Lethal Effects of Commercial Kaolin Dust and Silica Aerogel Dust With and Without Botanical Compounds on Horn Fly Eggs, Larvae, Pupae, and Adults in the Laboratory.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important bloodsucking ectoparasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic insecticides but as concerns about resistance increase, alternative tactics have come under heightened scrutiny. Four desiccant dust products: Surround WP, a kaolin clay-based wettable powder; CimeXa, comprised of silica aerogel; Drione, silica aerogel + pyrethrins; and EcoVia, silica aerogel + thyme oil, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround WP and CimeXa did not prevent egg hatching and (when mixed with manure substrate) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality within 6 hr and 24 hr, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 hr, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.

Economic Injury Level for Bermudagrass Stem Maggot (Diptera: Muscidae) in Bermudagrass Forage Production in Texas.

The bermudagrass stem maggot, Atherigona reversura Villeneuve (Diptera: Muscidae), was first reported damaging bermudagrass Cynodon dactylon (L.) Pers grown for forage in 2010 in the southeastern United States. Injury results from individual larvae feeding internally on the vascular tissue just above the terminal node of the grass stem. Injury slows plant growth and reduces forage accumulation. To address the need for economic guidelines to manage this new pest, the relationship between the percent of stems damaged by bermudagrass stem maggot and forage yield was measured in commercial bermudagrass hay fields in northcentral Texas. Yield loss was estimated to be 9.97 kg/ha (8.90 lbs /acre) for each percentage of stems with bermudagrass stem maggot damage. This relationship was used to calculate economic injury levels for a range of hay market values and control costs. The impact of stem damage on protein content, energy, and digestibility of bermudagrass hay was also investigated. Although there was a significant trend for declining forage quality with increasing stem damage, stem damage explained very little of the model's variability.

Comparative insecticidal activity of cypermethrin and cypermethrin-mix applications against stomoxyine vectors.

Stomoxyines are mechanical vectors of several pathogens of livestock with severe consequences such as low productivity from constant irritation and disturbance. In vitro and in vivo bioassays were conducted to confirm the efficacy of cypermethrin analogues on stomoxyines. Cattle treated with cypermethrin (Pantex 30 g l-1) and cypermethrin-mix (cypermethrin + oil from Senna occidentalis locally prepared by Fulani herdsmen) were compared using the restricted insecticidal application (RAP) method and a local Fulani application approach (FAA), while untreated cattle serve as control. A total of 550 speciated-fed Stomoxys niger were exposed to graded concentration of cypermethrin (Group A-D) at 30 µg/ml, 20 µg/ml, 10 µg/ml, 5 µg/ml, 1 µg/ml and 0.5 µg/ml. After 48 h, the flies were assessed for mortality. In vivo bioassay of behavioural responses to stomoxyines showed greater mean percentage repellence using RAP (94.6%) of cypermethrin when compared with FAA (46.3%). The sigmoidal non-linear regression model curve of in vitro bioassay showed cypermethrin (Pantex®-group A) to be most effective with LC50 of 1.52 µg/mL and it is significantly more effective than cypermethrin (Ectopouron®-group B) and cypermethrin-mix (Fulani cypermethrin mixture-group C) at 22.62 µg/ml and 20.62 µg/ml concentration, respectively. In this study, Pantex® demonstrated excellent stomoxyine repellence using RAP method with significant insecticidal effect. Therefore, the appropriate use of cypermethrin insecticides using RAP method is recommended for vector control to prevent African animal trypanosomiasis in Nigeria.

In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle.

This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.

In vivo effect of diflubenzuron, administered via mineral salt supplementation, against Haematobia irritans and Rhipicephalus microplus parasitizing cattle / Efeito in vivo do diflubenzuron, administrado via sal mineral, contra Haematobia irritans e Rhipicephalus microplus parasitando bovinos

Abstract This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females.

Resumo O objetivo deste estudo foi avaliar a eficácia do diflubenzuron, administrado via suplementação mineral, contra Haematobia irritans parasitando bovinos, em dois testes à campo. Concomitantemente, foi realizado testes em estábulo para determinar os efeitos de uma formulação diferente, com o mesmo princípio ativo, contra Rhipicephalus microplus , bem como a ação do diflubenzuron nos parâmetros reprodutivos de fêmeas de R. microplus recolhidas após desprendimento natural do hospedeiro bovino. Contra H. irritans, foi observado que foram baixos (≤ 31,3% ou 44,6%) ou nulos (0,0%) os índices de eficácia do diflubenzuron. A eficácia anti-R. microplus do diflubenzuron, observada em intervalos semanais, variaram de 0,0% a 13,7% durante todo o período experimental. Com relação aos parâmetros reprodutivos das fêmeas de R. microplus recolhidas, foi observada eficácia nula (0,0%) para o diflubenzuron. Conclui-se que as diferentes formulações administradas via sal mineral no atual estudo, contra H. irritans e R. microplus parasitando bovinos, não apresentaram eficácia satisfatória. Este agente também não mostrou efeito deletério sobre os parâmetros reprodutivos de fêmeas de R. microplus.

Short communication: Relationship of activity and rumination to abundance of pest flies among organically certified cows fed 3 levels of concentrate.

The objectives of this study were to evaluate activity, rumination time, and their association with 3 kinds of pasture flies for organic dairy cows (n=57) fed 3 grain supplementation strategies during the grazing season from May to September 2013. Cows were assigned to 1 of 3 replicate supplementation groups: (1) no corn-grain supplementation (100% pasture, PAS, n=19); (2) low corn-grain (2.72kg/cow per day, LG, n=19); and (3) high corn-grain (5.44kg/cow per day, HG, n=19). Cows calved during 2 seasons (fall and spring) at the University of Minnesota West Central Research and Outreach Center, Morris, from October to December 2012 and March to May 2013. Supplement (corn-grain and minerals) was fed in a total mixed ration of corn silage and alfalfa silage, and at least 30% of diet dry matter intake for LG and HG cows consisted of pasture. Activity and rumination time (daily and 2-h blocks of time) were monitored electronically using HR-LD tags (SCR Engineers Ltd., Netanya, Israel) for 125d. Activity (cow body movement and head movement) was reported in activity units from SCR DataFlow II software, and rumination times were reported in minutes per day. PROC HPMIXED in SAS (SAS Institute Inc., Cary, NC) was used for statistical analysis, and independent variables were season of calving (fall or spring), month of grazing (June to September), supplementation group, and interactions of month of grazing and supplementation group. Replicate was a random effect with repeated measures. Daily activity was higher for PAS cows (1,138 activity units) than for HG cows (1,001 activity units), and LG cows (1,019 activity units). Daily activity was highest in July (1,258 activity units) and lowest in September (819 activity units). Rumination was not different for PAS (397min/d), LG (384min/d), or HG (370min/d) cows. Daily rumination was greater in September (402min/d) than in July (361min/d). Daily activity increased rapidly between 0600-0800h and 1600-1800h. From 1800 to 2000h, cows had a rapid decline in activity until 0600h the next day. All supplementation groups had the greatest rumination activity from 0200 to 0400h and the least between 1000 and 1200h. Greater activity of cows on a herd basis was moderately correlated with increased fly populations. Monthly activity patterns of grazing cows were associated with fly populations on cows.

Comparisons of antifeedancy and spatial repellency of three natural product repellents against horn flies, Haematobia irritans (Diptera: Muscidae).

BACKGROUND: Horn flies are among the most important biting fly pests of cattle in the United States. Horn fly management is largely dependent upon pesticides, which ultimately leads to the rapid development of insecticide resistance. Alternative control strategies, including repellents, have shown promising results in reducing fly biting. In the present study, we examined the efficacy and longevity of recently identified natural product repellents against horn flies. RESULTS: Catnip oil, geraniol and C8910 acids reduced horn fly feeding in a laboratory bioassay and also exhibited spatial repellency in the olfactometer. Residual activity was observed for up to 3 days in laboratory assays; however, 24 h of residual effectiveness was observed from the two repellents when applied on cattle in the field. The limited residual effectiveness was correlated with the high volatility of the major active repellent compounds. CONCLUSION: All three natural product repellents effectively repel biting horn flies, exhibiting both feeding deterrence and spatial repellency. They may be used for developing an effective push-pull strategy with a slow release matrix that can prolong their effectiveness for horn fly management.

Effects of Haematobia irritans infestation on weight gain of Nelore calves assessed with different antiparasitic treatment schemes.

Effects of Haematobia irritans infestation on weight gain of 18 to 20 months old non-castrated Nelore calves, were investigated, under field conditions, using different antiparasitic treatments. Sixty animals were divided in three groups, with 20 bovines each: T01 (untreated control); T02 (treated with Cypermethrin 15 g+Chlorpyriphos 25 g+Citronellal 1 g, as a whole body spray, on days 0, 30, 60, 90 and 120 post-treatment); and T03 (treated on day zero with an ear tag impregnated with Diazinon 6g on the left ear). Counts of H. irritans were conducted on day 30, 60, 90, 120 and 150 post-treatment (DPT). On the same experimental dates, animals were individually weighed, seeking to evaluate the effects of parasitism on the development of animals in each group. From this study it is concluded that T03 had significantly higher efficacy (>90%, till 90 DPT), based on H. irritans fly counts, compared to T02 which showed little or no effect. At the specific conditions of the present study, an average of approximately 90 flies (mean difference of flycounts between groups T01 and T03) was associated with a difference of 20 kg/animal in 150 days.

Enhanced repellency of binary mixtures of Calophyllum inophyllum nut oil fatty acids or their esters and three terpenoids to Stomoxys calcitrans.

BACKGROUND: An assessment was made of the repellency to female stable flies of tamanu nut oil fatty acids or their esters alone (each 0.5 mg cm(-2) ) or in combination with cuminyl alcohol, cuminaldehyde and α-phellandrene (each 0.25 mg cm(-2) ), using an exposed human hand bioassay. Results were compared with those of synthetic repellent DEET (0.25 mg cm(-2) ). RESULTS: Based upon protection time (PT) (time to first bite of stable fly), oleic acid, linoleic acid, methyl oleate or methyl linoleate synergised the repellency of each monoterpenoid and DEET. For example, the binary mixture of oleic acid and cuminyl alcohol (PT 2.05 h) resulted in significantly greater repellency than either oleic acid (0.55 h), cuminyl alcohol (0.70 h) or DEET alone (1.50 h). The binary mixtures of oleic acid and cuminyl alcohol or DEET (PT 2.10 h) did not differ significantly in repellency. The structure-activity relationship indicates that the degree of saturation, the side chain length and the functional group of fatty acids appear to play a role in determining the fatty acid repellency to stable flies. CONCLUSION: Mixtures formulated from fatty acid and monoterpenoid could be useful as potential repellents for protecting humans and possibly domestic animals from bites caused by stable fly.

Insecticidal and repellent effects of tea tree and andiroba oils on flies associated with livestock.

This study aimed to evaluate the insecticidal and repellent effects of tea tree, Melaleuca alternifolia (Myrtales: Myrtaceae), and andiroba, Carapa guianensis (Sapindales: Meliaceae), essential oils on two species of fly. For in vitro studies, free-living adult flies were captured and reared in the laboratory. To evaluate the insecticidal effects of the oils, adult flies of Haematobia irritans (L.) and Musca domestica L. (both: Diptera: Muscidae) were separated by species in test cages (n = 10 per group), and subsequently tested with oils at concentrations of 1.0% and 5.0% using a negative control to validate the test. Both oils showed insecticidal activity. Tea tree oil at a concentration of 5.0% was able to kill M. domestica with 100.0% efficacy after 12 h of exposure. However, the effectiveness of andiroba oil at a concentration of 5.0% was only 67.0%. The insecticidal efficacy (100.0%) of both oils against H. irritans was observed at both concentrations for up to 4 h. The repellency effects of the oils at concentrations of 5.0% were tested in vivo on Holstein cows naturally infested by H. irritans. Both oils demonstrated repellency at 24 h, when the numbers of flies on cows treated with tea tree and andiroba oil were 61.6% and 57.7%, respectively, lower than the number of flies on control animals. It is possible to conclude that these essential oils have insecticidal and repellent effects against the species of fly used in this study.

Repellent effectiveness of seven plant essential oils, sunflower oil and natural insecticides against horn flies on pastured dairy cows and heifers.

Plant essential oils (basil, geranium, balsam fir, lavender, lemongrass, peppermint, pine and tea tree), mixed with either sunflower oil or ethyl alcohol, were applied at 5% concentrations to the sides of Holstein cattle. Pastured cattle treated with essential oils diluted in sunflower oil had less flies than the untreated control for a 24-h period. However, the essential oil treatments were not significantly different than the carrier oil alone. Barn-held heifers treated with essential oils and sunflower oil alone had significantly less flies than the untreated control for up to 8 h after treatment. Basil, geranium, lavender, lemongrass and peppermint repelled more flies than sunflower oil alone for a period ranging from 1.5 to 4 h after treatments applied to heifers. All essential oils repelled > 75% of the flies on the treated area for 6 and 8 h on pastured cows and indoor heifers, respectively. Geranium, lemongrass and peppermint stayed effective for a longer duration. Essential oils mixed with ethyl alcohol demonstrated less repellence than when mixed with the carrier oil. Safer's soap, natural pyrethrins without piperonyl butoxide and ethyl alcohol alone were not efficient at repelling flies. Essential oils could be formulated for use as fly repellents in livestock production.

Efficacy and longevity of newly developed catnip oil microcapsules against stable fly oviposition and larval growth.

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is one of the most important pests of cattle and costs U.S. cattle producers billions of dollars in losses annually. In this study, the efficacy of catnip oil encapsulated in gelatin in oviposition deterrence and larval growth inhibition in stable flies was examined under laboratory conditions. More than 98% inhibition of stable fly larval growth and female oviposition was observed in larval and oviposition media treated with encapsulated catnip oil (0.5 g). Further, dose-response tests showed that as little as 0.1 g of encapsulated catnip oil provided > 85% oviposition deterrence. The release of nepetalactones from the capsules was more rapid when the capsules were placed on a moist substrate rather than a dry substrate. Encapsulated catnip oil also exhibited antibacterial activity, supporting the hypothesis that its inhibition of larval growth may be based on its killing of the bacteria on which larvae feed. The use of encapsulated catnip oil can provide an alternative control strategy for stable fly management.

Behavioural and electroantennogram responses of the stable fly (Stomoxys calcitrans L.) to plant essential oils and their mixtures with attractants.

BACKGROUND: Insect olfactory organs possess many olfactory receptor neurons, which detect many different sets of odorants in nature. In order to feed on blood meals, stable flies locate host animals and humans using chemical cues such as 1-octen-3-ol and butyric acid. In the present study, behavioural and electroantennogram (EAG) response patterns to repellent volatiles from essential oils (EOs) of Zanthoxylum piperitum and Z. armatum in combination with the attractants were investigated. RESULTS: Components of the EOs such as cuminaldehyde, citronellal, neral, linalool, linalool oxide, terpinen-4-ol, 1,8-cineole, and piperitone induced remarkable repellent behaviours in the stable fly. EAG responses in the fly antenna to these chemicals showed a dose-dependent manner. The patterns of behavioural and EAG responses were significantly altered depending on the ratios of 1-octen-3-ol or butyric acid to the EOs or compounds in the air mixtures. CONCLUSION: The present study demonstrated that the Zanthoxylum EOs decreased the levels of response of flight behaviours of the stable fly towards host volatile compounds. The combinations of odorant mixtures of the attractants with the EOs and their components affect the representation of behavioural and EAG responses of the flies. The summation and integration patterns of olfactory responses measured by the EAG indicated that the peripheral olfactory networks in antennae could process the odorant complexity of different odorant mixtures between attractants and repellents.

Weight gain and control of endo- and ectoparasites of beef heifers treated with allopathic, herbal and homeopathic drugs / Ganho de peso e controle de endo e ectoparasitas de novilhas de corte tratadas com medicamentos alopáticos, fitoterápicos e homeopáticos

The aim of this study was to evaluate the efficacy of herbal, homeopathic and allopathic treatments for parasites in beef heifers during two experimental cycles of 318 and 313 days. Treatments: NC - negative control (untreated); HH - treated with homeopathic preparation Homeo bovis Parasitário®; PC - (positive control) - treated with 10% moxidectina® and an acaricide formulation of cypermethrin, chlorpyrifos and piperonyl butoxide®; HF ­ treated with homeopathic preparation Fator C&MC®; and FN - treated with neem cake (torta de neem®) and with neem oil (óleo de neem®). Parasite egg count (EPG), horn fly (Haematobia irritans) and tick (Rhipicephalus (Boophilus) microplus) assessment and animal weighting were performed at 28-day intervals. Blood samples were collected at the first cycle to assess the immune response. Horn fly infestation was not affected by any treatment (P>0.05). The mean number of ticks, which was low in both cycles, was lower (P<0.05) in the first cycle in animals that received PC treatment. In both experimental cycles, the mean EPG of the PC-treated animals was lower (P<0.05) than the animals receiving other treatments. Treatments had no effect on the immune response (P>0.05). The animals treated with allopathic drugs were 22 to 30 kg heavier (P<0.05) than untreated animals or animals treated with alternative drugs.

O objetivo do trabalho foi avaliar a eficácia de tratamentos fitoterápicos, homeopáticos e alopáticos contra ecto e endoparasitas na recria de novilhas, em dois ciclos experimentais subsequentes de 318 e 313 dias. Tratamentos: CN - controle negativo - não tratado; tratamento HH - tratado com homeopático Homeo bovis Parasitário®; tratamento CP ­ controle positivo ­ tratado com moxidectina 10%® e uma formulação acaricida contendo cypermetrina, clorpirifós e butóxido de piperonila®; tratamento HF - tratado com homeopático Fator C&MC® e tratamento FN - tratados com torta de neem® e com óleo de neem®. A contagem de ovos nas fezes (OPG), a infestação por Haematobia irritans, Rhipicephalus (Boophilus) microplus e pesagem dos animais foram realizadas em intervalos de 28 dias. No primeiro ciclo foi coletado sangue para avaliar a resposta imume. A infestação por mosca-dos-chifres não foi influenciada por nenhum dos tratamentos (P>0,05). Nos dois ciclos o número médio de carrapatos foi baixo e apenas no primeiro foi menor (P>0.05) no tratamento CP em relação aos demais. A média de OPG no tratamento CP foi mais baixa que nos demais tratamentos nos dois ciclos experimentais (P<0,05). Não houve efeito de tratamentos na resposta imune. Os animais do tratamento CP ganharam entre 22 a 30 kg de peso vivo a mais (P<0,05) que os não tratados ou tratados com medicamentos alternativos.

The repellency of lemongrass oil against stable flies, tested using video tracking.

Lemongrass oil (Cymbopogon citratus) is an effective repellent against mosquitoes (Diptera: Culicidae) and house flies (Diptera: Muscidae). In this study, its effectiveness was assessed on stable flies (Diptera: Muscidae) in laboratory conditions. First, we demonstrated that lemongrass oil is an active substance for antennal olfactory receptor cells of Stomoxys calcitrans as indicated by a significant increase in the electroantennogram responses to increasing doses of lemongrass oil. Feeding-choice tests in a flight cage with stable flies having access to two blood-soaked sanitary pads, one of which was treated with lemongrass oil, showed that stable flies (n = 24) spent significantly more time in the untreated zone (median value = 218.4 s) than in the treated zone (median value = 63.7 s). No stable flies fed on the treated pad, whereas nine fed on the untreated pad. These results suggest that lemongrass oil could be used as an effective repellent against stable flies. Additional studies to confirm its spatial repellent and feeding deterrent effects are warranted.

Substrate properties of stable fly (Diptera: Muscidae) developmental sites associated with round bale hay feeding sites in eastern Nebraska.

Residues at sites where stationary feeders were used to provide hay as supplemental forage for cattle during the winter are developmental substrates for immature stable flies, Stomoxys calcitrans (L.), in the central United States. Spatial patterns in physical (substrate depth, temperature, water content), chemical (pH, electrical conductivity [EC(lab)], total nitrogen [N] and carbon [C], ammoniacal nitrogen [NH(4)-N], extractable phosphorus [P]), and biological (microbial respiration rate) substrate properties for two feeding sites were estimated and the correlations between these properties and adult emergence were characterized. Hay feeding sites had a circular footprint with residues extending ≈7 m from the feeder. With the exception of extractable P and total N, all substrate properties exhibited spatial patterns centered on the feeder location. Adult stable fly emergence densities were significantly correlated with substrate microbial respiration rate, NH(4)-N concentration, EC(lab), total C concentration, pH, and moisture content. Logistic regression indicated that EC best predicted the probability of stable flies emerging from a substrate and that the other properties did not provide additional information. A better understanding of the physical, chemical, and biological conditions needed for stable fly larval development may help in identifying previously unrecognized developmental habitats and management of this pest. Targeted implementation of management practices such as sanitation and chemical treatments can be applied to smaller areas reducing labor and improving cost effectiveness.

Nepetalactones from essential oil of Nepeta cataria represent a stable fly feeding and oviposition repellent.

The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most serious pests to livestock. It feeds mainly on cattle and causes significant economic losses in the cattle industry. Standard stable fly control involving insecticides and sanitation is usually costly and often has limited effectiveness. As we continue to evaluate and develop safer fly control strategies, the present study reports on the effectiveness of catnip (Nepeta cataria L.) oil and its constituent compounds, nepetalactones, as stable fly repellents. The essential oil of catnip reduced the feeding of stable flies by >96% in an in vitro bioassay system, compared with other sesquiterpene-rich plant oils (e.g. amyris and sandalwood). Catnip oil demonstrated strong repellency against stable flies relative to other chemicals for repelling biting insects, including isolongifolenone, 2-methylpiperidinyl-3-cyclohexen-1-carboxamide and (1S,2'S)-2-methylpiperidinyl-3-cyclohexen-1-carboxamide. The repellency against stable flies of the most commonly used mosquito repellent, DEET, was relatively low. In field trials, two formulations of catnip oil provided >95% protection and were effective for up to 6 h when tested on cattle. Catnip oil also acted as a strong oviposition repellent and reduced gravid stable fly oviposition by 98%.

Contact and fumigant toxicity of a botanical-based feeding deterrent of the stable fly, Stomoxys calcitrans (Diptera: Muscidae).

The stable fly, Stomoxys calcitrans (L.), has been considered one of the most serious biting flies of confined and pastured livestock. The economic losses caused by the stable fly to the cattle industry in the United States exceed $2 billion annually. Current practices for managing stable flies using insecticides provide only marginal control. Insecticide resistance has also been recently reported in stable flies. The present study reports the use of plant-based insecticides, for example, essential oils, as alternatives for managing this fly pest. The toxicity of several plant essential oils and selected ingredient compounds was evaluated by contact and fumigant toxicity bioassays. Catnip oil (20 mg dosage) showed the highest toxicity against stable flies, the shortest knock-down time (∼7 min), and the quickest lethal time (∼19 min). Toxicity levels similar to catnip oil were found among three insect repellent compounds (N,N-diethyl-3-methylbenzamide, 2-methylpiperidinyl-3-cyclohexene-1-carboxamide, (1S,2'S)-2-methylpiperidinyl-3-cyclohexene-1-carboxamide). No differences in knock-down and lethal times were found among the catnip oil and its two active ingredient compounds. Similar stable fly mortality was observed using a 20 mg dose of catnip oil in a modified K&D system and a fumigant jar. When catnip oil was topically applied to stable flies, the least lethal dose was 12.5 µg/fly, and a 50 µg/fly dose resulted in 100% mortality. The blood-feeding behavior of stable flies was also negatively affected by the topical application of catnip oil, and the effect was dose-dependent. This study demonstrated that catnip oil has both contact and fumigant toxicity against the stable fly and thus has the potential as an alternative for stable fly control.

Chemical composition and fumigant toxicity of the essential oils from 16 species of Eucalyptus against Haematobia irritans (Diptera: Muscidae) adults.

Oils extracted from various species of Eucalyptus (Eucalyptus badjensis Beuzev & Welch, Eucalyptus badjensis x Eucalyptus nitens, Eucalyptus benthamii variety dorrigoensis Maiden & Cambage, Eucalyptus botryoides Smith, Eucalyptus dalrympleana Maiden, Eucalyptus fastigata Deane & Maiden, Eucalyptus nobilis L.A.S. Johnson & K. D. Hill, Eucalyptus polybractea R. Baker, Eucalyptus radiata ssp. radiata Sieber ex Spreng, Eucalyptus resinifera Smith, Eucalyptus robertsonii Blakely, Eucalyptus rubida Deane & Maiden, Eucalyptus smithii R. Baker, Eucalyptus elata Dehnh, Eucalyptus fraxinoides Deane & Maiden, E. obliqua L'Hér) were obtained by hydrodistillation. The chemical composition of essential oils was determined by gas chromatography coupled to mass spectrometry. Essential oils were mainly composed of 1,8-cineole, alpha-pinene, alpha-terpineol, 4-terpineol, and p-cymene. Vapors from these essential oils and their major components were found to be toxic to Haematobia irritans (L.) (Diptera: Muscidae) adults. An aliquot of each oil was placed in a cylindrical test chamber, and the number of knocked down flies was recorded as a function of time. Knockdown time 50% was then calculated. Results showed that essential oil of E. polybractea had the highest knockdown activity of 3.44 min. A correlation was observed between the content of 1,8-cineole in the Eucalyptus essential oils and the corresponding toxic effect.

Efficacy evaluation of a commercial neem cake for control of Haematobia irritans on Nelore cattle / Avaliação da eficácia de uma torta comercial de nim para o controle de Haematobia irritans em bovinos Nelore

Much attention has been given to the development of botanical insecticides to provide effective natural control of cattle ectoparasites without harming animals, consumers, and environment. This study evaluated the efficacy of a commercial neem cake in controlling Haematobia irritans infestation on cattle. The study was conducted at the Embrapa Southeast Cattle Research Center (CPPSE), in São Carlos, SP, Brazil, from April to July 2008. The neem cake mixed in mineral salt in a 2 percent concentration was provided to 20 Nelore cows during nine weeks and had its efficacy evaluated by comparison of the infestation level against a control group. Fly infestations were recorded weekly by digital photographs of each animal from both groups and the number of flies was later counted in a computer-assisted image analyzer. Quantification of neem cake components by high-performance liquid chromatography revealed the presence of azadirachtin (421 mg.kg-1) and 3-tigloyl-azadirachtol (151 mg.kg-1) in the tested neem cake. Addition of the 2 percent neem cake reduced mineral salt intake in about 22 percent. The 2 percent neem cake treatment failed to reduce horn fly infestations on cattle during the 9-week study period.

Muita atenção tem sido dada ao desenvolvimento de inseticidas vegetais buscando-se um efetivo controle de ectoparasitas de bovinos, sem prejudicar animais, consumidores e meio ambiente. Este estudo, realizado de abril a julho de 2008, na Embrapa Pecuária Sudeste, em São Carlos, SP, Brasil, avaliou a eficácia de uma torta comercial de nim (Azadirachta indica) no controle da mosca-dos-chifres (Haematobia irritans) em bovinos. A torta de nim, misturada ao sal mineral na concentração de 2 por cento, foi fornecida a 20 vacas Nelore, durante nove semanas, e sua eficácia foi monitorada através de contagens semanais nos grupos tratado e controle. Infestações individuais foram registradas por meio de fotos digitais em todos os animais de ambos os grupos, e o número de moscas foi, posteriormente, quantificado com o auxílio de um sistema de análise de imagem computadorizado. A quantificação dos componentes da torta de nim, por cromatografia líquida, revelou a presença de azadiractina (421 mg.kg-1) e 3-tigloyl-azadirachtol (151 mg.kg-1). A adição da torta de nim a 2 por cento reduziu o consumo de sal mineral em cerca de 22 por cento. O tratamento com torta de nim a 2 por cento não reduziu as infestações por mosca-dos-chifres em bovinos durante as nove semanas do estudo.