Number Of Horn Flies Research Articles

Efficacy of Brahman breeding in the management of insecticide-resistant horn flies (Diptera: Muscidae) on beef cattle.

The efficacy of Brahman breeding used as an alternative tactic to manage insecticide-resistant populations of adult horn flies, Haematobia irritans irritans (L.), was determined. Concentration-mortality bioassays done at Booneville and Hope, AR, in 1988 and 1989, respectively, showed that horn fly populations were resistant to diazinon, pirimiphos methyl, tetrachlorvinphos, and methoxychlor. Data showed loss of field efficacy for coumaphos and delnav. Mean horn fly counts on Braham cows were significantly lower than on Angus cows for all sampling dates in 1989 and 1990. Mean fly counts on Brahman x Angus cows were approximately intermediate to the two purebred mean fly counts. Brahman breeding caused significant reductions in the number of organophosphate-resistant horn flies, which had been equal to or greater than that obtained from continued spraying with organophosphate insecticides. The Brahman x Hereford cows, which have one-eighth greater Brahman breeding than the Brangus cows, had fewer horn flies on 48 of 56 sampling dates in 1988-1990 and significantly fewer flies on 37 sampling dates. The effectiveness of Brahman breeding in causing lower numbers of insecticide-resistant horn flies significantly increased as the percentage of Brahman breeding increased.

Evaluation of Ivomec Pour-On for the Control of Horn Flies in West Central Nebraska, 1993

Abstract Ivomec® pour-on was evaluated in two studies at two different locations in West Central Nebraska. In study No. 1, Ivomec was applied to 72 yearling steers located at the Gudmundsen Sandhills Laboratory, Whitman, NE. The steers were weighed and the Ivomec was applied at the recommended rate. A second application was made 28 d later, 7 Jul. A group of 44 cows served as an untreated control. In study No. 2, Ivomec pour-on was compared to 1% Co-Ral dust bags (force-use, to obtain water) for horn fly control. This study was located near North Platte, NE, in native range. Ivomec was first applied to 41 heifers 27 May at the recommended rate and subsequent applications were made about every 28 d until the end of the study. Treatment dates were 27 May, 30 June, and 4 Aug. Eighty heifers utilized the 1% Co-Ral dust bags and a group of 10 cows served as an untreated control. Horn fly counts for both studies were recorded at weekly intervals by counting the total number of horn flies on both sides on an animal.

Ivermectin cattle pour-on: duration of a single late spring treatment against horn flies, Haematobia irritans (L.) (Diptera: Muscidae) in Missouri, USA

Late spring treatment of cattle with a single dose of pour-on ivermectin (0.5 mg kg-1 body weight) resulted in reduced horn fly populations for approximately 6 weeks, with percentage efficacy exceeding 80% for at least 26 days post-treatment. Bioassay with house flies of dung from treated cattle demonstrated suppression of fly emergence for 11 days post-treatment. The subsequent increase in horn fly numbers on the treated herd was predicted by a developmental rate equation interpreted by the time of cessation of larval fly inhibition in field dung.

High Levels of Pyrethroid Resistance in Horn Flies (Diptera: Muscidae) Selected with Cyhalothrin

Lambdacyhalothrin cattle ear tags controlled horn fly, Haematobia irritans (L.), for 14 wks or longer during 1986-1988 in Georgia, USA. In 1989 and 1990, control of < 50 horn flies per side of cow was achieved for < or = 4 wk because of high levels of pyrethroid resistance in horn flies selected with lambdacyhalothrin. The highest resistance ratios (RRs) were seen in 1989. These were 498 for lambdacyhalothrin; 92,000 for fenvalerate; and 54 for permethrin. RRs for cypermethrin as high as 8,800 were estimated in 1990 when the RR for fenvalerate was only 1,060. No cross-resistance to diazinon was detected. These high levels of pyrethroid resistance seem to have a large component of metabolic resistance. Synergistic coefficients as high as 3,600 were determined by addition of nonlethal amounts of piperonyl butoxide. Resistance development in a no-pyrethroid-use area indicates movements of > or = 3km by sufficient numbers of horn flies can significantly change the RR.

Interactive Response of the Horn Fly (Diptera: Muscidae) and Selected Breeds of Beef Cattle

Statistically significant differences were observed in the population density of the horn fly, Haematobia irritans irritans (L.), on different breeds of beef cattle. The European breed Chianina had a population density of horn flies generally less than or equal to 50% than that of the British cattle breeds (Angus, Hereford, Polled Hereford, and Red Poll) and another European breed (Charolais). Generally, no significant difference existed among numbers of horn flies on Hereford, Polled Hereford, and Red Poll cows in 1988 or among Angus, Hereford, Polled Hereford, and Red Poll cows in 1989. Factors other than color appeared to be involved in the selective process between the horn fly and its host. Population densities on two white European breeds (Charolais and Chianina) were significantly different on all weekly intervals except for 4 wk in both 1988 and 1989. No significant difference existed among Charolais and British breeds except during 4 wk in 1988 and 3 wk in 1989. When weaning weights of all calves were adjusted for the effects of age to 205 d, sex of calf, and age of dam, the indirect effect of the horn fly on weaning weight showed a significant linear regression. Each 100 flies per cow caused a reduction of 8.1 kg in calf weaning weight. Cows within each breed with low numbers of horn flies weaned significantly heavier calves than cows with higher numbers of horn flies.

Control of Face Flies and Horn Flies with Experimental Diflubenzuron Boluses, 1988

Abstract Two bolus formulations of 4.75 g (9.7% AI) flaked and powdered diflubenzuron were administered to beef cattle to test their efficacy against horn flies and face flies. Commercially available Vigilante° and methoprene boluses were used as standard treatments. Experimental diflubenzuron and Vigilante boluses were administered to cattle at the rate of 1 bolus/250 kg body weight. Methoprene boluses were administered at a rate of 1 bolus/300 kg body weight. Herd size ranged from 20-48 adult cattle/herd, and all herds were geographically located within 30 miles of each other. Two similar untreated herds were observed to compare treatment effectiveness. All treatments were administered between 20 May and 24 May. Horn fly numbers were estimated on one side of each animal, and face flies were counted on the head and face of the same animals.

Efficacy of Terminator and Atroban Ear Tags on Resistant Horn Fly Populations, Meat Animal Research Center, Clay Center, Nebraska, 1987

Abstract Three groups of 200 crossbred cow/calf pairs, maintained on separate native range pastures at the Meat Animal Research Center, Clay Center, Nebraska, were used in this study. Terminator ear tags were applied to one group of cows (one tag/cow); Atroban tags were applied to another group of cows (one tag/cow); and the third group of cows received no insecticide treatment. There were about 200 cow/calf pairs/treatment. Ear tags were applied during the first wk of Jun. Fly numbers were recorded on a bi-monthly basis, counting the total number of horn flies on both sides of a cow. A minimum of 15 cows were included at each fly oounting period.

Efficacy of Terminator Ear Tags on Pyrethroid-Resistant Horn Flies and on Calf Weaning Weights and Performance, Gudmundsen Sandhills Laboratory, Whitman, Nebraska, 1987

Abstract Crossbred cow/calf pairs, maintained on University of Nebraska-Lincoln Sandhill native range pastures, were selected for use in this study. Three treatments were evaluated: Treatment I, cows tagged with one Terminator ear tag, calves not tagged; Treatment II, calves tagged with one Terminator ear tag, cows not tagged; and Treatment III, cows and calves not treated. Cow/calf pairs were allotted to treatment by cow weight with an equal number of steers and heifers/treatment. The number of cow/calf pairs/ treatment were as follows: Treatment I, 49 cows/calf pairs; Treatment II, 50 cow/calf pairs; Treatment III, 50 cow/calf pairs. The animals were tagged and weighed 2 Jun, and the cow/calf pairs were then placed in appropriate pastures. The 3 pastures were of equal size (623 acres) and had an excellent stand of native grass. Pretreatment horn fly numbers were recorded prior to the start of the study, and on a bi-monthly basis thereafter. Fly numbers were recorded by counting the total number of horn flies on both sides of a cow. A minimum of 15 cows were included during each fly counting period.

Evaluation of Ear Force Ranger, Optimizer, and Saber Ear Tags on Pyrethroid-Resistant Horn Flies, Gud-Mundsen Sandhills Laboratory, Whitman, Nebraska, 1989

Abstract On 16 May, Ear Force Ranger (10% permethrin, 6.8% chlorpyrifos and 4.2% PBO) ear tags were applied to 90 yearling steers (one/steer). On 31 May, Optimizer (20% Diazinon) ear tags were applied to 50 cow/calf pairs (one/cow). On 1 Jun, Saber (10% Lambdacyhalothrin) ear tags were applied to 75 yearling steers (one per steer). Fifty cow/calf pairs were used as a comparison. Fly counts were initiated 8 Jun and continued on a weekly basis. Fly counts were recorded by counting the total number of horn flies on an animal, with a minimum of 15 animals included in each fly counting session.

Control of Face Flies and Horn Flies with Experimental Diflubenzuron Boluses, 1988

Abstract Two bolus formulations of 4.75 g (9.7% AI) flaked and powdered diflubenzuron were administered to beef cattle to test the formulations’ efficacy against horn flies and face flies. Commercially available Vigilante and methoprene boluses were used as standard treatments. Experimental diflubenzuron and Vigilante boluses were administered to cattle at the rate of 1 bolus/250 kg body weight. Methoprene boluses were administered at a rate of 1 bolus/300 kg body weight. Herd size ranged from 20 to 48 adults/herd, and all herds were located within 30 miles of one another. Two similar untreated herds were observed for comparison of treatment effectiveness. All treatments were administered between 20 and 24 May 1988. Horn fly numbers were estimated on one side of each animal, and face flies were counted on the head and face of the same animals.

Impact of Red Imported Fire Ant (Hymenoptera: Formicidae) Predation on Horn Flies (Diptera: Muscidae) in a Cattle Pasture Treated with Pro-Drone

Pro-Drone (1-(8-methoxy-4,8-dimethylnonyl)-4(1-methylethyl)benzene), an insect growth regulator, was applied monthly to a 7-ha pasture in South Carolina from April to December 1984 and again from April to September 1985. Foraging red imported fire ant (RIFA), Solenopsis invicta Buren, populations decreased in the treated field from an average of 186 RIFAs per bait station in April 1984 to 11 RIFAs per station in June 1984. In the untreated field, foraging RIFA populations increased from 186 per station in April 1984 to 226 per station in June 1984. During the remainder of 1984 and through October 1985, the average number of RIFAs per bait station never exceeded 10 in the treated field, while in the untreated pasture RIFAs were significantly greater. The number of adult horn flies, Haematobia irritans (L.), emerging from manure piles in the treated pasture was55%greater than the number that emerged from piles in the RIFA infested field.

Horn fly and face fly control with the Dustacator® combination mineral feeder and livestock dusting device (1988)

Dustacators (combination mineral feeders and livestock dusting devices) were used for four beef herds at Kansas State University in 1985. Loose mineral was supplied in all four Dustacator tubs, which were adjusted to low settings. Permethrin dust had no apparent effect on horn flies. Co-Ral® from two sources and Rabon® provided approximately 65% horn fly reduction during the 53-day test period. The 1986 experiment compared the effects of Dustacator mineral tub height adjustments and loose vs. block mineral. Co-Hal 1% dust from a single source was used in all treatments on two Simmental herds and two Polled Hereford herds. Excellent horn fly control was achieved and maintained except for a temporary increase in horn fly numbers in early September in all treatments. Face fly control was inadequate in all treatments in both years. Use of block mineral was related to reduced mineral consumption and self-application of more insecticide dust. High tub adjustment was related to greater mineral consumption but reduced self-application of insecticide. The degree of fly control was not correlated with amount of insecticide used either on a per-cow or per-herd basis. Simmentals consumed nearly twice as much mineral per head as Polled Herefords, but they used only 20% more insecticide. Including the cost of 1% Co- Ral dust and equipment costs amortized over 5 years, Dustacators provided acceptable horn fly control and some reduction of face fly numbers for $1.62 per cowlcalf pair, plus labor.

Wide-area treatment of cattle for horn flies and face flies (Diptera: Muscidae) in south-central Nebraska.

Baseline data on seasonal population fluctuations of horn flies, Haematobia irritans (L.), and face flies, Musca autumnalis De Geer, on cattle in Clay County (south-central), Nebr., were obtained in 1982. In 1983, a study area where all cattle were treated chemically with 10% permethrin or 1% coumaphos for flies was established. Treatments were applied in an attempt to reduce fly populations before they began producing diapausing individuals (i.e., to reduce number of flies that overwintered successfully and retard repopulation of the area the following season). Treatment significantly reduced (96% reduction; < 8 flies per animal) horn flies seen on cattle throughout the treatment period, but number of face flies on cattle did not seem to be reduced. In 1984 only horn flies were monitored on cattle from randomly selected herds in each of four 3.2-km concentric strips within the treatment area and from untreated herds surrounding the treatment area. Analysis showed no differences between horn fly numbers in any areas at any time during the season. Thus, mode of repopulation was indiscernible. In south-central Nebraska, wide-area treatment against flies did not delay fly repopulation of the area during the season following treatment.

Beef Cattle Fly Control with Diflubenzuron (Vigilante tm) Bolus, 1986

Abstract Fifty g Vigilante boluses containing 4.9g AI diflufbenzuron were evaluated for the control of horn flies and face flies under field conditions. Herds were pastured cow/calf operations located within a 40-mile radius in central Kentucky. Control herds were similar operations located within 4 miles of the treated herds. Boluses were administered to cattle with a balling gun at a rate of 1 bolus/250 kg body weight between 1 May and 15 May. Another comparison herd was tagged with Guardian (tm) ear tags during she same period and evaluated concurrently for fly control. Herds were treated as follows: 102 steers (A) treated at a rate of 1 bolus/steer; 45 cows/calves (B) treated at rate of 1.5 bolus/cow and 0.5 bolus/calf; 55 cows and 8 calves as untreated controls (conAB); 39 heifers (C) at 1 bolus/animal; 30 cows (conC) untreated; 30 cow and 12 calves at 1.5 bolus/cow and 1 eartag/calf (D); 38 cows tagged with Guardian ear tags (T) at rate of 2 tags/cow; and 30 cows untreated (conDT). The number of horn flies and face flies were counted on 10 cattle from each herd every 2 weeks. Horn flies were counted on one side of the animal; sice flies were counted on the face and head of the same animal. Fresh manure from 5 animals of each herd was collected biweekly and bioassayed utilizing newly hatched colonized horn face and house fly larvae. Twenty-five larvae were placed in 50-100 g of feces and larval mortality calculated by counting adult (mergence. Bioassays were performed on bolused cattle only.

Methoprene Bolus for Horn Fly Control in Wyoming, 1986

Abstract Two herds of experimental cattle were used. A herd of Hereford cattle was divided into 3 groups and treated on 27 Jun. The 3 groups were: (1) an untreated group of 13 cows, 2 heifers, and 13 calves; (2) a treated group of 39 cows, 7 heifers, and 35 calves in which cows and heifers received "bolus 1"; and (3) a group of 41 cows, 12 heifers, and 36 calves in which cows and heifers received "bolus 2." The second herd consisted of 76 yearling steers of mixed breeds, and was treated on 10 Jun. This herd was divided into: (1) an untreated group of 16 steers; (2) a group of 30 steers which received "bolus 1;" and (3) a group of 30 steers that received "bqlus 2." All treated animals weighed ^ 660 lb and received one of two formulations of a 3% methoprene bolus. The cow/calf groups as well as the steers were pastured in adjacent fields. Pasture size of the untreated, bolus 1, and bolus 2 groups were 58, 192, and 210 ha for the cow/calf groups, and 23.1, 63.6, and 63.6 ha for the steers, respectively. Horn fly numbers on one side of each of 15 untreated and 30 treated steers and 14 untreated and 15 treated cows were recorded on days 3, 7, 14, and every 2 weeks thereafter.

The Efficacy of Max-Con Insecticide Impregnated Ear Tags for the Control of Resistant Horn Fly Popula Tions on 3 Western South Dakota Ranches, 1986

Abstract High numbers of horn flies (200 side) on beef cattle treated with insecticidal ear tag:; containing synthetic pyrethroid insecticides (fenvalerate/permethrin) were reported in the Mission area (Todd County) in late 1985. In order to receive better control of this pest in western South Dakota during the 1986 fly season the Max-Con@ insecticide impregnated ear tag containing 7.0% cypermethrin, 5.09! chlorpyrifos and 3.5% piperonyl butoxide was tested on herds of 70 Black Angus beef cattle south of Colome (Tripp County) on the Cottonwood Range and Livestock Research Station in Jackson County and to a herd of white faced Herefords near Martin in Bennett County.

EFFICACY OF INSECTICIDAL EAR TAGS ON FLY CONTROL AND MILK PRODUCTION OF DAIRY COWS

Twenty Holstein cows were blocked into two groups of 10 cows each to evaluate an insecticidal ear tag (8% fenvalerate) on fly control and milk production. One group received one tag in each ear while the control group remained untagged. Each group was allowed access to an exercise-pasture lot of similar size. Forages were fed in the lots and grain was fed in the barn at milking. Tagging resulted in a 99.9% reduction in horn flies over the 16 wk of the trial. However, other flies (house, stable and face) were not controlled to the same extent. As horn fly numbers decreased the number of the other flies increased on tagged cows. Tagging resulted in an overall increase in milk yield by 1.06 kg/d for the trial but not all weeks of the trial showed significant responses. Milk fat and protein percentages were not different between tagged and control animals. Key words: Diptera, dairy cattle, milk production, fenvalerate, ear tags, fly control

Dimilin Boluses, Guardian Ear Tags and Rabon Mineral Blocks for Cattle Fly Control

Abstract Ten percent 50g Dimilin boluses were compared to 0.463% Rabon Sweetlix mineral blocks and 7.5% Guardian ear tags for face fly and horn fly control on cattle. Five mixed-breed beef cow-calf herds and 1 herd of mixed-breed heifers were assigned to treatments as indicated in the table below. Ear tag treatments were done on 13 and 21 Jun at the rate of 2 tags/hd, and bolus treatments were administered on 21 Jun at the rate of 1 bolus/50kg of body weight/cow; calves received 0.5 bolus each. The Rabon Sweetlix mineral blocks were placed on 2 covered mineral feeders at the rate of 1 block/5 cows on 5 Jul. New Rabon blocks were added when 0.67 of the original amount was consumed. Horn fly numbers were estimated on 1 side of each of 10 cows and the total face flies found on the faces of these same cows were recorded. The mean number of flies was used for determining fly reduction.

Comparison of Guardian and Ectrin Ear Tags for Control of Face Flies and Horn Flies, 1983

Abstract Guardian (5% and 7.5%) and Ectrin (8%) ear tags were applied at the rate of 2/hd to cows and calves on 18 and 19 May for fly control evaluation. Two similar untreated herds served as controls. On 12 Rug. the Guardian treatments were terminated due to numerous lost tags. A new test was started 17 Aug. in which two of the previous Guardian treated herds were tagged with a new Guardian (7.5%) ear tag design; cows and calves were tagged as before. One previous Ectrin herd and 1 untreated herd were used to compare the efficacy of the new Guardian ear tag. Pace flies were counted on the face of each of 10 cows in each herd and the number of horn flies on 1 side of the same cows were estimated. The mean fly numbers for each treatment is reported.

Comparison of Ficam and Ectrin Ear Tags for Face Fly and Horn Fly Control, 1983

Abstract Five cow-calf herds were used for comparing the effectiveness of 10, 15 and 20% Ficam (bendiocarb) ear tags with 8% Ectrin ear tags in controlling face flies and horn flies on pastured cattle. Cows in each treatment herd were tagged with 2 tags/hd during the first wk of June; calves were not tagged. Face flies were counted on the face of 10 cows/herd and horn fly numbers on one side of the same cows were estimated. The 20% Ficam treatment was terminated prematurely because of a change in the management of the cattle.