White spots on orchids

Sticky Substance On Orchid Leaves – What Causes Sticky Orchid Leaves

Orchids are one of the most beautiful, exotic flowering plants. In the past, famous orchid growers such as Raymond Burr (Perry Mason) used to have to go to great lengths, distances and costs to get their hands on orchids. Now they are available in most garden centers, greenhouses and even big box stores, making orchid growing an easy, inexpensive hobby for anyone. However, even the most experienced of orchid growers can encounter problems – one being a sticky substance on orchid leaves. Read on to learn about common reasons for sticky orchid leaves.

Sticky Stuff on Orchids

Many people who are new to growing orchids panic at the first sight of any sticky stuff on orchids. Avid gardeners know that sticky substances on plants are oftentimes the secretions, or ‘honeydew’ of insect pests, such as aphids, mealybugs or scale insects. Although these pests certainly can cause a sticky substance on orchid plants, there is a natural sap that is produced by some orchid flowers and buds.

Orchid growers call this clear, sticky stuff “happy sap.” While this happy sap is produced by the flowers, probably to attract pollinators, it can drip a lot, causing sticky orchid leaves or stems. So, if orchid leaves are sticky, it could simply be attributed to this clear sap, which washes off the plant surfaces easily and is no cause for concern.

Treating an Orchid with Sticky Leaves

When you see any sticky substance on orchids, it is best to thoroughly investigate all the plant surfaces for insects. If you see ants running around on your orchids, it is a sign that there are aphids or mealybugs present, as they have a strange symbiotic relationship with these pests. Aphids, mealybugs and scale can go unnoticed under plant leaves, at leaf joints and even on the flowers and buds, so closely inspect every bit of the orchid plants.

Honeydew is prone to sooty mold, which will form gray to brown sticky, slimy patches on orchid foliage. Sooty mold is a fungal infection that can cause significant damage if left untreated. Aphids, mealybugs and scale can also cause great damage and even death to infected orchid plants.

If you suspect your orchids have any of these pests, thoroughly wash all the plant tissues with horticultural oil or rubbing alcohol. You can periodically use horticultural oil or neem oil to prevent future infestations. These oils can also prevent an array of fungal diseases.

If your orchid has dark brown to black sticky, wet looking spots on the foliage and stems, this could be a sign of a serious bacterial infection. Infected plant tissues can be taken or sent to your local extension office for an exact diagnosis. However, there is no treatment for bacterial infections of orchids. The diseased plants should be removed and destroyed to prevent further infections.

Some fungal diseases may also produce sticky brown to black rings on orchid foliage. In the case of fungal diseases, the infected foliage can be removed and horticultural oils can be used to prevent further infections.

North of England Orchid Society –

Here are a few, in no particular order:- ….

Slugs.
Even if you think you haven’t got any problem with these night-time assassins, you should always be vigilant for their silvery trails, sprinkle at regular intervals with a good slug liquid, and if you feel adventurous, take a torch-light trip into the growing area after dark, a good well aimed boot is something they have not grown immune to.
Weevils.
When you wonder why there is suddenly a ragged in one of your best grown leaves, or chunks missing out of its margin, or the flowers then most likely you have weevils; arm yourself with a bottle of something suitable from the garden centre and follow the instructions. Its no use spraying the once, you must have strict regime of spraying every 5 days or so over a period of three weeks to eradicate most pests and their eggs as they hatch.
Common Scale.
There are two types of scale which you are likely to encounter when growing orchids;- The first one attacks Phalaenopsis in particular, and can migrate to most other soft leaved plants, look on the underside of the leaves for these hard brown limpet like creatures, if you have only one or two, wipe them off with a cloth soaked in methylated spirits, or resort to a systemic insecticide regime as mentioned in the above paragraph, systemic insecticides act by being absorbed into the plant tissue, effectively making the plant poisonous to its attacker, but they should be used with care, do not exceed the stated dosage to avoid damaging the plant.
The other can be very nasty, and primarily has a taste for Cattleyas and their cousins, but can adapt to devouring other orchids such as Vanda’s, this is:- Boisduval scale. A very fancy name for a real horror, you may notice flat round scales on the underside of the leaves, which if left unattended will produce a whole shipment of what appears at first to be a white fungus or mealybug, these are the nymphs by the thousand, and they are setting off to desiccate the rest of you collection.
The trouble we have in the UK is that it is a tropical insect, and many of our pesticides do not treat the problem, one we have found to be of use recently is Doff, you may have to search around to find it, it is very effective against this type of scale, and several other pests as well, you will probably have to give the plant a good cleaning after a couple of weeks or so for aesthetics. Prior to treatment, take an old toothbrush, dipped in methylated spirits, and having removed any old sheaths ( papery coverings from around the pseudobulbs), scrub gently to remove the majority of the adults.
Mealybug
Usually appears as a cotton wool ball around leaf axils, or inside the sheaths of new shoots, the above fungicide pesticide soon sees them off, but again if its very localized, then methylated spirits on a cotton bud sees them off wonderfully.
Thrips, greenfly, blackfly, spider mite.
They all find a niche somewhere, the latter is another difficult customer to deal with, and in addition to spraying, it is a good idea to wipe the leaves and stems of infected plants with a methylated spirit soaked cloth, every few days if necessary to kill the eggs.
SPOTS AND DISEASES.
Orchids can fall foul of leaf rot, mildew, botrytis and many other pathogens, by and large, providing there is a good air movement around the plant, and that by nightfall the leaves are fairly dry, then fungal infections should not be a problem, and correction of the bad condition, along with a fungal spray (check with the garden centre that it is safe for orchids) should do the trick, a fast fix for a localized leaf infection is to dust a little cinnamon onto the infected area !
VIRUS.
It is very difficult if you have a plant suffering from a virus disease to identify which particular type it is, and most likely a useless exercise anyway, as viruses are almost impossible to cure, thankfully, providing you are hygienic around the growing area, and that any tools used on the plants are thoroughly sterilized after use between different plants, you should not encounter this type of problem.
Viruses are the most widespread disease problems affecting orchids and fortunately most of them are rare and in many cases hardly cause symptoms.
Only a few orchid viruses are common and can cause problems, the two most important of these are Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). These viruses are found throughout the world and have a wide host range, affecting many orchid genera.
CymMV virus infection causes leaves to show a mosaic pattern of light and dark green areas, or black/brown necrotic spots often appearing as a line with sunken areas on both sides, Petals may develop lines of necrotic spots, however floral symptoms may be delayed up to 10 days after opening, so healthy appearing flowers may be sold on
ORSV virus infection causes necrotic spots, sunken areas, chlorotic streaks, line patterns and ring spots on leaves and stems. Cattleyas and their hybrids display colour breaks with irregular streaks of pigmentation.
Floral symptoms render the plant valueless, while the leaf symptoms make it unattractive as a house plant.
Both viruses are easily transmitted from plant to plant by contaminated cutting tools, work surfaces, used pots and hands. Therefore, if an infected plant is added to a collection, the virus can easily be spread to healthy plants through propagation and other normal day-to-day plant care practices. Both these viruses which affect orchids are very stable and lose their infectivity very slowly, so sap from an infected plant that has dried onto tools, pots or benching provides an excellent source of infection. They can remain infectious for weeks or longer under the right conditions. The greatest risk of spread is via vegetative propagation from an infected mother plant and is the easiest way to find yourself with more virus infected plants.
If plants to be meristemmed are displaying suspicious symptoms, they should always be tested for viral infection first, before introduction to a greenhouse.

TREATMENTS
Should be carried out giving due consideration to the instructions for use and safety provided by the manufacturers of the control substances we list below; solutions which we have used and found to be satisfactory for ourselves, the decision to try one or more of these in your environment must be yours and made under your own responsibility.It is always a good idea to try and remove as many of the pests and their eggs a possible before applying insecticides.
Pure methylated spirits (not surgical spirit) is excellent for this purpose, apply a little on a cloth and wipe both sides of the leaves, for the less aggressive pests this alone can be a cure in itself.
Don’t expect a one off cure, several applications given over a period of three weeks at five day intervals may be needed. do not use more than one insecticide at a course of treatment or you may build up resistance to it.
One home made cure can be produced in the kitchen if you want a non toxic insecticide, here is the recipe for you to try at your own risk :- Six heaped teaspoons of ascorbic acid (vitamin C.) three teaspoon of plant friendly detergent (non ionic) and a pint of water, spray onto aphids and suchlike, the mixture will kill any insects which absorb oxygen through their skin, but not their eggs. As prevention is always better than a cure, treat new plants with respect, quarantine them if possible, try not to let intake fans suck air in from anywhere near a flower border or hedge, and always be prepared to sacrifice a “well infected” plant for the sake of the rest. It will not work on all pests
One or two of our members resort to a more agressive treatment which they swear by – try it at your own risk.
Fill a bucket with fresh water, and add household bleach ( Domestos) add enough to give a frothy appearance when mixed in. remove the plant from the pot, shake off all the compost, and immerse the roots and plant fully in the bucket for about 5 minutes, after which rinse the pant in clean water and re pot.
SYMPTOMS AND CAUSES.
Irregular markings on leaves, discolored or uneven patches on flowers possible viral infection.
Uneven pieces removed from leaf border weevils.
Un-natural silvery underside to leaves spider mite.
Silvery trails on plants and benches slugs or snails.
Holes in leaves or flower stems or flowers slugs or snails.
Dark mildew on leaves, hard limpet creatures underside of leaves common scale.
Cotton wool type of stuff ( brownish creature inside of mass) mealybug.
Flat scales on mainly underside of leaves and or tiny white fluffy masses boisduval scale.
Depressed dark spots possibly with lighter ring round them fungal infection.
Limp flaccid leaves on Phalaenopsis etc. root problems.
Dark brown or whitened patches on leaf sunburn.
Yellow or very light green leaves but plant flowers too much light.
Dark green leaves but plant does not flower too little light.
Flower buds develop then turn yellow and drop off shock.
Leaf tips turn brown over feeding.
Honey dew on leaves greenfly.
Plant falls out of pot earthquake.
Read Cultural Information…

Categories, orchid pests, treatment, North of England Orchid Society

What You Need to Know About Phalaenopsis Orchids and Mold

You’ve taken care to select a beautiful, healthy orchid for your home. You’ve started your orchid care routine, and things are looking good. But when you go to water your orchid on its next scheduled watering day, you notice what looks like a coating of fuzzy white mold on the top of its roots or the potting media. What gives? Is your orchid moldy? Growing some other kind of fungus?

Let’s explore this fairly common problem. Here’s what you need to know about Phalaenopsis orchids and mold:

Fungi can affect Phalaenopsis orchids

Fungi often enters the orchid through damage on a leaf or the stem. If left unchecked, a fungus can spread down to the roots. So it’s important to inspect your plant for any signs of damage and address them.

It might not be mold: White substance on the orchid potting media

The appearance of a white substance on top of the orchid’s potting media can mean several things.

It can mean it has been overwatered or it does not have enough air circulation.

Another cause of white substances on the potting media could be the use of tap water, which can leave minerals and other residues behind. If you’re using tap water to water your orchid, try using distilled water that has had impurities removed.

What to do: To remedy this, stop watering your orchid until the roots are grayish or white in color. Once this has happened, resume your normal watering schedule.

If you do notice mold on your plant, it is harmless. One way to combat this is to make sure your orchid has enough air circulation. During the summer, you can simply open the windows for adequate air circulation. During the colder months, just turn a fan on low to circulate the air. If you’ve repotted your plant, make sure you don’t use a moss media as this type of media can hold excess water.

White cottony blobs on Phalaenopsis orchids

If you notice what looks like fluffy cotton blobs on the leaves of your orchid, these are likely mealybugs and not mold. Mealybugs are small white wingless insects that feed on the plant’s tissue. They also produce a sticky substance, so your plant’s leaves will feel tacky.

What to do: If you discover mealybugs on your orchid, isolate it from other plants and spray it with a horticultural oil, insecticidal soap or isopropyl alcohol. Because of their tiny size, it is easy for mealybugs to hide in crevices and other unnoticeable areas. If you have other plants in the house, be sure to check their trays, lips of pots and leaves to ensure they are free of the pests.

Take particular care to spray the horticultural oil or insecticidal soap in folds, branch bases or midrib areas of your orchid. If you’re using isopropyl alcohol instead, you will need to rub the leaves and any other areas where you find mealybugs with a cotton swab or cotton ball dipped in the alcohol. While the initial alcohol treatment will remove the hatched mealybugs, you’ll need to do a follow up treatment to remove any that haven’t hatched. Just hatched mealybugs will appear as tiny yellowish spots.

It’s important to note that heavy mealybug infestations can do serious damage to an orchid. If you notice your plant is showing signs of decline from an infestation despite treatment, it may be time to consider discarding it and purchasing a new orchid.

The appearance of what looks like mold on an orchid can have many causes. When evaluating your orchid, keep in mind actual mold on the surface of your plant will not harm it and there are several causes.

How to Care for Orchids – Pests and Diseases : Mealybugs

Question: What is that white stuff on my orchids?

Answer: Mealybugs!

Mealybugs are serious pests of orchids and next to scale insects are probably the most difficult to control pests of orchids. Most definitely, they need to be dealt with immediately upon discovery.

DAMAGE CAUSED:
The damage done to plants by mealybugs is considerable, causing a loss of vigor and a weakening and loss of leaves, buds, and flowers through their feeding. In addition, mealybugs create copious amounts of honeydew which make plant parts sticky and attracts ants. (Want to get rid of ants? Check out the other posts in my How to Care for Orchids – Pests and Disease series.)

REMEDY:
Probably the most popular home remedy against mealybugs is to swab and daub plants with a cotton-tipped swab or ball of cotton dipped in isopropyl (rubbing) alcohol. On hard-leaved plants, gentle rubbing with the fingers, a cotton ball, cotton-tipped swab, or a soft infants toothbrush is effective. Remove all mealybugs, large and small. Afterwards, you will still need to repeat the alcohol treatment to remove the tiny yellowish spots which are the recently hatched crawlers. Pay particular attention to the folds, crotches, branch bases, midrib areas, and roots. Spraying the alcohol with a misting bottle or small pump sprayer is effective, but dribbling alcohol into tight areas is necessary as eggs are often well hidden, hence the need for thoroughness and repititon.

Many home growers will mix with alcohol a small amount of mild liquid dish detergent, and sometimes mineral oil, neem concentrate, or horticultural oil. Vegetable oils will work, too, but in sunlight they can turn rancid quickly, and become smelly and lose effectiveness. One recipe for a 1.5 liter spray bottle is to mix a 50:50 solution of isopropyl and water, with a few drops to about a teaspoon of liquid soap to act as a spreader, and a teaspoon of one of the oils.

ps. Don’t forget to check out Ryan’s Free Growing Orchids Tips. He offers incredible advice all about Orchid Pests & Diseases!

Warmest wishes from sunny Florida,

Carol
The Orchid Care Lady

+ Courtesy of South Dakota State University

Tags: Caring for Orchids, Disease, Growing Orchids Indoors, How to Care for Orchids, Pests

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Common Orchid Diseases: What It Means For Your Orchid’s Health

Is your orchid sick? There are many different reasons why your orchid may not be in great health, and a few symptoms can be signs of a much larger overall problem…

Cymbidium Mosaic Virus and Odontoglossum Ringspot Virus are two different types of orchid diseases. Cymbidium Mosaic Virus appears on the flower of the orchid as streaking or discoloration, and Odontoglossum Ringspot Virus shows upon the leaves as spotting, discoloration, and distortion. Both of these viral infections have no known cure, so if you detect one of these viruses in your orchids you need to get rid of the plant as soon as possible so that the virus doesn’t spread to any of your other plants.

Bacterial Brown Spot is a bacterial disease that will appear on the orchid leaves as a small blister-like spot that will eventually turn brown and produce a bacterial liquid. This is a disease that needs to be detected quite early because it can kill a plant very rapidly. Once you notice the spot you should get a sterile instrument and cut out the infected area. Once the area is cut you need to spray the area with Physan 20 or Phyton 27. If neither of these solutions are readily available, then you can use either cinnamon or Listerine as an alternative. If this disease is not detected early, then it may have spread to the crown of the orchid and this almost always leads to orchid death.

Black Rot is an extremely contagious disease and turns parts of the orchid black. The disease usually starts on the leaves, shoots, or roots and can spread quickly, particularity when the temperature and humidity are high. To treat black rot, remove the infected tissue with a sterile tool, and spray a fungicide on the area you’ve cut.

Botrytis is a fungus that shows up as little black or light brown spots on the orchid’s flowers. To help prevent botrytis from spreading, always remove wilted blooms or those that have already fallen off of the plant. You will want to remove any affected flowers using a sterile instrument and then spray the area where you’ve removed the bloom with a fungicide. Botrytis is contracted through leaving moisture on the flowers, usually after watering. The droplets of water left on the flowers encourage the growth of Botrytis.

Collar Rot, also known as Southern Blight, is a rapid collapse and rotting of the roots and lower parts of the leaves. The base of the orchid will turn a creamy yellow color and the other affected tissue turns brown. White fungal growth can sometimes be detected growing on the stems, pseudobulb, and leaves. If this disease is detected early enough, you can cut the affected areas with a sterile instrument and spray with a fungicide. This fungus thrives in a warm and humid environment, so in order to prevent this disease you can keep your plant in a slightly cooler, drier spot after you treat to help reduce the likelihood of further spread. If the collar rot is a severe case and is widespread throughout the entire plant, it is next to impossible to treat.

When trying to save your diseased plant, it is very important to never cut directly into the infected area and then cut into a healthy area, as this will spread the disease throughout the plant. Orchids are fairly tough plants and can be revived from many different problems as long as those problems are detected early enough. By inspecting your orchid periodically, you will be able to detect those problems early on and treat the issue at its source.

Next Steps: Where do you go from here?

A couple options:

#1 – More Free Orchid Tips!
At a minimum, I strongly recommending signing up for our orchid tips newsletter (it’s free!). That’ll give you some additional (more detailed) step-by-step tips you can start using with your orchids right away…

#2 – Get Access to ALL My Articles on Orchids…
If you’d like to learn everything you need to know about caring for ALL types of orchids we also have something called the Orchids Made Easy Green Thumb Club.

The Green Thumb Club includes a number of different benefits – including weekly lessons on all different orchid care topics delivered to you in a special, password-protected members area. You also get the opportunity to get YOUR actual questions answered in my weekly “Ask The Orchid Guy” column, which you can check out here.

The Green Thumb Club costs less than a meal at McDonald’s – and ALSO includes all sorts of ADDITIONAL benefits, including exclusive discounts at orchid suppliers from 20-40% off as well access to our “orchid diagnosis tool” which helps you identify what problem might be plaguing your plant.

Because the club is backed by a full 100% money-back guarantee for a full 30 days, if after checking it out you decide that it’s not for you or that you didn’t get value you out of what you learned – no problem! Simply send us an email to let me know, and you’ll receive a fast and courteous refund. Put it this way: If you’re not happy, I’m not happy!

(By the way, this here will give you access to 50% off the cost of membership. A little “gift” for reading this article all the way to the end :-))

All my best,

Ryan “The Orchid Guy” 🙂

IMPORTANT: To learn everything you need to know about caring for your orchids, if you haven’t already I strongly recommend signing up for the “Orchid Care Tips & Secrets Newsletter” my wife and I publish by clicking here.

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Common Orchid Ailments

Drooping leaves

When orchids take on a droopy, wrinkly appearance this is usually a sure sign of a watering problem and in most cases a root problem. Either way, the pot has been kept overly wet and soggy (sitting in water) and has experienced root loss and therefore cannot up take water, or has been left extremely dry and has had no water to uptake. Quite ironic that leaving your orchid in a pool of water would cause it to suffer from thirst!

The first thing to do is to remove the potting media and determine the problem…brown and mushy roots= too much water, grey and shriveled roots= not enough. If the plant was under watered a 5-10 minute soak in clean, warm water would help a bit. Next remove all dead or soft roots and wash the plant under tepid water. At this point it would be recommended to treat the plant with an anti-bacteria/fungal like Phyton 27 or ground cinnamon at the least before repotting. Make sure to choose a pot that is just big enough for the remaining root system even if this means going DOWN in pot size. This is very important; sometimes you need to take one step back to take one step forward. At this point, if it has suffered from major root loss it would be helpful to stabilize the plant in its new pot by either using a rhizome clip or simply wiring the plant into the pot after repotting. Water the plant thoroughly and set it out in filtered light avoiding any extreme conditions.

The next couple of weeks will be the most important. This is when you want to encourage new root growth with a balance of higher humidity and a slight restriction of water in the pot. Do this by not watering for the next 10 days coupled with misting the leaves regularly. This should encourage new roots to break into the new potting media in search of water. After the first 10 days resume normal watering. Keep in mind the old leaves won’t recover from the droopy appearance but the new leaves that grow will be turgid and wrinkle free.

Bud Blast

One of the most frustrating things that can happen is watching the development of new orchid buds only to have them yellow and shrivel before they ever open. The developing buds of an orchid are by far the most sensitive part of the plant. Bud blast can happen to any species of orchid but Phalaenopsis are usually the most susceptible to this issue .

Some of the more common causes for this problem are: A sudden change in environment, a plant being left too dry, over watering or sitting in water, exposure to very dry/hot air or near a heating vent or fire place, exposure to cold drafts or near an a/c vent, air pollution from any source, ethylene gas from fruits/vegetables…..to read this list it’s a wonder that any of our orchids ever bloom! Actually it’s much easier to prevent than it sounds. Just avoid any possible stress to the plant and water properly. But even sometimes when everything seems right it’s very common to see the last couple of buds drop regardless of care. Another tip; the darker the space for your blooming orchid the more fully open flowers you should have on the plant. An orchid with all buds WILL NOT open in a dark room.

Spots on Flowers (Botrytis)

Typically seen on white or light yellow/green flowers- Botrytis is caused when persistently wet, humid condition happen in cool to cold weather, most commonly in areas with poor airflow. If spotted it’s best to avoid further spread by removing flowers from the plant and in effect the growing area too.

FOLIAGE PROBLEMS

Crown Rot

Crown rot on a Phalaenopsis treated with cinnamon Severe crown and collar rot on a Paphiopedilum

Crown rot is caused when water is left in the top or “crown” of a plant under cool conditions. This is most commonly seen in Phalaenopsis or Paphiopedilums but can occur in any orchid that has leaves that form a crown. Under these conditions rot develops in the rhizome (in monopodial orchids this is the center column where leaves grow from) and quickly works its way down to the base killing all of the tissue that connects the leaves to the rhizome. It can happen very quickly and if unchecked can result in total loss of all foliage. If caught quickly though the plant can recover and grow either a new crown or more commonly, a basal set of leaves (keiki) that eventually will reach flowering size. If you experience crown rot, remove all affected tissue with a clean cutting blade and sprinkle cinnamon on the surface can help but many times once it’s spotted it’s too late to save the plant. This is another reason to ensure good airflow in your growing space and always try to water early in the day to ensure your plants are dry by night time.

Occasionally, orchids will yellow 1-2 bottom leaves with no need to worry as this is quite common and can occur from a sudden change in environment or some water resting in the folds of the lower leaves. Either let these fall off or peel them off with a downward pull on the leaf.

Spots on Leaves and or Buds

Many orchids can experience spots on the foliage which are usually of no concern. These can be caused by physical damage from the handling or shipping of plants and will not spread or become a further problem. Some Oncidiums are susceptible to fine black or brown spotting on their leaves that doesn’t seem to affect other plants and these usually do not spread or become an issue (an example of this is the famous “chocolate” orchid Oncidium Sharry Baby). Sometimes orchids can inherit a particular sensitivity to spotting that was passed down from one of its parents. Many of these hybrids have been remade with this issue in mind and the breeders have selected plants that do not show this problem.

If the spots do spread or become larger or are soft and watery, then it’s most likely a bacteria/fungal problem and should be treated as such. Segregate the plant from any others and remove or cut away any effected tissue making sure to cut around and not through rotting tissue with a sharp, sterile tool (such as a disposable razor blade). Treat the plant with a bactericide/fungicide made for use ON plants (such as Phyton 27, Captan, Thyomil, etc) or sprinkle cinnamon over the area. This will usually solve any issues and after a week or so the plant could be put back with your other orchids.

Always avoid letting standing water sit on horizontally held foliage and try to water earlier in the day to ensure your plants dry off by night fall. Constant air movement is a must and should be maintained at all times.

Leaf tip die-back

Leaf tip die back can happen for several reasons but is usually caused by a case of severe over-fertilization or using extremely bad quality water. Another cause can be otherwise docile water and fertilizer impurities building up over time in the potting media. If it’s been many years since you’ve repotted this would probably be the case. This can be avoided by proper leaching of the potting media each time you water making sure to flush the pot thoroughly. At the next opportunity re-pot the orchid with fresh media and a clean pot.

In some cases particular orchids can be more susceptible to leaf tip die-back because of their needs for high quality water (Phragmipediums are one such example). It’s best to use Reverse Osmosis/Deionized or Distilled water if available making sure to use the appropriate pure water fertilizer when feeding.

Another cause can be severe under watering of your plants. In this situation the leaf tips dies from the lack of water reaching this area of the leaf. Water and leach your pots thoroughly when needed to avoid this problem.

Bulb Rot

Sometimes older back bulbs on sympodial orchids will turn brown in appearance and become mushy and decayed. If it is on the very end bulbs and not towards the center of the pot, you can sometimes cut through the rhizome and pull out the affected bulbs without repotting. If it doesn’t seem to want to come out easily or the bad bulbs are in the center, repotting will be the only option. Make sure to cut out any bad tissue (including any areas of the rhizome that may be affected) and treat with a bactericide/fungicide or dust with cinnamon. This can be a very common occurrence in Cymbidiums that have not been repotted for years.

“Accordion Pleating” Look To Foliage

This is almost always caused by very low humidity or inconsistent watering while new growth is developing. This usually occurs in orchids with thin foliage and can affect a large number of different species. Some of the more common orchids you see this in are Miltoniopsis and their hybrids. Try to raise the humidity around your orchids or make sure to be more diligent about watering while your plants are in active growth. In my experience this is more of a cosmetic issue than anything. The plants can flower just fine and by solving the watering or humidity problem the new growths will develop normally. Just be careful that newly developing flower spikes don’t get caught in the pleated foliage causing a deformed inflorescence.

PESTS

Orchids are only affected by a handful of pests. But all of the most common “house plant” or tropical plant pests can become problems with your plants. Anyone who has grown orchids for any significant amount of time has dealt with bugs. And any orchid grower who makes the claim that their plants don’t, can’t, or won’t get bugs is either lying to him or herself or is extremely naive. If you suspect that any of your orchids have insects, the first thing to do is to isolate them from the other plants in your collection. Most pests are relatively slow moving but by the time you notice, they more than likely have spread to others. The number one piece of advice that I can offer is to be diligent no matter how small the problem may seem. A small problem today can turn into a big headache in 2 weeks. And when using any insecticides, ALWAYS use the appropriate safety precautions. Also make sure to complete a full cycle of treatments since these pests have different stages in their life cycle and each stage may be affected differently by the same insecticide. Think as if your doctor has prescribed you a round of penicillin, partial treatments only serve to help the insects build resistance, while 3- 4 treatments 7-10 days apart can do wonders.

Mealy Bug

Mealy bug appears as a white cottony mass on the underside of leaves, at the base of buds and even on the flowers themselves. If not controlled they can cause leaf and flower deformities and yellowing of the foliage. In warmer weather they will quickly form colonies in the crevices between leaves and can have a special taste for Phalaenopsis and Paphiopedilums. Spot treat with straight Rubbing Alcohol on a cotton ball/q–tip or directly from a sprayer diluted at 50% with a good squirt of mild soap (note: I have never seen RA negatively affect any orchids before but use good judgment and do not spray in warm weather or direct sun and not into the pot. After spraying RA I will usually wait 5 minutes then rinse off the plant). Safers Soap , Neem Oil or Horticultural Oil could be useful if you are in the home since they are relatively benign (except for the smell)…the only problem is that at times it seems they are benign to the bugs also! These can be good non-toxic approaches if only a small number of plants are affected but don’t expect to control them in a medium/large group. They are best controlled with a systemic insecticide.

Scale

In orchids the most common types you encounter are: brown scale, soft scale, and Boisduval scale and none of them are fun to deal with. Scale can be very pervasive and if not handled swiftly can take years to eradicate. A lot of our “experienced” orchid friends have seen scale become a major problem in their collections as they get older in life and have less energy to keep up with the maintenance of their plants. Most times scale will be introduced through another orchid that already has it or other tropical house plants (older Ficus, Scheffelara and Palms are notorious for having scale). But ants can be a major carrier of scale. They have a somewhat interesting relationship. The ants carry the scale to the host and once established the scale secrete excrement as they feed on the plant and the ants harvest the sugary secretion! So…many times if you notice ants on or around your orchids (or your Ficus) you will see a sticky residue on the ground or furniture in the area (if in the home). This is sometimes the first thing to bring your attention to the scale.

A decent way to attack scale is with an old (or new) toothbrush dipped in Rubbing Alcohol. Wear rubber gloves and scrub the scale off of the pseudo-bulbs with the RA wetted toothbrush. This could be done at anytime but is easiest when repotting. This can be a very effective way to deal with scale infested Cattleyas, Dendrobiums or other sympodial orchids, just make sure to peel away the dry sheaths along the pseudo-bulbs since this is a favorite hiding place. Another first approach technique (or a spot-killing trick) is to spray the affected area with leaf shine. We use Design Master but other brands such as Pokon Leaf Shine works as well. They work by suffocating the scale on the spot. Just spray and the next day wipe off the scale with a towel.

Keep in mind that the 2 above tricks only work on small scale (no pun intended) applications and a long term approach involving a full cycle of systemic insecticides is the best choice. The above techniques coupled with other less toxic choices like Safers Soap, Neem Oil, or Horticultural Oil could be the best choice in the home though.

Aphids

Aphids are small soft bodied insects that tend to cluster around areas of soft growth (developing leaves or flower spikes or buds) and produce a honeydew type substance that can also attract ants and be a growth medium for sooty mold. Most outdoor gardeners are very familiar with aphids since they also love rose bushes. In fact, those rose bushes could be the reason you have them on your orchid! Aphids tend to appear in the home or greenhouse in the spring but could show up at anytime of the year. The only good thing is that they usually disappear as fast as they appeared and for minor infestations can be washed off the plant quite easily with mild soapy water. Ladybugs are a natural predator of aphids and in the spring you can usually find them for sale at a local garden center, but this only works in enclosed spaces and for just as long as there are aphids…then the Ladybugs disappear too.

The best approach is to treat the same as Mealy Bug.

Thrips

Severely thrip-damaged Cattleya flower

Thrips aren’t as common in orchids as the above mentioned pests but if they are present they are the most menacing. They have a way of staying unnoticed to the human eye until the flowers have opened and the ever present chewed-away outer edge of your favorite orchid flowers appear. Against a light colored flower they can be easy to spot, they are brown/black/yellow and have a thin and long appearance.

Thrips tend to come in (the home or greenhouse) during warmer weather and usually come from outside flowering plants. In the home treat with Safers Soap/Horticultural Oil but the best approach is still a systemic insecticide applied for a full cycle and possibly used in conjunction with a growth regulator.

Slugs/Snails

Yet another garden pest that also has a taste for exotic fare…slugs and snails can be a very frustrating problem in the greenhouse. Since they tend to like wet and damp areas you usually don’t see them in the home. So if you grow in the house consider yourself lucky, because there is nothing more disappointing than waiting for flowers to open only to have a slug eat his way across the petals the first night its open! If you catch them, discard as you see fit. But its best to bait with any of the dozens of products marketed for the garden. Just be sure to keep them away from pets or little ones.

Other Orchid Ailments

Confirmed Orchid Viruses

Get Rid of Orchid Scale Once and For All

Author: Celeste Booth

Care and Culture, Insects

There are not many pests that can severely damage an orchid collection, but along with mealybugs and aphids, scale is one of orchids’ biggest pests. It is a small insect that can devastate a collection of orchids. A small infestation will result in marred areas on the leaves and large infestation can kill the whole plant. The process to remove them can be complicated but early detection and careful management can prevent the destruction they can cause.

Different Types of Orchid Scale

There are 27 varieties of scale and two main types, soft scale and hard scale. Scale range in size from one to five millimeters and, in certain life stages, can be difficult to see without magnification. Male soft scale appears grayish to white and can look similar to mealybugs. Soft scale damages the plant by sucking sap from the plant. It also leaves behind a sticky excretion called honeydew. Hard scale does not leave this excretion. A large infestation of males will appear powdery and white. Adult females create larger scales that protect eggs. Soft scale can be found along the underside of leaves, along the stem, and even in the roots and rhizomes. Cattelyas are particularly susceptible to a type of brown soft scale called Boisduval scale. Boisduval scale often appears on the undersides of leaves along the midribs and underneath the sheaths. It occurs naturally outdoors in California and Florida, but can appear in greenhouses in any climate. Hard scale is rarer on orchids, but can be identified by its hard brown domes of the adult female.

The Life Cycle

The life cycle of scale is very brief. Scale moves from eggs, to the nymph stage called crawlers, to adults in the matter of a little less than two months, and there may be several generations of scale within a year. These cycles are fastest in an indoor or greenhouse environment. As a result, management, once orchids have been infested, is very difficult. The caretaker must be very persistent in his or her approach and must apply treatment at least every ten days. If you have been using the same treatment for more than a few months and still have scale problems, you must switch treatments as some of the scale may have become immune. The scale is most easily treated during its crawler stage, this is also the stage when it moves between plants. The last stage of the life cycle for a female scale is when it hardens and lays eggs under the protective covering that it is named for. Once the eggs are laid and the shield is hard the scale dies.

Prevention

-Scale

The easiest way to avoid a scale problem is to stop it before it starts. Scale spreads easiest from plant to plant, and occasionally on air currents. So, it is likely that a scale problem come from a new plant that is introduced to a collection. Be sure to inspect any new plants and even quarantine them for two weeks to see if any evidence of scale appears, because not all stages of scale are visible to the naked eye. If scale does appear, you can treat this plant separately and avoid introducing scale to the whole collection. If you notice scale on a plant you already have, quarantine it right away, while you are treating it, and a short time after to make sure it doesn’t reappear. This should hinder the movement between orchids. Movement will also be stopped between orchids if leaves from different plants are not allowed to touch one another.

If you keep your orchids outdoors, you will also have some assistance from natural predators and parasites. Ladybugs like to eat soft bodied insects and will eat scale. Wasps can also lay eggs inside the hardened scale, they will then feed off the scale eggs and emerge as adult wasps, effectively killing the scale in their first stages of development.

Treatment

For a small infestation, you can rub the scale with isopropyl alcohol on a cotton swab to remove them. This can be hard on the plant, so don’t do it too often or if there a large amount of scale. There is also the possibility of chilling the plant with the fast evaporating alcohol. You may want to wipe away extra alcohol from the leaf so that it doesn’t damage the leaf tissue, especially if the plant is in windy location. If you can, move the plant away from any air currents. Another option for management suggested by the Canadian Orchid Congress, is to carefully wash the whole plant in warm water with grated soap (be sure the soap is mild and not ammonia-based, as this will cause damage to the plant). The plant must be washed every other day for a month. Then it must remain separate from other plants for two weeks to ensure no new scale appears.

The next level in treatment, if the previous two home remedies do not work, is to use horticultural oil. This oil must be applied thoroughly to the orchid. Scale hides well in the sheaths, along the base of the plant, and both the top and bottom of the leaves. It can be easily missed and infest the plant again. The oil works by smothering the scale, so any surface that is not covered will not be effectively treated. The oil can burn the plant’s leaves if used on a hot day or in direct sunlight. Take care to keep the orchid shaded during treatment. Also, take care to follow the directions on the labels very carefully so that you do not damage the plant.

Orchid and Beetle

Finally, if the horticultural oil does not take care of the problem, you may have to use chemicals. Some insecticides are available for use on orchids. Make sure they are labeled for use on ornamental plants, and seek help from a technician if you are unsure if the chemical combination is safe for your orchids. Always follow the label carefully and do not use a concentration any more or less than suggested, too little may be ineffective and too much will kill the plant. Remember that insecticides can be harmful to people and pets. If you cannot spray the orchid outside because of weather, place the plant in a large plastic bag and then spray it. Once the spray has settled, remove the bag and place the plant in an area away from any air currents.

If your plant has had a large infestation you may have scale in the roots. If this is the case, remove the orchid from its container, and shake all of the old growing media loose. You can wash the roots, or if you are using an insecticide, spray the roots. Then repot the plant in a new, clean container with new growing media.

Care tips to remember

Remember, as you care for your orchids, that scale can be devastating and any measures you take as a precaution against it are worth the extra effort.

  • Always quarantine new orchids for two weeks before displaying with your collection.
  • Check all of the orchids in your collection regularly for signs scale and remove potential problems immediately.
  • Keep plants separated and do not allow leaves of different plants to touch one another.
  • Once plants have been treated for scale, keep them separated from your collection for two more weeks to ensure the treatment was successful.

If you are battling a scale infestation, be sure to stick with the treatments, repeating them about every ten days. With your persistence and care your orchid collection can be kept scale free and beautiful.

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