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Hello everyone, I am the Pippi shrimp selected by the first Zhengda wing. Recently, farmers have reacted that many neatly arranged small holes have appeared on some corn leaves in the garden, as if they were punched by a puncher; it is not like a disease, but it is not a familiar symptom of insect pests. In fact, this is the manifestation of corn borer pests, the field is also commonly known as corn "drill heartworm", which will cause damage to heart leaves, stems, and spike sticks. So, what are the specific habits of this pest? How to prevent it? I'm going to talk to you about it today.
<h1 class="pgc-h-arrow-right" data-track="3" >, understand pest habits, and control is more comfortable</h1>
1. Physical characteristics
Corn borers are most severely affected by corn at the larval stage, and the appearance of larvae varies slightly from age to age. Only when we have a sufficient understanding of its form can we quickly identify and immediately prevent and control it. They are about 20-30 mm long, the head is dark brown, the color of the insect body is light brown, dark gray-brown, grayish yellow, etc., there are longitudinal black-gray stripes on the back of the insect, and there are regularly arranged small round spots. Adults are moth-shaped, mostly yellow-brown, with transverse reddish-brown wavy stripes on their wings. You can refer to the following figure.
2. Harmful habits
Corn borers are more rampant in high temperature and high humidity environmental conditions, can breed multiple generations a year, often at night. For the Guangdong region, the corn borer is in full bloom from mid-March to mid-September. With the different phenological periods of maize, the focus of damage of corn borers is also different. Taking spring maize as an example, they bite the heart leaf at the early spring heart leaf stage, moth the female ear and male ear at the pregnant ear stage, feed at the top of the filament at the silk stage and then moth into the panicle shaft and grain, and overwinter on the ear shaft and residual stem after the corn harvest, and continue to breed and invade in the following year.
<h1 class="pgc-h-arrow-right" data-track="30" > second, understand the symptoms of harm, early detection, early prevention</h1>
(1) Heart lobe:
Heart leaves are the first to be harmed by corn borers, and they are also the ones we need to pay the most attention to. Because the corn borer is very hidden, the difficulty of prevention and control is mainly here, and only by finding its traces as soon as possible can we prevent the expansion of its harm. The larvae will crawl into the heart leaf to feed on the heart leaf flesh, and when the heart leaf is unfolded, neat small holes appear, resulting in "flower leaves".
(2) Stem or spike stalk:
As the larvae grow, they will moth into the stem or ear stalk, and we will not easily find their insect bodies. However, at the orifice of the moth it causes, there are often piles of yellow-brown powdery excrement, which can become a way for us to identify. In addition, the stems that encounter corn borer food are very fragile and are easy to bend from the borer holes in the wind.
(3) Corn cob:
Due to the outer skin of the corn cob, it is also difficult to find in the early stages of the corn borer diet. Unless the outer skin has been peeled, the corn kernels can be partially eaten, leaving gaps and decaying black mold. However, since corn borers enter the corn cob often from the top of the filament to eat in, so we can pay more attention to the top, observe whether there is black rot and excrement, and peel the corn in time to check.
<h1 class="pgc-h-arrow-right" data-track="31" > third, learn prevention and control methods to prevent the harm from expanding</h1>
The corn borer should be mainly prevented and supplemented by treatment, and the best period for prevention and control is its spawning period, that is, the corn trumpet mouth period, which is also the period of 11 stretched leaves.
1. Biological control
The red-eyed bee is a natural enemy of the corn borer and feeds on the eggs of the corn borer. Therefore, we can release red-eyed wasps during the spawning period of corn borer for control. Generally, the release of 10,000-20,000 heads per mu has a better effect, which can be divided into 2-3 releases, and the release effect is better on sunny days.
2. Physical prevention and control
Due to the phototropic properties of adult corn borers, we can trap adults with black light or frequency-vibration insecticidal lamps after finding signs of adult activity. Place a lamp every 30-40 acres of land, the height of the lamp is 1.5-2 meters from the ground, and the effect is better when a large area is used continuously.
3. Chemical control
Because corn borers often hide in corn stalks and corn cobs for harm, the control effect of spraying is not particularly ideal. Especially in the late stage of corn growth, the height of the straw is too high, and it is difficult to spray by hand. The best chemical control periods are the heart leaf stage and the corn trumpet period.
The heart leaf stage is mainly controlled by the method of sprinkling granules, which can be controlled by 0.5% octyl thion granules, 2.5% ceviyin granules, 3.6% insecticidal double granules, and Thuringiensis granules. 2 grams per plant, after the dew dries in the morning, the granules are concentrated in the heart leaves, and the leaves are shaken so that the particles roll down to the bottom of the heart leaves.
The medication in the loudspeaker period should be mainly to kill eggs, and the more effective pharmaceutical ratios are: 5% methyl vitamin salt 20 grams + 5% chlorofuran benzamide 20 ml; 12% insect mite nitrile · methyl vitamin salt 40 ml + 5% lice mite urea 20 ml, etc., mixed with water 60-80 for a uniform spray.