Black rot control of Cymbidium

Symptoms of black rot in Cymbidium

In the early stages of black rot infection, small brown wet spots with yellow edges will appear on the underside of the leaves, and then gradually spread out. The middle part of the old lesions is dark brown or black, and water will seep out when squeezed, while the old lesions will become dry and black. The leaves of infected orchids turn yellow and gradually fall off, with the parts near the base of the leaves becoming noticeably discolored, and the pseudobulbs turn black after being infected.

Methods for controlling black rot of Cymbidium

Once discovered, the infected parts and organs should be removed promptly and burned or buried deeply. You can spray with 0.1 % to 0.2 % copper sulfate solution or 400-500 times diluted 50 % fungicide wettable powder.

During the maintenance period, spray frequently with 100-150 times diluted 50 % Thiram, or 500 times diluted Zinkelin or sprinkle directly on the diseased part. You can also spray 500 times diluted 80 % Dasheng M-45 wettable powder to prevent this disease.

In addition, keeping the orchid shed ventilated and avoiding moisture can inhibit the spread of this disease.