Symptoms of black rot Prevention and control methods of black rot

Grape black rot occurs in all grape producing areas in China, except for a few areas, and the damage is generally not serious. Sometimes, due to the large number of infection sources, suitable environmental climate or susceptibility to diseases, etc., large losses can also be caused.

Black rot mainly damages grape fruits, especially near-ripe fruits, and can also damage leaves, petioles, shoots and other parts. The symptoms are as follows.

Fruits: small purple-brown spots at the beginning, gradually enlarged, brown at the edges, grayish-white in the middle, slightly sunken. As the fruit matures, the lesion can continue to expand to the entire fruit surface, and the diseased fruit is covered with small black dots with clear grains (Color Figure 39), which are the conidia or ascomycetes of the pathogen.

Leaves: Lesions mostly occur at the leaf margins, initially with reddish-brown near-circular small spots, and then expand into large spots with black edges and grayish-white or light brown spots in the middle (Coloring 41), with a diameter of up to 3 4 cm, and many small black spots on the lesions, arranged in a faintly visible ring-like shape (Coloring 42).

Petioles or new shoots: dark brown, oblong slightly sunken lesions with many small black spots on them, and the growth of new shoots is stunted.

It is mainly harmful to leaves. The lesion gradually spreads from the lower leaf to the upper leaf. The surface of the leaf is partially yellowed, and there are gray-white lesions with indistinct outlines on the back of the leaf, and a dense gray-white mold layer.

Soon after, mold also forms on the surface of the leaves, and finally, the leaves curl up and dry up, resulting in poor fruit set, poor fruit growth, and early coloration. Greenhouse and greenhouse cultivation often occur. In arch trellis cultivation, it mainly occurs during mulching, but when the humidity is high, it continues to spread even after the plastic film is removed.

Tomatoes grown in greenhouses and greenhouses in early spring, late autumn and winter with insufficient ventilation can be affected. Dense planting and excessive irrigation are prone to disease, growth failure, especially during harvest fertilizer, the incidence is very high. As a precautionary measure, resistant varieties should be cultivated, ventilation should be taken into account, and over-irrigation and dense planting should be avoided.

Medication period Control object Control method Crop seedling setting period (planting and seedling water) and leaf development stage Prevention.

Bacterial wilt, root black rot, black shin disease early and middle stage.

At the first sight of the disease, the top leaves appear softened and slightly wilted at noon, and can recover in the morning and evening, with mild lesions at the root terminals)**.

Bacterial wilt, root black rot, black shin disease Precautions 1In time, the whole plant with wilting and serious root lesions should be cut off from its rhizomes, and the diseased holes should be sterilized.

2 In case of heavy rain within 3 days of medication, this product should be used again 1 day after the rain. Eradicate the diseased plant in time and carry out chemical sterilization treatment.

3. In the rainy season, dig deep drainage ditches in the tobacco fields in the sick area, drain the water in a timely manner, and reasonably lay out the drainage ditches to avoid the flow of water from the sick area to the healthy area, resulting in cross-infection.

4. When irrigating, the root system of the whole plant should be fully irrigated. Product Advantages This product is a plant-derived Chinese medicine liquid biological preparation, green and pollution-free, broad-spectrum, non-pesticide harm, no residue, no pollution, no drug resistance, sustainable use; It has the effect of promoting roots and strengthening seedlings, and can effectively improve soil quality and improve crop disease resistance.

It is easy to get black rot when raising more meat in summer, so I collected these treatment methods and used them later.

Succulent black rot is caused by the fungus Fusarium oxysporum (which does not necessarily cause the same fungus in different plants), a facultative parasitic fungus that can both infect plants and survive in soil. Like other plant pathogens, there is infraspecific differentiation and can infect many plant hosts.

In addition to the survival of leaf mold pathogens attached to the surface of glass, plastic film, brackets, pillars and other surfaces in greenhouses, greenhouses, small arches, etc., the rolling also remains on the diseased leaves to form a source of infection. It can also be transmitted through seeds. The conidia album chain generated on the lesion is only blown to the leaf by the wind, and the hyphae invade from the stomata after germinating the germination tube, and the disease occurs about 2 weeks later, generating numerous conidia on the back of the leaf.

These conidia are scattered by the wind and gradually spread. Leaf mold prefers a temperature of 20-25 and a humidity of more than 95%.

1) Implement a quarantine system, and it is strictly forbidden to bring diseased seedlings into the new area of Huaikuan.

2) Diseased seedlings can be soaked in 48 hot water to kill some nematodes; Or dip the root with 10% imidacloprid wettable powder 1000 times.

3) The diseased plants were excavated in a 55 60 cm ring around the canopy to cut off the topsoil, sprinkled with 3% phosphine granules kilogram hectares, and applied in early March and mid to late July in Guangdong.