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A high proportion of triatomine insects, vectors for Trypanosoma cruzi trypanosomes, collected in Arizona and California and examined using a novel assay had fed on humans. Other triatomine insects were positive for T. cruzi parasite infection, which indicates that the potential exists for vector transmission of Chagas disease in the United States.

Infestations of buildings by Argentine ants,Linepithema humile(Mayr), were monitored on the campus of the University of California, Los Angeles. Foraging ant activity peaked during the hotter months of the year. The mean monthly maximum temperature, but not rainfall, positively correlated with indoor infestation frequency. Neither garden size nor the predominant groundcover vegetation correlated with the number of foraging ants at baits within gardens. Although the number of foraging ants outside a building varied over 40-fold, ant density in gardens did not predict the likelihood of infestation within the building. Also, the type of vegetative groundcover employed did not predict infestation frequency. There was, however, a significant negative relationship between the size of the garden outside of a building and the number of infestations. Given the large foraging area ofL. humileworkers, buildings next to small gardens may be infested simply because they lie within the “normal” foraging area of a colony. The best predictor of which rooms were infested within buildings was the presence of a water source. Thus providing water for ant colonies outside and away from buildings may be one method of integrated pest management to reduce the proclivity of ants to infest structures.

Chagas disease is an emerging infectious disease in North America due to the immigration of individuals from endemic areas. The parasite has been transmitted to patients in non-endemic areas by blood transfusion and organ donation. Only six autochthonous cases have been described in humans in the United States yet the parasite is widespread among native mammals and resident triatomines are competent vectors. We attempted to determine if common southwestern triatomines, Triatoma protracta and Triatoma rubida have the potential to amplify the disease among human residents of the Southwest. The defecation patterns of the bugs were studied while feeding upon immobilized mice. Wild-caught adult male and female triatomines were observed feeding one to three times for a total of 71 observed feedings. T. rubida (15 bugs) appeared to be more aggressive, beginning feeding shortly after being placed in proximity to the host (within 2.3 min) whereas Triatoma protracta (12 bugs) was more deliberate, beginning feeding, on average, at 4 min. There were 40 observations of T. rubida, which fed for 27.9+/-13.6 min, whereas T. protracta fed for 22.8+/-7.5 min (n=31). Bugs were weighed pre- and post-feeding and T. rubida females ingested>T. protracta females>T. rubida males>T. protracta males. Weight gain did not correspond to the feeding duration. Defecation occurred on 42% of the feedings (30 of 71), and no bugs defecated on the host. The majority of the defecations occurred within 1 min of feeding, usually at the time of repletion. A large proportion of defecations occurred after the bugs left the vicinity of the host. All bugs and at least one fecal smear from each feeding bug were tested for Trypanosoma cruzi and 21% of T. protracta were positive by PCR (4 bugs and 1 feces). No T. rubida tested positive for T. cruzi. The bugs' defecation pattern is similar to that reported >50 years ago. Furthermore, there is no indication that they are becoming more domesticated in the desert Southwest. Thus, based on our observations, we do not believe that T. protracta and T. rubida pose an imminent risk for transmission of Chagas disease to residents of the southwestern United States.

American Entomologist • Fall 2009 Two French scientists, Charles Richet and Paul Portier, codiscovered anaphylaxis in 1901. The lion’s share of the credit went to Richet, an eminent physician and Professor of Physiology at the University of Paris, while Portier was an assistant in the Laboratory of Physiology at the Sorbonne. A history of their discovery given from the perspective of Portier’s contributions is well covered by May (1985). Their collaboration began as guests on the oceanographic research vessel of Albert I, Prince of Monaco, as commemorated by a stamp (Fig. 1). The prince and his scientific director suggested the topic for their research on this scientifically historic cruise. They were to conduct experiments on the toxicity of venoms from the Portugese man-o-war, Physalia physalis. In the definitive experiment conducted after they returned to Paris, Richet and Portier exposed two dogs to weak doses of sea anemone actinotoxin and then repeated the injection at various time intervals. No reaction was noted until an injection 26 days after the beginning of the experiment, when both dogs became extremely ill and died shortly thereafter. Richet (1913) proposed two factors that were necessary and sufficient to cause an anaphylactic reaction: “increased sensitivity to a poison after previous injection of the same poison, and an incubation period necessary for this state of increased sensitivity to develop.” To name this reaction, Richet first proposed the term “aphylaxis,” later coining the term anaphylaxis (“without protection”) because it was more euphonious. For their studies on hypersensitivity reactions, Richet was awarded the 1913 Nobel Prize in Medicine or Physiology, while Portier, although his contribution was significant, did not share in the Prize and was barely mentioned in the Nobel address. Given the academic tradition at that time, it was not unusual for the more distinguished senior scientist to overshadow the lesser-known junior scientist, and Portier, a humble man, apparently did not feel slighted and remained friendly with Richet until the latter’s death in 1935. Portier made other important scientific contributions, including entomological studies concerning the physiology of aquatic insects and a treatise on the biology of butterflies published in 1949, when he was 83. Anaphylaxis described. Current definitions of anaphylaxis reflect advances in our understanding of its physiological basis: an acute systemic allergic reaction resulting from the release of chemical mediators following an immunologic reaction that is typically mediated by immunoglobulin E (IgE). IgE is one class of antibodies produced by the immune system in response to foreign substances. Individuals who suffer allergic reactions produce greater quantities John H. Klotz, Jacob L. Pinnas, Stephen A. Klotz, and Justin O. Schmidt Anaphylactic Reactions to Arthropod Bites and Stings

Formica perpilosa Wheeler is a serious economic ant pest on table grapes grown in the Coachella Valley, California, and Hermosillo, Sonora, Mexico. This ant aggressively tends hemipteran pests, such as the vine mealybug, Planococcus ficus Signoret, and disrupts natural control by predators and parasitoids. Efforts are underway to develop control measures against F. perpilosa using granular bait, yet little is known about the colony life cycle or foraging characteristics of this ant. We studied the seasonal activity, mating behavior, and density and spatial characteristics of F. perpilosa nests in vineyards as well as its foraging and recruitment behavior. Nests were active from early February to mid-October. Mating flights occurred in early August and again in the first two weeks of September and new colonies were founded by a single queen. F. perpilosa rapidly colonized a new, non-infested vineyard with ca. 9% of the vines infested after 1.5 y. In September the proportions of infested vines at 5, 20, and 30 y old vineyards were 18.6, 21.8, and 16.2%, respectively. This ant is seasonally polydomous and nest density increased ca. two-fold at the 5 and 20-year old vineyards between February and September. Foraging and recruitment primarily occurred up to 6.39 m from a home nest. The implications of these studies for controlling F. perpilosa using low-toxic bait delivery systems are discussed.

A liquid bait delivery system containing borate was evaluated for controlling the Argentine ant, Linepithema humile (Mayr), in an organic citrus orchard. Two concentrations of disodium octaborate tetrahydrate (1% and 0.5%) were tested in 500-mL capacity bait stations placed at the base of trees. Both concentrations significantly reduced ant activity over the 11-wk duration of the test when compared with controls. However, the 1% concentration of borate significantly reduced ant activity up to 76 m away from the treatment, whereas the 0.5% did not. Compared to ant control with contact insecticides, the bait delivery system uses less insecticide and is more target-specific, reducing environmental contamination.

Liquid ant baits were evaluated for control of Argentine ants, Linepithema humile (Mayr), and associated mealybug pests ( Pseudococcus species) in commercial vineyards. In all trials, liquid baits were an insecticide dissolved in 25% sugar water. In 2000, two liquid baits—crystalline boric acid and imidacloprid—were deployed in ground-based dispensers at rates of 85 (site 1) and 175 (site 2) dispensers per ha. Season-long ant densities were significantly lower than a no-insecticide control in only the boric acid treatments, and at only 1 of 2 sites. In 2001, four liquid baits—imidacloprid, fipronil, and thiamethoxam, each mixed at 0.0001% (A.I.)—were delivered in ground-based dispensers at a rate of 120 dispensers per ha. There was no treatment impact on ant or mealybug densities. In 2002, a liquid bait—thiamethoxam, mixed at 0.0001% (A.I.)—was delivered in ground-based (site 1) and canopy-based (site 2 and 3) dispensers that were recharged every 2 wk and cleaned every 4 wk, and deployed at rates of 160 (sites 1 and 2) and 620 (site 3) dispensers per ha. There was a significant reduction of season-long ant densities in liquid bait treatments at all sites, and of mealybug densities at 2 of 3 sites; crop damage was significantly lower in the liquid bait treatment at all sites. The results are discussed with respect to the methodologies used to deploy liquid baits and the development of a viable commercial program.

This study investigated the effects of the permethrin-impregnated plastic on ant mortality and foraging rates, and tested its potential for preventing ants from colonizing potted soil. Direct exposure to the plastic for as short as 1 min caused significant mortality of both red imported fire ants, Solenopsis invicta Buren, and Argentine ants, Linepithema humile (Mayr); however, red imported fire ants were more susceptible than Argentine ants. Knockdown of virtually all ants initially occurred within 15 min after exposure. However, some moribund ants recovered from the effects within 24 h. For example, after 1 min of direct exposure to the permethrin-impregnated plastic, 70% of Argentine ants and 5% of red imported fire ants recovered from the treatment. In established colonies of Argentine ants, significantly fewer ants foraged for food up posts treated with the plastic compared with untreated posts. In addition, colonies responded to introduction of the treatment by significantly reducing their overall foraging rates, even on untreated posts. When pots filled with moistened soil were introduced into established ant colonies, 82% of Argentine ants and 99% of red imported fire ants moved into the soil. In contrast, when a 1-cm-wide coil of the plastic was placed under the pot, no ants moved into the soil. The potential for use of these materials in nursery production is discussed.

Assimilation of boron by Argentine ants, Linepithema humile (Mayr), fed boric acid—sucrose water solutions was affected by the addition of sorbitol. Concentrations of 10 and 20% sorbitol reduced boron assimilation by 38 and 67%, respectively, thereby significantly reducing the toxicity of the solutions. The effect of solution pH on mortality indicated that the ionized borate molecule was less toxic than the neutral boric acid species. Electron microscopy revealed that ants fed low concentrations of boric acid (0.5%) show gross abnormalities in the microvilli and cells lining the midgut.

The red imported fire ant, a pest newly introduced into California, threatens households, agriculture and wildlife. This study estimates the costs and benefits of a public program to eradicate the ants. The results show that almost all agricultural activities would be affected should the ants become established; however, households would incur the majority of costs. The total estimated cost if red imported fire ants become established would be between $387 million and $989 million per year in California. Given current funding levels for eradication of red imported fire ants, for the expected benefits to be at least as great as the expected costs, the probability of successfully eradicating the ants needs to be at least 0.65% if the annual costs of establishment are $989 million and 1.67% if they are $387 million.

Current control methods for the black carpenter ant, Camponotus pennsylvanicus (De Geer), include the use of remedial and preventative residual sprays as well as toxic baits. We evaluated the acceptance of three baits (Maxforce, Niban, and Baygon) to field colonies of the black carpenter ant in the spring and fall. Maxforce bait granules were more readily accepted than either Niban or Baygon bait granules in the spring. A change in food preference from protein to sugar by the black carpenter ant appeared to reduce the number of Maxforce bait granules removed in the fall, resulting in no differences in bait acceptability. The longevity of Dursban 50W and Tempo 20WP were evaluated in the summer and fall on painted wood panels. Panels aged outside for 15 d under prevailing weather conditions exhibited increased LT50 values. For each sampling period, panels aged on the south face (in the sun) exhibited less insecticidal activity (i.e., large LT50 values) than panels on the north face (shaded; small LT50 values). At each sampling period, Tempo 20WP provided smaller LT50 values than Dursban 50W. Because of changing dietary preferences, our data highlight the importance of using various bait types for carpenter ant control. Moreover, the application of residual spays should be made to locations protected from direct sunlight.

We investigated whether the Argentine ant, Linepithema humile (Mayr), trail pheromone, Z9-16:Ald, could enhance recruitment to and consumption of liquid sucrose solutions. All tests were done as paired comparisons with a 10% sucrose solution as food. In the laboratory, mixing 20 microl of a 10-microg/ml solution of the pheromone with 50 microl of the 10% sucrose solution increased the number of ants feeding by150%. In a field test, we combined the trail pheromone with a 10% sucrose solution in 50-ml vials. These vials were covered with a plastic membrane that has 1.5-mm-diameter holes punched uniformly across its surface. Ants could drink from the holes after the vials were inverted. For half of the vials, 1 microg of the pheromone was put onto the plastic membrane before the vials were filled with a 10% sucrose solution. The remaining vials had no pheromone on the plastic membrane. After 4 h we measured the consumption in each vial. Bait consumption with the pheromone was enhanced by 29%. In a 2nd series of tests, vials were left outside for 24 h. The consumption rate was 33% higher with the pheromone compared with the controls that didn't have pheromone.

Recruitment to different concentrations of sucrose in water and toxicity to boric acid in different concentrations of sucrose water were evaluated in the laboratory for use against the Argentine ant, Linepithema humile (Mayr). Recruitment of ants to 50% sucrose water was significantly greater than to 25% sucrose water, which was greater than to 10% sucrose water. Over the dose range from 0.2 to 1.0% (wt:vol) boric acid, LT 50 s (95% CL) ranged from 5.6 (5.2-5.9 d) to 1.4 d (1.3-1.6 d) in 10% sucrose water and 5.0 (4.7-5.3 d) to 1.7 d (1.5-1.9 d) in 25% sucrose water. Based on these laboratory results, a 0.5% boric acid in 25% sucrose water bait was formulated and evaluated against an infestation of Argentine ants in a water production plant. Over the 10-wk duration of the bait study, structures where control baits (25% sucrose water) were applied did not show a significant change in ant population numbers, whereas those receiving the boric acid bait showed a significant and continuous reduction (80%) of ants.

Boric acid-sucrose water baits were evaluated in the laboratory for toxicity, consumption, and efficacy against the red imported fire ant, Solenopsis invicta Buren. Over the dosage range from 0.02 to 1.0% boric acid, LC50s (95% CL) ranged from 1.27% (1.05- 3.88%) at 3 d to 0.11% (0.09-0.13%) at 8 d. Amount of bait consumed was related inversely to the concentration of active ingredient. High concentrations of boric acid bait (5%) were consumed at a lower rate than the control (10% sucrose water). In large fire ant colonies exposed continuously to 4 concentrations (0.25, 0.5, 0.75, 1.0%) of boric acid bait, workers and brood were reduced by 90% at 6 wk. Therefore, low concentrations of boric acid are necessary for delayed toxicity and reduced repellency.

A 1% boric acid-sucrose water bait was evaluated for efficacy in reducing structural infestations of Pharaoh ants, Monomorium pharaonis (L.), at 2 sites. One of the sites was an apartment complex with a natural infestation of Pharaoh ants. The other site consisted of a group of small buildings that were purposely infested with Pharaoh ants. Treated and untreated (control) bait stations were replaced once a week for 3 wk at each site, then removed from the study site. Significant reductions in the number of foraging ants at both sites were attained in the 1st week after exposure to the boric acid bait and was maintained thereafter for 7 wk in the apartment complex and for 8 wk in the small-building complex.

The kissing bug, Triatoma rubida (Uhler) is a common hematophagous bug in Tucson, AZ, and is responsible for causing severe allergic reactions in some bitten individuals. DEET, picaridin, tea tree oil, peppermint oil, and citronella oil were tested for repellency to T. rubida and its ability to probe and feed on a small restrained rat. No long range repellency was observed with any of the test materials. The lowest repellent concentrations observed were: 10% DEET, 7% picaridin; 30% tea tree oil, 3.3% peppermint oil, and 0.165% citronella oil. Only citronella oil was able to stop all probing and feeding by T. rubida. Citronella oil appears to be a promising potential repellent to prevent sleeping people from being bitten by kissing bugs.

A 1% boric acid-sucrose water bait and 0.9% hydramethylnon granular bait were evaluated for efficacy against small laboratory colonies of Tapinoma melanocephalum (F.); Argentine ants, Linepithema humile (Mayr); and Pharaoh ants, Monomorium pharaonis (L.). T. melanocephalum workers were reduced by 97% in the 1st wk and brood reduced by 96% in the 3rd wk when colonies were exposed to boric acid bait for as few as 3 d. The hydramethylnon bait did not significantly affect colony growth. L. humile colonies exposed to boric acid bait for 3 d resulted in reductions of 75 and 88% for workers and brood, respectively, by the 3rd wk. L. humile colonies exposed continuously caused a 90% reduction of workers and brood by the 3rd wk. Workers and brood in colonies exposed to hydramethylnon bait were reduced 86 and 77%, respectively, after 3 wk. After exposure to boric acid bait for 3 d, M. pharaonis workers and brood were reduced 73 and 50%, respectively, by 8 wk. A continuous exposure of boric acid or hydramethylnon baits caused reductions of 90 and 60% for workers and brood, respectively, by 3 wk.

On any spring day across North America, you may hear radio commercials for pest control companies promising an end to the invasion of “Big Black Ants.” The entomologists among us will recognize this “plague” as the seasonal return of carpenter ants, although the homeowner facing scores of large ants foraging in his home will care little of the taxonomy of Formicidae.

The oral toxicity of boric acid to the Florida carpenter ant, Camponotus abdominalis floridanus (Buckley), was evaluated in laboratory tests. The ants were provided a sucrose water-based bait containing various concentrations of boric acid. Over the dosage range from 0.02 M (0.13% w/v) to 0.50 M (3.13% w/v) boric acid, median lethal times (LT50s) (95% CL) ranged from 9.7 (8.1–13.3) days to 1.5 (1.2–1.7) days. Over the same dosage range (0.02 M to 0.50 M), LT90s (95% CL) ranged from 27.1 (18.0–59.5) days to 4.2 (3.6–5.1) days. Some of the advantages of using boric acid as a bait toxicant for ants include its delayed activity and its solubility in water.

A complete picture of Chagas disease requires an appreciation of the many species of kissing bugs and their role in transmitting this disease to humans and other mammals. This chapter provides an overview of the taxonomy of the major species of kissing bugs and their evolution. Knowledge of systematics and biological kinship of these insects may contribute to novel and useful measures to control the bugs. The biology of kissing bugs, their life cycle, method of feeding and other behaviours contributing to the transmission of Trypanosoma cruzi are explained. We close with a discussion of vector control measures and the allergic complications of kissing bug bites, a feature of particular importance in the United States.

A complete picture of Chagas disease requires an appreciation of the many species of kissing bugs and their role in transmitting this disease to humans and other mammals. This chapter provides an overview of the taxonomy of the major species of kissing bugs and their evolution. Knowledge of systematics and biological kinship of these insects may contribute to novel and useful measures to control the bugs. The biology of kissing bugs, their life cycle, method of feeding and other behaviours contributing to the transmission of Trypanosoma cruzi are explained. We close with a discussion of vector control measures and the allergic complications of kissing bug bites, a feature of particular importance in the United States.

The oral toxicity of the delayed-action insecticide hydramethylnon, in contrast to the acute toxins chlordane and imidacloprid, was evaluated in free-foraging workers of the black carpenter ant, Camponotus pennsylvanicus (DeGeer), gathering insecticide-laced, sugar-milk baits. Hydramethylnon was slower acting than either chlordane or imidacloprid. When workers fed upon 500-ppm baits, hydramethylnon killed ants significantly more slowly (LT50 [95% CL] = 12.7 [12.5-12.9] d) than did chlordane (1.3 [1.1-1.4] d) or imidacloprid (0.3 [0.1-0.5] d). All toxicants were transferred via trophallaxis (i.e., indirect exposure). In ants exposed to a single forager that fed upon a 500-ppm bait (i.e., the donor ant), hydramethylnon caused death significantly more slowly (LT50 [95% CL] = 12.2 [11.9-12.4] d) than did chlordane (4.1 [3.8-4.4] d) or imidacloprid (0.9 [0.8-1.0] d). In both direct and indirect exposures, significant concentration-dependent time delays before mortality were observed with each toxin. Donor ants in indirect exposures survived after gathering and transferring sugar-milk bait laced with chlordane or hydramethylnon but did not survive their exposure to imidacloprid. On the basis of these and other analyses, we identify delayed-action toxins suitable for carpenter ant baits.

Bartonella henselae, the causative agent of the illness referred to as cat scratch disease, is a common infection, particularly in children, and clinicians need to be aware of its potential transmission to humans by arthropod vectors such as fleas and ticks in addition to animal bites and scratches. The absence of a vertebrate bite or scratch does not preclude infection with B. henselae.Literature regarding arthropod transmission of B. henselae was reviewed.B. henselae appears to be transmitted among cats and dogs in vivo exclusively by arthropod vectors (excepting perinatal transmission), not by biting and scratching. In the absence of these vectors disease does not spread. On the other hand, disease can be spread to humans by bites and scratches, and it is highly likely that it is spread as well by arthropod vectors.Clinicians should be aware that a common illness, infection with B. henselae, can be transmitted by arthropod vectors and a history of an animal scratch or bite is not necessary for disease transmission.

Purpose: Cat scratch disease is a common infection, particularly in children, and clinicians need to be aware of its potential transmission to humans by arthropod vectors such as fleas and ticks in addition to animal bites and scratches. The absence of a vertebrate bite or scratch does not preclude infection with Bartonella henselae. Methods:Literature regarding arthropod transmission of B. henselae was reviewed. Results:B. henselae and related bacterial species are transmitted among cats and dogs by arthropod vectors. In the absence of these vectors, disease does not spread amongst the animals. On the other hand, disease can be spread to humans by bite and scratch as well as by arthropod vectors. Animals commonly infected with B. henselae and arthropod vectors are discussed. Conclusions:Clinicians should be aware that a common illness, cat scratch disease, can be transmitted by arthropod vectors and a history of an animal scratch or bite is not necessary for disease transmission.

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 bifenthrinorfipronilsprays following standardpractices. During 2008,pin streamapplicators, spray-freezones andrestricting 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 µ gL −1 at 1 week post-treatment and 2.5 µ gL −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 µ gL −1 at 1 week post-treatment and 0.01 µ gL −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. c � 2010 Society of Chemical Industry

Physicians in the United States should familiarize themselves with "kissing bugs" endemic to their area of practice and appreciate the medical implications of their bites. Bite victims often seek advice from physicians about allergic reactions as well as the risk of contracting Chagas disease. Physicians are generally knowledgeable about the role of kissing bugs in the transmission of Trypanosoma cruzi in Latin America. However, they may be unaware of (1) severe allergic reactions to kissing bug salivary antigens, (2) the widespread occurrence of T. cruzi amongst vertebrate hosts of kissing bugs, and (3) the incidence of T. cruzi among kissing bugs (T. cruzi may infect >50% of sampled bugs). Despite the potential for Chagas disease transmission, the major concern regarding kissing bugs in the United States is anaphylactic reactions to their bites resulting in frequent emergency department visits, especially in areas of endemicity in the Southwest.

Oral toxicities of delayed-action insecticides abamectin, dechlorane, and sulfluramid were characterized in free-foraging Camponotus pennsylvanicus (DeGeer) workers gathering insecticide-laced, sugar-milk baits. Abamectin acted significantly faster than either dechlorane or sulfluramid. When workers fed upon 500-ppm baits, abamectin killed the ants faster (LT50 [95% CL] = 1.06 [0.88-1.23] d) than either dechlorane (5.82 [5.62-6.00] d) or sulfluramid (6.20 [5.76-6.65] d). All toxicants were readily transferred by trophallaxis. In ants that were exposed to a single forager that had fed upon a 500-ppm bait, abamectin caused death more rapidly (LT50 [95% CL] = 2.56 [2.29-2.81] d) than did dechlorane (6.71 [6.35-7.05] d) or sulfluramid (6.96 [6.06-8.42] d). In both direct and indirect exposures, significant concentration-dependent time delays before mortality were observed for all toxins. Based on the effective lethal time for 90% (ELT90) of the exposed workers, the concentration dependence of the time delays for dechlorane and sulfluramid were equivalent, and both were active over a wider range of concentrations than abamectin.

The oral toxicity of boron compounds to the Argentine ant, Linepithema humile (Mayr), was evaluated in laboratory tests. The ants were provided 25% sucrose water containing 0.5 and 1% boric acid, disodium octaborate tetrahydrate, and borax. Lethal times of these solutions were a function of the concentration of boron. In field tests, the ants showed no discrimination between disodium octaborate tetrahydrate and boric acid. There was a significant reduction in consumption of sucrose water with >1% boric acid.