/JIs^Pine-Tai^iM^Repe a> IssucJ August 1, 19) S ^ UBRARY STATE PLANT BOARD Screw Worm Control f IP By W. E. DOVE WHAT TO DO I Provide a chute or brake for the treatment of wounded or screw- worm infested animals. 2- Examine all livestock for wounds, daily if possible, and when such animals are found, apply pine- tar oil (Specific gravity 1.065, dehydrated and acid free) to the wounds to prevent screw worm infestation. '2 Fence a small pasture near the house or watering place where animals infested with screw worms can be treated every day until the wounds are healed. Animals may be fed and kept in screened sheds. A Use benzol (90 percent commercial) to kill the screw worms and any eggs on or around the wound, and then apply a thin but even coat of pine-tar oil over the wound to keep the flies away and to aid healing. ^ When wounds are difficult to treat, or where they occur in valuable animals, the services of a competent veterinarian should be secured. ^ Perform operations, such as marking, branding and castrating during the winter, that is, after killing frost and long enough before April 1 , so that the wounds will be healed by that date. Use emasculators of the pincer type as far as possible in castrating. y Have all young dropped between November 15 and April 1st. In Florida and south Texas this period should be restricted to midwinter. O Look for the Gulf Coast Tick, which attaches on the inside of the ear, especially of sheep. If this tick is present, make a light application of pine-tar oil to the tick-infested area with a swab. Many cases of screw worms are caused by this tick. Q Burn carcasses of all animals as soon as possible after death as a sanitary measure. lO Look after your livestock and prevent screw worm losses. Eradication of the screw worm is impractical but the insect can be controlled. INFORMATION ON SCREW WORMS NOT CONTAINED IN THIS PAPER MAY BE SECURED FROM THE FOLLOWING U. S. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C. BUREAU of ENTOMOLOGY and PLANT QUARANTINE SCREW WORM CONTROL Bureau of Entomology and Plant Quarantine, v. S. Department of Agriculture, Division of Insects Affecting Man and Animals. W. E. Dove, Director, Screw Worm Educational and Control Program, 402 Glenn Building, Atlanta, Georgia R. A. Roberts, Supervisor for Georgia, P. O. Box 497, Tifton, Georgia T. F. McGehee, Supervisor for Alabama, 5 1 5 Dexter Avenue, Montgomery, Alabama W. G. Bruce, Supervisor for Florida, P. O. Box 178, Gainesville, Florida D. C. Parman, Supervisor for Mississippi and Louisiana, P. O. Box 1190, Hattiesburg, Mississippi H. M. Brundrett, Supervisor for Texas, P. O. Box 2292, Beaumont, Texas W. H. Clarke, Supervisor for South Carolina, Walterboro, South Carolina or from the Screw Worm Control Committees of South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana and Texas THE TRUE SCREW WORM FLY (Cochliomyia americana), Cush. ^ Vatt. ADULT FEMALE SCREW WORM CONTROL Screw worm control depends upon a proper understanding of (1) how screw worm flies develop, (2) how to recognize screw worm cases, (}) how to treat screw-worm infested wounds, and (4) how to prevent screw worm flies. The true screw worm lives only upon the healthy- flesh of animals and it is this maggot which causes most of the damage to livestock. Several kinds of maggots may be found in wounds and, strange as it may seem, some are actually beneficial to the animal by eating away dead and diseased flesh, or by destroying disease germs. HOW SCREW WORM FLIES DEVELOP The screw worm maggot is the young of a certain kind of fly. A picture of the fly which produces these worms is shown on the opposite page. It is called the true screw worm because it is the harmful species. It is usually the first one to lay its eggs upon the broken skin of an animal. This injury may be a cut, scratch, tick bite, or a wound of any kind. The true screw worm fly does not develop in decaying meat, but many people M. S. Yeomans, State Entomologist for Georgia, kindly furnished color plates of the screw worm fly. think so because large numbers of flies which look like the true screw worm fly can be found feeding and laying eggs on dead animals. The true screw worm fly breeds only in living animals. Eggs are laid on the wound and young maggots begin to appear in 10 to 12 hours. They immediately bore their way into the flesh and feed in clusters so as to form pockets in the wounds. More and more flies come to lay their eggs until finally there are large numbers of worms eating into the flesh. Unless the animal is found and the destructive maggots are killed, it may die in a very short time. If the maggots are not killed, they become fully grown in 4 to 6 days and drop out of the wound to the ground where they change into flies about 10 to 14 days later. The flies then mate and the females are ready to lay eggs in 7 to 10 days. HOW TO RECOGNIZE SCREW WORM CASES When screw worms are present in a wound, there is a bloody discharge and a characteristic odor. For all practical purposes, a bloody discharge is sufficient evidence to identify their presence. A hard swelling usually accompanies a screw worm infestation. Bloody frothing from the mouth sometimes indicates that the lips or gums of the animal are infested. Common blow- fly maggots do not cause bleeding in wounds. 'Ai'jfr''* Animals very often become weak and thin because of screw worm attack and they stray away from the herd. Infested sheep and goats hide themselves in under- brush, trying to keep away from the flies. This habit makes it hard to find infested animals in time for early treatment. HOW TO TREAT SCREW-WORM INFESTED WOUNDS Use only benzol and pine-tar oil. These are the only materials recommended by the Bureau of Ento- mology and Plant Quarantine. Benzol is used to kill the screw worms. Pine-tar oil is used as a dressing for wounds and for repelling flies. Before these materials are applied, the portions of the animal covered with discharges from the wounds should be carefully cleaned. Wounds containing blood and serum must be carefully swabbed with cotton, because benzol does not readily kill screw worms pro- tected by fluids in the wound. Immediately following the swabbing, a light application of commercial benzol is made to the wound with an oil can or syringe, which retards the flow of blood. Three or four minutes should be allowed for the benzol to reach the screw worms. A second light application is then made, and dry cotton is inserted in the opening of the wound. This cotton plug should remain in the wound so that the screw worms can have sufficient time to breathe «rATE .^SJ^'^BOAI©. and be killed by the gas of the benzol. It is recom- mended that stockmen leave the cotton plugs and screw worms in the wounds. Pine- tar oil (specific gravity 1.065, acid free, dehydrated) is then applied over the cotton plug and on the skin around the injured parts. It may be spread with cotton wrapped around a clean stick. The pine- tar oil repels flies and aids in healing. Following the first treatment, the reappearance of a bloody discharge from the wound indicates that living larvae are present. In such cases treatment with benzol should be repeated. If there is no further discharge, the condition suggests that the screw worms were killed and that only pine-tar oil should be applied. It is necessary to apply pine-tar oil every day or two until the wound has healed. HOW TO PREVENT SCREW WORM FLIES Screw worms must be prevented from breeding in living animals. This is the only method known at pres- ent for the control of the true screw worm fly. They cannot be destroyed or prevented from infesting animals by setting out flytraps or by burning dead animals because they are rarely attracted to traps and do not breed in carcasses. If this fly can be kept from breeding in living animals, it is believed that there will be little trouble from screw worms. SCREW WORM INFESTATION IN EYE OF STEER TREATMENT WITH BENZOL SHOWING COTTON PLUGS IN WOUNDS SHOWING APPLICATION OF PINE-TAR OIL OVER WOUNDS Fim OF mi M) CHUTE FOR PROPER HOT)LI1G CF RM3E STOCK CR0lN)rUriOF Penmchjte Section faciiig CHUTE TIE STRAP Poles tor pro andchal? 15' 5' 95 Ebles for ^ate bars 10'5' 1^ Poles torckitedopbars'l-5' 10 FUes for tie sirapsopcldc !)'('? 5 R)k>s for pffl? and ckilc bars 5'5' 9 Nails - '^Od 2^ Ihs SECTION OP fTENCE WHAT NOT TO DO I Do not ear-mark, brand, castrate, or dehorn animals during warm weather. If it is absolutely necessary to do so, apply pine-tar oil to the wounds immediately and every day until they are healed. During summer months, pincer type emasculators may be used for castration, except on boars. 2. Do not use remedies containing coal tar, creosote, or phenols, because such materials are likely to injure the wound or poison the animal. 7 Do not use unreliable patent medicines, especially those claiming to cure with one treatment. We recommend only benzol and pine-tar oil. A Do not probe the wounds with wire or sticks to get out dead worms. It starts bleeding, thus attracting flies, and may introduce serious infection by germs. ^ Do not depend on sprays to keep screw worm flies away, nor upon dipping of animals to kill screw worms in wounds. ^ Do not rely on flytraps and poisoned baits to prevent infesta- tion of animals. 7 Do not allow animals to be unnecessarily wounded. Do not allow nails, broken boards or other snags to remain where they will injure animals. Do not use dogs in handling livestock because their bites induce screw worm attack. O Do not build your hospital pasture on bushy land. Screw worm flies are worse in such locations. Choose high groimd if possible and cut out the brush. Q Do not fail to look over your livestock often and at regular intervals. Use Benzol to Kill S liiiJiiiiliiJiiiiiiiiiiiiiiii , 3 1262 09223 0357 Issued August 1, 19}f UNITED STATES DEPARTMENT OF AGRICULTURE BUREAU of ENTOMOLOGY and PLANT QUARANTINE Lee a. Strong, Chief DIVISION OF INSECTS AFFECTING MAN AND ANIMALS F. C. BisHOPP Principal Entomologist in Charge SCREW- WORM EDUCATIONAL AND CONTROL PROGRAM "W. E. Dove, Senior Entomologist^ Director