Kill White Flies Dead!
Cape plumbago (Plumbago auriculata) — One of Grumpy’s favorite sources for blue flowers!
Q: I live in South Florida and my cape plumbago and ficus hedge has been infested with white fly. There is a lot of dead wood on the underside of the plants and they are thinning out rapidly. I can’t afford to replace them – I have over 130 feet of plumgago beds.
Any suggestions?
Thank you,
George DeBarros
A: White flies are among the worst, most intractable of all garden pests. These insects multiply like crazy, spread from plant to plant, and are very hard to get rid of.
There — feeling better?
Having said that, there is a a strategy you can follow to get them under control. It involves rotating the the use of a several different insecticides, which is necessary because white flies quickly build up resistance to any chemical that is used over and over again.
So do this:
1. Apply Ortho Systemic Insect Killer according to label directions. This product is absorbed through leaves and stems and kills sucking insects for several weeks. You can get this at most garden and home centers For more info about this product, click here:
2. A month later, apply a second systemic insecticide, called Bayer Advanced Tree and Shrub Insect Control. You mix this product with water and then use it to water your plants. It’s absorbed by roots. It takes some time to start working, but when it does, usually lasts for an entire growing season. You can get it at most garden and home centers. For more info about it, click here and then on “products”.
3. Once you get the white flies under control, monitor the situation by brushing the foliage with your hand from time to time. If any white flies are there, you should see them fly. Another sign of their presence is sticky honeydew and black mold on foliage and stems. If you see either of these signs, spray according to label directions with a third product, Oil Away horticultural oil, an organic pesticide made from refined cottonseed oil. You can order it from Gardens Alive!
After step 3, rotate use of the three products as you see evidence of the white flies. This should control them without leading to development of resistance. Do not spray if no white flies are present, as this is overkill.
For more expert and fascinating advice from Grumpy on how to care for cape plumbago, see “Curtains for Cape Plumbago?” by clicking here:
grumpygardener.southernliving.com/grumpy_gardener/2008/05/curtains-for-ca.html
Grumpy
“Do not spray if no white flies are present, as this is overkill.”
This entire program to kill them off made me shudder. What a lot of work!
Is there anything we can do to prevent them from moving in?
I called in an airstrike, so to speak, because George’s plants were being overrun. When plants become totally infested with white flies, you really have three choices — let them die, pull them up and throw them away, or call in the big guns. George didn’t want to get rid of his plants or let them die, so we called in the big guns.
But, like I said, airstrikes aren’t necessary if the problem isn’t that serious. I don’t recommend applying insecticides as a preventative when no insects are present. What you need to do is monitor your plants and when you see a problem, treat it quickly before it gets worse.
I planted daylilies this spring, because I read where they were hardy, and relatively “pest resistant”…and supposedly thrived in dry or moist soils. Well…they started out blooming wonderfully, then one morning, it looked as though something had sliced the a bloom clean off the stem….and disappeared with it! This continued until all of the blooms and buds on all five of my plants were gone. Completely vanished! At first I thought some sort of pests had attacked, but if so, they took every last piece of evidence with them, leaving a clean slice where the bloom had been. I have inspected for pests,including snails and slugs , but cannot find anything. What might this be, and what should I do?
Deer love daylilies and they feed at night when you’re asleep. Sound like a deer job to me.
Deer love daylilies and they feed at night when you’re asleep. Sounds like a deer job to me.
Can you treat the ground before planting in an area that was infested the year before with white flies. If so, what can I use? Thanks
Sorry, Anita, but that won’t work, because white flies have wings and can fly over from your neighbor’s yard.
will the chemical approach to controlling white flies hurt my well established gardenias?
Marsha,
If you apply these products according to label directions, they will not harm your plants.
I have read and plan on following the 3 step instructions to kill the whiteflies, but I must also ask, will these steps also kill the natural whitefly’s predator…the dragon fly? If anything I wish to invite more dragon flies to my neighborhood to help rid the problem.
Please advise.
Thank you!
Systemic insecticides only kill insects that feed on plants. They will not harm insect predators like dragonflies. In any case, if you have a lot of whiteflies, having dragonflies around will make little difference, because whiteflies reproduce so quickly.
I live in the DC area and have whitefly on a number of potted plants. Many of them are herbs or edible plants so I am hesitant to use these chemicals. Any natural suggestions?
Katherine,
You can use either horticultural oil or insecticidal soap. Both are very safe. However, neither has any residual action and kills only by contact when wet. Therefore, controlling the problem means repeat spraying. Be sure to wet all leaf and stem surfaces. Don’t bring any plants indoors that show signs of whiteflies or they will spread to every houseplant.
There are currently two different whitefly species that have been invading South Florida. What’s worse, these flies are spreading rapidly through neighborhoods and can cause damage to trees and shrubs in just weeks!
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