Damage symptoms: corn leaf blight major damage leaves, serious damage also bract and leaf sheaths. Before onset of the lower leaves of the plant, scale-up. The lesions are long fusiform, taupe or yellowish brown, 5-10 cm long and 1 cm wide. Some lesions are larger, or several lesions are connected into large irregular shape, and the leaves are scorched when severe. In rainy and humid weather, the gray spot of black mold can be densely formed on the lesion. In addition, there is a lesion that occurs on resistant varieties, spreading along the veins, showing brown necrotic streaks, surrounded by yellow or light brown chlorotic circles, no spores or minimal spores.
Control methods: use comprehensive measures to resist disease-resistant varieties, strengthen cultivation management, and re-apply drug protection.
1. Selection of resistant maize varieties and maize hybrids resistant to large and small spot diseases.
2. Implement a system of rotation and collapse. Avoid continuous corn, autumn plowing soil, plowing sick plants, eliminate bacteria source; fuel used for corn stover, early spring, after processed, and rid corn borer; compostable plant debris to full maturity, most fat Straw Good to apply in corn fields.
3. Improve cultivation techniques and enhance corn disease resistance. Early sowing of summer corn can alleviate the onset; planting with wheat, peanuts and sweet potatoes, planting in wide and narrow rows; rational irrigation, paying attention to field drainage.
4. Spray control. Before and after corn stagnation, the rate of diseased plants in the field was over 70%, and when the diseased leaf rate was 20%, spraying began. Good anti-effect agents include: 50% carbendazim WP, 50% carbendazim WP, 90% mancozeb, 500 times water, or 40% emulsifier 800 times spray. 50-75 kg of liquid per acre, spray once every 7-10 days, a total of 2-3 times. Commonly used agents: carbendazim, diclofenac, mancozeb, and gram.
Symptoms of corn borer: Corn borer clusters in the heart of the corn seedlings, sucking and sucking. As the plant grows concentrated on the new leaves, it is harmful. At the booting stage, it is densely polluted in the flag leaf and the sheath. While sucking the corn juice, it excretes a lot of honeydew. The honeydew on the leaf surface affects photosynthesis, which is easy to cause mold parasitism. The damaged plant grows weak, stunted, and the yield declines. .
Control method:
1. Agricultural control (1) Elimination of weeds in the field to reduce the source of insects;
(2) Remove the tassel of the central bud strain and reduce the amount of insects;
2. Chemical control of granules. Use 50 ml of 40% dimethoate, 0.5 kg of water, mix 15 kg of sand, and spread 1 g per acre. Use 50% anti-Converse WP, 6-10 grams per acre, 60-75 kg spray with water, or 50 ml with 40% omethoate EC, 50-75 kg water. 75 kg of liquid per acre.
Commonly used agents: Dimethoate, Omethoate, Kangwei, 10% Dagongchen WP.
Symptoms of corn borer: Corn borer is larvae. The first-instar larvae feed on young leaves to form ribs and mosaics. After 3 years of age, the larvae invaded into the stalk, which was harmful to the flower buds, tassels and ears. The nutrient and water transport of the damaged corn was blocked, the growth was weak, the stems were easy to fold, and the ears were poorly developed, which affected the fruiting. The larva damages the cotton into the tender stem, causing the upper part to die, and the cotton bolls cause ringing, decay and deadlock.
Control method:
1. Agricultural control treatment of wintering host straw, in the spring, wintering larvae phlegm and pre-feathering treatment.
2. Chemical control (1) At the end of the spring corn leaf, the rate of flower plant rate is 10%. The mid-leaf rate of the heart leaf is more than 20%, or 100 pieces of corn have more than 30 eggs, which need to be prevented again.
(2) Summer corn is once prevented at the end of the heart. When the ear rate of the ear is 10% or 100%, and the ear filament has 50 heads, it should be prevented immediately.
(3) Gutian needs to be controlled when there are more than 5 eggs per thousand seedlings.
The medicament can be obtained by granules, 50% of parathion emulsifiable concentrate 500 ml and appropriate amount of water, and uniformly mixed with 25 kg of sieved (25-60 mesh) cinder or sand granules. At the end of the corn leaf stage, 1-2 grams of granules are applied per plant. In addition, insecticidal double or hydrobromide, or monocrotophos may be used.
3. Biological control (1) release of Trichogramma, in the end of the spawning period of the corn pupa to the end of the spawning period, the release of Trichogramma 2-3, release 10,000 to 20,000 per acre.
(2) Using Bt emulsion, 200 ml per gram of emulsion containing more than 100 spores per gram, formulated into granules for application or mixed with a spray.
(3) Using Beauveria bassiana to seal, 100 grams of powder per cubic meter of straw (50-10 billion per gram of spores) is sprayed on the mites before the corn mash.
Commonly used agents: parathion, insecticidal double, hydrogen bromide, 4000 IU / microliter of suspension of Bacillus thuringiensis, 8000 IU / microliter of suspension of Bacillus thuringiensis.
Source of information: Modern Rural Newspaper
Yellowing Resistance Test Chamber
A yellowing resistance test chamber is a specialized piece of equipment used to evaluate the yellowing resistance of materials. It is commonly used in industries such as automotive, aerospace, and construction to assess the long-term color stability of materials exposed to various environmental conditions.
The test chamber simulates accelerated aging conditions by subjecting the material to controlled levels of heat, humidity, and UV radiation. These factors can cause materials to undergo yellowing or discoloration over time, which can negatively impact their aesthetic appeal and performance.
During the test, samples of the material are placed inside the chamber, and the temperature, humidity, and UV exposure levels are adjusted according to the desired testing parameters. The samples are typically monitored over a specified period, and any changes in color or yellowing are visually assessed.
The yellowing resistance test chamber helps manufacturers determine the durability and color stability of materials, allowing them to make informed decisions regarding product development and quality control. It can also be used to compare the yellowing resistance of different materials or evaluate the effectiveness of protective coatings or additives in preventing yellowing.
Overall, the yellowing resistance test chamber is an essential tool for industries that rely on materials with long-lasting color stability, ensuring that products maintain their desired appearance even after prolonged exposure to harsh environmental conditions.
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