How to identify watermelon anthracnose and how to prevent it?

Infection characteristics: watermelon anthracnose occurs in a wide range of time periods, which can affect the whole growth period of watermelon. Leaves, young stems, and fruits were the main targets of infection.

Infected at the seedling stage, black-brown lesions appear on the edge of the cotyledons, the edges fade green and gradually turn yellow-brown, there is a light red viscous substance on it, and the conidia appear black in the later stage. The first step is to choose disease-free seeds, or soak seeds for disinfection before sowing.

After sowing, drainage should be done, especially in low-lying terrain melon fields, to avoid water accumulation. Crop rotation with non-melon crops is also recommended. Prevention and control step 2:

Prune the diseased leaves in time and burn them intensively to prevent expansion; Do not plant densely and keep it well ventilated. Prevention and control Step 3: Fertilizer and water combination management.

Choose fully decomposed organic fertilizer, and try to use high ridges or high furrows to cover cultivation. Control the amount of watering, avoid flood irrigation, and pay attention to small water watering.

Anthrax tends to cause the leaves of plants to turn yellow and wilt a little. You can use plant-specific insecticides, evenly spray on the leaves of plants, and should not be watered during the medication, otherwise there will be no effect.

Anthracnose can occur throughout the growth period of melon crops, but it is the most severe in the late growth period of the plant, resulting in stem and leaf death and fruit rot. To prevent and control watermelon anthracnose, on the basis of doing a good job in comprehensive prevention and control, we should focus on selecting disease-resistant varieties, reducing field humidity to below 70 percent, and doing a good job in protecting the whole growth period.

1. Prevention and control methods of watermelon anthracnose

1. Choose high-quality disease-resistant watermelon varieties, and disinfect seeds and seedlings before watermelon seedlings and transplanting, which can effectively reduce the source of disease.

2. Avoid heavy planting, and it is recommended to implement crop rotation with non-melon crops.

3. Strengthen the application of well-rotted farmhouse fertilizer and microbial organic fertilizer, not partial application of nitrogen fertilizer, more phosphorus and potassium fertilizer, increase the potential of watermelon seedlings, and improve disease resistance.

4. Watermelon is suitable for planting in sandy soil, to prevent water accumulation on a flat ground, pay attention to ventilation and drainage in precipitation, and use drip irrigation to water in a dry environment, and can not flood irrigation, reduce the humidity of watermelon planting and reduce the occurrence of diseases.

5. Reasonable control of planting density and increase light transmission and ventilation can make the photosynthesis of watermelon achieve the best.

6. After watermelon fruit setting, mancozeb, pyrazole dysen, chlorothalonil, difenoconazole and other agents can be sprayed for disease prevention.

7. After the onset of the disease, it is recommended that farmers choose 800 times of 70% methyl tobuzin wettable powder and 2500 times of 25% pyrazoxystrobin emulsifiable concentrate for prevention and control, and spray once every 7 days, and the effect is very good.

2. Symptoms of watermelon anthracnose

1. Leaf infection.

When the leaves are damaged, there will be yellow water-stained round spots, which will expand to brown later, and the lesions will be easily perforated, and dark red mucus will appear in humid environments.

2. Infection of melon vines or petioles.

At first, it is a water-soaked yellow-brown oblong spot, slightly concave, and then turns black-brown, and the whole plant dies after the lesion surrounds the stem for a week.

3. Fruit infection.

At first, there will be small dark green water-stained spots, and then they will expand into round lesions, with neat edges, sunken, dark brown, and cracked fruit rot.

At this point, the introduction of watermelon anthracnose prevention and control is here, if farmers want to grow high-yield watermelons, we must master scientific planting skills and pest control methods, so as to effectively improve the efficiency of watermelon planting.

Strictly disinfect the seeds and seedling soil, cultivate disease-free and robust seedlings, improve the ventilation and light transmission conditions in the field, promote the healthy growth of plants, and improve plant disease resistance. If diseased leaves and fruits are found in the field, they should be removed in time and taken out of the field to be buried and destroyed.

You can use drugs to prevent and control it, or you can use some more nutritious fertilizers, so that you can prevent the appearance of this disease, so that watermelons can grow particularly well.

At this time, pesticides should be sprayed in time, and then timely watering and fertilization are also needed, and then it is also necessary to ensure the right planting temperature and humidity control, and it is also necessary to kill insects in time.

Prevention and control measures for watermelon anthracnose 1Select watermelon varieties with strong disease resistance and no pollution 2Seed treatment 3

Implement crop rotation and stubble 4Strengthen water and fertilizer management 5Grafting disease prevention 6

Chemical starvation in pure prevention and control 1) open field production 2) shed production.

Watermelon Anthracnose Symptoms:Watermelon anthracnose can damage the leaves, leaf stalks, vines, fruit stalks and fruits of watermelons.

The leaves are infected, and the leaves have yellow water-stained round spots at the initial stage of infection, and the later spots gradually expand and are attached to concentric ring patterns, and the lesions are centimeters in diameter, easy to perforate, brown, and the outer edge is often accompanied by a yellow halo. Usually the lesions are more uniform in color, with scattered black dots on them, and when the ambient humidity increases, a pink viscous gelatinous substance appears.

In the later stage, the diseased leaves are prone to dry up and break and premature senescence. When watermelon seedlings are sick, they first appear brown round lesions on the cotyledons, and then the base of the young stem turns black-brown, shrinks, or even folds upside down.

At the onset of the adult plant, there are light yellow water-stained round spots on the leaves, which turn brown in the later stage, the edges are purple-brown, the middle part is light brown, and show concentric wheel lines, and the lesions are easy to cause perforation and dryness after expanding and fusing with each other.

The petiole or vine is infected, and the initial appearance is a water-soaked yellow-brown fusiform or oblong concave lesion, and then the lesion gradually expands and turns black-brown, and the lesion can overflow and perforate, and finally causes the plant to fold and die.

The fruit stalk is infected, and the young fruit is dark in color at first, and then gradually shrinks to death. The fruit is infected, initially as a dark green oil-stained small spot, and then gradually expands into a round dark brown lesion with a concave surface and a ring pattern, usually with the growth of the lesion, cracks will appear in **.

When the air humidity is high, small black particles appear on the lesions, and there are pink sticky conidia masses, and in severe cases, the lesions are patched and the watermelon rots.

Infection cycles

The melon anthrax fungus mainly overwinters on diseased plants or in the ground. The seeds carry the fungus, and the mycelium attached to the mucous membrane of the seed epidermis can also overwinter. In addition, melon anthrax bacteria can also live a certain saprophytic life on old wood in greenhouses or plastic greenhouses.

A large number of conidia produced by melon anthrax on overwintering organs are an important source of primary infection in the field.

The melon anthrax fungus latent inside the seeds can directly cause disease in seedlings. The conidia formed on the lesions of the year were re-infected. During harvesting, the conidia are transported by humans, insects or splashed by wind and rain, and spread to the gourd, and continue to infect the melon during accumulation and storage.