I got an e-mail from one of my readers a few years ago.
This gardener near Mohican State Park endured a terrible summer, because of the damage done to her zucchini, cucumbers and tomatoes. From what I can see on the pictures I agree with the reader. This is a picture of whitefly problems on a zucchini leaf.
Damage that is done by this insect can weaken the squash, cucumbers, or tomatoes and can kill the plants if the infestation persists.
When I took my classes at Agriculture and Technical Institute – Ohio State University in Wooster my greenhouse classes experienced whitefly threats on crops.
As a part of my training, I was taught to identify the culprit then begin the mitigation process. If you have a few whiteflies in some of your greenhouse raised plants, they can make it outside.
The whitefly: a primer
Whiteflies, or Trialeurodes vaporarium, feed on the sap, attaching themselves to the circulatory system of the plant or the phloem. As a reference, there are 1,500 known different species of whiteflies and 17 common whiteflies.
The whitefly has a toxic saliva and decreases the strength of the plant, when it attaches itself in particular stages of life as one of the three nymphal stages that feed on the squash. This whitefly nymph can reach the end of its nymphal cycle in three to four weeks as it feeds on the plant.
Each female can lay 400 eggs over a period of up to two months. One of the other ways that you know you have problems is that the leftovers of this insect can produce a black sooty mold that also can harm the plant. As this whitefly attaches itself to a plant it changes into a pupa and then progresses to the adult stages.
Managing the pest
One of the critical methods of managing any pest should include cleaning all plant damage by removal or processed through a good composting. When assessing the damage, you will see all kinds of little white dots on the bottom of the leaves. In all probability, you are looking at the eggs for next year.
One of the challenges in clearing out the plants that are infested with whitefly is that the brown plants can be very brittle and fragile as you would try to gather them.
Personally, I would gather the garden waste as much as possible and then go back over the areas with a lawn vacuum picking up the insect’s eggs as much as possible. I have also used my lawn torch to kill the eggs. This maintenance should help next year.
Damage can be mitigated by getting rid of the insects as early as possible. What I have used is a yellow sticky trap in the greenhouse to help identify whitefly. The insect is attracted to the yellow strip, and the glue holds the whitefly in place.
You then keep a log of the number of whiteflies on the strip, and you make your decisions based on the populations of insects you find. This can be done in a garden and can give you a basis for decision making to treat your plants. If you see only one or two whiteflies, you may not need to treat as vigorously.
These pests can also carry a number of other diseases, such as yellow leaf curl in tomatoes. Some of these diseases can also destroy the plants. Controlling these insects is a needed part of protecting the crops you plant.
Environmental approaches
One of the environmentally friendly approaches is to work on establishing an ecological
equilibrium of predators and parasitoids and other microbial controls that were once in place.
If you purchase an insect from an insect breeder then you can find the following predators taking care of the whitefly:
- Ladybugs
- Parasitic wasps
- Lacewing
These insects feed on whitefly and their larvae. You will need to know how to help the beneficial predator survive longer. I think this is better than an insecticide, which is also an alternative. Neem oil and insecticidal soap are also solutions. There are plants that repel insects and certain compost teas that also repel and confuse white flies. I hope to encourage you in that there are many solutions to your whitefly problem, but all will take a little work.
When looking for solutions to whitefly try to be friendly to the environment.
The leaves in our woods are falling early, because of the rain problem. If you see a challenge in your garden while you are taking your stroll this week, let me know what is happening and I’ll help if I can.
My e-mail is ericlarson546@yahoo.com.
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