Prevention and Control of Diseases and insect pests in Orchid Culture

(1) Orchid anthracnose

Symptoms: the disease harms orchid leaves, often occurs at leaf tip and leaf edge, and can also damage orchid fruit. At the beginning of the disease, the leaf showed a round or oval spot, then gradually enlarged, and in the later stage, the center of the spot was light. Brown or grayish white, dark brown or dark brown edges, clear boundaries between disease and health. The expansion of the disease spot is often limited by the leaf vein, and the disease spot on the leaf tip is often triangular, spreading downward from the leaf tip. The disease spot on the edge of the leaf is often semicircular, the disease part is brittle, and sometimes ruptured longitudinally. The size of disease spot varies with the width of orchid leaves. The spot on the fruit is dark brown and fusiform. In the later stage, a black dot-shaped conidial disk appeared on the disease spot.

Prevention and control methods:

① cut off the diseased leaves and burn them in time.

② should strengthen the cultivation management to keep the orchid cultivation environment ventilated and transparent, and the watering should be injected from the edge of the flowerpot to avoid watering.

③ chemical control. In the early stage of stubble disease, spray 25% carbendazim wettable powder 500 times and 70% mancozeb 600 times. According to the condition, the patients were sprayed continuously for 2 times, once every 7 to 10 days.

(2) Orchid leaf spot

Symptoms: orchid leaf spot occurs on the leaves, often in the middle of the leaves, the disease spot is brown spot at first, after enlargement, the disease spot is long oval to long strip. The margin is reddish brown, the inside is grayish brown. In the later stage, there are black grains scattered on the disease spot, that is, the conidium of the pathogen.

Prevention and control methods:

① should pay attention to timely disinfestation and improve ventilation.

During the onset of ②, 0.3% murmur0.5% Bordeaux solution or 65% Dyson zinc 800x solution was sprayed regularly.

(3) Orchid round spot disease

Symptoms: orchid round spot invaded the leaves. At the beginning, the leaves produced reddish brown dots, which rapidly expanded into semicircular or round dark brown spots. In the later stage, the lesions gradually faded in the middle, dark brown edges and light brown in the middle. There are yellowish-brown verrucous processes on both sides of the middle of the lesion, that is, the conidial disk of the pathogen. When there are more disease spots in leaves, the tissue between the disease spots will lose green, turn yellow and die.

Prevention and control methods:

① cleared the diseased leaves, and the fallen leaves were burned or buried deeply to reduce the source of infection.

During the growing season, ② plants were prevented and treated with 1 100 Bordeaux solution or 70% chlorothalonil 500x solution.