I read your article on whiteflies, which is one of the best I have found.
We have a greenhouse that was horribly infected with whiteflies last season. As we are about to start it up again, I wondered if we should treat the greenhouse now (will that help with any that may be dormant but will reemerge).
If we should treat now, what should we buy?
Also, I think we will use the Orthene fogger in season but wonder if it is not advised on tomatoes or anything we may eat.
Thank you for your help.
Whitefly populations will thrive all winter long inside a greenhouse regardless of how cold it gets outside. When people bring plants inside during the winter, many times pests like whiteflies will get active due to the warmth, moisture and ideal “weather” inside the confines of this protected environment. To insects, most greenhouses are perfect for them to live and thrive all year long. Essentially a micro ecosystem, most any greenhouse can host a wide range of common plant pests and populations can appear seemingly overnight.
Once whiteflies appear, the use of something like an ORTHENE FOGGER is usually needed to ensure you get all areas of the greenhouse. Liquid applications are effective but unless you drench the entire structure inside where the activity is noted, it’s hard to control active pest populations with spray alone. Aerosols like Orthene are usually needed to insure thorough pest eradication. However, Orthene is both costly and has a somewhat limited label compared to many of the liquid concentrates we have. Have you ever considered treating before problems appear? This approach works well for greenhouse environments.
In the long run, you’ll find it much easier to control pests inside your greenhouse by taking some simple preventive measures before populations appear. Depending on the product you choose to employ, you should be able to get at least several weeks of protection and potentially a few months of whitefly prevention if applied early enough. Take some time to review our WHITEFLY CONTROL article and you’ll see we have several actives which can be sprayed on a wide range of plants. BIFEN IT is a long lasting residual that’s Ok to use on any non-edible plant. A single treatment done inside a greenhouse can last 2-3 months. It’s odorless and highly effective on any nuisance pest.
We also have several organic options. These would be best for vegetable plants like tomatoes. MULTI INSECT KILLER and 3-IN-ONE CONCENTRATE are both good concentrates to use and safe enough for any plant and can be applied as often as are needed. Since they’re organic the treatment will only last a short time which means you’ll have to use it more frequently compared to something like the Bifen. I recommend using them once a month to insure whiteflies don’t appear; more frequently if you are treating a current infestation.
So in summary, use the Orthene Foggers only if you have failed to get control with one of the liquid treatments mentioned above. Since you’ve had a previous history of whitefly activity, I strongly recommend treating all the plants you bring inside the greenhouse right away, before the whitefly problem starts again, as this approach is both effective and in the long run will allow you to get through most seasons with very little in the way of insect activity. If you have further questions or concerns, please give us a call on our toll free 1-800-877-7290.