This article will detail whitefly growth cycle, explain why they are such a hard pest to control and then list treatment options which work.
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WHAT ARE WHITEFLIES? ^
Whiteflies are small winged insects which look more like moths than flies. They have a powdery wax which both protects them and is key to identification. They are active in all parts of the world and will thrive year round in the south but go dormant during the winter in northern states. Though whiteflies can be a tough and persistent pest, the right combination of materials combined with the right timing of treatment can solve any infestation.
Whiteflies have two main species which are active in the United States. The Citrus and the Greenhouse are most commonly found but others exist. Citrus whiteflies are found on just about any plant – not just fruit. Citrus whiteflies are hardy and will be active year round.
WHITEFLY BIOLOGY ^
Greenhouse white flies are easier to control and will go dormant as winter sets in around the country. Greenhouse whiteflies are more prevalent in greenhouses though plants which move to homes and gardens carrying active populations will surely enable them to still live. Both species develop from eggs and grow through a series of instars. The last instar is the pupa stage during which young change to adults.
Adult whiteflies will lay eggs in less than a week once they emerge. Eggs are very small; almost invisible. Eggs will be laid on the underside of leaves, in hard to see locations, in generally well protected parts of the plant.
Once the young emerge, they will immediately begin to feed. Though their development can occur in less than a month, a much longer development time frame is not uncommon. Cycles can take as long as a year if conditions are not so favorable. However, regardless of how long it takes them to develop, damage will certainly be happening to any host plant on which they reside.
WHAT DAMAGE CAN WHITEFLIES DO? ^
Whiteflies are a problem because they have piercing mouth parts which allow them to such plant sap. This behavior is what they do to feed and host plants are prone to many problems during such feeding. There are many problems that feeding whiteflies cause including:
- Leaf damage. Feeding whiteflies will cause leaves to turn up and brown, disabling them to perform their responsibilities. Damaged leaves look bad and promote decay fungus and bacteria to form.
- Sap drainage. Whiteflies have an insatiable hunger for plant sap and will suck as much of it as they can from the host plant. Young host plants will not be able to meet these demands and don’t stand much of a chance to survive; adult plants which loose vital sap are more prone to disease, heat stress and less likely to rebound from any environmental shock.
- Whiteflies excrete honeydew which lures other nuisance insects onto the host plant. These secondary insects will feed off the honeydew and effectively farm it for it’s nutritional value but invariably they will become established on the property or in nearby structures. This secondary insect infestation is usually some type of ant, wasp or beetle. Regardless, feeding whiteflies allow such populations to thrive. Furthermore, the honeydew goes bad and grows a mold known as Black Sooty. This mold damages host plants preventing them from processing food properly further contributing to the host plants demise.
- Whiteflies are unsightly when they populate any plant and if prized landscaping gets infested it really looks bad. Active whiteflies will buzz around host plants throughout the day and are very noticeable. They are annoying when active on fruit or flower producing stock and can easily be brought into the home with anything harvested off infested plants.
- Lastly, whiteflies are extremely prolific. Once they get established on any plant around the home or garden they will readily migrate and look to infest any other nearby vegetation. Whiteflies don’t discriminate; they will move onto any plant that has healthy and abundant sap. It is not uncommon to have local populations thrive on some field of weeds only to start migrating into someone’s prized roses.
HOW TO CONTROL WHITEFLIES ^
INSTALL WHITEFLY TRAPS ^
WHITEFLY TRAPS can first identify a true whitefly problem and they can help reduce the damage they do by reducing their numbers. Our traps are bright yellow which whiteflies will readily be drawn to as they leave local colonies seeking new host plants. These traps will serve you by catching these foraging reproductives before they are able to settle down and start feeding and egg laying. Furthermore, these traps can serve as an alarm alerting you to activity which may have begun to establish itself.
White Fly Traps: https://www.bugspraycart.com/traps/glue/aphidwhitefly-trap-4-pk
It is recommended that one be placed on any plant you wish to protect. Inspect them no less than once a week and if activity is found, be sure to start inspecting for any population which may be started. These traps can last up to two months unless they either fill up or the glue gets dried.
If you already have whiteflies active in your garden or house plants, there are several materials which can be used to keep them in check. Keep in mind that whiteflies are persistent. They reproduce quickly, like to hide on parts of the plant which makes the hard to reach when spraying and have certain stages which are not susceptible to chemical. For this reason it is important to choose the chemical of treatment carefully. Here are your options along with guidelines to get the most out of any spraying program you decide to employ.
BEST ORGANIC WHITEFLY SPRAY ^
We also have some slightly stronger organic formulations which will last longer meaning you won’t have to spray quite as frequently. Since whiteflies can be both persistent and stubborn, MULTI PURPOSE INSECT KILLER would be the next option if the Insecticidal Soap isn’t working well enough. 3 IN 1 CONCENTRATE is another great organic option which uses three actives so you get a true insecticide, miticide and fungicide “all in one”. Remember, when using any of the organic options it’s important to treat enough to keep the target pests under control. This could be as frequent as twice a week but in general, once every 10-14 days will do the job.
Organic Insect Killer: https://www.bugspraycart.com/organic/liquid/multi-purpose-insect-killer-24-oz
BEST WHITEFLY LIQUID SPRAY ^
The strongest option available is the use of some concentrated insecticide. There are many available for whiteflies but only a few work well. Two products which still are very active are PERMETHRIN and BIFEN. Permethrin is odorless and can be sprayed on any type of plant including fruits and vegetables. Bifen is the latest compound available and is very hot – only a little bit is needed, it won’t injure treated plants and it lasts a long time. These products will quickly kill off adults and several stages of developing larva.
However, there are several problems if you rely on them alone. First, as discussed earlier, whiteflies like to hide on plant structures making it very hard to get good coverage when treating. For this reason, it is imperative that you spray from every angle which is hard to do but a necessary evil. To help allow the chemical better reach all parts of the plant, add some SPREADER STICKER to the tank mix. This product essentially lets the spray “spread” so that applications are able to cover more of plant surface area. This extra coverage could be the difference between success and failure when spraying.
Spreader Sticker: https://www.bugspraycart.com/insecticide/additive/spreader-sticker
Another product you should consider adding to the tank mix is some NYLAR. This is one of the latest growth hormones which work on insects by interrupting their growth and development. For whiteflies, Nylar will stall the cycle so the colony is not able to create reproducing adults. If you have had a nagging, persistent problem with this pest in one or several plants, consider a tank mix with Bifen, Spreader Sticker and Nylar. This combination will provide control – period. The Bifen will kill off adults and live young. The Spreader Sticker will help get the best coverage possible insuring all of the colony is sprayed and the Nylar will prevent any new young that hatch from being able to become mature adults.
On a side note, the author had a Privet with a persistent problem that could not be solved with any of the products alone. However, adding the Nylar turned out to be the turning point. Only one more treatment was needed the season the Nylar was applied and since that time one application every spring has served to keep the Privet white fly free.
One last thought about using the liquids: be sure to do the application with a good sprayer. There are many “garden” type sprayers available but none the author has seen are able to deliver the spray from the nozzle with the right pattern needed to get maximum coverage. We have taken extra time to piece together several sprayers which will do the best job possible which means your efforts won’t be wasted. We have several SPRAYERS to choose from and the size you get should depend on how big of an area you need to treat. Most of these are used for pest control in the homes requiring fine mist like sprays which are actually perfect for whitefly applications. If you are going to go through all the time to get the right products to do the job yourself, make sure you have the right tools to make the application. The sprayers we list for this job will all work great.
Pump Sprayer: https://www.bugspraycart.com/good/pump-sprayers
WHITEFLY SYSTEMICS ^
Another great tool for the management of white flies is the use of systemics. These are products that are applied to the ground soil in which trees and plants are growing that you want to protect. Once applied, the material is then absorbed up through the root system of the plants and distributed throughout it’s leaves and stems. Once the active is distributed throughout the plant, insects like whiteflies won’t be able to feed on the treated plant.
This way of delivering the active ingredient is highly effective and long lasting so you don’t have to spray over and over. DOMINION 2L can be used for any tree or shrub that won’t yield vegetables or fruit and with one application lasting a whole season, it’s no doubt a super smart way to prevent white flies from ever starting.
For the vegetable garden, DOMINION FRUIT AND VEGETABLE is a slightly less concentrated version that’s labeled for most any garden vegetable, berry, nut, etc.
Dominion Fruit Vegetable: https://www.bugspraycart.com/insecticide/liquid/dominion-fruit-tree-insecticide-systemic
The one problem with systemics is that it can take awhile for the active to be fully absorbed and distributed throughout the treated plant or tree so you won’t get quick results like you will when spraying. For this reason, systemics are best used in the early spring just before your plants take off growing. And once in place and absorbed, long term control without spraying can be achieved.
Now if you are reading this and already have a whitefly problem, Dominion should still be employed. In fact, you can even spray it on the plant in place of the Bifen so the currently active white flies will be controlled during the time it takes for the soil injected Dominion to make it’s way throughout the plant. The point is don’t rely on the soil treatment alone if you have an active infestation. Still treat the soil but spray as well to avoid excessive damage during the time it takes for the Dominion to work it’s way into the plant.
WHITEFLY GREENHOUSE FOGGER ^
If you have a greenhouse or small confined area with whitefly activity, you might consider the use of some ORTHENE FOGGERS. Though this product does smell bad, it works great on whiteflies. Each fogger will treat up to 3000 sq/ft and won’t hurt the plants. Orthene is very active on white flies and will serve as a contact kill, a residual kill to get young as they emerge and because it’s an aerosol, there will be no where for the whiteflies to hide. The aerosol will naturally find it’s way into all parts of the plant which is a big help when having to treat small delicate plants that afford a lot of hidden areas for insects to hide.
Remember, this product shouldn’t be used in living areas since it does have an odor. So for a small greenhouse or other small area, install METERED AEROSOL MACHINES. These discreet machines have variable settings so you can set them to release a flying insect killer strong enough to kill off all active white flies. Inside each machine you’ll need either METERED INSECTICIDE or CLEAR ZONE. These are actually very similar products and their formulation is essentially the same. But the Metered Insecticide has an odor, kind of like chrysanthemum and the Clear Zone is odorless. Cans will last a month and because you’re using a machine to make the application, this setup is a big money saver and more important, it won’t take a break or vacation so you’re assuredly apply the right amount of material over time.
LONG TERM WHITEFLY PREVENTION ^
To protect your plants from having a whitefly breakout, there are some rules to follow.
- If you are in a region with a lot of local activity, don’t think you will be overlooked. Inspect for whitefly activity throughout the growing season and use some traps to help spot any colonizing on your plants.
- Start treatments as soon as you identify some activity and don’t rely on one or two sprayings to solve the problem. Once you think you have it solved be sure to check for new life every week.
- For any stubborn infestation you may have use the growth regulator to knock them out once and for all without having to spray over and over.
- Remember that removing infested plants will generally only do just that; remove a plant which had whitefly activity.
- All your other plants are just as likely to one day soon get them if you don’t start some preventive maintenance.
Whiteflies can be a persistent pest which seems to always be around and never go away. Use some traps to monitor local activity and once you have them, be persistent and precise with your applications. Remember, treating early is always best as it will save time, money and effort. Once you have the outbreak under control, be sure to watch for more and be particularly careful the following year since this is when most growers seem to forget and before they know what’s happened, their favorite rose bush is infested again.
CONTACT US ^
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