Vivi's Orchid Corner

November 2001 - Volume 6, Issue 9

"Insecticides and Fungicides
for Healthy Orchids"

Dear Orchid Friends:

Quite often I am asked, "What should I use to treat my orchids?". Here is a quick guide for insecticide and fungicide use:

Pesticides: Orchids are easily besieged by insects despite our best efforts to keep them insect free. The first rule of thumb is: Inspect your orchids! Be diligent in checking your orchids for thrips, scales, ants, whiteflies. Check your plants weekly. These pests can wreak havoc in a very short period of time. Thrips can destroy buds and blooms quickly. They are small and may escape our view if only doing a cursory glance at your orchids. If your orchid plants begin to look unhealthy, start observing them more closely to determine what is the problem. Perhaps you notice ants on your plants. They are dining on the sticky sap left from infestation.

The best medicine is to treat your orchids as soon as you see an insect problem. Then continue an established routine of preventative treatment with pesticides.

So… What to Use? Malathion™, Orthene™, Cygon™ and Dursban™ are the most common pesticides. Spreadable Sevin™ and Orthenex™ aerosols are also good choices. Consider alternating products when treating your orchids. This system may prevent any toxic buildup and may prevent the insects from developing a resistance to one single product. Consider spraying your orchids on a monthly basis. Be sure to follow the manufacturer’s directions. It is best not to use these products in the heat of the day during extremely high temperatures.

Use of a sticker spreader or a few drops of liquid soap mixed with your pesticide mixture will help the pesticide to stick to the plant.

For those wary of pesticides, use rubbing alcohol as a spray or dip Q-tips in the alcohol and scrub the stems, stalks to rid of scales. This is labor intensive, but is less caustic to your orchids, your environment and yourself.

Fungicides: Fungus occurs when airflow is hindered. Good air movement is the best tool to prevent against a fungal infection. South Florida has warm, moist, humid conditions - the perfect setting for fungal growth.

How does one determine if your plants have a fungus? It is a little more difficult to determine. If you have inspected your plants and cannot find any signs of insect infestation, think fungal infections. Your orchids may not look quite right, leaves are turning mushy, discolored. Crown rot is a form of fungus and is especially prevalent in South Florida. Phalaenopsis are susceptible to crown rot. Brown or black spots on orchid leaves are a sign of a fungus infection. Soft leaves or teretes with discolorations can also be a fungus infection.

So…what to use? Several fungicides are good choices. These include Captan™, Physan 20™, Dithane™. During those hot summer months, consider spraying your orchids on a weekly basis. Otherwise, spray your orchids monthly. Again, consider developing a regimen that uses alternating products.

Safety Tips: Any pesticide or fungicide must be used with great care. These are toxic products. Always follow the label directions. Protect yourself while using these products; wear gloves, masks, etc. Remove pets from the area.

One product may work better for you than another. Alternate sprays because one item may not be effective against all insects or fungus. It is important to have a consistent routine. It is difficult to rid your orchids of an infestation, so be diligent in your efforts. Don’t forget to use clean tools to reduce the risk of spreading diseases from one plant to another.

Most importantly, decide whether pesticides and fungicides are right for you. Only you can decide how this will affect your environment. Remember, these products should be used with care.

All of us experience a bout with an insect or fungus problem at one time or another. So don’t get discouraged. It takes a little work to keep your orchids healthy and happy. Good luck!

Vivi