Dust Application in Professional Pest Control William H. Robinson Technical Director, B&G Equipment Company

INTRODUCTION Some carriers can Dust formulations be made into a fine are very effective in powder, which treating pest harbor - increases surface ages such as cracks coverage. and crevices in Most dust formula - kitchens for cock - tions use a white or roaches, and wall voids for bed bugs and ants. gray color carrier so A small amount of dust provides long-term the application can be seen. The insecticide control of pests crawling in these enclosed and carrier are chemically joined, so that the spaces. There is renewed interest in the use of pattern of dust on the surface is the actual dust for bed bug, cockroach, and spider con - location of the insecticide. Silica aerogel is a trol, and there are new formulations and very fine dust and often does not improved dust application equipment. have a carrier. This material easily The effectiveness of dust depends on proper mixes into the air during applica - application. Dust formulations are a concen - tion and particles are small enough trated form of insecticide, so to be inhaled. Always wear only a thin surface coating is personal protective equipment needed. Dust application recommended by product labels. requires training, experience, and professional equipment. DUST APPLICATION The objectives of this bulletin The objective of a dust application is the same are to review important aspects as that for liquid application: create a lethal of using dust for controlling residue on a surface that will be contacted by a cockroaches, bed bugs, ants, crawling pest. The standard liquid spray places spiders, and other indoor pests. small droplets on a surface, while a dust appli - cation places small dry particles on a surface. DEVELOPMENT OF DUST INSECTICIDES Dust particles are smaller than droplets, but Developing a dust formulation for professional both formulations rely on the target pest to use begins with selecting an insecticide that crawl over a treated surface. provides quick knock-down and kill, and has an Dusting. Applying a thick layer of dust to a extended residual activity. The traditional surface is wasteful. Excess dust will actually pyrethroids, neonicotinoids, and other modern reduce efficacy by repelling a crawling pest classes of insecticides provide these features from a surface. The result of a dust application and many are available in dust formulations. should be a layer of The next step is to select an inert ‘carrier’ for dust particles on a the insecticide. This material helps protect the surface. An insect has active from ultraviolet light or to repel moisture to contact only a small and prevent clogging application equipment. number of particles for 2 Dust Application dust to be effective. More dust will not kill an Physical action. These materials damage the insect faster or make it any more dead. protective outer layer of the insect body. This outer layer is composed of a waxy or oily sub - Electrostatic charge. Dust particles stance that functions to protect the insect from applied through a professional loosing water. The fine particles of these prod - duster may have an electrical ucts act to absorb some of the oily layer, or charge. Dust forced through a scratch regions of the wax layer. Once the pro - plastic delivery pipe will have a tective covering is damaged, the insect will die positive electrostatic charge within a few days. when it leaves the application tip. Although this charge lasts for a short time, it Diatomaceous earth products are made from helps the dust cling to surfaces close to the tip. the fossilized bodies of aquatic diatoms.The Wood and some other surfaces have a natural structure of their skeleton negative charge, and attract positively charged absorbs the oily and wax dust particles. layer on the surface of insects. Diatomaceous Residual efficacy. The residual activity of dust formulations makes them ideal for treating earth (DE) is available as a fine powder, and inside wall voids, behind baseboards, and in typically no carrier is used. other undisturbed sites. When insecticide dust Silica and silica aerogel products are made applied away from light, humidity, and other from finely ground silica. This material is very environmental factors it remains active for absorbent and it months or even longer. The residual activity of removes the oils on silica aerogel is generally considered to be the skin of insects about 5 years. and the sharp edges can scratch the wax HOW DUSTS WORK layer. Silica aerogel is Bed bugs, cockroaches, spiders a porous material, and other crawling pests are and because it has an extreme amount of sur - killed when they pick up face area it is highly absorbent. Most silica particles of insecticide dust aerogel formulations contain the insecticide on their antennae and legs. pyrethrin, which acts as a flushing agent. The Once dust particles cling to the most common silica aerogel product, Drione ®, body or enter the mouthparts contains 40% amorphous silica and 1% after grooming, the lethal action begins. pyrethrins. Dust formulations have a physical or chemical Silica aerogel is effective in controlling a range mode-of-action, depending on the active of household pests. It can have a quick knock- ingredient. The dust formulations made from down effect, but death may take several hours. diatomaceous earth and silica, take several For example, the knock-down time for German days to kill. Death is through water loss and cockroaches is about 45 minutes, and death that may take several days to reach the lethal occurs in about 90 minutes; knockdown for level of about 30%. However, soon after bed bugs takes about 6 hours, and death contact with the dust-treated surface the occurs in about 20 hours. insect or spider will become inactive. Dust Application 3

Chemical action. crawling pests. The objective is to create a thin These materials layer of dust on all surfaces. attack the insect The equipment for dust application is designed nervous system to fit the treatment space: Electric dusters for and kill insects treating large spaces, hand dusters for treating that same was as liquid insecticides. When small spaces, and power dusters to treat every - dust particles contact the legs or antennae the thing else. active ingredient moves through the skin of the insect and enters the blood stream. ELECTRIC DUSTER Pyrethroid dust formulations attack the nerve This duster is for fibers and the insect dies quickly. The nervous treating large spaces, system is attacked at the junction of two with horizontal and nerves, or the membrane covering the nerves. vertical surfaces, with The result is excessive ‘firing’ of the nerves and a coating of dust. The shutdown of the entire system. large capacity tank can hold enough dust for Boric acid powder acts as a contact insecticide treating attics and crawlspaces without refill - because it penetrates the skin of insects to ing. The dust particles have an electrostatic (+) enter the body. The charge when they exit the application hose. The particles enter the wood rafters in attics and joists in crawl spaces body when the legs have a (-) charge. This results in a better appli - and antennae are cation because the dust particles are attracted cleaned through the to the wood surfaces. mouthparts. When quantities of boric acid are Treatment Zone. 20 square feet with the hose consumed, it acts as a stomach poison. attachment, 45 square feet with the plastic tube attached to the hose. Dust will move 10-15 feet SURFACES from the end of the hose or tube. Bare wood is common in most indoor locations Delivery Rate. 8 ounces per minute. treated with dust, such as behind baseboards and in wall voids. This is Application Rates: To treat a 50 square foot a porous substrate that space: can reduce the amount Tri-Die ® (1 oz. / 50 sq. ft.) = 8 seconds of insecticide transferred Pyganic ® (1.5 oz. / 50 sq. ft.) = 12 seconds to the legs and body of Tempo ® (8 oz. / 1,000 sq. ft.) = 3 seconds bed bugs and cockroaches as they crawl Delta Dust ® (8 oz. / 1,000 sq. ft.) = 3 seconds across it. Bare wood has deep furrows in the surface where dust particles may remain out- MINI-DUST-R of-reach of a crawling insect.

APPLICATION METHODS AND EQUIPMENT This hand-held duster is for treating small Insecticide dusts are suitable for treating be - spaces and voids. The extension tips are hind baseboards, headboards, wall voids, and heavy-duty plastic and are stored in the handle attics and crawl spaces. Basically, any enclosed to prevent loss. The fan tip can be used to space this is harborage or travel route for thoroughly coat the inside of enclosed spaces. 4 Dust Application

Treatment Zone. 2 to 3 square feet with the VERSADUSTER straight tip extensions, and the siphon tube positioned at the top. Dust will move about 36 inches from the end of the application tube. Delivery Rate. 1 to 4 ounces per stroke For Technicians using dust as an important part of their treatment protocol, the Versaduster is a Application Rates: Talstar ® PL (3 lbs. / 1,000 great choice. This compressed-air duster is used sq. ft.) = 1 stroke / sq. ft. for treating small spaces and enclosed voids with a limited amount of dust. The application BULB DUSTER tips include a crack-and-crevice tip along with This hand-held duster is for treating small several extensions. Application is with 1-second spaces and voids. The extension tips are pulls of the trigger and allows the Technician to heavy-duty plastic treat over many application areas in a short and this eliminates period of time with just the right amount of dust. the potential of elec - It’s virtually maintenance free and easy to use. tric shock with treat - Treatment Zone. 1 to 2 square feet with the ing wall outlets. crack-and-crevice-tip attachment tip. Dust will Treatment Zone. 4 to 5 square feet with move about 12 inches from the end of the the straight-tip attachment tube. Dust will straight-tip application tube. move about 24 inches from the end of the Delivery Rate. straight-tip application tube. 0.002 to 0.003 oz. per 1 second trigger pull Delivery Rate. .01 to .04 oz. per squeeze Application Rates: Application Rates: Borates, diatomaceous earth, silica aerogel, Drione ® (2 oz. / 100 sq. ft.) = 50 squeezes = or pyrethrin products: 10 trigger pulls 2 oz. Pyrethroids (Tempo ® and Delta Dust®): 4 Delta Dust ® (2 gr. / sq. yard) = 1 squeeze = 1 trigger pulls gram

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