There are pests and their are diseases. Diseases I avoid like the plague. They are difficult if not impossible to control, and frankly, unless you’re a professional orchid grower, not worth the hassle. A few simple rules will keep you relatively disease free:
- Segregate new plants. Whether you purchase an orchid or are given one as a gift, keep it away from your other orchids for weeks, longer if possible and convenient.
- Keep your orchids from touching each other. It’s almost completely impossible to keep them ever from touching, but your handling and display, including your regular placement of your orchids, should minimize contact. Believe it or not, even in this photo of a large group of my orchids on racks in front of a large window, there is not a single orchid situated where a leaf of one plant is touching a leaf of another.
- Sterilize tools if you ever cut orchids. Orchids aren’t normally “trimmed” the way an overgrown houseplant would be trimmed. But they may need a strategic cut or two when they are repotted, especially if you are separating the orchid into different sections to pot the pieces up individually to create new plants. Occasionally damaged areas of plants or leaves are cut off. Dipping the cutting instrument in alcohol should be sufficient to minimize the spread of disease.
- Go through a methodical process when watering plants. Always take them to a sink where you can thoroughly wet the bark. Simply pouring some water on the bark from a watering can typically won’t wet all the bark. The dry patches allow sections of roots to be under-watered which can stress and even kill sections of roots. I have this on good authority, from an elderly gentleman who spent his entire life professionally raising orchids in one of the most prestigious orchid businesses I have ever known. I purchased a number of my orchids from him years ago before he became too old to continue the business. And they are among my most prized possessions. His advice – ALWAYS thoroughly wet the bark every time you water and do it at a sink where they can be truly watered thoroughly. There is a reason for mentioning this besides giving good advice on watering practices. It’s your opportunity to look over the plant closely – twice a week. This way you will spot insects and other pests long before they become a problem. We’ll go into the treatment a little later. But the policy here is to inspect your orchids regularly, and during your watering ritual is a great time to do it.
- Keep a spray bottle of dormant oil mixed up and with your supplies. This will be your #1 ally in your battle against pests.
- And speaking of watering, as a regular practice do not wet the leaves. Water the bark. Thoroughly. You don’t have to avoid the leaves like a fetish or be paranoid if you ever get them wet. But you don’t want to routinely water the leaves unless they are particularly dirty and you are deliberately giving the orchid a cleaning. Wet leaves invite trouble. Yes, I know. In the wild the orchids are rained on regularly, perhaps daily. But we’re keeping them in an artificial environment, not their natural habitat. Our houses are (hopefully!) devoid of the beneficial insects and such that inhabit the plant’s natural environment. Especially don’t let water set in the crotches of leaves, notably the Phals. They have a tendency to catch water in the deep troughs where the leaves meet in the center. I’ve been told by an expert that this can lead to damage including rot. I don’t know first-hand because I avoid the practice and so have never found out the hard way. But I can tell you that keeping the leaves relatively dry on a regular basis has left my plants looking great! They certainly haven’t suffered from not having regular baths. And hey, this is my advice on my website and based on my personal experience. No, I’m not a botanist, and I am certainly not an expert in orchids. But I think my experience and success speaks for itself.
- Last, but by no means least, if you have what you suspect is a diseased orchid, throw it out! Immediately. There is simply no point keeping it unless it has very serious value to you. Diseases are difficult to treat, often involving toxic and harsh drugs and chemicals, and you may spread it to other plants before you know if you have successfully treated the one in question. One plant simply isn’t worth the risk. I’ve kept 50-100 orchids for many years, have sourced them from a wide variety of locations including mail-order, supermarkets, and home improvement stores. I simply won’t tolerate a plant that looks like it has a systemic disease.
So, what are we looking for? There are three pests that are most common, that you are most likely to run into, that are easily and safely treated if you keep an eye on your orchids.
The first is aphids. They are nasty little translucent little buggers that can absolutely coat a plant surface if left unchecked. They are sap-sucking insects that come in a variety of colors (most are green, unlike this photo) and can do a substantial amount of damage if left unchecked for even a short period of time. Fortunately, if you’ve heeded my advice and inspect your orchids every time you water, at the first sign of aphids – ZAP – you spray the orchid in question thoroughly with dormant oil. With good hygiene, especially if you keep your orchids segregated from other house plants that are more likely to be susceptible to aphids, you’ll seldom experience aphids. And if you do, you can knock them out thoroughly and immediately. The picture here is imported from a stock photo site because with my practices I have had so little problem with aphids I simply don’t have a photo of any. (It’s a close-up. Aphids are really tiny, but easily visible to the naked eye.)
Mealybugs are my personal #1 nemesis. They appear periodically on my orchids. They are tiny white critters and a cluster of them takes on the look of thick, white fuzz. I especially find them at the base of stems and in the tight folds of new leaves. Look for them in the smallest and tightest of places.
Some genus of orchids, like cattleyas, have a paper-like sheath around the base of the stems. It dries out over time but will stay in place like dry, thin parchment for ever if not removed. Once it’s dried out, I carefully pick it off as on the plant pictured on the left. Why? Because underneath this sheath is one of the favorite places for mealybugs to hide, breed, and multiply. I can’t tell you how many times I peeled back this thin covering to find colonies of mealybugs beneath them.
This picture is of the paper-like dried out sheath around the base of the stems of some cattleyas and their close relatives and crosses.
While common, and while devastating if allowed to get out of control, mealybugs are really no problem at all to take care of if caught early. Again, this points out the importance and value of those twice-weekly ritual of taking each and every plant to the sink, watering it thoroughly, and looking it over as it drains. See some mealy bugs? Take your trusty dormant oil and soak them immediately. In fact, where I see any pests on an orchid, I spray all of the surfaces of that plant.
Scale is the last pest that I find regularly. (That’s not to say my plants are the regular home of any of these pests. When I say regularly, I mean these three pests are generally the only ones I find, but I don’t find any of them more than a couple times per year.)
Scale on orchids look like tiny brownish flattened platelet-like critters. They can easily be scraped off with a fingernail, but again, better treated with dormant oil. The oil smothers the insects and kills them almost immediately. This photo actually shows what I saw first – it was a clear but sticky lumpy deposit on the surface of a leaf. When you find clear sticky deposits on orchids, it isn’t necessarily a bad thing. In fact, it’s a sign of a “happy” orchid under certain circumstances. It’s often referred to as “honeydew” and can refer simply to sap that some orchids produce more than others. In this instance, however, I know what it means. When I see this, I immediately start turning over leaves.
Here’s what I invariably find. Scale. The brown hard scale. It looks like, well, little hard brown scales! I get it occasionally. I don’t know where it comes from. I don’t know it I keep it 99% controlled so I simply don’t see it or if I actually do get rid of it when I find it and treat the plants in question and it’s simply something that comes around occasionally. It really doesn’t matter. It wouldn’t change anything. I still find it occasionally. You will read horror stories on some orchid sites and blogs about how devastating scale can be. And that’s true, but only if you let it get out of control. That’s easy to do. Just don’t get rid of it when you find it. Or don’t look your orchids over carefully on occasion. Or ignore signs like this when they appear.
But if you DO deal with it quickly each time it appears, it’s no big deal. That’s one of the advantages of my care practice – twice per week, EVERY plant to the sink for a thorough watering. While it’s draining I look it over. We are literally talking seconds per plant. So it’s not like I’m adding a really time consuming step to my care plan. That’s how I found this one. I started watering, noticed the honeydew-like substance on the leaf, turned a few over, and found the scale.
So, what’s next? Simply take the plant outdoors (or to the shower if it’s simply too cold) and spray it down with dormant oil. I rub off the few scales that I find. In this instance I found scale on four or five leaves. I had already washed the honeydew off with water while at the sink. It was actually in the low 40s today, and Phals shouldn’t be kept below about 55 degrees Fahrenheit. But a few minutes isn’t a problem. And that’s all it took. If you spend time researching scale and its treatment, you’ll read about alcohol and swabs. Spraying with insecticidal soap, even insecticides. But if the infestation is minor, dormant oil is all you need. And the treatment takes all of five minutes or less. I then put the plant someplace a little farther away from my other plants for a few days to make sure I’ve gotten it all, and that’s it! It’s simply not a big deal if you keep an eye on your plants and deal with pests as soon as they appear. I did have one really large Phal with a huge spray of massive white flowers. They were incredible. I noticed scale on the plant too late. It was on the leaves where I normally find it, and it was no problem to treat there. Unfortunately, I also found them on the flower spike and even on the blooms themselves. They really didn’t even shorten the life of the flowers. But boy, seeing them on the flowers themselves sure spoiled their overall beauty. The moral of the story, really do check over your orchids regularly and stop pests as soon as they appear! But I learned my lesson. I’m especially attentive this time of year and for the next few months to come when most of my orchids are flowering. I REALLY don’t want to miss another infestation until the plant is already in bloom. It’s easy to spray when the plants are still in spike or the bloom buds are still closed. It’s a lot harder – if not impossible – to treat the open flowers. It was too depressing a site to take pictures, although I should have if I had anticipated building this website.
There is a silver lining to spraying dormant oil on at least some of your orchids. It makes them look beautiful! Look at the shine on these leaves on the Phal I just treated. ! I don’t do this regularly just because I don’t know if there would be any unintended consequences. But I sure don’t mind the way my Phals look after they are sprayed!
While on this subject, there’s one more pest that will give you a very distinct “head’s up.” Ants. Yep. Occasionally you’ll find them on the windowsill or in a pot or crawling out of the bark, etc. If you see even ONE ant, pay attention. CAREFULLY go over your plants. There’s a pest growing somewhere. It’s even been said that ants will literally “farm” some of these pests, like aphids and scale. Their reward? The honeydew! Not the honeydew that is nothing more than healthy sap that some orchids produce (although even that healthy honeydew can attract ants and even some types of mold). But the sticky substance created by the pests. There is absolutely nothing else in a pot full of bark that’s of interest to an ant. So if you see one, it’s there for a reason. It’s been attracted to something. And dollars to donuts it’s an early warning of a pest infestation beginning.