Pests and Diseases

[Waldorbigbill]

A new story entry has been added:

Pests and Diseases

ugs create a host of problems and can seriously damage a collection if left untreated. Scales, mealybugs, aphids and mites are the most common orchid pests. You will find that bugs are attracted to certain genera. For instance, mealybugs like phalaenopsis and bifoliate cattleyas, while scale prefers cattleyas and cymbidiums. Aphids are attracted to the buds and flowers of dendrobiums and oncidiums, but they do not discriminate between orchid genera. Spider mites will show up when there is a lack of humidity especially on dendrobiums, oncidiums and cymbidiums.
Always keep a close eye out for bug damage. They like to hide under leaves and sheathing and, if left untreated, they will quickly spread through your collection. By removing old sheathing once it becomes loose, it will be easier to recognize the early signs of an insect problem. Scale depletes chlorophyll leaving yellow spots on the foliage. They also love to feast on the tender eyes at the base of the pseudobulbs. Aphids will leave a sticky residue on the foliage below where they are eating. Spider mites can be identified by the silvery scarring they leave under the leaves. The good news is that most orchid pests are easily exterminated. Home and garden sprays will provide a long list of bugs they will kill. We recommend spraying the plant, then manually cleaning it as much as you can with a Q-tip or toothbrush, followed by another treatment of spray. Follow up treatments after five to seven days may be necessary to fully eliminate the problem.

Schultz, Bayer and Ortho all carry a good line of sprays that are available at any garden center, hardware store or home improvement warehouse. For a less toxic approach, we recommend using denatured alcohol, neem oil or insecticidal soap. Remember to always be extra careful of what you spray, especially on the flowers, and always follow the manufacturer?s instructions to prevent plant and flower damage.

[Tindomul]

Excellent article. Extremely useful. Thanks for posting it. It helps me alot. I haven't encountered many of these pests and diseases yet, so Im a bit more wise thanks to you.

[Ross]

Nice article, but too bad the photos are so small. It would be easier to see the pests/disease if the images were larger. Much useful info in this article.

[LauraN]

I too really got a lot out of this article, but would really like it if the photos were larger, so that I could actually see the infected area.

[Ross]

Welcome Laura. Please post under Intros so folks can properly introduce themselves and thanks for the second on picture size.

[R Srinivasan]

The issue is why let pests take over your collection of orchids and other epiphytic plants. The infestation is generally an indication of poor lighting, inadequate breeze movement and under exposure to to bright light. I firmly beleive overcrowding of plants, over watering contribute a lot to pests. In all my forty years of orchid cultivation, pest seldom worried me save snails, slugs and tiny yellow corkscrew snails. These invaders come with nursery acquired potted plants, but can be controlled by wood alchohol based baits. As a preventive measure a periodic spray of branded pesticides keep all the insects away. Otherwise a healthy orchid always overwhelms pests. I must add here my recepie of orgnic control of pests: Make decoction of low-grade tea and tobacco(chewing variety) say 100 gms of each in 2 litres of boiling water. This should be diluted with equal measure of plain water and spray on plants. This definitely obliterates scales, mealy bugs and spider mites without staining the plants .

[LauraN]

Your recipe certainly sounds interesting. I'll have to give it a try. What exactly do you mean by low grade tea?
I totally agree with you on the conditions. I have had very few infestation problems and do try to keep good lighting, air flow and I do try not to overwater. My biggest infestation problem has to be ants. I'm not sure why and love to hear some views on why and if I need to do something about, and what that would be.

[R Srinivasan]

Originally Posted by LauraN

Your recipe certainly sounds interesting. I'll have to give it a try. What exactly do you mean by low grade tea?
I totally agree with you on the conditions. I have had very few infestation problems and do try to keep good lighting, air flow and I do try not to overwater. My biggest infestation problem has to be ants. I'm not sure why and love to hear some views on why and if I need to do something about, and what that would be.

Low grade tea , I mean, tea with high tanin content and less bouquet something we dont consume. This can be procured from shops dealing in loose tea and they are dust form. For instanse, ceylonese and Indian low altitude crops which are cheaper and the infusion is usually strong and of darker colour. When this is combined with tobacco, the resultant decoction brakes down the mucous membrane of insects with a deadly impact. This is almost like stinging of eyes by soap and perhaps worse for insects due to the persistance of the burning they suffer from this organic spray. I have used them on dahlia cuttings, then on various orchids without any damage to plants and at the same time taming the infestation dramatically , ants including.

[lyn]

I have heard that smokers should not touch orchids without washing thier hands first because of tobacco mosaic virus. Is that true? Is the chewing tobacco different from smoking tobacco? Also how often do you spray? I also have an ant problem and was using safers soap but it only knocks them down for about a week. Do ants hurt orchids? I heard they bring aphids! Is that true?

[mayres]

Yes it is true that ants "farm" both aphids AND mealy bugs. I can tell you from personal experience. The ants themselves are not a problem for orchids but you definately want to get rid of them because of what they bring WITH them. mike