Toxicity of formic acid to red imported fire ants, Solenopsis invicta Buren

BACKGROUND: Ants often compete with other ants for resources. Although formic acid is a common defensive chemical of formicine ants, it does not occur in any other subfamilies in Formicidae. No information on toxicity of formic acid to red imported fire ants, Solenopsis invicta, is available. This study examined its contact and fumigation toxicity to S. invicta in the laboratory. RESULTS: In a contact toxicity bioassay, 24 h LD₅₀ values of formic acid for workers ranged from 124.54 to 197.71 µg ant⁻¹. Female alates and queens were much less sensitive to formic acid than workers. At a concentration of 271.72 µg ant⁻¹, which killed 81.09 ± 16.04% of workers, the 24 h mortality was up to 39.64% for female alates and 38.89% for queens. In fumigation bioassays, 24 h LC₅₀ values ranged from 0.26 to 0.50 µg mL⁻¹ for workers, 0.32 µg mL⁻¹ for male alates and 0.70 µg mL⁻¹ for female alates. Complete mortality (100%) in queens occurred 24 h after they had been exposed to 1.57 µg mL⁻¹ of formic acid. At a concentration of 2.09 µg mL⁻¹, KT₅₀ values ranged from 23.03 to 43.85 min for workers, from 37.84 to 58.37 min for male alates, from 86.06 to 121.05 min for female alates and from 68.00 to 85.92 min for queens. CONCLUSION: When applied topically, formic acid was significantly less toxic than bifenthrin to red imported fire ants. Although its fumigation toxicity was lower than that of dichlorvos, formic acid had about an order of magnitude higher toxicity to S. invicta than to other insects studied so far. It may be worth investigating the use of formic acid for managing imported fire ants. Published 2012 by John Wiley & Sons, Ltd.     

Sub‐lethal effects of abamectin suppressing colonies of the leaf‐cutting ant Acromyrmex subterraneus subterraneus

An assessment of the sub‐lethal effects of abamectin on queens of the leaf‐cutting ant Acromyrmex subterraneus subterraneus (Hymenoptera: Formicidae) was carried out. A concentration‐response bioassay was conducted by exposing media workers (head capsule width ranging from 1.69 to 1.83 mm) to filter paper impregnated with abamectin residue. This bioassay allowed selection of the abamectin concentrations (0, 10, 50 and 100 mg AI ml⁻¹) to be used in the experiment in which eight queens were exposed to the insecticide. The highest concentration killed queens, but those exposed to lower concentrations survived and were placed back in their nests. Reductions in leaf consumption, fungus garden volume, and foraging activity were observed in colonies whose queens were exposed to higher abamectin concentration (50 mg AI ml⁻¹). Colonies with queens exposed to 50 mg AI ml⁻¹ were suppressed after 11 weeks. The dissection of queen ovaries revealed a marked decrease in the number of ovarioles per ovary and oocytes per ovariole with increased insecticide concentration. It would appear that, as abamectin‐exposed queens became reproductively impaired, producing little or no progeny, colony members were not replaced and this led to colony suppression. © 2000 Society of Chemical Industry     

外来物种红火蚁的化学防治技术

红火蚁的入侵已引起我国各界的关注,本文介绍了入侵红火蚁化学防治技术研究进展。按照化学防治策略可以分为以蚁巢为单元的局部处理和大面积全部处理,从施药技术角度可以分为浇灌和撒施毒饵两大类。浇灌技术主要是将药液灌入蚁巢内,其药液量是一个关键因子;毒饵适用的场所比较广泛,但是施药时间对控制效果影响比较大,一般在晚上施药效果较好,雨后不能马上使用毒饵。     

Impact of ant control technologies on insecticide runoff and efficacy

BACKGROUND: Insecticides are commonly used for ant control around residential homes, but post‐treatment runoff may contribute to contamination of surface water in urban watersheds. This study represents the first instance where runoff of insecticides was directly measured after applications around single family residences. During 2007, houses were treated with bifenthrin or fipronil sprays following standard practices. During 2008, pin stream applicators, spray‐free zones and restricting sprays to the house foundation were considered as management options. RESULTS: During 2007, the resulting runoff from the bifenthrin spray in the irrigation water had a mean concentration of 14.9 µg L^?1 at 1 week post‐treatment and 2.5 µg L^?1 at 8 weeks, both high enough to be toxic to sensitive aquatic organisms. In comparison, treatments with bifenthrin granules resulted in no detectable concentrations in the runoff water after 8 weeks. The mean concentration for fipronil used as a perimeter spray was 4.2 µg L^?1 at 1 week post‐treatment and 0.01 µg L^?1 at 8 weeks, with the first value also suggesting a potential for causing acute aquatic toxicity to sensitive organisms. During 2008, insecticide runoff was reduced by using spray‐free zones and pin stream perimeter applications. CONCLUSIONS: It is shown that insecticide runoff from individual home treatments for ants can be measured and used to improve techniques that minimize runoff. The pin stream application and applications limited to the house foundation should be further evaluated for their potential to reduce pesticide runoff from residential homes. Copyright © 2010 Society of Chemical Industry     

Combined use of a synthetic trail pheromone and insecticidal bait provides effective control of an invasive ant

BACKGROUND: Except for sex pheromones, use of pheromones in pest management has been largely unexplored. A high concentration of trail pheromone disrupts ant trail following and foraging, and thus synthetic trail pheromone can be a novel control agent for pest ants. In this study, a year‐long treatment of small areas (100 m² plots of urban house gardens) with synthetic trail pheromone, insecticidal bait or both was conducted to develop a novel control method of the invasive Argentine ant Linepithema humile (Mayr). RESULTS: The ant population could be maintained lower than or similar to the initial level only by combined treatment with synthetic trail pheromone and insecticidal bait. Actually, the ant population was nearly always lowest in combination treatment plots. Throughout the study period, the ant population in plots treated with either one of synthetic trail pheromone or insecticidal bait remained similar to no‐treatment plots. CONCLUSIONS: Combination treatment may be a more effective and environmentally friendly method for controlling invasive ants than conventional methods. Extermination of ants by insecticidal bait and inhibition of re‐infestation by pheromone may be the mechanism of the combination effect. This is the first study to show a significant effect of synthetic trail pheromone on ant population. Copyright © 2011 Society of Chemical Industry     

Acute toxicity of the bird repellent,methyl anthranilate,to fry of Salmo salar,Oncorhynus mykiss,Ictalurus punctatus and Lepomis macrochirus

Several laboratory and field studies have shown methyl anthranilate to be an effective, non-toxic and non-lethal bird repellent, with application potential for protecting crops, seeds, turf and fish stocks from bird damage. Furthermore, methyl anthranilate can be added to liquids for the purposes of protecting migratory birds, e.g. addition to waste water associated with mining and to standing water pools at airports. Mammalian toxicity data are favorable. Methyl anthranilate is used as a fragrance and food flavoring and is GRAS listed by the US Food and Drug Administration. Despite the favorable outlook for methyl anthranilate's use as a safe repellent, no data exist on its environmental fate and effects. We have tested the acute toxicity of methyl anthranilate in a static system against the fry of four species of fish. The LC₅₀ at 24 h for Atlantic salmon (Salmo salar L.) was 32.3 mg liter^?1, with the no observable effect limit at 6 mg liter^?1. The LC₅₀ at 24 h for rainbow trout (Oncorhynus mykiss Richardson) was 23.5 mg liter^?1, with the no observable effect limit at 5 mg liter^?1. The LC₅₀ at 24 h for channel catfish (Ictalurus punctatus Raf.) was estimated to be 20.1 mg liter^?1, with the no observable effect limit at 7 mg liter^?1. The LC₅₀ at 24 h for bluegill sunfish (Lepomis macrochirus Raf.) was estimated to be 19.8 mg liter^?1, with the no observable effect limit at 7 mg liter^?1..     

Effect of patch size on seed removal by harvester ants

The harvester ant Messor barbarus can be responsible for high weed seed losses in dry land cereals in Spain. Because weeds occur in patches, harvester ants have to be able to find and exploit patches. However, seed patches can differ in size and may, therefore, differ in the probability of being discovered and exploited. Here, 90 patches varying in size from 0.25 to 9 m² were created in three 50 × 50 m subareas in a cereal field. Oat seeds were sown as weed seed surrogates in the patches at 2000 seeds m^?2. After 24 h, those remaining were collected and the exploitation rate (the percentage of seeds removed per patch discovered by ants) was estimated. Harvester ant nests and the location of the seed patches were georeferenced and used to estimate distances between them. The patch encounter rate (the proportion of patches discovered by the ants) decreased slightly, but significantly, with decreasing patch size, though not the exploitation rate, which was lowest in the smallest patches (78–94%) and highest in the largest (99–100%). Seed patches that were not found or partially exploited were mostly located in subareas with a lower ant nest density or a longer distance away from the nearest nest than seed patches that were fully exploited. The results of this study indicate that the interaction between the spatial distribution of ant nests and the patchy distribution of seeds can create opportunities for seeds to be subjected to lower levels of predation.     

Evaluation of permethrin for the protection of cattle against mosquitoes (diptera: Culicidae), applied as electrostatic and low pressure sprays

Permethrin was tested for the protection of cattle against field populations of mosquitoes. Permethrin (500 ml of a permethrin 4·0 g liter^?1 aqueous emulsion) applied with a ‘Dual-Cloud’ electrostatic sprayer was effective in providing coverage of the cattle body surface of a group of four animals; 100 ml of a permethrin 5·0 g liter^?1 aqueous emulsion applied with a ‘Dual-Cloud'’ electrostatic sprayer as a total body spray to a yearling heifer provided 70% or better protection from field populations of mosquitoes for at least 72 h; 500 ml of a permethrin 1·0 g liter^?1 aqueous emulsion applied as a low-pressure spray to the body of a yearling heifer provided 70% or better protection from mosquitoes for at least 140 h. Permethrin applied as a total body-spray thus provides adequate protection to cattle from field populations of mosquitoes.     

4种杀虫剂对西昌市红火蚁的防控试验

在西昌市试验了4种登记用于红火蚁防控的杀虫剂对红火蚁的田间防控效果。结果表明:茚虫威饵剂施用24 d后对蚁巢和工蚁的平均防效分别为71.5%和96.5%,在另一时间段氟蚁腙饵剂施用23 d后对蚁巢和工蚁的平均防效为62.3%和77.0%,以上两种杀虫剂分别施用5次后对蚁巢和工蚁的防效都超过97%,适合在西昌市推广应用。高效氯氰菊酯粉剂施用24 d后对蚁巢和工蚁的平均防效分别为67.5%和76.0%,其杀灭速度较快,适用于应急防控。     

Effects of thuringiensin on European red mite (Acarina: Tetranychidae) mortality,oviposition rate and feeding

Effects of two formulations of thuringiensin (ABG-6162A and ABG-6266) on mortality, oviposition rate, and feeding of European red mite, Panonychus ulmi (Koch) were evaluated. Mite toxicities of the formulations were not significantly different. Immature instars were significantly more susceptible than adults. Low mortality of all instars was recorded after 3 d, indicating slow activity. The relationship between log (concentration + 1) of ABG-6162A and ABG-6266 and P. ulmi oviposition rate was best described by fourth-order polynomial equations, suggesting that thuringiensin both inhibits and stimulates P. ulmi oviposition. ABG-6162A affected oviposition at lower concentrations than ABG-6266. A quadratic relationship was observed between log (concentration + 1) of thuringiensin and P. ulmi adult female feeding. ABG-6162A reduced feeding more than ABG-6266 at concentrations ? 1 mg liter^?1. Toxicity to immatures and the sublethal effects described suggest that thuringiensin may control field populations of P. ulmi despite low initial mortality.     

0.05%氟虫腈杀蚁饵剂对红火蚁的传毒活性测定

应用联杯法等室内测定了0.05%氟虫腈杀蚁饵剂对红火蚁的引诱力、毒杀速度及其传导毒杀活性.结果表明,供试饵剂对红火蚁的引诱性、毒杀速度显著优于正舒(对照药剂).红火蚁觅食到供试饵剂的初始时间为2.00 min,与正舒的2.33 min达显著差异;供试饵剂处理后24 h的工蚁死亡率为80.65%,显著高于对照饵剂的50.15%;72 h的工蚁死亡率即达到100%.联杯法测定结果表明,0.05%氟虫腈杀蚁饵剂能通过工蚁的取食和交哺行为进行传导.供试饵剂受药杯中工蚁、幼蚁和蚁后3 d后死亡率均达到100%,显著高于对照饵剂.0.05%氟虫腈杀蚁饵剂引诱性强、对红火蚁具有高胃毒、高传导毒杀活性,可适用于防控入侵红火蚁.     

保幼激素类似物对红火蚁的作用研究进展

我国发现红火蚁已有4年,但防治技术、产品依然匮乏。为了改善、提高我国红火蚁的防治技术水平,本文就保幼激素类似物(JHA)对红火蚁的作用表现和防治效果进行了总结分析。JHA可以造成蚁后卵巢萎缩、产卵量减少,导致发育畸形和蚁群等级比例失调,如工蚁数量减少、生殖型幼虫比例以及处女蚁后数量增加等,并最终导致整个蚁群死亡。JHA杀虫剂活性高、低残毒、对环境污染小,在田间防治红火蚁效果彻底,并可有效地防止防治区红火蚁种群的再入侵（re invasion）,但JHA毒饵也存在着防治效果缓慢等问题。本文就克服此类问题作了初步的探讨。     

Effects of some foliar fungicides on the chrysomelid beetle Gastrophysa polygoni (L.)

The effects of the fungicides benomyl, thiophanate-methyl and triadimefon on the chrysomelid beetle Gastrophysa polygoni were investigated in the laboratory. Contact with a suspension of benomyl (1.5 g a. i. litre^?1 did not affect the hatchability of the eggs. Larvae were reared on shoots of knotgrass (Polygonum aviculare) that had been sprayed with suspensions of benomyl, ranging in concentration from 0.1 to 5.0 g a. i. litre^?1. The mortality to the adult stage, of larvae reared on shoots treated with concentrations of benomyl of 0.5 g a. i. litre^?1 and above, was significantly higher than that of control larvae. At concentrations of 2.0 g a. i. litre^?1 and above, no larvae survived to the adult stage. The LD₅₀ was 0.78 g a. i. benomyl litre^?1. The LT₅₀ values at concentrations of 1.0, 2.0 and 5.0 g a. i. benomyl litre^?1 were 22.6, 12.6 and 5.3 days, respectively. The mean weights of adults bred from larvae that had been reared on shoots treated with benomyl (0.5 and 1.0 g a. i. litre^?1) were significantly less than those of adults bred from control larvae. The mortality of larvae, reared on shoots of P. aviculare treated with triadimefon (0.5 g a. i. litre^?1) or thiophanate-methyl (1.0 g a. i. litre^?1), was also significantly higher than that of control larvae. Females kept on plants of P. aviculare treated with benomyl (1.5 g a. i. litre^?1) laid similar numbers of eggs to those kept on untreated plants, and the hatchability of the eggs was not affected.     

Effects of piperidine and piperideine alkaloids from the venom of red imported fire ants,Solenopsis invicta Buren,on Pythium ultimum Trow growth in vitro and the application of piperideine alkaloids to control cucumber damping‐off in the greenhouse

BACKGROUND: Pythium ultimum is a plant pathogen that causes significant yield losses on many economically important crops. Chemical treatment has been used for disease control. In searching for alternatives, venom piperidine and piperideine alkaloids from red imported fire ants were tested against P. ultimum in vitro, and piperideines were employed to control cucumber damping‐off in the greenhouse as drench treatments. Results Piperidine and piperideine alkaloids of the red imported fire ant significantly inhibited mycelium growth of P. ultimum. Piperidine alkaloids were stable at both room and elevated temperatures. The inhibitory activity positively correlated with the concentrations of piperidine alkaloids in the medium, and the EC₅₀ = 17.0 µg ml^?1. Germination of sporangia of P. ultimum was negatively correlated with the concentrations of piperidine alkaloids in the medium, and the EC₅₀ = 12.3 µg ml^?1. The piperideine alkaloid drenching treatment significantly improved seedling emergence and seedling height of cucumber. CONCLUSION: This is the first report describing the use of venom alkaloids from the red imported fire ant to inhibit P. ultimum in the laboratory and the application of piperideine alkaloids to control damping‐off disease caused by P. ultimum in the greenhouse. These findings may lead to the development of a new group of fungicides. Copyright © 2012 Society of Chemical Industry     

Inhibition of mitochondrial electron transport by hydramethylnon: A new amidinohydrazone insecticide

Hydramethylnon (AC 217,300) is a new amidinohydrazone insecticide registered under the trade names Amdro for control of the red imported fire ant and Combat and Maxforce for use against cockroaches. While this compound is slow acting, no major perturbations in either sensory or motor neurons of poisoned insects have been observed. However, symptoms of intoxication were accompanied by markedly depressed rates of oxygen consumption. Inhibition of cellular respiration was also observed in Chinese hamster ovary cells with an IC₅₀ of 2 × 10⁻⁶ M after a 30-min uncubation. This inhibition was not reversible by repeated washing with fresh medium or by prolonged incubation. A systematic investigation of the effects of hydramethylnon on mitochondrial respiration showed hydramethylnon to be a potent inhibitor of electron transport. Sequential isolation of the coupling sites of the electron transport chain with different substrates showed that hydramethylnon is an inhibitor of the electron transport chain in the region of coupling site II.     

Laboratory assays of select candidate insecticides for control of Dendroctonus ponderosae

BACKGROUND: The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae), is the most destructive bark beetle in western North America. Dendroctonus ponderosae can be prevented from successfully colonizing and killing individual trees by ground‐based sprays of insecticides applied directly to the tree bole. However, the future availability of several active ingredients, including carbaryl which is most commonly used in the western United States, is uncertain. Two novel insecticides, cyantraniliprole [Cyazypyr^?‐OD (oil dispersion) and Cyazypyr^?‐SC (suspension concentrate)] and chlorantraniliprole (Rynaxypyr^®), and carbaryl were assayed in both filter paper and topical assays. RESULTS: Compared with 20 000 mg L^?1 carbaryl (i.e. the maximum label rate for solutions applied to conifers for protection from bark beetle attack in the western United States), cyantraniliprole OD caused similar rates of mortality in D. ponderosae adults at 400‐fold weaker concentrations in both bioassays, while cyantraniliprole SC caused similar rates of mortality at 40‐fold weaker concentrations. Probit analyses confirmed that D. ponderosae is most sensitive to cyantraniliprole OD, while chlorantraniliprole was effective at concentrations similar to carbaryl. CONCLUSIONS: These results suggest that lower concentrations of carbaryl have merit for field testing than have been previously considered. While cyantraniliprole and chlorantraniliprole have similar modes of action, cyantraniliprole OD appears to have greater promise for protecting individual trees from mortality attributed to D. ponderosae attack and should be evaluated in field studies. Published 2011 by John Wiley & Sons, Ltd.     

Potential of barnyard grass to remediate arsenic‐contaminated soil

The present study investigated the arsenic (As) remediation potential of barnyard grass (Echinochloa crus‐galli L. Beauv. var. formosensis Ohwi), with a special focus on the behavior of As in the soil in comparison with rice (Oryza sativa L. cv. Nipponbare). For both plants, very little growth inhibition was observed in the As‐contaminated soil. The amount of As in the soil was reduced by the plant's uptake and the level of As in the soil water from the rice‐growing pots was remarkably lower than that in the plant‐free soil water. In the soil with the barnyard grass, the amount of As in the soil water was higher than that in the plant‐free soil water, but the amount of As in the soil and the amount of As that was adsorbed on the soil solid were reduced by the plant's uptake. At the highest As level in the soil (100 mg kg^?1), 249.60 and 101.26 µg As pot^?1 were taken up by the rice shoot and barnyard grass shoot, respectively, and total amounts of 1468.65 and 1060.57 µg As pot^?1 were taken up by the barnyard grass and rice seedlings, respectively. At the same As level in the soil, the As concentrations were 14.99 and 37.76 µg g^?1 in the shoot of barnyard grass and rice, respectively, and 486.61 and 339.32 µg g^?1 in the root of barnyard grass and rice, respectively. Barnyard grass took up more As than rice, but the As concentration in the shoot of barnyard grass was lower than that in the shoot of rice. A considerable amount of As was taken up by both barnyard grass and rice, suggesting that the plant species have the potential to remediate As‐contaminated soil.     

Organosilane insecticides. Part I: Biological and physical effects of isosteric replacement of silicon for carbon in etofenprox and MTI-800

Substitution of silicon for carbon was explored in etofenprox and MTI-800, primarily to establish the suitability of silicon for pesticide construction and to probe steric effects. It was shown that silicon is an effective building block for insecticides with subtle qualitative and quantitative differences relative to the carbon analogs. The silanes were slightly less toxic to insects than the carbon analogs (relative potency of 0.2-0.6) but the silane analog of MTI-800 was considerably less toxic to fish (0% mortality at ≥50 mg liter^?1) than MTI-800 itself (LC₅₀ = 3 mg liter^?1). The mode of action of both carbon and silicon compounds was similar in the intact, electrode-implanted cockroach and involved repetitive firing of a sensory nerve; potency measurements were also made using an in-vitro nerve assay. The possible metabolic and physicochemical contributions to the observed insecticide potencies were explored using synergism studies, physical chemistry measurements and quantum mechanical calculations.     

The influence of spray droplet characteristics on the efficacy of permethrin against the diamondback moth Plutella xylostella: The effect of drop size and concentration on the potency of ulv- and ec-based residual deposits

The effect of droplet diameter (36-274 μm) and concentration (10-400 g litre^?1) of permethrin on the knockdown and mortality of 2nd-instar Plutella xylostella larvae was investigated. Larvae were placed on brussels sprout leaf discs treated with residual deposits of permethrin applied as ULV or emulsion formulations. The LD₅₀ of permethrin decreased with droplet size at all concentrations tested. This effect could not be accounted for solely by increased drop numbers per unit area of leaf, suggesting that for both formulations transfer of permethrin to larvae is more efficient for deposits composed of small drops. The concentration of permethrin in the ULV formulation could be reduced to approach a minimum quantity of toxicant per unit area to maintain 50 per cent mortality. The approach to the minimum dose varied with drop size and drop number per unit leaf area. The ULV formulation was approximately 2.7 times more effective at killing larvae than the emulsion, presumably as a result of greater availability of toxicant and transfer to larvae.     

Argentine ant control around homes: efficacy of treatments and urban runoff

ABSTRACT

Pest management professionals in California receive more customer complaints about Argentine ants than for any other urban ant pest. Fipronil, applied as a 30 × 30 cm band around the house foundation, has become the preferred treatment used to control these ants. Unfortunately, fipronil is now showing up in urban waterways at levels that are toxic to aquatic invertebrates. Our recent studies are aimed at mitigating insecticide runoff while still controlling the ant infestations. A high priority is preventing fipronil runoff from the driveway to the street, where it can flow into drains and from there to urban waterways. In this paper, two related studies address these issues. Not treating driveways with fipronil reduced by two to three orders of magnitude its runoff when compared with earlier studies. However, not treating the driveway can reduce efficacy of treatments. Granular bifenthrin, indoxacarb, botanicals, and a thiamethoxam ant bait were tested as supplemental treatments. The gel bait showed the best result as a supplement, but only after 8 weeks. We have reduced fipronil runoff while maintaining efficacy of the ant treatments.