Corn seedling period is the period with the most species of pests, the most concentrated occurrence and the most serious harm in corn's life. Especially after the wheat straw was returned to the field, it created a favorable environment for some pests. It often causes corn to be bitten by insects after emergence, or to be eaten up on the upper part of the ground. The seedlings are well produced, but due to the harm of insects, the seedlings are short and the monopoly and even the seeds are destroyed, causing irreparable losses. It can be said that the seedling stage is the focus of pest control in corn throughout its life.
Corn emergence is affected by a variety of pests. For example, leafhopper , blind bug, thrips , leaf armor, rye straw fly, cyclone and clams , etc. These insects are mostly pests that harm wheat and continue to harm corn, which can cause large-scale occurrence and must be prevented and controlled.
pest hazard symptoms:
1, thrips , mainly harms the heart leaves. Generally, it harms young leaves in the seedlings, and can secrete toxins to prepare corn growth. There is a silver-gray pattern on the leaves, the leaves fade and yellow, and some leaves break, deform, and distort cannot spread like an ox tail. Corn seedlings can harm, seriously affecting the growth and jointing of corn.
2, straw fly, third and fourth generations, harms summer sowing corn, millet and other crops. corn seedlings can lay eggs, and maggot-shaped larvae will appear in about three days, and symptoms will occur on the two to four leaves of the corn. It mainly harms the heart leaves, causing adhesion and rot, showing dry hearts or various deformities. For example, the heart leaves cannot spread and grow in bunches and bent, the edges of the unfolded heart leaves become broken and yellow, and there are transparent mucus. Some of the leaves on the top of the victim are scattered and wrinkled, some of the leaves appear longitudinal cracks and truncated and white stripes, and some plants have abnormal tillering and cannot grow sticks. Variety, sowing period, and the amount of firewood are directly related to the harm caused.
3, corn cyclone , has a later harm than wheat straw flies. It is mainly caused by larvae that drill from the rhizomes into the seedlings, causing corn to wilt and dry hearts and curl and deformed leaves.
4, sticky insects and other pests . Generally, hazards can be formed in late June. The sticky insects are migratory and often cause serious local hazards to eat up all the seedlings.
5, other planthoppers , leafhoppers, blind bugs, and red spider , mainly harms leaves, pricks and sucks the juice of leaves, causing dead spots and dead spots on the leaves, and in severe cases, it can cause dead tips and dry leaves on the leaves. Although there are many types of pests that harm corn seedlings above, they have several common points:
First, the occurrence time is concentrated and the relative harm time is short. Generally, corn seedlings are the most harmful until late June;
Second, it shows that corn seedlings are prematurely harmful;
Second, it shows that corn seedlings are severely harmful;
Third, the heavy harm of wheat straw and firewood and grass is mixed and extensive field;
Fourth, the differences in severity occur between varieties
Prevention and control methods:
Understand the period and characteristics of these pests, let’s talk about comprehensive control of pests in corn seedling stage.
According to the characteristics of pest hazards in corn seedling stage, two points should be remembered in drug control:
First, it is better to spray the corn after the emergence of the seedlings early rather than late. Master the spraying of the first leaf seven or eight days after sowing.
Second, you need to spray the whole field without just spraying corn ridges.
Preventive and treatment medicine or formula:
thramid or bropronil or methyldiurethramide or thramide and other agents. Mix the following agents, avermectin , imidacloprid , acetamin , pyramidine , enedimethylammonium and other agents, water consumption per mu is 45 to 60 jin of whole field spray.
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