ANNOUNCEMENTS FOR Oct 5, 2003
PLACE:
Kalamazoo Valley Community College
Room
1510
6767
West O Avenue
Kalamazoo MI
49009
TIME: 2:00 PM
Society Meeting
Program
Annette Sobolewski from Galaxy Orchids
How to Successfully
Grow and Bloom Orchids in Your Home
Meeting:
·
Bring
plants for show and tell
·
NO
auction
·
Galaxy
orchids will have plants for sale – see below
Meeting:
Orchids are now only second to poinsettias
for the most purchased houseplant in the U.S.
Come and learn how easy they are to grow and bloom.
Annette Sobolewski will cover easy culture of orchids including water,
light, air, fertilizer, potting, and pest control problems. She will also cover how to display and enjoy
your orchids at home. Various unusual
kinds of orchids will be for sale.
There will be bags of potting soil for sale, Michigan State University orchid
fertilizer, plant supports and much more.
She will give 20% discount on preorders. Check the web site, and call her. She will call you back so that you do not have phone
charges. Call ahead for large bags of
potting soil, she has a very wide selection of types of potting soil. Fertilizer information at web site.
Galaxyorchids www.galaxyorchids.com
Darlene Heart galaxyorchids@aol.com
& Annette Sobolewski annastas@tir.com
TREASURER’S
REPORT:
At our Sept. meeting we received income of
$97.61 ($88.00 from the auction and $9.61 in refreshment donations). Our expenses were $146.93 ($125.10 for door prize plants and $21.83
for postage). Our total assets are
$2,648.69 in checking and $2,156.19 in savings.
Meeting dates
and rooms
All meetings are scheduled for room 1510 EXCEPT the January 2004 meeting which will be in Room 4380 Membership Info:
Dues are: $10 for single member; $15 for
couple/family. Check should be made out
to Dunes-Kalamazoo Orchid Society, and can be mailed to Ginnie Hessler, 2503
Lamond Dr., Kalamazoo, MI 49008
Email Address?
If you have an email address, and you are
not getting the newsletter via email, please send the address to
me. It is much easier, faster and less
expensive to get the email version to you!
My email address is glf@proinnovation.com
Officers President:
John Talpa 269 649-4340 jtcompany@bizloop.com;
Treasurer: Ginnie Hessler 269 382-3824 tivth@sbcglobal.net; Secretary Greg Filter 269 -979-7626 or 269 -979-7974
gregf@proinnovation.com;
Program: Russ Hibbard & Georgiann McWilliams call: or FAX 269
685 2268 or 269-685 1167, fax 1 269 685-6506, email, georgiann@charter.net Refreshments: Ginnie Hessler 269 382-3824
Web Site Address: http://www.proinnovation.com/dko
Refreshments: Joe Kanamueller
269-375-0405; Russ and Gerogiann
269-685-2268; November: Dave and
Virginia Middleton 269-628-4637; Larry Galdes 269-383-4423
Scale
Insects article:
Here is the link to the article on scale
insects. It seems that some email
servers and clients did a POOR job of transferring the content. Many of you got garbled versions. My apologies.
http://nat_hist.sdstate.edu/orchids/pests/scales.htm
Scale Insects on Orchids*
(Continued
from last month)
Scale management is usually a protracted and serious effort, and never much fun. Light infestations restricted to one or a few plants can usually be treated with household products rather than concentrated insecticides. When possible, immediately isolate infested plants from others to prevent the crawlers from moving amongst them.
Because the life cycle of scales can be so short combined with the overlapping of generations, in order to bring a serious problem under control you will need to do a treatment every 2-5 weeks, depending on the life cycle period of your particular problem scale species. Consequently, the key to scale control is persistence.
Management methods that are the least toxic to people, pets, and plants, are the most time consuming and laborious. Insecticidal methods, including horticultural oils, soaps, and synthetic insecticides are progressively more toxic (to both the insects and humans!) and more expensive, but less work. Regardless of method or chemical used, you must remain vigilant and expect to make at least 2-3 applications 10-16 days apart.
Because of plant costs, personal attachment to orchids by owners, and the over-riding desire to avoid insecticides whenever possible a number of effective “home remedies” for scale control are available. Be aware that non-insecticidal treatments may not be highly effective for elimination of scales. Thus, they should be viewed as controls, not eradicators. Also, many common home chemicals are extremely toxic to humans, pets, and plants even in diluted forms, often being proportionately more toxic than the feared insecticides.
Probably the most popular home remedy is to swab and daub plants with a Q-tip or ball of cotton dipped in isopropyl (rubbing) alcohol. Do not use other alcohols, such as ethanol or methanol, that will penetrate the plant tissues rapidly and cause considerable damage! The concentration of the isopropyl seems to make little difference; the common 70% available in stores is satisfactory. On hard-leaved plants, gentle rubbing with the fingers or a soft infants toothbrush is effective, with or without the alcohol massage. Remove all scales, 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 midrib, other veins, and leaf edge areas. Closely monitor your plants to get an idea of the life cycle of the particular species of scale that is your problem, but expect to repeat treatment against the immatures every 1-2 weeks.
A common alternative to the swab and daub method is to spray the alcohol with a misting bottle or small pump sprayer. Many home growers will also mix-in a small amount of mild liquid dish detergent, and sometimes mineral oil, neem oil, or horticultural oil. 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 1/4-1/2 teaspoon of one of the oils. But, it seems that every grower has their own proportions of these ingredients, none of which seem to work significantly better than another. Caution is urged, however, as excessive amounts or too strong of a detergent, or use of an ammonia-based chemical cleaner may damage your plants, particularly buds and flowers. This is particularly true of dish-soaps and household detergents that could remove natural protective waxes from plant tissues. Also, alcohol sprays are not effective against eggs protected by the scale covering, hence the physical removal of the scales by hand is more effective and provides more rapid control.
A potential problem with alcohol treatment that is occasionally reported may be chilling of the plant. The rapid evaporation of alcohol cools the plant tissues. Especially with air movement that increases evaporative cooling, this chilling is suspected of over-cooling tissues and creating zones of dead cells that may become necrotic from bacteria or fungi. On warm or breezy days consider wiping any residual alcohol with a tissue instead of permitting it to evaporate off the plant. Such problems and tissue drying are found particularly on soft or thin-leafed orchids (e.g. Oncidiinae).
Given an extreme infestation you may see scale developing on the roots and rhizomes. At this time, or anytime you observe a heavy infestation, then you may need to consider replacing the potting medium. The potting medium can harbor eggs and crawlers, so dispose of it in a compost pile or in the garbage. When repotting, a close inspection, and if necessary a very gentle cleaning of scale and spraying of the roots before repotting is essential. Use caution with the cleaning of roots because of the delicate nature of the velamen.
Horticultural oil, neem oil, mineral oil, insecticidal soaps, and sterilants form the next stage of chemical control of scale insects. The oils and soaps are often regarded as “organic” or non-chemical methods, but this is a misconception or an extremely broad concept of “organic.” Indeed, neem oil is extracted from the neem tree, but horticultural oils and mineral oil are petroleum distillates. Likewise, insecticidal soaps are a solution of synthetic pyrethroids mixed with a detergent (soap) that is made from petroleum products. Sterilants are anti-bacterial and anti-fungal chemicals that are also often effective on algae. However, all of these solutions are generally considered safer for humans, pets, and plants than usual insecticides. None provide absolute control over pests, but frequent use during the presence of pests frequently reduce insect populations to below self-sustainable levels in small orchid collections.
Horticultural, mineral, or neem oil solutions smother the insects, so complete coverage of all sprayed plants is essential. These oils are mixed with water and usually a plant-safe detergent for enhancing the spreading and sticking of the oil. The main caution with these oil solutions is that they should never be applied to plants on hot days (>85 degrees F) or in direct sunlight, as to prevent burning of tissues. Leave the plant in shade until the application has dried.
Insecticidal soaps are usually solutions of a synthetic pyrethrin, piperonyl butoxide as a synergist (to enhace the effectivenss of the pyrethin), and sometimes a plant-safe detergent. As with oils the detergent acts as a surfactant and spreader for dispersing the pyrethrin evenly, and as a mild caustic against the insects. Also, to prevent sunburning apply the chemical and allow it to dry in shade. Pyrethroids are synthetic analogs of pyrethrum, the natural extract from certain Asteraceae. Caution should be urged with so-called “safe” insecticidal soaps as some plants are sensitive, particularly tender new tissues, and when mixed with hard water. Some non-orchid ornamentals will drop leaves and abort flowers when sprayed with insecticidal soaps, so caution is urged with prized orchids. Though piperonyl butoxide is usually regarded as safe for plants, it can cause allergies and respiratory problems for users and may contribute to phytotoxicity problems.
Sterilants are usually Physan 20, RD20, or Consan 20, and these are used as anti-bacterial, anti-algal, and anti-fungal agents. These solutions are all composed of isomer cocktails of ammonium chloride and all have the same antibiotic activity. These chemicals can be used in diluted form, according to label directions, usually for controlling bacterial and fungal diseases on orchids. However, at these same dilutions there is some limited effectiveness on scale crawlers and other delicate insects. Frequent use of sterilants for insect control is not recommended, due particularly to potential damage on new growth, buds, and flowers, and should be done under shade to prevent sunburn.
Persistent populations of scale or infestation in many plants often demand the need for use of synthetic insecticides. There are few insecticides specifically registered for use on orchids, but there are several common, inexpensive, home-and-garden chemicals labeled for ornamental plants. Insecticide formulations not labeled for ornamental plants are often mixed with solvents that aide in the application of the active ingredient for specific purposes. These solvents, not necessarily the insecticide itself, often produce phytotoxicity and may seriously damage or kill plants. Thus, never use any insecticide that is not specifically labeled for ornamental plants.
There are many insecticides available for ornamental plants, but some are not tested on orchids, and others are generally too expensive or otherwise readily available for the small keeper or grower. Some of the more available and effective insecticides that come in various brand names are acephate (e.g., orthene [wettable powder]), malathion (liquid), diazinon (liquid), and carbaryl (water-based emusifiable concentrate). Fertilizer/systemic combinations for roses and other ornamentals, usually with disyston or disulfoton, may be effective but are not widely tested on orchids. Also, caution should be given to the fertilizer effect on your plants in combination with other nutrients. Of course, always follow label directions and never, never, never exceed the minimum recommended concentration given in mixing directions! Recommended solutions are based on extensive testing for selected pests and plants. Orchids are tough plants, but are sensitive to many chemicals, particularly under direct sunlight or high heat, and while certain species may not react to a given formulation others may, so testing is justifiable.
Some insecticides are occasionally discontinued for use because of some discovered hazard. For example, Cygon used to be available, but it no longer recommended and labeled for orchids because it will damage many plants, especially the buds and flowers, and is extremely hazardous to use. Although most insecticides with discontinued labels are legally allowed to be “used up”, it may be best to dispose of such chemicals rather than continue their use and risk damage or loss of plants, or increase your own health hazard.
Most home orchid keepers and growers in northern states that need to apply insecticides during inclement weather need special care for applications. If you cannot spray out of doors, place your plant(s) inside a large plastic bag (remove the bag after the spray has settled!) and let the plant ventilate where the fumes will not be wafted around the house or work area. Again, you may have to consider removing the potting medium, spraying the plant, and repotting it with new media in a clean pot when the spray has dried.
Research on the use of insect growth regulators, botanical insecticides, and their application to ornamental plants is increasing, but incomplete. Insect growth regulators, such as kinoprene (tradename = Enstar II), are synthetic forms of juvenile hormone which is highly important in insects at critical stages of their metamorphosis. The use of growth regulators interrupts the normal development of the insects, including orchid pests such as scales, mealybugs, aphids, and whiteflies. Apparently, there is little good and reliable information on their use on orchids, but an increasing number of growers are reporting satisfactory results with Enstar II and there does not seem to be any plant health problems noted thus far. Also, they are regarded as safe for humans and pets.
Azadirachtin (tradenames = Azatin and Neemazad) is a plant derived (neem tree) chemical, or botanical insecticide, that is a chitin inhibitor. Chitin is a primary component of the insect integument, or exoskeleton. Azadirachtin reduces the insects’ ability to properly develop its integument and causes mortality through incomplete development. There is little information available on this chemical for use on orchids, but it is available on a wide variety of ornamentals and is labeled for greenhouse applications.
Heavy infestations of scale, especially on many plants may require severe control methods. In such situations, you may need to consider the use of a synthetic insecticide. On the extreme side if you have a plant showing signs of decline from scale you may have to seriously consider destroying that plant, as the low likelihood of rejuvenating that plant may not justify the expense and effort of continued treatments. After all, the destruction of a sick plant can be used to justify the purchase of a new and healthier plant!
If you are battling scale for long periods of time (e.g., >9 months) and have been using the same insecticidal control method then you may have built a bigger problem that you started with. Depending on the length of time of your problem and the intensity of chemical use you could have selected a population of resistant scales. The best resolution to this is to change methods and chemicals occasionally; that is, do not use the same chemical mix more than 3-4 times sequentially. After isolating infested plants give them a thorough application of something different from what you have been using. For example, if you used insecticide then switch to an oil, soap, or different insecticide.
Generally, never use an insecticide not labeled for ornamental plants. Whenever using oils, soaps, and insecticides, be thorough, change formulations frequently, and do not use less than the minimum concentration of mixture. Too little of a chemical enhances resistance, while too high of a concentration may damage the plant. Never use chemicals prophylactically, that is do not routinely use chemicals as a preventative as it is a waste of chemical (and money!) and such use allows resistant scales to develop. Finally, keep up the manual removal of all scales, if possible. Removing the egg laying adults is as important as killing the nymphs. Again, you need to monitor the cycling of your scales to optimize spray effect and minimize total number of sprays.
*Updated from the November 2000 issue of the Newsletter of the South Dakota Orchid Society.