Common diseases of rubber trees and their prevention and treatment methods

Rubber tree anthracnose

Symptoms

Anthracnose mainly harms leaves. When the disease occurs, many light brown or white spots of varying sizes will grow on the leaves. In the early stage, it often occurs on the tip or edge of the leaves, and gradually spreads to the leaf surface, causing many small black spots to appear on the leaves. In severe cases, most of the leaves appear black and dry. Anthracnose sometimes also harms new shoots, causing the branches to wither and gradually die.

Prevention and control measures

Combine pruning with removing diseased branches, leaves and dead tips to reduce pathogens.

Pay attention to light transmission and ventilation, avoid placing them too densely, choose disease-free plants and use cuttings to propagate seedlings.

After new shoots grow in early spring, spray 1% Bordeaux liquid. From June to September, spray 1% Bordeaux mixture, 0.3 degrees Baume lime sulfur mixture, or 0.5% potassium permanganate once every half month. In addition, before or in the early stage of the disease, spray 500-800 times diluted 50% thiophanate-methyl wettable powder, thiophanate-methyl, thiophanate-methyl, carbendazim and other wettable powders, and use each agent alternately during spraying.

Gray spot disease of rubber tree

Symptoms

The main transmission route of gray spot disease is wounds, or invading through the stomata of leaves. In the hot and rainy season, the disease peaks when the temperature is around 20 degrees Celsius. The disease is more serious from September to October. Small gray spots appear in the early stage, expanding into irregular shapes, grayish white inside and dark brown edges. Later, the diseased leaves dry and crack, and black granules appear. The incidence rate is high during thunderstorm season and low during sunny days.