to 800, generally sprayed once, remember, the drug should not be excessive, this drug, the ground tiger mole cricket is effective.

The occurrence of corn borer is closely related to precipitation, and the environment with air humidity of about 80 is the most favorable for disease damage, especially in the period of more precipitation from late June to late August, the incidence of corn borer is relatively high. Pathogens generally invade from wounds or stem joints, heart leaves and other young tissues, especially after being infested by pests such as bacterialhorses, Swedish flies, aphids, etc., which will aggravate the occurrence of disease, high temperature and high humidity are conducive to the epidemic of diseases, and the disease is more serious in the south or field irrigation halls, low-lying or poorly drained plots.

Curvularia cornis leaf spot and large and small spot disease At the beginning of the disease, spray with 50% carbendazim wettable powder 500 times, or spray with 70% thiophanate-methyl, wettable powder 800 times, it is recommended to spray again every 7 10 days! No matter how long it takes a week, crops within a radius of twenty or thirty kilometers will have different degrees of armyworm pests and diseases. The most serious corn seedlings only have one leaf left, and once we find that there are pests and diseases in the corn field, we need to spray insecticides in time.

When encountering corn diseases and insects, you can spray pesticides to kill the insects, and then fertilize it to supplement nutrients.

Pesticides should be sprayed or the surrounding weeds should be treated, and the temperature of the surrounding environment must be controlled to avoid these pests and diseases.

With drug control, pesticides can be sprayed inside the corn field, which can kill some pests.

In the middle stage of corn heart leaves, take Beauveria bassiana and fine sandy soil, mix them in the ratio of kilograms: 5 kilograms, prepare granular agents, and put them directly in corn heart leaves, which can play the purpose of killing corn borer larvae. Another method is to use Beauveria bassiana sealing technology to control corn borer, spraying Beauveria bassiana powder on the residual corn straw before the larvae overwintering in early spring begin to recover, with a dosage of 100 grams per cubic meter of straw stack, which can effectively control corn borer.

First of all, we must spray some pesticides, and we must prune the branches and leaves in time, and we must water and fertilize, and we must observe the production status of corn in time.

It is necessary to spray chemicals in advance, and it is also necessary to monitor in real time, so that the presence of this insect can have a good control effect.

First of all, when planting, we must choose the soil is more fertile and broad land, and we must use farmhouse fertilizer when fertilizing, do not use the fertilizer bought outside, and often water the plants, but also to prevent the occurrence of pests and diseases, if there are small insects, then we must spray insecticides in time. I think that if we can do a good job in these aspects, we will definitely be able to prevent the phenomenon of corn pests and diseases.

Generally, the pathogen is from the wound or heart leaf, the relatively young tissue into the corn, you can spray some anti-virus agents, in the fertilization, you can add some compound fertilizer to improve the fertility of the soil, timely watering, supplement the sun.

You can spray pesticides for prevention and control, select well-bred corn varieties for planting, remove disease residues in time, carry out reasonable fertilization according to the condition of the field, and trap adults with black lights at night.

When the sun is about to set, you can spray some tetrachlorofen pesticides, which can control pests and diseases, and the insect control effect is better.