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EEOS Original Articles |
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The many articles in our Orchid Culture section can solve most of your culture issues. Check them out before submitting a question. |
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AOS Culture Sheets |
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The AOS Culture Sheets are very thorough guides for growing orchids successfully. Read the one pertaining to your kind of orchid before asking a culture question. |
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Ask Your Own Question |
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If the articles and culture sheets in our Orchid Culture section did not solve your problem, feel free to submit your own orchid culture question. |
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(Posted on March 9, 2004) |
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Question |
| My Zygopetallum (sp) may or may not have root rot. The older leaves are turning brown; younger ones, growing out from older pseudobulbs are still green and healthy looking (though maybe a bit light green in color) and there is new growth. Not a lot of root showing above ground. When I tried to remove it from pot to check the condition of the roots, I found I could not get it out... looks like we need a new pot????? All new soil??? Please help soon as this fragrant beauty is one of my favorite plants. Thanks for your help. |
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Nancy Whitney - Seattle, WA - USA |
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Answer |
| Nancy, from the description of you plant, I think I would make sure the plant doesn't have a spider mite or other insect problem, before you repot this time of year. If you do repot, always use fresh potting medium and a clean pot. I found a good information source: try www.plantfacts.com and search for zygopetalum. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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Answer |
| If the new growth looks healthy and the plant is so rootbound it's hard to get out of the pot without breaking, I'd wait until spring to crack the pot or really force the plant out of the pot, then repot. Check over the roots and remove dead ones and treat with Dithane or other systemic fungicide if you have evidence of root rot. We're not too familiar with Zygopetalums, as they are a cooler growing orchids and struggle in S. Florida. |
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David Schaffter |
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Answer |
| Hi Nancy. If it does turn out that you have spider mites or another insect problem, you can treat your plant as follows: for mites, try PENTAC with some liquid soap to help as a spreader; for most other insects, you can use ORTHENE (also with a few drops of liquid soap). For more information on pesticides, please read the article Chemicals in the Garden by Dr. Bert Pressman in our Orchid Culture section. |
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Fred Armando |
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(Posted on February 20, 2004) |
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Question |
| What is the best insecticide I can use for ensign scale and if I have a serious problem with thrips, what's the best way to deal with that problem?. I spray with a insecticide today and in a week I still have the problem. What can I do? |
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Gary Patterson - Kingston - Jamaica |
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Answer |
| Gary, try revisiting the Orchid Culture section of our website and checking the culture section in Articles by the EEOS for an article by Dr. Bert Pressman on insecticides. Also, you might want to read some of the other questions people have asked about the same subject in the Pests & Pesticides category of this section. |
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Bob Stipe |
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| Try using Orthene wettable powder once every 2 weeks, or an insecticidal soap once a week. |
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David Schaffter |
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(Posted on February 14, 2004) |
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Question |
| Lately, my orchids seem to be infested with two types of pests; very small white and black pests. They always come to the top of pot when I water the orchids. The black ones are hard to catch because they seem to be jumping around. Could you tell me what they are and how to get rid of them? |
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Daniel Tran |
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Answer |
| Try drenching the entire plant and medium with a solution of orthene. |
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David Schaffter |
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(Posted on February 10, 2004) |
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Question |
| I've been having problems with small black flies on my orchids. I believe they will go into the soil and lay their eggs and the larvae will eat the roots. What can I use to get rid of this problem? |
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Susan Morton - Pickering, Ontario - Canada |
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Answer |
| Susan, that's a new one on me. You should contact a local orchid society in your area to see if anyone else has that problem. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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| Try drenching your soil or potting medium with a mixture of orthene and water. |
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David Schaffter |
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(Posted on February 5, 2004) |
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Question |
| I have a phalaenopsis that has lost all of its leaves. I have heard that once this happens, they have passed away.None of the leaves turned yellow, they just fell off. I have a feeling that one of my sweet little plant loving kitties may have been a little too loving.. The amazing thing that keeps me hoping, is the fact that it has BEAUTIFUL roots. The roots are thick, green, and growing profusely in the sphagnum moss, and on the wood of its planting box. I have numerous other orchids, and this is the only one that has experienced such a thing. Is there any hope for my sweet little darling? I have been caring for it as I do with my others. Thank you. |
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Heather L'Huillier - Pensacola, FL - USA |
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Answer |
| Heather, your cat damaging your plant might be one cause, or it may be rot due to water standing in the leaf axils. When watering always be sure to water only the medium & not the leaves, unless you can turn the plant over to drain the water off. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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| You can try and resurrect the plant but you might have to wait until spring for some warmer temperatures. Just leave it alone and make sure you don't put water into the crown area, as this will possibly cause rot. |
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David Schaffter |
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(Posted on
February 5, 2004) |
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Question |
| I have a Degarmoara Skywalker Red Star. The blooms are being eaten. Attached to the underside of the blooms are a few long segmented-looking tubes that are bulbous at the ends and appear to have mouth parts and/or a few legs at the ends (not a bunch of legs along the tube like a millipede). They are mobile. Shed black fecal pellets. What do I have and how do I treat it? Thanks. |
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Elaine - USA |
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Answer |
| If you can physically remove the critters, that is the best way. You might try some snail bait in and around the plant. Also, try spraying the plant with orthene wettable powder. |
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David Schaffter |
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(Posted on December 31, 2003) |
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Question |
| I live in a Life Care system with a 2/3 Olympic size swimming pool. In one corner area of about 5 x 12 feet there is a crowded group of commercial origin, mixed species orchids. The area drainage is down toward the pool but has a separate drain entry of good quality. Bathers walk barefoot across this area on the way into the water. In this past year they have become a problem with a sooty, granular looking fungus which has no clear edges, tends to be circular on the leaves and apparently is active on the leaf ends. About 40% of the suceptible varieties are moderately involved. I have been watering by soaking the plants in a tub in water with 30-30-30 fertilizer [very weak] about once a week. What agent and technique may I safely use for this problem? |
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Gilbert Jay - Fayetteville, AR - USA |
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Answer |
| You might try spraying your plants with RD-20, a greenhouse algecide and disinfectant. Check the labels and follow instructions, and see if it's safe to use where people walk. Part of the problem might be poor air circulation, which allows the algae to flourish. You might try to mount some big pedestal fans outside the pool area and aim them down to get the air moving around your plants. |
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David Schaffter |
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(Posted on September 30, 2003) |
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Question |
| I have over one hundred orchids. I grow in a basement room especially built for them. I purchased a jewel box orchid about three years ago and I have noticed that it has some dark spotting on the leaves and also on a few of my other catts. I was wondering what fungicide to use on them and do you rinse them off after spraying or just leave it? I saw Safer brand but it didn't say for orchids. Can you use a fungicide when the plants are in bloom or do you have to wait? Thank you. |
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Sandi Frederickson - Andover, IL - USA |
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Answer |
| Sandi, a good fungicide to use would be Dithane, but the Safer brand would probably work as well. The key to prevent it is good air circulation and watch your watering habits. Please check the Orchid Culture section of our website for more detailed information. There are numerous articles written by our members as well as articles by the American Orchid Society on orchid care, pests, and diseases. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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Answer |
| I use dithane as an all round fungicide. Kocide is copper based and is tough on dendrobiums, and some others. Probably the best thing you can use is a fan to constantly move air over the plants and keep the fungus spores from settling and getting established. |
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David Schaffter |
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(Posted on June 16, 2003) |
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Question |
| I have trouble with small snails on the pot of orchids. How can I kill them all? Thank you. |
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Mike Tran - Katy, TX - USA |
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Answer |
| Hi, Mike. You might try Ortho Snail & Slug pellets around your orchid pots. I've also heard that a small dish of beer next to the pot does the trick. I tried the beer, but my dog likes beer as well as I do! Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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Answer |
| Snail bait, which can be purchased at Home Depot or a local garden center, works good on snails and slugs. |
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David Schaffter |
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(Posted on June 16, 2003) |
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Question |
| I finally mustered the courage to ask my question: Why do some of my 200 orchids begin to rot or turn black during the very wet season/weather? This has been happening lately, like in the last month or so with our heavy showers and downpour. Is there anything I can do to prevent this from recurring??? Please help me. Thank you! |
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Rita Baumann - Miami, FL - USA |
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Answer |
| Rita, your orchids (especially vandas) are staying too wet. During this wet weather, it's best not to water at all. If they do get watered, they need plenty of air movement and to dry out before nightfall. Get rid of the bad leaves and spray heavily with fungicide such as Captan or RD-20 about every two or three days. You might also want to check out our Orchid Culture section. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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Answer |
| If you use a systemic fungicide, like Dithane, that will help. Another trick is to buy a box fan (Home Depot has them for $10) and run it at night to help dry out your orchids. The air movement is very important for your orchids, especially if they stay wet or damp from our frequent rainy weather. Some orchids, like Phals, just cannot take all the rain we've been having lately, so they must be grown under cover so they stay dry at night. |
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David Schaffter |
| What are the different types of fungus? |
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Nikita |
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| I assume you are interested in the types that may affect orchids. There are many types that cause problems for plants. I suggest you look for AOS Publication for the handbook Orchid Pests and Diseases for a complete list of fungus that affects orchids. You can find it on the AOS web site (www.orchidweb.org) |
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David Schaffter |
| I am losing a long battle with mealybugs that I can't seem to keep off my phalaenopsis plants. I think I could get them with Cygon2e but also think it may kill the plants. I am currently using q-tips and alcohol, but it seems like I am taking one step forward and two steps backward. Any advice on controlling these little varmits? Thanks. |
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Donald Sprague - Urbana, OH - USA |
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Answer |
| Donald, you might try Orthene wettable powder mixed 2 tablespoons per gallon. A couple of drops of dishwashing liquid in the sprayer will help emulsify the water for better absorption. It is a systemic and works on a variety if pests. You can get it at any garden center, (Home Depot, Lowes, ect.) A lot of us use Ortho Fire Ant Killer mixed as above. Stay away from premixed stuff as some of them are oil based. This should help get rid of those pesky critters. Thanks for the question and for visiting the EEOS web site. |
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Bob Stipe |
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| First, try using the powder orthene. It can be purchased in Home Depot, labeled as Fire Ant killer. It's a white powder that's systemic and smells bad. Mix 3 teaspoons with 1 gallon of water and then put about 2 to 4 drops of mild dish soap in with it. Spray on the plants, making sure you wet the mealybugs thoroughly. Repeat this operation in 10 more days. Make sure your Phals get good air movement. You can use cygon, but you may want to cut down on the concentration a little, and make sure the orchids don't get too warm after you spray. You might try spraying them in the late afternoon. |
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David Schaffter |
| Hello, I've been having problems with a certain fungus called Fusarium. My family recently started an orchid business and have been keeping orchids in a greenhouse. What causes this fungus and what's the best way to get rid/control it? Are there any fungicides we could use? (We have various kinds of orchids.) Thank you. |
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Alice Wu - Toronto, Canada |
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| I'm not familiar with that type of fungus. You might try other nusery growers in your area, or else look into some of the past AOS Orchid Bulletins for further information. Some of the fungicides we use are Dithane, a systemic, and Kocide, a copper-based fungicide. Some plants are sensitive to copper, such as dendrobiums. We also use RD-20, which is a greenhouse disinfectant, but it has some qualities to work on fungus. Check with other growers to see how they control the fungus, then apply the same techniques to your collection. |
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David Schaffter |
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| Fusarium has caused big problems in the US and Canada, especially with food crops like tomato and watermelon. I did a quick search on the USDA web site and found that some people have been using methyl bromide to fight the fungus, with some success. But apparently, the use of methyl bromide is being discontinued due to concerns about ozone depletion. There's one study being conducted in which scientists are trying to use other strains of Fusarium to fight the fungus. I suggest you get in touch with the USDA or Canada's equivalent Agriculture and Agri-Food Canada (AAFC) to find a solution that not only works, but is also safe. I sent an inquiry to the USDA's Molecular Plant Pathology Laboratory on this subject and I will post any new information I obtain here on the EEOS web site. |
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Fred Armando |
| Help! Sweet ants have taken over our greenhouse full of orchids. We have nests in a number of pots and superhighways of ants running in between. We have tried a number of pesticide solutions, such as: Combat baits, diatomaceous earth, products containing borax, and flooding individual plants. Has anybody found a solution to this kind of ant invasion? Nothing that we've come across has worked so far. A few ants we can live with, but the level of infestation makes it difficult to bring the plants indoors when they are in bloom, and we fear damage to the plants. |
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Cynthia |
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| Try Orthene wettable powder from Home Depot. It comes in a black container & is used for fire ants. Mix with water (2 teas. /gal), drench the orchids, making sure enough runs down into the pot to wet medium & roots. This will work good for scale, mealy bugs, & other insects. If ants are living in the medium, it is a good indication that it's breaking down & you might want to repot everything this spring. |
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David Schaffter |
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| That is odd: diatomaceous earth should have worked for you. But you have to remember that it is a different pesticide from the others you mentioned. It does not poison the ants. Rather, the very fine, sharp edges of this "white dust" desiccate the insects' exoskeletons upon contact and they dehydrate and die within hours. The insects also die when they eat the dust. However, it does not attract the ants with bait, so you can't use it the same way. It should be sprinkled across the "ant superhighways" and around the nests. The ants have to walk on it in order to die. It may also be sprinkled in the pots, on top of the medium, but it will run off the next time you water the orchid. You mentioned flooding individual plants. That will not kill the ants. They will just relocate the nest. For sweet-eating ants I have used a product called Terro with good success, but it does contain Boric Acid. You can pick it up at Home Depot or Wal-Mart. There's also another possibility: the chemicals you mention in your question are all baits (except for diatomaceous earth). If nothing has worked it is possible that you don't have sweet-eating ants, but grease-eating ants and they are just not being attracted to the baits you're using. In that case, Orthene (as David suggested above) will work, since it kills on contact. It might be a good idea to collect a few ants, place then in a ziplock bag and take them to a Home Depot or garden center in your area for identification. |
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Fred Armando |
| I've heard that it is useful to use an algaecide when watering the orchids to help keep down fungus infestation. Pool algaecide was recommended as being cheap to use. It was mentioned that 1 tblsp per gallon of water was OK. However I hesitate to use it in that strength as it is recommeded at 2 1/2 oz per 5000 gal for the pool. Any ideas on the subject? Thanks. |
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Eleanor Sanfilippo - Miami, FL - USA |
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| With all the rain we've been having, it is a good idea to spray with some sort of algaecide. RD 20 is a good algaecide for use on plants, orchids, and in greenhouses. Use at the recommended dose of 2 teaspoons/gallon. I have heard of people using pool algaecide for their orchids since it is a little cheaper. If you do use the pool algaecide, do your homework. Check to see if the chemicals are the same as RD 20. I think they are. Also, check the concentration of the chemicals (expressed as %) in each one. You should adjust your algaecide concentration to match that of RD 20. Then you can use at the recommended dosage of 2 teaspoons/gallon. If you are unsure of any of this, go buy a gallon of RD 20. It's better to be safe than sorry. It's only $10 - $15 and it is made for the nursery industry. One gallon will last quite a while or you can split it with a friend and help each other out. |
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David Schaffter |
| I am having a serious problem with thrips. I was advised to remove all hibiscus bushes which I have done. I have sprayed the entire yard with Orthene and still the problem exists. I keep getting blooms from healthy plants that are deformed. How do I eradicate them?? |
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Roger de Meillac - Miami, FL - USA |
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| Roger - Thrips get into young buds or flowers and destroy the tissue by tunneling through the developing petals & sepals. You cannot see them at work until it's too late. You only see the damage when the flower opens up, revealing a deformed flower with what appears to be tracks across the flower parts. Thrips are also found on hibiscus and especially gardenias. Thrips usually strike around springtime when the weather warms up and it is still dry. Watering your orchids during this time will help. I spray my orchids with orthene wettable powder as soon as the weather starts turning warm, around March. That way, the systemic insecticide gets into the plant and discourages thrips. You cannot kill thrips once they are inside a developing bud. You might spray your hibiscus & gardenias at this time also. This is one time where a preventative application of an insecticide can be effective, before the problem develops. I count on spraying my orchids every spring, before it really warms up, in anticipation for thrips. |
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David Schaffter |
| How can I get rid of blacks ants from my orchids? |
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Marlin |
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| Try using orthene wettable powder on your orchids, making sure you drench the orchids & the medium throughly. |
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David Schaffter |
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| Just to complement David's answer: you can find Orthene wettable powder at Home Depot. It is a white powder sold as " Fire Ant Killer," usually in the Inside Garden department. It is water soluble and has a very strong smell. |
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Fred Armando |
| My Vandas have what looks like scale: very small, brush-off-able, tan dots attached to the leaves. I have up-rooted, divided them, soaked them for a couple of hours in soapy water and sprayed them with a Pyrethrens solution. Do you think this will do it, or what do you suggest? |
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Chuck - Broward County, FL - USA |
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| Chuck - That sounds good what you have done so far, but you might want to go over the scale with a toothbrush when you are using those chemicals. Scale has a waxy, protective shield that makes it hard for some chemicals to penetrate. Also, spray your orchids with Orthene wettable powder. Orthene is a systemic that gets into the plant and attacks the pests over a greater period of time as they eat. |
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David Schaffter |
| What should I do for the large number of ants on my orchids? |
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Stephanie - Miami, FL - USA |
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| The ants by themselves do no harm to the orchids, but they can transmit scale, which can be a problem. I would use an insecticide such as orthene wettable powder mixed with water. When applying to potted plants, make sure you drench the medium thoroughly, since this is where the ants probably live. To keep from getting the ants in the future, check orchids for any broken down or decayed medium, and repot as necessary. This is where they like to hide and make their nests. |
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David Schaffter |
| I have been having problems with what I think are mealybugs (white cottony bugs) on my phalaenopsis. They don't seem to attack my vandas. So far I've been using swabs with alcohol to treat individual plants, but they just won't go away. They particularly like to hang out under the leaves. Is there a good pesticide to use on mealybugs that will get rid of them once and for all? And also, is there a difference between liquid and powder pesticide (in the case of Orthene)? Is one more effective than the other? |
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Fred - Miami, FL - USA |
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| Mealybugs are identified by their white, cottony appearance. In order for an insecticide to penetrate this protective layer, the addition of a wetting agent is necessary. Soap is a good, cheap wetting agent. The use of an insecticide soap such as Safers will work. A stronger, more lasting (Systemic) insecticide is Orthene wettable powder. Just make sure you add your wetting agent, such as a drop or two of liquid detergent. Also, make sure you spray under the leaves in order for the spray to contact the pest. Sometimes a liquid pesticide will use an oil base carrier instead of water. If the weather is really hot, you can risk burning the foliage of tender leaves with an oil based chemical. I prefer using wettable powders. Orthene wettable powder can be purchased at Home Depot in the black plastic containers labeled Fire Ant Killers. You know you got the right stuff when you open it & are hit with its strong, pungent odor. Its white and extremely fine and dissolves in water quite easily. |
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David Schaffter |
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