OrchidSafari ARCHIVES*

1. PRE-DISCUSSION MAILOUT

2. TRANSCRIPT

PRE-DISCUSSION MAILOUT

OVERCOMING MAJOR CHALLENGES TO MAINTAINING PLANTS IN CULTIVATION - pests and diseases, pesticide toxicity, weeds, stress

by Marilyn H.S. Light
Copyright 1998

(with adaptation from "Growing Orchids in the Caribbean", M. Light, 1997, Macmillan, Basingstoke) AOS Book List #BK256

ESSENTIAL STEPS FOR EFFECTIVE CONTROL OF PESTS AND DISEASES

1. Identify the pest or disease;
2. Identify any factor(s) that may have contributed to the outbreak;
3. Determine the most effective immediate solution to the problem; and
4. Develop a strategy to avoid similar problems in the future.

Reduce the impact of diseases in an orchid collection through sanitation and cultural practice.
1. Keep the growing area free of dead leaves and spent flowers.
2. Remove and burn diseased foliage and flowers.
3. Use sterile cutting tools.
4. Treat cut surfaces with powdered charcoal or a fungicidal powder.
5. Maintain good air movement within the growing area.
6. Provide a light regime appropriate to the plant type.
7. Do not crowd the plants.
8. Cull plants that become easily reinfected despite good cultural practice.

STRESS
When an orchid does not bloom, the cause may be insufficient light, inappropriate daylength, too high or too low temperature. Some orchids are habitually shy bloomers. While the absence of flowers may simply be annoying, plants being grown under less than ideal conditions may become a target for infection or infestation because of being under cultural stress. The causative stressor must identified and dealt with as much as the pest or disease. We otherwise risk losing the plant.

HIGH TEMPERATURE
Temperature can be the greatest obstacle to successfully raising and flowering orchids. Some orchids require a substantial temperature differential 10-18F (5-10C) between night and day in order to thrive. Not all individuals in a population can be expected to react the same way. The best way to get warmth- tolerant orchids is to purchase a division or mericlone of a proven clone or take a chance with a flask of hybrid seedlings bred for warmth tolerance. Those individuals best adapted to your growing conditions will be more vigorous, disease-resistant, and will bloom more easily at maturity. If the opportunity exists, take less thrifty plants from your collection to a garden at a higher altitude or give them to a grower able to provide better temperature differential. Even a hundred meters (300 ft) difference in elevation can make a difference. Think about the growing conditions before taking out the sprayer.

LOW TEMPERATURE
Just as high temperature can adversely affect some orchids, colder temperatures can be a problem for others. Often, cold intolerance, which can occur at 50F (10C), will express itself in leaf symptoms. Leaves may become yellow, blotchy, spotted, or may drop off. Mark which plants behave this way so as to avoid future difficulties.

WATER QUALITY
Certain orchids are highly sensitive to dissolved minerals in water. If orchids such as Masdevallia and Promenea are displaying leaf discoloration, leaf drop or other symptoms that might suggest disease, think water quality first. Stop applying fertilizer. Leach minerals from the compost using deionized or rain water. Watch for new leaves and roots. If growth resumes and appears normal, mark the plant as one to be watered only with deionized water. Fertilizer can be applied later on but only in very dilute amounts. Flush afterwards with plain water.

BUD BLASTING
Buds that yellow and drop before opening are said to blast. This frustrating problem can happen if the orchid and buds are subjected to stress such as too high or too low a temperature, drought or air pollution such as smoke and exhaust. Brush fires and automobile exhaust can both produce ethylene in concentrations that lead to premature aging of flower buds. Buds may also blast after a plant is moved, ironically to protect the buds from rain, sun or pests. Some cultivars of Dendrobium and Phalaenopsis are definitely more prone to bud drop. As the problem is primarily one of culture, control lies in keeping orchids stress-free during the blooming season.

PESTS
"Pests never arise spontaneously. They come from somewhere."

SPIDER MITES
Mites are tiny relatives of spiders. They damage leaves of Phalaenopsis, Dendrobium and many other orchids, especially during hot, dry periods when the grower should be especially vigilant. Damaged leaves will appear scorched, the surface silvery and pitted. Plants will be more resistant to attack if grown cooler or if sprayed frequently to assist evaporative cooling. Biological control measures using Predatory Mites may be appropriate. If choosing this course of action, pesticide use must be stopped. Purchase a mite predator that will thrive under the ambient growing conditions. Infested orchids can also be treated by spraying them with a miticide scheduled for use on orchids in our State or Province. Thoroughly wet the foliage using a wetter/sticker to improve adherence of the pesticide. Mites, like insects, can become resistant to pesticides. Alternate pesticides to avoid resistance to any one. The Agriculture Department probably can recommend an effective product for local use.

OTHER PESTS
There are multitudes of insect pests that attack orchids. Sucking insects such as aphids pierce plant tissues in their quest for nourishment and while doing so lay the plant open to the introduction of viruses. Tender shoots and flower buds are most vulnerable. Rasping mouthparts of thrips scrape tasty morsels from leaves and flower petals, rendering flowers useless for exhibition or sale. Snails and slugs feed at night leaving a slimy trail through their path of destruction.

Some pests are more easily controlled than others. While mechanical barriers or concerted hand-picking will control most slug infestations, it is almost impossible to stop tiny thrips entering an orchid collection if the orchids are directly exposed to the outdoors. Thrips can carry out their destructive rasping within a semi-open bud or amongst the tender folds of a leaf. Before you even know they are present, heart-rending damage is done. There is no better control than grower vigilance.

THRIPS
A heavy thrips attack will devastate orchid blooms. All orchids can be attacked but damage is often restricted to certain kinds of orchids in a mixed collection. Adult thrips can jump and fly although they are weak flyers. They feed and lay eggs in orchid buds and blooms. Pale yellow nymphs attack flowers and buds close to where they hatched, damaging buds even before they are fully opened. The flowers appear scorched but on close examination, characteristic silvery marks and tiny black droppings can be seen. One of the most insidious thrips infestations now showing up in collections is the Greenhouse Thrips, Heliothrips haemorrhoidalis, a pest of Avocado and Orange crops on the West Coast. This species is a slow-moving hermaphrodite. It lays its eggs within the tissue of susceptible plants including certain Epidendrum (plants and flowers), Cattleya (flowers only, Dendrobium (flowers and foliage), Paphiopedilum (foliage), Sarcochilus (foliage), and oddly enough, it attacks Sobralia (foliage), the latter being immune to almost all other kinds of pest attack.

Never store Gladiolus corms or onion bulbs near your orchid collection as these bulbs frequently harbor thrips. Monitor the thrips population by placing susceptible plants such as Catasetum within the collection or by hanging blue sticky strips. In small collections, Thrips can be controlled by isolation of infested plants, hand removal of nymphs and adults and disposal of infested leaves, flowers and buds which might contain eggs.

Contact pesticides will kill thrips if the insects are actually touched by the appropriate chemical agent. Nymphs hidden in buds will escape being touched by the pesticide. A biological control agent might prove effective in larger collections that are not being sprayed with insecticides. A vial of the parasitoid Thripobius semiluteus pupae taped to plant leaves within the infested collection will help control Heliothrips. As with many biological control agents, their success also spells their demise as the parasites have nothing more to feed upon. Re-introduction may be required.

MEALY BUGS AND SCALE INSECTS
These sucking insects can be especially difficult to control although biological agents may be of some use. When an infested plant is placed directly amongst uninfested plants, immature crawlers will quickly move to infest neighbors. Always isolate newly acquired plants.

Mealy bugs and Scale insects are resistant to many insecticides. White, cottony mealy bugs hide in leaf sheaths and among roots. Scale insects are shield-shaped and of various colors and sizes. They feed on the undersurface of leaves and in flowers and are frequently clustered along midribs and veins or cleverly disguised to blend in with the normal contours of a plant part. Scale insects excrete 'honeydew' which sticks to leaves, attracts ants, and supports the growth of black sooty mold. When you see sticky leaf surfaces, look under the leaf above for the culprits.

When purchasing orchids, be vigilant for any whitish fluff that might exist on a leaf or stem. As mealy bugs crawl, they leave some of their covering behind. That tiny piece may tell of hidden horrors beneath the bark!

Insect Growth Regulators such as Applaud and Enstar are innovative insecticides that interfere with larval development and the egg-laying ability of sucking insects such as mealy bugs, white fly, aphids, scale insects and leaf hoppers. Read the product instructions carefully to decide rates of application and appropriate precautions.

There are also several biological control agents to choose from.

PESTICIDE TOXICITY
Many pesticides are harmful to humans, pets, fish and beneficial insects. Certain products will damage orchids, especially the flowers. Read the product label and follow all instructions carefully. Use only products licenced for use on orchids in your country, state or province. Always test a new product on a few plants representative of the collection before applying it to all the orchids. Some orchids such as Psychopsis papilio are more sensitive than others. Never apply pesticides when the orchids are heat- or drought-stressed. Follow all safety precautions recommended by the manufacturer including safe disposal of spray, unused pesticide and containers.

For more information about BIOLOGICAL CONTROL AGENTS
see http://ipmwww.nscu.edu/biocontrol/anbp/HomePage.html

Canadians should consult www.natural-insect-control.com

VIRUS DISEASES
Virus is one of the most dreaded diseases of orchids. There is no known cure although some plants appear more resistant to damage than others. An infected plant remains a constant source of infection for others in a collection. Virus can cripple, disfigure and weaken plants. Two viruses, Cymbidium Mosaic Virus (CMV) and the Odontoglossum Ringspot Virus (ORSV) are transmitted solely by the grower. They are most commonly spread with a cutting tool contaminated with infected sap. Other viruses are spread by insects. Bean Yellow Mosaic Virus is spread from infected bean plants by aphids to orchids, especially Masdevallias, then between susceptible plants if aphids infest the collection. The presence of viruses can be determined by laboratory testing procedures.

VIRUS DISEASE (all orchids)
SYMPTOMS: Deformed or disfigured foliage and flowers; streaked blooms (color break). Some infected plants exhibit no symptoms at all. CONSEQUENCES: Failure to thrive; reduced flower production. Infected plants are reservoirs of infection with chance of spread to other specimens. CONTROL: There is yet no known cure! Destroy by burning all confirmed infected plants. Isolate suspected plants. Always use sterile cutting tools when dividing or potting plants and when cutting flowers. Do not re-use old compost.

Steps to keep virus infection out of a collection.
1. Assemble a collection of virus-free plants. Seedlings in flask are less likely to be infected than divisions of plants long in cultivation.
2. Test plants for the presence of virus.
3. Use sterile cutting and potting tools. Sterilize cutting tools after each use by soaking for 10 minutes in a solution of either 10% liquid bleach or saturated trisodium phosphate solution.
4. Destroy by burning or at least isolate proven infected plants.

How to prepare Saturated tri sodium phosphate (TSP) solution Add 1/2 cup of TSP to 2 gallons of hot water. CAUTION The solution is very corrosive. Mix well using a wooden paddle. Add more TSP until some crystals remain undissolved. A saturated solution is necessary to inactivate virus.

OTHER DISEASES

LEAF SPOTS AND BLOTCHES
Leaf-spotting fungi such as Cercospora, Septoria and Phyllosticta produce unsightly speckles and blotches on the leaves of orchids such as Cattleya, Dendrobium, Oncidium, and Vanda. The spots are rough to the touch. Microscopic examination will reveal the presence of fungus tissue and distinctive spores. Premature leaf fall reduces plant vigor and flowering potential. Severely infected plants may die prematurely.

CONTROL: Burn diseased material. Improve air circulation. Spray with appropriate fungicide.

BLACK ROT
Black Rot is a particularly aggressive infection of Cattleyas caused by the fungus, Phytophthora. A new shoot suddenly turns black: the rot moves rapidly, killing the rest of the plant. A whitish 'bloom' of fungus spores may be seen on the diseased tissue. Heat-stressed orchids are more susceptible. This disease is more prevalent during wet weather: it is spread primarily by splashing water.

CONTROL: Disease spread primarily by splashing water. Shelter plants from rain. Isolate infected plants. Burn diseased material. Spray or dust with appropriate fungicide.

BLACK LEG / DRY ROT
Dendrobiums and Vandas growing in waterlogged potting or bedding materials are susceptible to a slow but inexorable rot of the roots and stem from below. The causative fungi are Fusarium and Rhizoctonia. Pseudobulbs become spongy and discolored. The leaves, especially in Vanda, will yellow and drop off, one by one, until none are left and the plant dies. Plants can be salvaged. Uninfected pseudobulbs of Dendrobiums can be removed to allow keikis to form. If a Vanda has many aerial roots, sever the stem above the line of infection. Since the disease is caused primarily by poor culture, fungicides are not recommended for control.

CONTROL: This disease is caused primarily by poor culture. Fungicides are not recommended. Use potting / bedding materials appropriate to the plant type. Replace potting materials before they become stale and waterlogged. Burn infected material. BACTERIAL SOFT ROT
Soft rots are difficult to diagnose but whatever the causative agent, they can be devastating to an orchid collection. Orchids will be more vulnerable to infection if they are over fertilized, given insufficient light and ventilation, and if they are permitted to remain wet especially in the crown. Rots are a problem during the wet season, also after storms when plants are bruised and torn by high winds. Shelter susceptible plants from rain. Be vigilant for rot during the wet season.

BACTERIAL SPOT/ROT (Pseudomonas, Erwinia)
SYMPTOMS: Soft, brown, smelly, fluid-filled blisters on leaves and in the crown of Phalaenopsis, Paphiopedilum, Catasetum. CONSEQUENCES: Highly contagious. Crown rot will quickly kill a plant. Leaf spots can be excised and the plant saved. CONTROL: Withhold water. Improve ventilation. Remove and burn infected tissue. Be careful not to break the blisters. Consider the fertilizer being used: reduce the nitrogen and increase the potassium component. Pot Phalaenopsis so that the crown drains freely. Use Physan-20©, 7.5 ml in 5 liters (1/2 Tbsp. per gallon) as a preventive spray.

WEEDS
Various plants will grow in containers with orchids, competing with them for fertilizer and water. Weeds include Oxalis, Peperomia, Lace Plant (Pilea) and ferns. The grower should be alert to the invasion of weeds. Not only do they compete with the orchids for space but they can also harbor pests. Remove the weeds by hand before they become firmly established and reproduce.

AN INTEGRATED APPROACH - RESPONSIBLE MANAGEMENT OF ORCHID PESTS AND DISEASES

Attitudes towards pest and disease management have changed markedly over recent years. There is now a greater awareness of the delicate balance of plant health and susceptibility to pests and diseases. Plants stressed because of inappropriate culture including light regime, temperature or nutrient status can be more susceptible to pest and disease problems. An orchid must be considered with its environment if one is to adequately deal with occasional pest or disease problems.

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TRANSCRIPT

Pest and Disease Management
By Marilyn Light
Wednesday, April 8, 1998

Present were 22:

James 55SS
marylois
207.115.58.81 (visiting)
Josh319
Jane5536
sparkysteve
BCPRESS
marilyninOttawa
Doug fulcrum5
ChuckMyr
Peggy platystele
Earl uncleearl
121133ellen
gaillevy
Camille-vanda
Evlyn
bmtorchids
KB Barrett
Jerry Rodder
Neo.falcata1
Marla
Miami Al

marilyninOttawa
Hello everyone. Tonight we are going to discuss that *favorite* subject - pests and diseases. We all have a considerable investment in our orchid collections. Let's keep them healthy and blooming! I sent out a substantial amount of reading material. I hope everyone has had an opportunity to review. While doing the research for this session, I learned a lot more about biological control agents. Is anyone using these or has had experience with one or more kinds?

55SS
If you are talking about ladybugs and lacewings, once the nasties are gone, so are they... I have used them out in the yard for stuff, but never indoors... Has anyone tried ladybug or like in a shade house?

marilyninOttawa
The commercilly available ladybeetle may help with aphids in a shadehouse but are likely to disperse. There are various other aphid predators and parasites which might also help. Do you have a warm or cool shadehouse?

55SS
No shadehouse yet, but will be warm in summer.

marilyninOttawa
The problem with an open shadehouse is that biological control agents will escape. Do you expect a problem with aphids? Which sorts of orchids will you be growing in the shadehouse?

121133ellen
Is there any value in adding Rd20 to your watering to help prevent bacterial or fungus infections?
To continue the question, what about Protek?

marilyninOttawa
Regarding additions to water to supposedly reduce the problem with diseases. If the water is already contaminated with injurious damping-off fungi such as Pythium (water molds) or with bacteria that have been feasting on plant debris in the water, then an addition of some agent to kill these organisms could be useful. Water coming directly from a tap will not contain these organisms. Water coming from a cistern may. I have no personal experience with Protek. If plants are grown under good light conditions (for their type), if the atmosphere is buoyant (breezy), and if the plants are not over-fertilized then they should be sufficiently resistant to infection not to need assistance.

Jane5536 ( [L.I. N.Y])
Yes, not crowding is something that we are all guilty of-just can't say no!

marilyninOttawa
OK Crowding. We are all guilty and I am equally so BUT I have observed that the more space I have between plants, the better shaped they are for showing. If ribbons rather than freedom from disease is what makes us behave, then thank goodness for competitions!

121133ellen
Marilyn how do you feel about the use of horticultural oil like Sun Oil?

marilyninOttawa
I have seen horticultural oils in use but am reluctant to use them myself. They do work but one must be careful about use under hot conditions.

121133ellen
Thank you, Marilyn, I'll give someone else a turn.

platystele (Peggy in Wisc)
l found hort oils gunk up my sprayer.

Jane5536 ( [L.I. N.Y)
Should you treat to prevent or only when you have a problem?

uncleearl (Earl from Vacaville, CA)
IMHO, you should strive to use only when needed, Jane. A good topic for discussion all by itself. (;^)

marilyninOttawa
Good question, Jane. As you may have gathered from my pre-read piece, I tend to go with the flow. Grow the plants well and they or at least most will resist pests and diseases. One used to do preventative spraying but this is no longer recommended, at least at the hobbyist level. It is very worthwhile to monitor your plants regularly. Use indicator plants or sticky strips to monitor insect problems *before they become big ones*.

Jane5536 ( [L.I. N.Y)
Thanks, Marilyn - I always felt that way becuz you can set up a resistance later.

Fleur (Tasmania)
Do sticky strips work with aphids?

marylois
What kind of sticky strips do you employ, Marilyn - and where do you stick 'em?

marilyninOttawa
Where to stick the strips? The cards can be suspended within the orchid collection, placed in metal or plastic holders in pots. There is also a new sticky tape that can be wrapped around trays.

JCY8S (John in SUNNY Arcadia, CA)
Can you make 'sticky strips' by coating yellow strips with petroleum jelly?

Evlyn
I use fly paper strips--got them at the dollar store.

marylois
Thought maybe flypaper would have some 'bad' chemicals???? IF not, it's the way to go!

Evlyn
No, Lois--they are sticky only.

bmtorchids (Barbara in No. Calif)
I found the alcohol and 409 mixer use it often, it's better then the strips.

JCY8S (John in SUNNY Arcadia, CA)
Barbara - I use straight alcohol in a sprayer bottle to battle my mealy bugs but it does seem a losing battle. Guess I will have to go to a true pesticide.

bmtorchids (Barbara in No. Calif)
John, yes for the mealy bugs, you do have to use something stronger. Alcohol without the 409, it doesn't stay on he plant long enough to kill the buggers.

JCY8S (John in SUNNY Arcadia, CA)
Barbara - it seems to kill but only those that are out of the egg stage.

marilyninOttawa
There are two kinds of sticky strip, blue and yellow. Yellow attracts fungus gnats, various wasps and flies and flying aphids. Non-flying aphids are definitely attracted to yellow but may have difficulty reaching the strip if it is hanging in mid air. Blue strips attract thrips but again, only the flying adult stage.

121133ellen
Marilyn, do you isolate new plants before putting them with your collection?

marilyninOttawa
Definitely Ellen. It pays to isolate newly acquired plants and plants returning from shows. The period of isolation can vary according to what you might expect to show up. Mealy bugs are a horror that often appear with newly purchased plants. Thank goodness I practice isolation. Last year I purchased a lovely Anectochilus. It looked perfectly OK. Two weeks later I saw some white fluff. I looked closer and AAAAA...Mealy Bugs. I removed each bug with fine forceps. Re-isolated and thankfully there was no recurrence. One does not always need to use a pesticide when problems are still small.

(If there are aphids on plants at a show then they will gravitate towards yellow-flowered orchids. I now routinely cut off flowers when returning from a show...ML)

Jane5536 ( [L.I. N.Y)
Does anyone like pepperwax?
(I have not used this Jane but maybe someone else has...ML)

Evlyn
You can also paint a product called Tangle Foot on something and hang it up.

platystele (Peggy in Wisc):
l haven't seen mealy bugs in a few years in my basement set up (knock on wood....!).

marylois
Ed Wright says 'never tangle with Tangle Foot - it will win every time.'

platystele (Peggy in Wisc):
Tangle Foot??

Evlyn
Try Dysiston (systemic diazanon), John.

marilyninOttawa
These sticky strips are pretty inexpensive. We have used vegetable oil and I suppose the petroleum jelly would work too! As Evlyn says, fly paper can work as well. Cards cost 45-68 cents apiece.

marylois
I'm going to do sticky strip on tags in the pots...sounds like just the thing.

121133ellen
I'm going with the sticky strips too, Lois.

gaillevy ( Boca Raton, Fl) I understand that there is an orthene granule available now, anyone tried it?

marylois
Where do you get the yellow and blue sticky strips you speak of, Marilyn?

JCY8S (John in SUNNY Arcadia, CA)
Evlyn - I have never heard off it. It might not be available here in CA but I definitely will look for it. A systemic would be great. Is that a brand name?

121133ellen
From where, Marilyn?

bmtorchids (Barbara in No. Calif)
Evlyn, I don't think we can get that in Calif.

marilyninOttawa
John. Why not try the Mealy bug parasite or Australian Lady Beetles for your Mealy Bug problem?

Evlyn
Tangle Foot will always win against the bugs.

sparkysteve (of Boca Raton Florida)
I use Orthene, oil based and diazinon--and I use either very very seldom.

marylois
Me, too, sparks. Wettable powder diazinon, once in spring, once in fall (when move is made to lath house, and before moving back in.)

121133ellen
Marilyn, is there any way to stop or reduce condensation during the dull winter months?

marilyninOttawa
Ellen, Condensation arises when there is considerable difference between the outdoor and indoor temperature and when the humidity indoors is high. By reducing the frequency of watering, misting, humidifying, etc, you will reduce the quantity of condensate and thus the inexorable dripping. Another alternative is to improve the insulation at the roof level by using triple sealed units (expensive).

JCY8S (John in SUNNY Arcadia, CA)
Marilyn. I have twice purchased the mealy bug parasites and the thrip one also. The thrip one seems to have worked but the mealy bug one was a waste of money and VERY expensive at that!!

marilyninOttawa
I have used Tanglefoot to stop earwigs and sowbugs from crawling up my shadehouse supports. Please remmber that the sticky cards are to mostly monitor the presence of pests, not to capture all of them.

bmtorchids (Barbara in No. Calif)
The only thing I don't like about the sticky stip is you have to hang right there by the pot, every you want to move the pot you get stuck to the strip.

Camille-vanda (from N Miami)
Anyone know about yellow blotches on Vandas?

marilyninOttawa
Camille. Are the large yellow blotches on the leaves?

Camille-vanda (from N Miami)
Marilyn - yes, on leaves.

marilyninOttawa
Camille. This is diagnosis from afar but do you think that the cause could be sun scorch? If a Vanda, particularly a strap-leaf Vanda is turned such that the leaves are aligned differently to the sun, exposed leaf surfaces can be damaged.

KB Barrett (Kathy in N. Calif)
Marilyn, any suggestions on how to handle stressed plants that grow mounted or in baskets? I have a couple of Ascdas that I let get too dry indoors this winter and they dropped bottom leaves and the roots dried up. They are now outdoors in a tent-like greenhouse, getting much better humidity, but alot of light. Do you think that increase in light acts as a favorable stressor, forcing new growth (given adequate nutrition/water) or a 'straw to break the camel's back'?

sparkysteve (of Boca Raton Florida)
Kathy, send it down here!

KB Barrett (Kathy in N. Calif)
Sparky, only if I can come with it! I need some sun and beach! Actually Marilyn, don't even try to answer that question! In reading it back there's too many variables, and you'd have to see the plants.

marilyninOttawa
Kathy. I have revived Ascdas and Vandas by placing them in a transparent plastic bag together with a bit of damp moss then leaving them to hang out of direct sun in a warm place. A sure sign that the plant is responding is a plumping of the leaves and the emergence of a root nub. Temperature will be a better trigger for renewed growth than light alone. Day length may have an effect too. Too much light may work in reverse. Take care.

Evlyn
Orthene granules are packaged for roses--this contains fertilizer. Lois where can you get sticky strips you could put in a pot? The ones I get are rather large and oblong --like 4 x 6.

marylois
That sent me to the storeroom...Di-Syston is toxic to fish and birds...doesn't have ingredients on label (must have had an attached folder when bought)...no, it's not orthene. BTW the Wundergrow bottle says 1-2 tsp/gal potted plants; 3-4 tsp/plants in sun...let's ask Jerry as the 'plants in sun' might be ornamentals and such...all my orchids are under 60% shade cloth - inside or outside.

Evlyn - I've never had any - have just decided to get them as indicators *s* Maybe I don't have to spray in spring after all...but generally I've seen a scale or two at those times (if I'm lucky and don't have an infestation - fingers crossed so far this year).

marilyninOttawa
Sticky cards are carried by most major nurseries. I would suggest asking locally. You can visit the site I mentioned in the pre-discussion material. They give prices and therefore must be marketing the product.

sparkysteve (of Boca Raton Florida)
I think it's more critical to control your plants rather then the bugs!

Jane5536 ( [L.I. N.Y)
I think a lot of it is control-control.

marilyninOttawa
As far as I understand it, Orthene is a broad spectrum insecticide which kills both on contact and by systemic action. Its use is restricted in Canada to licensed agriculturalists. Di-Syston is a granular product recommended for use against aphids and mites. I would caution you with this as it is quite toxic.

121133ellen
Do the insecticidal soaps work at all?

bmtorchids (Barbara in No. Calif)
For a day or two, Ellen.

121133ellen
Marilyn, I bought several phrags from a South American dealer. Is there anything I can do to help them acclimate to their new surroundings?

marilyninOttawa
Lois. What pest are you protecting your plants against when you use Diazinon in spring?

graphicgreg (lotsabloomin)
I would like to mention that Diazanon is bad business and only slightly less toxic than Cygon.

marilyninOttawa
Phrags respond well to moderate temperatures, bright, indirect light and lots of fresh water. I would start them in plain New Zealand sphagnum moss and keep this thoroughly moist. Then I would observe the plants for signs of new growth, especially root growth. Transparent pots are great for this.

bmtorchids (Barbara in No. Calif)
Marilyn, yes I like those transparent pots. I only have a few, I don't know where to buy them other then mail order.

marilyninOttawa
I am sorry but I know of no other source than mailorder. Occasionally, they turn up at the local nursery. It pays to keep ones eye open.

KB Barrett (Kathy in N. Calif)
Barbara, Harry Tolen bought a bunch and is offfering them for sale.

Evlyn
Does anyone know the cost of the clear pots?

KB Barrett (Kathy in N. Calif)
Barbara, Evlyn you can email Harry and ask him this is his 'private' address HTolen6067@aol.com

marylois
I use the Diazinon mainly for cockroaches! But it clears out nearly everything else that might be there as well. I know it is toxic - that's why I chose WP...I use a mask to mix it, and Robert sprays it.

marilyninOttawa
Since many of you use pesticides, I thought I would tell you why I do not. I have found that few pesticides actually work at controlling an orchid pest. Many of our pests are greenhouse varieties, long since resistant to whatever product has been used before. Vigilance works against pests. Hard work such as removing all infested plants from their pots, carefully cleaning and re-potting them works too. While all the plants are out of the infested growing area, give the area a super scrub to eliminate eggs, and lingering individuals.

Lois. Do you have the big roaches or the smaller German cockroaches. You can bait for the big ones with a mixture of brown sugar and borax. Works well!

KB Barrett (Kathy in N. Calif)
Marilyn, you do this on a routine basis, or an 'as needed' basis? I'm speaking of the 'give the area a good scrub' portion of your recommendation.

bmtorchids (Barbara in No. Calif)
Marilyn, I have a better deal, since I have the pest contral guy spray my yard, about every 2 or 3 months, I just ask him to spray the out side of my GH. Top and door too. This way not only no ants, no bugs either. marylois
Ah, Marilyn - not in the deep south! They run through the St. Augustine grass, waiting for your door to open and beat you in! Everyone has to spray regularly to keep them out of the house much less the greenhouse .I also set off two water-based Contact bombs in the greenhouse in the fall after everything is in.

marilyninOttawa
Kathy, I clean my growing area annually, either just after I move all the plants outdoors or just before they come back in. This means the trays are scrubbed with bleach solution then hosed down once a season.

Miami_Al
Marilyn, I don't use much pesticide. I do have one question. Does anyone have any chemicals to get rid of a white cottonlike thing that sometimes grows in the roots?? I see it usually on cats that have tree fern in the mix. Any solutions other than clean and repot??

marylois
Me too - re the cleaning - inside walls scrubbed - benches vacuumed and scrubbed, and I use a Dobie and take off all the green algae growing on the outside of my clay pots as well on anything not scheduled for repotting...know it's stupid, but I can't stand it!

KB Barrett (Kathy in N. Calif)
Marilyn, bleach in what concentration? 10:1 water to bleach?

marilyninOttawa
You can use 1:10 or 1:20. Both will work. You must refresh the bleach solution and not reuse.

I used to have lots of all kinds of roaches when I lived in Barbados, even the huge South American ones on occasion, and these were never a problem for orchids.

sparkysteve (of Boca Raton Florida
Al---it's snowy mold---and stop using bark---that will help.

marilyninOtawa
Al. I wonder if you are seeing a cottony fungus growth or are you referring to white powdery mineral deposit?

marylois
Well, Louisiana roaches eat leaves, but especially out of pot roots - Steve, what's your experience with roaches? And slugs! In the summer you cannot walk across a paved porch or sidewalk without stepping on slugs!

Miami_Al
Sparky, I knew you would come to my rescue!! Is that caused by excess dampness?? Someone said I needed to acidify the water to prevent it. Any thoughts, anybody??

Evlyn
Yes, Al. 2 tablespoons of Pine Sol to a gallon of water. Pour in pot.

graphicgreg (lotsabloomin)
Al, if you are using tree fern, adding a little redwood chips to the mix will eliminate the snow mold.

KB Barrett (Kathy in N. Calif) Al, are you talking about snowmold? I actually got rid of a slight infestation with RD-20 applied weekly for 2-3 weeks. 1 tsp/gal. Repotting is best though.

Miami_Al
Marilyn, it's not salt deposits, it's snow mold as Sparky said.

marilyninOttawa If the white fluff is snow mold then I wouldn't worry about it. Miami_Al
Pine Sol?? this I got to try. I'm so far behind in repotting I'm sure I will find some of that stuff.

gaillevy ( Boca Raton, Fl)
Well gang, I'm going to sleep, will see you on Saturday nite, no movie this week. Have a good rest of the week.

marilyninOttawa
Goodnite gail. Thank you for your input.

graphicgreg (lotsabloomin)
For what it's worth, our pest and disease program consists of three fungicide sprays in the spring about three weeks apart; Aliette, Cleary's and Truban. Pest control is done on an 'as needed' basis. First line of defense is to scrub scaly plants with alcohol and a toothbrush. SCALE IS OUR MAJOR PROBLEM BUT WE have finally gotten it under control. Dr. Bronners peppermint soap mixed at a rate of 1-tsp/qt will control aphids, mealy bugs, and spider mites with repeated applications every 3 or 4 days. AND, you can brush your teeth with it. See pest-of-the-day at: http:/www.orchidworks.com/ozone

marilyninOttawa
Good night, everyone. Thank you for providing an interesting forum for the discussion of pest and disease control. It seems that we have a variety of challenges depending upon where we hang our orchids!

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