Introduction: House flies, soldier flies and other non-biting flies can and often do become a problem in poultry buildings. They do not bite or feed on the birds but may carry pathogens because of their habit of feeding on manure, dead birds and other waste materials. Poultry manure is an excellent development material for fly larvae. Caged layer operations concentrate a large amount of manure in a relatively small area and therefore create an ideal situation for producing many flies. Flies and odor coming from poorly managed buildings may result in legal action against the producer. Science Daily (Mar. 16, 2009) — Researchers at the Johns Hopkins Bloomberg School of Public Health found evidence that houseflies collected near broiler poultry operations may contribute to the dispersion of drug-resistant bacteria and thus increase the potential for human exposure to drug-resistant bacteria. The findings demonstrate another potential link between industrial food animal production and exposures to antibiotic resistant pathogens. Poultry Lice Poultry lice are small, wingless insects with chewing mouthparts. The most common in Nebraska are brown chicken lice and chicken body lice. Less important are large chicken lice, shaft lice, chicken head lice, fluff lice, and several other species which are rarely present. Poultry lice chew dry skin scales and feathers; they do not suck blood. Irritation from louse mouthparts and movement on birds causes appetite loss, weakened condition and susceptibility to diseases. Egg production is reduced, and heavily infested birds refuse to eat and gradually lose weight. Lice can be observed moving on the skin when feathers are parted, especially around the vent, head and under wings. Poultry Mites Several kinds of mites attack poultry. The most common are chicken mites and northern fowl mites. Occasionally scaley-leg mites are a problem. Chicken mites feed at night. During the day they stay in cracks around roosts and interior portions of poultry houses. At night, they feed on the birds as they roost or nest. Chicken mites are very small, grey to yellow in color, but darken after filling with blood. Control of chicken mites is directed more to their hiding places in houses than to the birds. Northern fowl mites remain on poultry. They are very small, red or brown. Feathers are discolored by excrement and eggs, and the skin is scabby. Control of the northern fowl mites must be directed to the birds. Chicken and northern fowl mites suck blood, resulting in emaciation and lowered egg production. Continued heavy infestations can kill the birds. Scaley-leg mites burrow under the skin, especially on the lower legs and feet. Legs become scaley, swollen, and exude lymph. Severely infested birds may be crippled or unable to walk. In addition to treating with insecticides, legs may be dipped in a mixture of raw linseed oil, 2 parts, and kerosene, 1 part. Bedbugs The common bedbug and several other closely related insects feed on poultry. They are flat, wingless, bloodsucking insects about 1/5 inch long when fully grown and have a very distinctive pungent odor when crushed. Bedbugs feed at night, hiding and laying eggs behind insulation, in wall cracks, loose boards, nests and other dark areas during the day. At night they move to sleeping birds and suck their blood. Small, dark fecal dots around cracks, roosts, and on eggs are observed frequently. Bedbugs can be carried into poultry houses by other birds; they also can be carried from poultry houses into human dwellings and become a pest of people. Control must be directed inside the housing, using the materials suggested for residual fly control. (See Table III.) Flies House flies are the most persistent and common pest, although other species such as blow flies and little house flies are present. House flies do not bite poultry, but are severe nuisances, and can spread some poultry diseases. House flies are present because of poultry manure and exposed wet feed, which are ideal breeding materials. Manure management is most important for house fly reduction Manage manure under caged birds so the moisture content is reduced to allow coning (approx. 35-40% moisture). If manure can’t be dried, spread it in the fields every 5 days. In liquid manure pits, the manure should be liquified rapidly to reduce fly breeding. Manure that remains partially solid in pits creates an ideal breeding site. In some management practices, agitating the liquid in pits has greatly reduced fly breeding. Chemical controls are valuable, but should be considered secondary to manure management practices. Many poultry operations use a combination of good manure management and one or more of the chemical controls . Effective and economical fly control depends on: 1) good sanitation practices to remove fly breeding areas, 2) proper use of insecticides to kill adult flies, 3) treatment of manure with an insecticide to control maggots if needed, and 4) good management practices throughout the year, especially in controlled environment buildings.


The first, most important step in fly control is prompt and regular removal of waste material where flies breed. Flies lay eggs on wet, decaying material. This includes waste feed, broken eggs and dead birds. The maggots that hatch from these eggs cannot develop in manure or other dry materials. Keep droppings dry. Repair water leaks, both in water supply lines and building roofs. Soldier fly infestations usually start around the outside of open buildings where rain and snow have blown onto the manure and made it wet. The caged layer operator has two options available when considering the frequency of manure removal:

  • Weekly removal. Removing manure once each week during the active fly season (May through October) and throughout the year in controlled environment buildings doesn’t allow sufficient time for the maggots to develop into adult flies. Predators and parasites that feed on the eggs and maggots also are removed. Occasional insecticide treatment to control adult flies may be needed.
  • Occasional removal. The manure is allowed to cone up under the cages and dry and is removed once or twice a year. The predators and parasites develop to their maximum. If manure becomes wet, flies will become a problem. Occasional insecticide treatment to control adult flies may be needed as well as occasional spot treatment of manure to control maggots. Removing the manure from under one row of cages at a time instead of cleaning an entire building will leave a stock of beneficial insects and mites to move into the new manure.

The manure that is removed should be thinly spread in fields, not piled outside the buildings. If good sanitation practices are followed, less insecticide will be needed and that used will be more effective. Fly control in open houses Acceptable fly control in open houses requires strict attention to sanitation and manure management, supplemented with the use of insecticides as baits, residual sprays and spot treatment of manure for maggot control. Baits consist of an insecticide and an attractant, which serves to draw flies to the insecticide. Start spreading the bait as soon as flies begin to be numerous. Place bait where flies congregate during the day — window ledges, doorways, on the floor between cages, etc. During the first four or five days, scatter dry bait heavily enough that it can be seen. Continue to put out bait each day for the next week, using smaller amounts than for the first application. After the first 10 days, apply bait every two to four days to those places where the most flies were killed during the initial baiting. To make a liquid bait, mix the proper amount of insecticide with water and add sugar, corn syrup or molasses. Follow the directions on the container label. Use a sprinkling can to spread the bait on the floor. On a dirt floor or where the floor is dirty, apply the bait on pieces of burlap, cardboard, etc. Apply new, fresh bait every two to four days. Continue to use bait regularly during the summer. Don’t stop as soon as fly numbers are knocked down. If you do and the numbers build up, you will have to start all over again with the heavy initial baiting. Residual sprays leave a deposit of insecticide that the fly contacts when it lands on the treated surface. Residual sprays will remain effective for a few days up to several weeks. Apply the first spray around doors and windows, walls, ceilings and rafters in late spring or early summer as soon as flies begin to be a problem. Repeat applications as needed. Apply 1 gallon of spray per 500 to 1,000 square feet of surface. On unfinished wood, brick or concrete surfaces, wettable powder formulations will give longer lasting control than emulsifiable concentrates Maggot control. Maggots should not develop in manure that is kept dry. If the manure becomes wet, correct the cause of the moisture. If maggots develop in the wet manure, make spot applications of one of the recommended maggot sprays to the infested manure. Apply as a coarse spray or with a sprinkling can. Apply approximately 1 gallon per 100 square feet of surface area. Maggots are something most people don’t like to see in and around their home. Generally white and resembling a worm or caterpillar   Most maggots have a tendency to “gross out” even the toughest of men. In most cases one will see hundreds if not thousands at one location and the way they move makes it appear as though 10 times as many are actually present. Maggots are almost always the young of some type of insect   Most commonly the young of some specie of fly, maggots could be young beetles, moths or many other local and common insects. Virtually all insects hatch out young which will start its life as a type of worm-like creature. Fly larva – or maggots as they are more commonly known- will almost always be white. They might have a tan, brown or black head but most people just see white. This is due to the sheer numbers that most people will happen upon when they first find any in or around the home. Since many insects will start out in this form, there is no common size nor location where they may be found.   Maggots are generally associated with either garbage or a dead animal. However, they can readily feed on almost anything organic This list includes but is not limited to carpeting, wallpaper, pet food, bird seed, pets, couches, clothing, furniture, pet hair, people hair, live animals, plants, fruit, vegetables, cooked meat or food, compost piles and just about anywhere in the home or immediately adjacent to it. Though maggots serve to “recycle” most any type of garbage or other decaying matter, most people don’t want them in and/or around the house!   Nature has a way of finding a place for most any living creature and maggots are no different. They are clearly responsible for the recycling of almost anything which is considered waste. There are even maggots which are so highly specialized that they can only eat certain types of waste. These species are so highly developed that the adult stages will actively seek out the special food requirement their young must have and only when such a food supply is found will they lay their eggs.   Once the eggs hatch, the larva (maggot) doesn’t even have to search for food. Most maggots will feed for a few days to a few weeks depending on species, and then it will migrate away from the food supply to seek a good location to undergo metamorphosis. This is the stage during which the “maggot” turns into the adult. This usually occurs inside a cocoon or shell like  case in which the insect will literally transform into an adult Once this stage is completed – which could take a week, a month or even a year – the adult will emerge with generally only two things in mind: finding a mate and then reproducing.   Since there are many things in and around the home which can serve as food for maggots, all it takes is a fertile adult female laying some eggs and a local infestation can ensue In general, the faster the food supply is likely to go bad and rot, the faster the  life cycle of the maggots which will want to eat it.   For example, over ripe fruit and vegetables may attract several types of flies which will be able to complete their life cycles in under one week. Maggots may only need to feed for a day or two which insures the species will propagate – even if there is only a limited amount of food around on which to feed. On the other hand, fly maggots, like Blow Flies, will feed for a slightly  longer time. Generally this type of maggot will feed on dead animals. They are commonly found in homes which had an animal die somewhere inaccessible. This is quite common due to the use of Rodenticide and the mistaken belief that the mice or rats that eat it will “go outside to seek water” or “dry up when they die so they don’t release any odor”. Nothing could be further from the truth!   In fact, the most common cause of maggot problems in the home is due to flies which have been attracted to the rotting corpse of some animal. And the most common animal they are finding are either rats, mice or squirrels with the most common cause of the animal death being contributed to the use of a rodenticide.   When maggots are found in or around the home, they are usually found in one or two stages Stage one infestations are when the maggots are found on the food they need to eat. This many times will be a dead animal that has died in the attic, crawl space, under a deck, in the wall or some other area. Once dead, it will begin to decay. This process releases gases and odors which will attract flies and other insects. These insects will start laying eggs on  the body and larva could hatch in as little as a  day or two. If the dead animal is large enough, the inhabitants of the structure will detect its presence because the smell will become stronger with every passing day. At some point there will a search for the source of the odor and if the animal is found, don’t be surprised to find a lot of maggots as well.   Feed-through fly control: Insecticide may be applied to the droppings of caged laying hens by incorporation in the feed. This ensures even distribution in the droppings and is very labor-economical. An adequate batch mill is required for even distribution of the material in large quantities of feed.   DISCUSSION   New chemistries were introduced over the years, and the flies responded by developing resistance to organophosphate, carbamate, and pyrethroid insecticides (Boxler and Campbell, 1983; Plapp, 1984; Scott and Georghiou, 1986; Scott et al., 1989; Kaufman et al., 2001b; Butler et al., 2007; Kozaki et al., 2009; Memmi, 2010) as well as to growth regulators such as diflubenzuron and cyromazine (Bloomcamp et al., 1987; Shen and Plapp, 1990). The use of continuous delivery systems such as feed-throughs and frequent use of residual premise treatments has exacerbated the problem, resulting in efficacy losses of once-effective materials such as cyromazine and permethrin, respectively (Sheppard et al., 1990). Crossresistance also poses challenges and can shorten the effective life of what were thought to be novel chemistries. For example, the avermectins were thought to have a novel mode of action, and initial tests against house fly were encouraging (Geden et al., 1990; Geden et al., 1992b), but flies with high levels of pyrethroid (e.g. Ectiban and related products) resistance showed high levels of cross-resistance to abamectin (Scott, 1989).   During the past 10 years, several promising new insecticides were introduced in bait form that, at least for a time, provided control of populations that were resistant to older chemistries. Spinosad (Elector) and neonicotinoids, such as imidacloprid (QuickBayt) and nithiazine (Quick Strike), were highly effective at the time of their introduction to the market. However, resistance to spinosad was documented almost immediately after market entry (Shono and Scott, 2003; Deacutis et al., 2006). Imidacloprid has essentially become a victim of its own success. At the time of its introduction in 2004, the QuickBayt products containing imidacloprid provided such superior performance and such a rapid fly knockdown that it quickly dominated the fly control market. Sprayable formulations of this sugar bait product followed soon afterwards. Early warning signs of resistance appeared within 2 years of product rollout (Kaufman et al., 2006) and have now reached levels where product failure is imminent (Kaufman et al., 2010a,b; Memmi, 2010).   There are a number of alternatives to conventional chemical insecticides for fly control. Histerid beetles and macrochelid mites feed ravenously on fly eggs and young larvae and have been studied extensively (reviewed by Geden, 1990; Kaufman et al., 2000, 2001a, 2002; Achiano and Giliomee, 2005). Larvae of some species of the fly genus Hydrotaea (Ophyra) are facultative predators of house fly larvae that have been used for fly control (Nolan and Kissam, 1987; Geden et al., 1988; Turner and Carter, 1990; Turner et al., 1992; Hogsette and Washington, 1995; Farkas et al., 1998; Hogsette et al., 2002).   Pteromalid parasitoids that attack the fly in the pupal stage are the best known fly biocontrol agents and have been used extensively for operational fly control for decades (Morgan et al., 1975; Rutz and Axtell, 1979; Morgan and Patterson, 1990; Geden et al., 1992a; Skovgaard and Nachman, 2004; Geden and Hogsette, 2006). Biopesticides in the broad sense including microbial agents and botanicals have received less attention and are the subject of this review.   Nematodes Steinernematids and Heterorhabditids. Steinernematid and heterrhabditid nematodes have been studied extensively for control of filth flies, with mixed results. In laboratory studies using substrates that are favorable for nematode survival, fly larvae are highly susceptible to most of the entomogenous nematodes that have been tested (Renn et al., 1985; Geden et al., 1986; Mullens et al., 1987a; Taylor et al., 1998). However, results on more natural substrates have generally been disappointing. An early report suggested that nematodes were effective for controlling fly populations in British Columbia poultry houses (Belton et al., 1987), but several other studies have demonstrated that the nematodes perform poorly in poultry and pig manure (Geden et al., 1986; Georgis et al., 1987; Mullens et al., 1987a; Renn, 1995, 1998). Cow manure, especially when mixed with soil or bedding, may be a more suitable habitat for nematode use (Taylor et al., 1998). Adult flies are less susceptible to parasitism than larvae on treated filter paper but can be infected by visiting bait stations with parasites (Renn et al., 1985; Renn, 1998). In spite of these mixed results, nematodes are widely available from commercial sources that promote their effectiveness for control of fly larvae.   Paraiotonchium muscadomesticae. The life cycle of P. muscadomesticae is similar to that of P. (Heterotylenchus) autumnalis in the face fly, Musca autumnalis (Coler and Nguyen, 1994; Geden, 1997). Young adult nematodes are deposited from the ovaries of infected female flies into fly breeding habitats, where they mate and females seek mature fly larvae. Mated female nematodes penetrate the larval cuticle and enter the haemacoel. As the fly develops into the adult stage the nematodes go through first a parthenogenetic and then a gametogenetic generation resulting in the production of ca. 30,000 nematodes per fly. The nematodes then move into the ovaries of the fly where they are deposited during “mock oviposition” events. Infected flies live about half as long as uninfected flies and do not produce any eggs. The parasite, which has only been found in Brazil, appears to be fairly specific for house flies. So far, two attempts to get P. muscaedomesticae established outside its home range have been unsuccessful, but it may have potential as a biopesticide if appropriate production, formulation, and storage methodscan be developed.   Fungi Entomophthora muscae complex. Adult house flies are susceptible to infection with the fungal pathogens Entomophthora muscae and E. schizophorae, which typically kill the flies 4-6 days after exposure to conidia. Flies become infected when exposed to conidia discharged from cadavers of infected flies. The intensity and duration of conidial discharge and the survival of conidia depends on temperature and relative humidity (Mullens and Rodriguez, 1985; Krasnoff et al., 1995; Six and Mullens, 1996; Madeira, 1998; Kalsbeek et al., 2001a). Natural epizootics are common in the fall months in temperate regions, with infection rates commonly exceeding 50% (Mullens et al., 1987b; Watson and Petersen, 1993; Steinkraus et al., 1993; Six and Mullens, 1996). Although E. muscae is an important natural regulator of fly populations it remains unclear whether this pathogen can be manipulated as a biopesticide. Mass-rearing methods have been developed to produce large numbers of infected flies , and field releases of E. muscae and E. schizophorae have resulted in increased disease prevalence (Kramer and Steinkraus, 1987; Steinkraus et al., 1993; Geden et al., 1993; Six and Mullens, 1996). The impact of releases on fly control may be dampened by the need for high fly populations to sustain epizootics (Geden et al., 1993) and by the ability of the flies to mitigate the effects of infection by resting in warm areas to raise their body temperature (behavioral fever) (Kalsbeek et al., 2001b; Watson et al., 1993).   Beauveria and Metarhizium. Field populations of house flies and stable flies usually have low rates of infection with B. bassiana and M. anisopliae (Steinkraus et al., 1990; Skovgaard and Steenberg, 2002). In laboratory bioassays, larval and adult flies are highly susceptible to these entomopathogens. Virulence varies widely depending on strain and formulation, and adult house flies are particularly susceptible to sugar baits with B. bassiana conidia (Kuramoto and Shimazu, 1992; Geden et al., 1995; Watson et al., 1995; Darwish and Zayed, 2002; Lecuona et al., 2005). Laboratory and field data indicate that use of entomopathogenic fungi is compatible with other natural enemies including C. pumilio and the parasitoids Spalangia cameroni and Muscidifurax raptor (Geden et al., 1995; Kaufman et al., 2005; Nielsen et al., 2005). Although much of the research in this area has concentrated on B. bassiana, some strains of M. anisopliae have been demonstrated to have superior performance against both adult and larval house flies (Mishra et al., 2011).   Data on efficacy under field conditions are limited but encouraging. Watson et al. (1996) applied B. bassiana to the inside walls of calf hutches and observed up to 47% infection among house flies in the treated hutches. Kaufman et al. (2005) found that space sprays with B. bassiana in poultry houses provided fly control comparable to that observed in houses treated with pyrethrin. Three weekly aerosol conidial applications in Venezuelan poultry sheds provided 100% control of adult flies, although fly populations recovered quickly once treatments were stopped (Cova et al., 2009a,b).   B. bassiana is commercially produced for fly control in the US under the trade name BalEnce ( One disadvantage of B. bassiana and M. anisopliae is the rather long time that is required to kill the host, typically 4-6 days. However, a recent comparison of 34 strains identified several with LT50’s of less than 24 hours (Mwamburi et al. 2011a). Such rapid kill rates would place B. bassiana biopesticides in a more competitive position relative to conventional chemical insecticides. Further increases in kill rates could be achieved by genetic modification of the pathogen to accelerate cuticular penetration. The potential for this approach was demonstrated by Fan et al. (2010), who fused a Bombyx mori chitinase to a protease in B. bassiana. The chimeric pathogen was substantially more virulent than the wild-type, presumably because of improved binding and delivery of proteases to the target cuticle. This is an exciting development that could lead to significant improvements in efficacy of biopesticides based on this agent.   Beauveria bassiana has many advantages and has been developed into commercial fly control products. B. bassiana is compatible with other biological agents and strains with superior kill rates have been identified. Field tests of this pathogen in poultry houses and calf hutches have been largely positive. New developments in genetic modification of B. bassiana could lead to new faster-acting biopesticide products that are competitive with conventional insecticides. Early research with exotoxin-producing strains of Bacillus thuringiensis was promising, but the shift in emphasis to endotoxin-only strains with high activity against Lepidoptera limited discovery of fly-active strains. Surveys have suggested that strains with high levels of the Cry1B endotoxin are more virulent than other strains for muscoid flies. Recent successes with B. thuringiensis var. israelensis on poultry farms suggest that Bti warrants further study. House fly salivary gland hypertrophy virus (MdSGHV) has the appealing property of shutting down reproductive development in adult flies but attempts to develop infective baits have been hampered by the refractoriness of older flies to oral infection. Space sprays to treat flies directly may have more potential for delivering MdSGHV into fly populations. Essential oils with substantial amounts of 1,8-cineole, pulegone, limonene, and menthol have high toxicity against fly adults. Combinations of house fly-active oils (e.g., rosemary, peppermint, pennyroyal mint, blue gum, bay laurel) could be more effective than products that focus on single active constituents. New formulations and possible use of synergists could increase the efficacy of botanicals for fly control.   This study was conducted to evaluate the virulence of 10 Iranian isolates of entomopathogenic fungi,Beauveria bassiana (Bals.) Vuill. and Metarhizium anisopliae (Metch) Sorok. and introduce the most virulent isolate for microbial control of the house fly Musca domestica L. under the laboratory conditions. Three bioassay methods were used: Topical, oral and bait method. Fungal isolates were first screened by immersing adults and medium sized larvae in a suspension containing 108 conidia mL-1. Percentage mortalities ranged from 28-100% were recorded for adults and larvae and five isolates were found to be relatively more virulent. Data clearly show that there is a wide range in the response of the two stages (larvae and adult) of the house fly to the action of the tested isolated of B. bassiana and M. anisopliae. LC50 values in bait method for adults were 1.65×106, 1.7×106, 1.9×106, 2.9×106 and 3×106 conidia g-1 for the 5 highly virulent isolates designated Ma437C, Bb187C, Bb429C, Bb428C and Bb796C, respectively. Dose of 5×107 conidia g-1 bait resulted in up to 90% mortality within 3.5-6.5 day after exposure. Topical application for larvae resulted in LC50 values of 7.3×104, 1.1×106, 1.6×106, 2×106 and 2.9×106 conidia mL-1 for the isolates, respectively. Oral application of 109 conidia g-1 larval bedding resulted in larval mortalities of 98.4, 5 6 and 35.2% for Ma437C, Bb187C and Bb429C, respectively. Due to lower LC50 and LC90 values and shorter lethal time, Ma 437C was the most virulent isolate for house fly larvae and adult. (   The beetle Alphitobius diaperinus (Panzer), considered a worldwide pest in the poultry industry, is difficult to control and it is a vector for pathogens. The objective of this study was to evaluate the biological control of the lesser mealworm, by strains of fungi Beauveria bassiana, Cladosporium sp. and Trichoderma sp. Larvae and adults of the A. diaperinus were inoculated with suspensions of conidia in the concentration of 107 conídia.mL-1. The B. bassiana isolate caused higher insect mortality as compared to Cladosporium sp. and Trichoderma sp. isolates, with the larvae being more susceptible than adults. The entomopathogenicity of B. bassiana was further evaluated with 200 larvae and 200 adults of A. diaperinus inoculated with suspensions 106, 107, and 108 conidia.mL-1, and observed for ten days. Larvae mortality started at the fourth day at the lowest concentration, and the adult mortality was only observed on the sixth day at the concentration of 108 conidia.mL-1. (   Bacteria Early work with Bacillus thuringensis against filth flies was encouraging. For instance, considerable maggot control was achieved by feeding Bt spore formulations to cattle and chickens and thereby delivering the bacteria to fly breeding sites in manure (Burns et al., 1961; Miller et al., 1971). Promising results were also obtained by mixing Bt directly with fly breeding substrates (Rupes et al., 1987). In these early studies, exotoxin-producing Bt strains were used, and flies were more susceptible than most other insect orders to the exotoxin (Carlberg, 1986). However, resistance to exotoxins developed quickly in house flies that were already resistant to chemical insecticides (Harvey and Howell, 1965; Wilson and Burns, 1968). Moreover, safety concerns over vertebrate toxicity led to a prohibition on the use of exotoxin-containing Bt products in the US in the mid 1980’s (McClintock et al., 1995; Tsai et al., 2003).   When the focus shifted to Bt strains that do not produce beta-exotoxins the results with flies were often disappointing, possibly because the discovery process favored strains producing delta-endotoxins with high activity against Lepidoptera (Al-Azawi and Jabbr, 1989; Lonc et al., 1991; Sims, 1997). Indrasith et al. (1992) identified several strains with good activity against adult house flies. Subsequently, Johnson et al. (1998) identified other strains with activity against house flies and determined that the endotoxin Cry1B was found in all the Musca domestica-active strains. The Cry1B endotoxin may be the key item in the activity of these strains for higher flies (Zhong et al., 2000; Lysyk et al., 2010).   The Cry1B producing YBT-226 strain, for instance, is a proprietary strain owned by Dupont with high fly activity (Zhong et al., 2000). The cry1B gene is also present in the fly active strains HD2 and HD-290, of which there is a mutant (HD-290-1 a.k.a. HD-290-I) that produces only Cry1B (Brizzard et al., 1991). These results suggest that a screen of Bt isolates with the Cry1B toxin could reveal strains with superior activity against house fly.   Lately there has been increased interest in the discovery and use of Bt strains for fly control. Promising new strains have been identified in Korea (Choi et al., 2000; Oh et al., 2004).   Labib and Rady (2001) reported that Bt was more effective for fly control on Egyptian poultry farms when it was added to the birds’ food than when it was applied directly to the manure.   Similar results were noted on South African poultry farms using a locally obtained strain of B. thuringiensis subsp. israelensis (Bti) (Mwamburi et al., 2009, 2011b). Earlier testing with Bti indicated that this subspecies had little effect on flies, either because of gut pH conditions or lack of receptors for the endotoxins in most strains (Vankova, 1981; Wilton and Klowden, 1985). The recent successes in South Africa suggest that Bti should be reexamined for use against house   MdSGHV virus Salivary gland hypertrophy virus of house flies (MdSGHV) is one of three members of the Hytrosaviridae, a recently described family that includes pathogens of adult house flies, tsetse flies (Glossina spp.), and the narcissus bulb fly (Merodon equestris Fabr.) (Abd-Alla et al., 2009; Lietze et al., 2011a). The virus infecting house flies is an enveloped, double stranded, circular DNA virus with a 124,279 bp genome (Garcia-Maruniak et al., 2008, 2009). MdSGHV was first discovered infecting flies at a dairy farm in central Florida in the early 1990’s (Coler et al., 1993). Infected flies do not exhibit any external disease symptoms. The most conspicuous feature of infection is the presence of greatly enlarged (hypertrophied) salivary glands with a blue-whitish appearance that often dominate the abdominal cavity of the fly when dissected.   Both sexes can be infected, with somewhat higher prevalence rates in males. Viral replication and morphogenesis is restricted to salivary gland cells, although complete virions are also found in asymptomatic tissues such as midgut, ovaries, fat body and brain (Lietze et al., 2010). The ovaries of females that are infected as young flies do not develop, probably because infection blocks hexamerin and yolk protein gene transcription (Lietze et al., 2007). Infected flies of both sexes have reduced mating success and shorter life spans than healthy flies (Lietze et al., 2007). Stable fly (Stomoxys calcitrans), which occurs sympatrically with house fly, supports viral replication in the laboratory but does not show the classic symptoms of salivary gland hypertrophy (Geden et al., 2011b). Because of its recent discovery, little is known about the ecology and epizootiology of MdSGHV in the field. Coler et al. (1993) found infection rates on a Florida dairy farm to be generally low. In a subsequent field survey, Geden et al. (2008) observed that infections were positively correlated with fly abundance, with highest infection rates from June through August. Survey results from the US and Denmark (Geden et al., 2011a) indicate that prevalence is typically low, 0.5-5% but occasional spikes of over 30% infection have been observed. Although most of the research on the virus has been conducted in Florida, infected flies have been collected throughout the world (Prompiboon et al., 2010).   The mechanisms of MdSGHV transmission are still not completely understood. There is no vertical transmission from mothers to progeny, no venereal transmission, and no evidence that flies acquire the infection as immatures (Lietze et al., 2007; Geden et al., 2008). Infected females deposit ca. one million virus particles each over a period of seconds when they feed on solid foods (Lietze et al., 2009). Healthy flies can become infected when they are given food or water from cages of infected flies, and even when they are housed in cages from infected flies and given clean food and water supplies (Geden et al., 2008).   Viable virus particles pass through the alimentary tract of infected flies and are deposited with feces, albeit at low rates (Lietze et al., 2009). These elements are all suggestive of oral acquisition by healthy flies when they cofeed with infected flies. However, flies are only susceptible to oral infection during a narrow window after adult emergence; the peritrophic matrix of older flies renders them largely refractory to oral transmission (Lietze et al., 2009). When viremic flies are introduced into a population of healthy flies and monitored over time, the result is decreasing infection levels until a stasis level of ca. 10% is reached (Lietze et al., 2011b). The opportunities for using MdSGHV as a biopesticide in a food bait appears to be limited. However, it has been discovered recently that flies are surprisingly susceptible to infection when they make direct contact with low-dose aqueous virus suspensions (Geden et al., 2011a).   Large numbers of infected flies can be produced easily with this method and virus suspensions can be applied as space sprays with conventional mist blowers and other equipment. Further research with new formulations to improve stability, shelf life and adherence to target flies could greatly improve prospects for use of MdSGHV as an operational biopesticide.   Botanicals Essential oils are generally known to have fumigant insecticidal properties, and the mode of action may involve elements of acetylcholinesterese inhibition and octopaminergic effects (Isman, 2000). Additional effects can be seen in behavior modification (attraction/repellency) and contact toxicity for different life stages (Koul et al., 2008).   Natural oils are complexes of many biologically active constituents including terpenes, acyclic monoterpene alcohols, monocyclic alcohols, aliphatic aldehydes, aromatic phenols, monocyclic ketones, bicyclic monoterpenic ketones, acids, and esters (Koul et al., 2008). The composition of oils from a particular plant species can be affected by the plant tissues extracted, cultivar variation, climatic and growth conditions, and the methods used for extraction and analysis.   For this reason, there have been considerable efforts to examine the effects of individual components that are common to those essential oils known to have insecticidal properties (Isman, 2000; Koul et al., 2008).   Preparations of plant materials have long been used to kill or repel flies. Over 100 years ago, Howard (1911) described a method for making a fly adulticide from quassia (Quassia amara) wood that he had seen in “old dispensaries”. He also pointed out that “the butchers in Geneva have from time immemorial prevented flies from approaching… by the use of laurel oil”. Essential oils of bay laurel (Laurus nobilis) include large 1,8-cineol (eucalyptus) and linalool fractions (Palacios et al., 2009b). With the advent of synthetic chemical insecticides there was little research on botanical extracts until resistance problems in house flies became acute in the 1970’s.   Sharma and Saxena (1974) evaluated the effects of a range of individual terpenoids on house flies and found a wide variety of effects. Some acted as attractants but had inhibitory effects on embryonic or larval development (eugenol and fernesol) whereas others repelled gravid females and inhibited embryonic/larval development. Fly responses to terpenoids were highly dose-dependent, and some were attractive at low concentrations but repellent at high ones. Larvicidal effects of the tested materials were modest at all doses. In another study, neem extracts and refined azadirachtin were moderately toxic to larvae of the horn fly (Haematobia irritans), but doses required to control house fly larvae were deemed too high to be practical at the time (Miller and Chamberlain, 1989). Khan and Ahmed (2000) later observed up to 85% mortality of adult house flies after exposure to neem extract, which suggests that this product warrants further study. Ezeonu et al. (2001) found that extracts of sweet orange peels (Citrus sinensis) were effective as fumigants against adult flies. Malik et al. (2007) provided an excellent review of the status of botanicals against house fly at that time.   In the past few years there has been renewed interest in the topic of essential oils for fly control. Palacios et al. (2009a,b) examined the efficacy of essential oils of 21 medicinal and edible plants against house fly. Of the edible plants, essential oils from orange peel and eucalyptus leaves were the most toxic to flies; the principal components of these oils were limonene (92.5%) and 1,8-cineole (56.9%), respectively. Of the medicinal plants, the most toxic to house flies were those whose essential oils were high in pulegone, menthone, limonene, and 1,8-cineole. In a survey of 34 plants conducted by Pavela (2008), essential oils of rosemary (Rosemarinus officinalis) and pennyroyal mint (Mentha pulegium) had high activity against adult flies in both fumigant and contact toxicity assays. Pennyroyal mint was the most effective overall, and GC/MS analysis of the extract indicated that pulegone made up 83.3% of the extract. Pulegone is also highly toxic to larvae of Aedes aegypti L. (Waliwitiya et al., 2008). Oil of rosemary is high in pinene and 1,8-cineole (Jamshidi et al., 2009). Essential oils of peppermint (Mentha piperita) and blue gum (Eucalyptus globulus) were the most effective of 6 plant extracts examined by Kumar et al. (2011) and had both insecticidal and repellent properties.   Application of an emulsifiable concentrate formulation of peppermint oil in field tests resulted in over 95% control of house flies (Kumar et al., 2011). The principal components of peppermint oil are menthone (20.9%) and menthol (41.5%) (Palacios et al., 2009b). As part of an assessment of plants native to Chile, Urzua et al. (2010) recently found that essential oils from Haplopappus foliosus (Asteraceae) had high activity against adult house flies; limonene was the most abundant component in the extract. Taken together, these results do not point to any single component of essential oils that stand out as the critical element that accounts for activity against house flies.   Complex interactions may occur among major and minor constituents in an unforeseen manner that affect insecticidal activity.   Similarly, mixtures of essential oils from different plants may have higher activity than individual extracts in ways that are difficult to predict. A new product on the US market, EcoExempt IC, is a combination of essential oils of rosemary and peppermint. Unpublished results in our laboratory indicate that this combination is effective as a space spray and a residual surface treatment for house fly adults. Judicious use of synergists could improve efficacy further. Addition of piperonyl butoxide can reduce the LC50 of essential oils and their individual constituents by several orders of magnitude (Waliwitiya et al., 2008). Further research on blends of essential oils and improved formulations and delivery systems could lead to substantial improvements in the performance of botanicals for house fly control.   SOLUTION FLYRID CONTAINS Beauveria bassiana 4 x 10^8 CFU/ml Metarhizium anisopliae 3x 10^8 CFU/ml B. thuringiensis subsp. Israelensis 1 x 10^8 CFU/ml Bacillus Sphaericus 1.5 x 10^8 CFU/ml Bacillus subtilis 0.5 x 10^8 CFU/ml Specific enzymes in the category of Chitinase, Protease   SUGGESTED METHOD OF USAGE Preventive: Dilute Flyrid 4-6 ml/ L water and spray liberally over the litter and surroundings of the sheds @ 2.5-4 ml diluted liquid per sft once in 10 days Curative: Double dose