Prevention and control of diseases and insect pests of edible fungi, how to control orchid anthracnose

Symptom

Orchid anthracnose is infected by anthracnose, the leaves suffer the most, other organs can also be damaged. In the early stage of the disease, reddish-brown or black-brown round or oval spots appeared in the middle of the leaf, and the disease spot on the leaf edge was semicircular. With the expansion of the disease spot, many small disease spots will heal to form wavy or striped dark brown disease spots. If the leaf tip is sick, the disease spot will spread downward, causing the leaf to die in segments; if the disease occurs at the base of the leaf, it will cause the whole page to die seriously. In the later stage of the development of the disease, the disease spot looks like a wheel, at which time the center color of the disease spot becomes light and grayish white, and there will be longitudinal cracks on some disease spots.

Morbidity regularity

The pathogen of anthracnose began to infect the old leaves of orchids in early April, expanded rapidly from May to June, aggravated the disease in the plum rain season, and gradually stopped after July. The new leaves of orchids began to develop at the end of July and developed rapidly in August. If a typhoon strikes at this time, the leaves and plants will be injured and the disease will be aggravated. The pathogen of orchid anthracnose can survive on the leaf for 9 months and in the plant for more than a year, even if the pathogen is scattered on the potted topsoil where orchids are grown. You can live for about a year. So once you get sick, if you don't treat it, the disease will happen year after year.

Prevention and cure method

The prevention and control of orchid anthracnose should first strengthen the cultivation and management of orchids. Orchids raised indoors should be ventilated and transparent to reduce environmental humidity. Outdoor open-field cultivation should build shade sheds to avoid exposure and torrential rain. Orchid planting should not be too dense, pots and pots should maintain a certain distance. Watering should be slowly irrigated in the basin soil to avoid the whole plant drenched and make the bacteria spread downward. In winter and early spring of the following year, special attention should be paid to keeping warm so that it will not suffer frost and frost damage, so as to enhance its ability to resist diseases. In the early stage of the disease. Diseased leaves can be cut off to restrain the spread of the disease. Chemical control can be used to spray 50% carbendazim wettable powder 500 times or 50% topiramine wettable powder 500 times in the plum rain season and July-September typhoon season, once in about 10 days and 3-4 times in a row.