A Simple Guide to Cymbidium Orchid Care (Part Three)

According to observation, the main pests currently harming Chinese cymbidium orchids are two kinds: red spider mites and scale insects. Red spider mites do the greatest damage to new leaves, sucking the sap from within the leaves and causing speckled spots all over the leaves. To deal with red spider mites, it is not advisable to use a single pesticide; for example, use a mixed spray of dimethoate, which has systemic action, and 800-times diluted methamidophos, which has contact and stomach-poison action, spraying once every 10 days for two consecutive sprays. Specialized acaricides such as propargite and dicofol can also be used. Scale insects are the most common pests found on Chinese cymbidium orchids, living by sucking the sap of the orchid plants. There are two kinds, armored scale and mealy scale, mostly caused by poor ventilation. Armored scale is flat and round, and can cover the orchid leaves and pseudobulbs; some orchid vendors often pass off fake spots caused by armored scale as genuine spots for sale. Mealy scale looks like white dust, and in severe cases forms a solid mass, causing orchid leaves to wither rapidly. Due to the development of pesticide resistance, ordinary pesticides have become ineffective against scale insects. At present the most effective pesticide is methidathion, applied as a 500-times dilution twice a year (once during the growing season, once after the onset of winter), which can ensureorchidsafety. Insecticides should be sprayed on sunny mornings, and washed off with water the next morning. Because I recommended methidathion, I once saved several orchid gardens. I remember one time when I visited a friend and took the opportunity to look at theorchidshe grew on his arcade corridor. It would have been better not to look; one glance was enough to shock me. It turned out that his more than one hundred pots oforchids(which should have had more than one thousand orchid leaves) had every single leaf, from top to bottom and on every side, completely covered with scale insects. I am afraid that many orchid plants had even had the growth points on their pseudobulbs eaten away, and would never sprout again. I said to that friend: "Your family is not well off, and the orchids were all bought with hard-earned money, so why don't you take good care of them? Even if you don't sell the orchids for money, it would still be nice to trade some varieties with other orchid friends for fun." Not long afterward I brought him a bottle of methidathion, and once it was applied, within a few days the previously dense masses of scale insects fell off in patches. Excerpted from "Orchid Treasure Classic" Macao, China Feng Gangyi