Rougose Spiraling Whitefly – By Mark Govan, Host “Florida Gardening”

Over the last several months there has been a massive invasion of a plant killing pest that has been ravaging our palm trees, ornamental plants, and even many of our hardwood trees. This pest, the Rugose Spiraling Whitefly, entered the southern regions of our state in 2009 and has been steadily moving North through Central Florida. This pest is resistant to most commonly used insecticides including Bifenthrin and in many cases even professionally applied material. This week I will tell you what you need to know to identify this pest, its most common plant hosts, and how you can manage this destructive pest. I believe that if you are a plant lover like I am, then you need to be aware of this pest so you can save your trees and plants from this devastating pest. Please pay close attention to this information.

Whiteflies have always been a destructive pest of both plants and vegetable crops. Those of you growing vegetables or even hedges have probably seen whiteflies fluttering around your plants as you brushed against them. Common whiteflies have always been difficult to control and I cannot tell you have many plants I have either pulled up or replaced because of ineffective control measures available to combat them. The Rugose Spiraling Whitefly elevates these problems to a whole new level.

Identification of this pest is the first thing you should be aware of. The actual adult stage of this insect is about 1/16th of an inch long and looks the same as other species of whiteflies. The key identifying characteristic of this pest is the spiraling egg masses laid on the leaves of your plants by the adult stage of this insect. These egg masses are circular measuring anywhere from a half inch to over an inch in circumference (see photos enclosed). During our summertime temperatures, these eggs can hatch in about eight to fifteen days. Once the eggs hatch, the first instar (growth stage) or crawler stage begins its cycle of destruction.

The crawler stage allows the immature whitefly to move a short distance from where the egg was laid and locate a new feeding area. This is especially important because as this pest grows and feeds on the foliage, the entire leaf surface may be covered by new eggs. Once a new feeding site is chosen, the crawler attaches itself to the host leaf and starts to feed. During this stage, whitefly nymphs will pierce the leaf with its mouthparts and suck plant juices for nourishment. This pest will go through four stages of development as it grows. During these growth or nymphal stages, the whitefly will not move again. Only during the adult stage will this pest be able to move again to lay more eggs. Because the whitefly is susceptible to predators during the feeding stages when it is immobile, this pest exudes a waxy coating which protects the whitefly nymph from both predators and control products including environmental conditions.

In severe infestations, the entire leaf and stems of plants may be covered with these waxy outer coverings. At first glace homeowners may not notice the spiraling effects of the adult whiteflies egg laying patterns, especially in severe infestations where the waxy coatings cover the entire leaf. However, there is one tell tale sign most homeowners will see even if their plants or trees are too tall or they do not scout their plants regularly. Because the feeding of this pest is so voracious, the honeydew excreted by this insect literally covers the ground, plants, stems, and sidewalks beneath plants infested with these pests. If you have noticed your plants leaves or the trunks of your palm trees turning black or becoming sticky, then you may indeed have this pest.

Homeowners living along the beaches or canals have seemed to be among the first to have this pest attack their trees and plants. Homeowner associations and Resort property owners should contact their landscape companies or pest control companies to scout for this insect on their grounds monthly. If you find that you have this pest or you suspect that you have this pest but are just not sure, then you should bring a sample to your local County Extension Office in your area for proper identification. Just because you do not live along the beaches does not mean you do not have to worry about this insect. The beach communities were just the first of us that have had to deal with the Rugose Spiraling Whitefly. Unfortunately, this pest has now moved beyond the beaches and into our communities.

The list of infected plants is ever growing but there are several plants my company, ABC Pest Control, has found to be magnets for this pest. Some of the plants you should pay very close attention when scouting for this insect are the: Copperleaf, Norfolk Island Pine, Gumbo Limbo, Ti plants, all Figs, Mangoes, Avocadoes’, Oak Trees, the Bird of Paradise, and all Palm Trees. This small list is nowhere complete and if you have any of the trees above that have this pest, then you can count on just about any plant growing beneath these trees will also have this pest. Once you have positively identified that you have this pest then you will need to control them. This is the hard part.

Many if not all of the products you have been applying yourself in a regular maintenance program will not be effective in treating this pest, Even if you are having your plants treated by a professional service, they may not be treating your larger trees which require a separate application. Also, you need to be aware of some of the natural enemies of this insect and make sure you are not killing them off at the same time you are trying to control this pest. The options available to you may not be available at your local garden center but I will give you some suggestions of where to find these products.

The only controls recommended for this pest are applications of Neonicotinoid insecticides. Neonicotinoid insecticides are true systemic insecticides that must be applied as a foliar spray, a basal stem application, a soil drench application, or by trunk injection into the vascular system of the plant. Unfortunately most of these products are very expensive and I recommend you seek the use of a professional Pest Control Company to treat your plants or trees. However, if you want the information to do this application yourself then I will tell you the Trade Names of the products you need to purchase.

If you are going to treat ornamental plants or shrubs that are infested with the Rugose Spiraling Whitefly then I recommend you purchase Coretect, Safari, or Meridian. These products are fairly easy to apply to ornamental plants but you must read the label and apply the recommended amount of product which depends on the height of the plant you are treating. Make sure that if you are applying a foliar spray that you will need to make a special effort to spray both the upper and lower sides of the leaves and the stem if you are going to get control of this pest. Re-applications must be made at seven week intervals to maintain an effective control plan.

Hardwood trees and Palm trees infested with this pest should be treated only by a professional. Because you cannot spray these materials into the air because of their proximity to a body of water or because of drift, then tree injection will be your only remedy for this problem. Tree injection should only be done by a professional pest management company like ABC Pest Control. ABC has had specialized training in the proper use of the equipment necessary to inject trees and palms and the products needed to control them. One of the good things about tree injection is that the injections are only necessary one time per year and these treatments are environmentally friendly because there is no spraying done. All material is placed directly into the trees vascular system and this also helps protect predators that feed on these pests.

These products are available at most Do-it-Yourself pest control stores or if you are in Pinellas County, ABC Pest Control in Largocarries them. The Rugose Spiraling Whitefly is a terrible destructive pest and a menace to our plants and trees. Regular scouting of plant material and keeping your plants healthy and stress free will also help combat this pest. If necessary contact a professional to care for your trees. I hope you have learned how better to manage your garden and trees with the information I am providing. As always enjoy your garden and remember, without plants, we would not be here.

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