5 Common Orchid Pests and How to Handle Them
Orchids are astounding and beautiful plants. Orchid pests, on the other hand, are decidedly not! It is heartbreaking to spend so much time and effort caring for an orchid plant only to see it suffer. The great news is these pests can be prevented and treated. The key to success and healthy plants is in the identification.
One of the most common pests, aphids are tiny light green or black insects that feed on plant juices. They cause leaves to become curled, yellowed or distorted and stunt plant growth. They especially like new flower buds. In addition to harming the plants directly, aphids produce a sticky sap called “honeydew” which sooty mold and ants. The ants like to “farm” the aphids and will move them from plant to plant to produce more honeydew. This can spread other diseases from plant to plant, making the initial problem much worse.
The most common reason for aphids is that they came into your house or garden from an infected plant. The little bugs spread quickly so one infested plant leads to much more very quickly. Treating an aphid infestation is quite easy, thankfully. A strong spray of cold water over the leaves can dislodge them. Or, dust the plants with flour which the aphids dislike and they will leave. If those methods don't work, neem oil or insecticidal soap will take care of them. Yellow sticky card traps work well, too. If you have ants, you'll need to get rid of them as well.
These are a common little fly with dark bodies and grey-ish black wings. The neat thing about these pests is that while they are not much of a threat to your orchid, they can be an indication of poor plant health. Fungus gnats seek out fungi, not plants. If fungi are sprouting in your potting soil, then the soil is too moist and decaying quickly.
To keep fungus gnats away, replant your orchids and use a potting mix with charcoal or coconut fiber in it to slow the decay. Let the soil dry between watering. If the infestation is very bad, yellow sticky card traps work wonderfully to get rid of them.
These little white or whitish-gray bugs are common and a big threat to orchid plants. They are good at hiding and love eating roots, rhizomes, and the underside of leaves. It can take a magnifying glass to see these pests. You won't miss their calling card, though. Loss of leaves, buds, flowers, and weakening of the plant are the most common symptoms.
Mealybugs can come from an infected plant or blown-in via the wind. They travel quickly from plant to plant and will hide out under pots, in crevices, on benches, and trays. A small infestation can explode quickly.
In outdoor environments, mealybugs have natural predators in wasps, beetles, and lacewings. Heavy rains will also wash the bugs off the plants. Indoor management is much more difficult. Remove any plants that are infected to protect the others. Treat all plants with an insecticidal every 10-14 days to interrupt the insects' growth cycle. Last of all, look everywhere around the plants for stragglers, including all other potted plants you have.
Another tiny, highly destructive, pest, mites are almost impossible to see unless you are looking for them. Mites stab stems and leaves with their needle-like mouth and suck the sap out. This seriously damages plants, disfigures them, and weakens them considerably. Leaves will turn yellow and drop off.
There are many types of mites and they range in color. A test to see if what you have is mites is to look at the underside of your orchid's leaves. The leaves will look silvery. Also, wipe a white cloth over the underside of a leaf and check for reddish or brownish streaks. Those are mites!
Mites spread quickly because as their colonies become crowded, some winged mites form and they fly to a new plant to create a new colony. Also, because they are so tiny, they are almost impossible for the human eye to see without a magnifying glass.
Insecticidal treatments don't work for mites. The first step in combating mites is to increase the humidity. They prefer a dry environment. Then, wash all the leaves. If this isn't working, using a biological control of predatory mites usually will. They will eat the pest mites, however, it is important to make sure you have enough to handle the extent of your infestation.
Another microscopic insect that likes to drink plant sap, thrips cause deformed foliage and destroy flowers. They especially like new flower buds. Flower blooms will turn brown prematurely and will be discolored. Leaves will wilt and eventually drop.
To check for thrips, blow gently into an open flower and look for little insects moving around. Use blue or yellow sticky traps to monitor pests and check it weekly. If you see tiny black specks on the traps, you have thrips. They are difficult to get rid of and difficult to control because they can be on all surfaces of the plant, depending on where in their lifecycle they are, including under the soil.
A pesticide can be used to treat the infestation but that will not take care of the ones in the soil. Apply the pesticide weekly to catch them in all stages and alternate chemicals to reduce any chance of increased resistance to one. Insecticidal soaps and biological controls can also be used but not in conjunction since the insecticides will kill the predatory mites too.