The toxicity and horizontal transfer of a new formulation of fipronil, 0.5% fipronil dust, was tested against Coptotermes formosanus Shiraki in the laboratory. The formulation was applied in three different ways: 1) Directly applied to termites (donors) and mixed with untreated termites (recipients) at three ratios, viz., 50 donors: 50 recipients, 20 donors: 80 recipients and 10 donors: 90 recipients. 2) Applied onto the surface of 3 mm thick sand or soil substrate in a petri dish and then topped with another 3 mm thick sand or soil layer whereupon termites were released. 3) Applied to the inner surface of a tube (either 5 cm or 15 cm long) that connected two foraging dishes, one containing dry sand and the other moist sand plus a wood block and termites were released into the dry sand dish. All donors and >93% of the recipients were dead by 42 h after treatment in the direct treatment experiment. Significant mortalities of both donors and recipients were observed at 5 h after treatment at all donor: recipient ratios. During this period, the mortality of the recipients (but not donors) at 10:90 was significantly lower than those at the other two ratios. All termites were dead at 65 h after exposure (HAE) on the sand treatment and at 190 HAE on soil treatment. More than 96% mortality was observed at 40 HAE on the sand treatment as compared with only 6% mortality onsoil treatment during the same time period. In the tube treatment experiment, > 97% mortality was observed at 90 h after release for both tube lengths as compared with < 3% mortality in controls. About half of the termites were dead by 15 h after release regardless of the tube length. Our results showed that 0.5% fipronil dust is nonrepellent and readily transferred from treated to nontreated termites.
The compound [3,5-di- (α,α,α-trifluoromethyl) -N-ethyl-anilino] methylenemalononitrile, tested under the code number MON-0856, was selectively toxic to insects. High activity was exhibited to Lepidoptera larvae; moderate activity was obtained against Coleoptera; and low activity was noted against Diptera, as well as against parasitic Hymenoptera and predaceous Heteroptera. It was active upon topical application to larvae, by foliar application to plants, and systemically in plants when applied to the soil.
Toxicity and behavioral effects of nootkatone and two of its derivatives, 1,10-dihydronootkatone and tetrahydronootkatone, to Coptotermes formosanus Shiraki were investigated on workers from two different colonies by using topical application assays, repellency assays, and sand barrier assays. The acute toxicity of the nootkatones on workers from both colonies increased as the saturation of the molecule increased, but the difference was significant for only one colony. The results of the repellency assays showed a similar trend of efficiency; the threshold concentration for significant repellency was four-fold higher in nootkatone treatments (50 ppm) than in the reduced derivatives 1,10-dihydronootkatone or tetrahydronootkatone (12.5 ppm). In sand barrier assays, a concentration of 100 ppm of any of the three chemicals significantly reduced termite survival, tunnel building, and food consumption after a 12-d exposure. Termites preexposed to 100 ppm nootkatone-treated sand and placed in containers without nootkatone for 15 d continued to exhibit abnormal feeding and digging behaviors; survivorship, tunneling, and feeding activities were significantly reduced by 83.5, 63.2, and 95.4%, respectively. Termites pretreated for 12 d at concentrations of 50 and 75 ppm nootkatone and tetrahydronootkatone returned to normal digging activity after they were removed from the treatments, but their feeding activity was significantly reduced.
Specimens of a strain of Sitophilus granaries (L.) selected for 67 generations for resistance to methyl bromide (LWR) were 1.3 times heavier than those of an unselected (LWN) strain. The LC50 values of these strains to fumigation with 1,2-dibromoethane (EDB) were 2.75± 0.09 and 1.46±0.05 µliters per liter, respectively, a 1.9-fold difference in tolerance. Twenty-five percent of this susceptibility difference was correlated with the greater weight of the LWR strain.
There was no significant difference in the respiration rate between LWN and LWR insects of the same weight. The respiration rate at 27°C was weight dependent, and heavier insects had a lower rate of gas exchange per milligram of tissue. EDB uptake as measured with the aid of radio labeled fumigant was also weight dependent, and the heavier the insect, the lower was the concentration of fumigant per milligram of tissue after fumigation. The significance of greater weight as a protection against fumigation is discussed in relation to vigor tolerance.
Five compounds from structurally-modified, biologically active plant materials were evaluated for their antifertility effect on Cochliomyia hominivorax (Coquerel). When 0- to 5-day-old flies were treated orally with concentrations of 0.01–1.0% of three and 0.1–1.0% of two of the compounds, complete sterility of female flies was obtained, whereas only J2644 (2,4-bis (1,1-dlmethylethyl)-6-(4-methoxyphenylmethyl)phenol) affected fertility of males. The sterilants did not adversely affect the insemination and fecundity rates, and only the highest dosages of J2706, (2,4-bis(1,1-dimethylethyl)-6-(1-phenylethyl)phenol), J2693 (5-(2-propenyl)-6-(methoxyphenylmethyl)-1,3-benzodioxole), and J2581 (5-ethoxy-6-(4-methoxy-phenylmethyl)-1,3-benzodioxole), (1.0%) proved lethal to the flies.
J2419 (2,4-bis(1,1-dimethylethyl)-6-(phenylmethyl)phenol, or J2644 continued to be effective up to the 3rd gonotrophic cycle when most of the flies were already dead. Exposure to 0.25% of J2644 for the 1st 24 or 48 h halved or eliminated fertility, respectively. Increasing dosages by 4-fold did not significantly affect efficiency of the chemosterilants. Single meals of 1.0% J2644 or of J2419 were effective in giving complete sterility.
Neither chemosterilants J2644 (2,4-bis(1,-1-dimethylethyl)-6-(4-methoxyphenylmethyl)phenol) nor J2581 (5-ethoxy-6-(4-methoxyphenylmethyl)-1,3-benzodioxole) affected fertility of male and female Aedes aegypti (L.), significantly when pupae were treated at 1 to 5,000 ppm concentrations. The observed reduction in hatchability of eggs from normal females mated with treated males did not exceed 32%. The reduction in hatchability of eggs from treated females mated with normal males was ca. 28%. Longevity of males (5,000 ppm) was not affected by either sterilant at indicated doses.
A variety of substituted 1,3-benzodioxoles, catechols, and quinones were examined for larvicidal activity against 3rd-instar Culex pipiens quinquefasciatus Say. Several compounds were quite effective larvicides, showing activity comparable to or greater than that demonstrated by Monsanto larvicide MON-0585 (2, 6-di- tert-butyl -4-(α, α-dimethylbenzyl) phenol. These compounds appear to inhibit the development of larvae into pupae or adults. Symptoms of intoxication paralleled those obtained from the treatment of mosquito larvae with farnesoic acid or MON-0585.
The threo and erythro isomers of the insect repellent Rutgers 612, 2-ethyl-1, 3-hexanediol, have been separated by preparative gas chromatography, characterized, and tested biologically against the yellow-fever mosquito, Aedes aegypti (L.). Repellent activities of the isomers are equal.
Several new 1,3-benzodioxole derivatives were synthesized and examined for synergism of carbaryl toxicity to houseflies, Musca domestica L., and for inhibition of aldrin epoxidation by rat liver microsomal oxidase. Synergism data for several of the derivatives confirmed predictions made earlier by another worker. Several of the 4,5-disubstituted-1,3-benzodioxoles were outstanding in their effectiveness in synergizing the toxicity of carharyl. A direct relationship between synergistic activity and inhibition of microsomal aldrin epoxidation was not observed. Data on inhibition of microsomal oxidase revealed that the catechols are often more potent inhibitors than the related 1, 3-benzodioxoles.
Field trials were conducted in Guatemala to evaluate the importance of 1,4 diaminobutane (putrescine) in traps baited with ammonium acetate, trimethylamine, and putrescine. For the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), there were no differences in percentage of females captured in coffee and citrus or in percentage of males captured in citrus in traps with ammonium acetate and trimethylamine lures (females in coffee, 26.4 +/- 6.27%; females in citrus, 35.7 +/- 5.35%; males in citrus, 37.7 +/- 7.48%) versus ammonium acetate, trimethylamine, and putrescine lures (females in coffee, 36.6 +/- 9.64%; females in citrus, 41.1 +/- 5.18%; males in citrus, 37.1 +/- 6.09%). Percentage of males captured in coffee was reduced significantly when putrescine was not used with the ammonium acetate and trimethylamine (39.9 +/- 4.34 versus 31.6 +/- 5.29%). Lower percentages were captured in traps baited with ammonium acetate and putrescine, and the lowest percentages were captured in traps baited with putrescine and trimethylamine. When population level as indicated by capture in traps baited with ammonium acetate, trimethylamine, and putrescine was considered, a higher percentage of C. capitata males were captured in traps baited with all three components when one or more flies per trap per day were captured in coffee, and a higher percentage of females were captured when less than one fly per trap per day was captured in citrus. Percentage of the Mexican fruit fly, Anastrepha ludens (Loew), captured was significantly higher in traps baited with ammonium acetate and putrescine and significantly lower in traps baited putrescine and trimethylamine than in all other treatments. Results indicate that putrescine may be deleted when monitoring established populations of C. capitata but should be used in traps used to monitor A. ludens or to detect new infestations of C. capitata.
1,8-Cineole isolated from Artemisia annua was tested against Tribolium castaneum (Herbst) for contact toxicity, fumigant toxicity, and antifeedant activity. The adults of T. castaneum were more susceptible than larvae to both contact and fumigant toxicity of 1,8-cineole, and LD50 and LC50 values of 108.4 microg/mg body weight of adult insect and 1.52 mg/liter air were found, respectively. Furthermore, 14-d-old T. castaneum larvae were more tolerant than 16- and 18-d-old larvae and adults to the contact toxicity of 1,8-cineole, but the 16- and 18-d-old larvae have similar susceptibility. In contrast, all the larvae (14-18 d old) of T. castaneum were much more tolerant than the adults to the fumigant action, but larvae of different ages had similar susceptibility. The compound 1,8-ciineole applied to filter paper at a concentration of 3.22-16.10 mg/cm2 significantly (P < 0.05) reduced the hatching of T. castaneum eggs and the subsequent survival rate of the larvae. Adult emergence was also reduced by 1,8-cineole. Feeding deterrence of 81.9% was achieved in T. castateum adults by using a concentration of 121.9 mg/g food, whereas larvae showed 68.8% at the same concentration.
When a new formulation of the β-exotoxin of Bacillus thuringiensis Berliner of the International Minerals and Chemical Corporation (IMC 10,001) was tested against Heliothis virescens (F.), it was about 1/5 as toxic to neonate larvae as a preparation of the θ-endotoxin that had a potency of 16,000 international units/mg. Its primaly anion against larvae less than 4 days old was insecticidal; larvae that survived emerged as normal adults. However, when IMC 10,001 was incorporated into the diet of 4- or 8-day-old larvae, the length of the proboscis was reduced in those animals surviving to adulthood. When a spray of the formulation containing 40,000 μg/ml was applied to leaves of cotton plants the biological activity persisted between 6 and 12 days after application.
Xylella fastidiosa (Wells, Raju, Hung, Weisburg, Mandelco-Paul, and Brenner) is a bacterial pathogen transmitted by several sharpshooters in two tribes of Cicadellinae (Proconiini and Cicadellini). Here, we compared the transmission efficiency of X. fastidiosa in coffee (Coffea arabica L.) and citrus [Citrus sinensis (L.) Osbeck] by Cicadellini [Bucephalogonia xanthophis (Berg) and Dilobopterus costalimai Young] and Proconiini [Homalodisca ignorata Melichar and Oncometopia facialis (Signoret)] sharpshooters that occur in both crops. At different seasons, healthy adults of each species were submitted to a 48-h acquisition access period on citrus or coffee source plants infected with X. fastidiosa isolates that cause Citrus variegated chlorosis (CVC) and Coffee leaf scorch (CLS), respectively, and then confined on healthy seedlings of the corresponding host plant for a 48-h inoculation access period. No significant effect of inoculation season was observed when comparing infection rates of citrus or coffee plants inoculated by vectors at different times of the year. In citrus, the transmission rate by single insects was significantly higher for H. ignorata (30%) in relation to B. xanthophis (5%) and O. facialis (1.1%), but there was no difference among vector species in coffee, whose transmission rates ranged from 1.2 to 7.2%. Comparing host plants, H. ignorata was more effective in transmitting X. fastidiosa to citrus (30%) in relation to coffee (2.2%), whereas the other vectors transmitted the bacterium to both hosts with similar efficiencies. Despite these variations, vector efficiency in coffee and citrus is lower than that reported in other hosts.
Studies were conducted in tropical greenhouses to elucidate the role of UV light (UV) for the orientation and flight behavior of the thrips Ceratothripoides claratris (Shumsher) (Thysanoptera: Thripidae), an important pest on tomato (Lycopersicum spp.), in the hot and humid tropics of South-East Asia. Four greenhouse types characterized by different combinations of UV-absorbing or -transmitting plastic films and nets on the roof and sidewalls, respectively, were used in these studies. In choice experiments C. claratris always preferred the environment with higher UV intensity. Furthermore, natural thrips populations around the greenhouses were captured during the majority of control dates in lower numbers on sticky traps on the outer sidewalls of greenhouses clad with UV-absorbing materials compared with UV-transmitting materials. The immigration of thrips into the UV-absorbing greenhouses also was impeded, as measured by sticky traps on the inner side walls. UV-absorbing plastic roofs showed the most pronounced deterrent effect for thrips movement toward greenhouses, and the UV-absorbing net effectively reduced thrips numbers crossing the net barrier into the greenhouse. A simple extension of UV-absorbing plastic roof around conventional greenhouses clad with UV-transmitting plastic and net reduced thrips capture rates inside the greenhouse up to 77% when thrips was released at 1 m distance from the net walls. These results are discussed in the context of wavelength dependent insect vision and the dilemma of tropical greenhouse constructions, i.e., physical pest exclusion versus appropriate ventilation to ensure a conducive microclimate for plant growth.
Residues of Niagara NIA-10242 (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamate) and its substituted furanol, Niagara NIA-10272 (2,3-dihydro-2,2-dimethyl-7-benzofuranol) dissipated to nondetectable levels in 14 days when Niagara NIA-10242 was applied to Coastal bermuda grass. Residues of neither compound were detected 14 days after application of the insecticide at a rate of 1 lb per acre. However, residues of NIA-10242 (its substituted furanol was not detected) were found to be relatively stable in Coastal Bermudagrass silage stored for 30 days and also in corn silage stored for 56 days. The NIA-10242 residues in corn silage fed to lactating cows for 56 days did not inhibit blood cholinesterase activity, nor were they detected in the milk.
Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries.
Commercial field corn (Zea mays L.) hybrids transformed to express some or all of the lepidopteran insect-resistant traits present in SmartStax corn hybrids were evaluated for insecticidal efficacy against a wide range oflepidopteran corn pests common to the northern United States, during 2008 to 2011 at locations in 15 states. SmartStax hybrids contain a pyramid of two Bacillus thuringiensis (Bt) derived events for lepidopteran control: event TC1507 expressing Cry1F protein and MON 89034 expressing CrylA.105 + Cry2Ab2. These studies focused on characterization of the relative efficacy of each event when expressed alone or in combination, and compared with non-Bt hybrid. Corn hybrids containing pyramided insecticidal proteins Cry1F + Cry1A.105 + Cry2Ab2 (SmartStax) consistently showed reduced plant feeding damage by a wide range of lepidopteran larvae compared with single event and non-Bt hybrids. Corn hybrids expressing TC1507 or MON 89034 as single or pyramided events were consistently efficacious against Ostrinia nubilalis (Hübner). SmartStax hybrids had less injury from Agrotis ipsilon (Hufnagel) and Striacosta albicosta (Smith) than corn hybrids containing only event MON 89034 but were not more efficacious than single event TC1507 hybrids. Corn hybrids with event MON 89034 provided better control of Helicoverpa zea (Boddie), than event TC1507 alone. Spodoptera frugiperda (J.E. Smith) efficacy was higher for hybrids with pyramid events and single events compared with the non-Bt hybrids. The spectra of activity of events TC1507 and MON 89034 differed. The combination of TC1507 + MON 89034 provided redundant control of some pests where the spectra overlapped and thereby are expected to confer a resistance management benefit.
Studies were conducted across the southern United States to characterize the efficacy of multiple Bacillus thuringiensis (Bt) events in a field corn, Zea mays L., hybrid for control of common lepidopteran and coleopteran pests. Cry1F protein in event TC1507 and Cry1A.105 + Cry2Ab2 proteins in event MON 89034 were evaluated against pests infesting corn on above-ground plant tissue including foliage, stalks, and ears. Cry34Ab1/Cry35Ab1 proteins in event DAS-59122-7 and Cry3Bb1 in event MON 88017 were evaluated against the larvae of Mexican corn rootworm, Diabrotica virgifera zeae Krysan and Smith, which occur below-ground. Field corn hybrids containing Cry1F, Cry1A.105 + Cry2Ab2, Cry34Ab1/Cry35Ab1, and Cry3Bb1 insecticidal proteins (SmartStax) consistently demonstrated reductions in plant injury and/or reduced larval survivorship as compared with a non-Bt field corn hybrid. Efficacy provided by a field corn hybrid with multiple Bt proteins was statistically equal to or significantly better than corn hybrids containing a single event active against target pests. Single event field corn hybrids provided very high levels of control of southwestern corn borer, Diatraea grandiosella (Dyar), lesser cornstalk borer, Elasmopalpus lignosellus (Zeller), and fall armyworm, Spodoptera frugiperda (J.E. Smith), and were not significantly different than field corn hybrids with multiple events. Significant increases in efficacy were observed for a field corn hybrid with multiple Bt events for sugarcane borer, Diatraea saccharalis (F.), beet armyworm, Spodoptera exigua (Hübner), corn earworm, Helicoverpa zea (Boddie), and Mexican corn rootworm. Utilization of field corn hybrids containing multiple Bt events provides a means for managing insect resistance to Bt proteins and reduces non-Bt corn refuge requirements.
A study to determine yield response to the Russian wheat aphid, Diuraphis noxia (Mordvilko), was conducted during the 1997-1998 and 1998-1999 growing seasons at three eastern Colorado locations, Akron, Fort Collins, and Lamar, with three wheat lines containing either Russian wheat aphid-resistant Dn4 gene, Dn6 gene, or resistance derived from PI 222668, and TAM 107 as the susceptible control. Russian wheat aphids per tiller were greater on TAM 107 than the resistant wheat lines at the 10x infestation level at Fort Collins and Akron in 1999. Yield, seed weight, and number of seeds per spike for each wheat line were somewhat affected by Russian wheat aphid per tiller mainly at Fort Collins. The infested resistant wheat lines harbored fewer Russian wheat aphids and yielded more than the infested susceptible wheat lines. Wheat lines containing the Dn4, Dn6, and PI 222668 genes contain different levels of antibiosis or antixenosis and tolerance. Although differences existed among sites and resistance, there is a benefit to planting resistant wheat when there is a potential for Russian wheat aphid infestations.
The compound cis -11-tetradecenyl acetate was identified as a male sex stimulant of Ostrinia nubilalis (Hübner). The compound has the same gas-liquid chromatographic and biological properties as the natural pheromone.
In 2006-2008, we tested (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene (pentaene) with the pheromone components (Z)-11-hexadecenyl acetate (Z11-16:Ac) and (Z)-9-tetradecenyl acetate (Z9-14:Ac), as sex attractants for four sympatric species of coneworms, Dioryctria Zeller (Lepidoptera: Pyralidae) in slash (Pinus elliottii Engelm.) and loblolly pine (Pinus taeda L.) seed orchards in Georgia and Louisiana, respectively. The addition ofpentaene increased catches of male southern pine coneworm, Dioryctria amatella (Hulst), in wing traps baited with Z11-16:Ac, whereas catches of Dioryctria disclusa Heinrich in traps baited with Z9-14:Ac were unaffected by the addition of pentaene. The effect of pentaene on male Dioryctria merkeli Mutuura & Munroe was inconsistent. In 2006, pentaene seemed to inhibit attraction of D. merkeli to traps baited with Z9-14:Ac, whereas in a subsequent trial in 2008, moths were equally attracted to Z9-14:Ac with or without the pentaene. We caught too few Dioryctria clarioralis (Walker) in any experiment for meaningful analyses. Our field results with pentaene and the unresolved complexity of the taxonomy, ecology, and management of southern coneworms support the need for a comprehensive examination of the chemical ecology of Dioryctria spp.
This work describes the results of an experiment that was conducted in the vineyard of the American Farm School, Thermi, Thessaloniki Greece, during 2001. Its aim was to study the efficacy of two formulations of Bacillus thuringiensis Berliner (wettable powder and dust) to control the larvae of Lobesia botrana Denis & Schiffermueler (Lepidoptera: Tortricidae). The experimental results showed that the two formulations of B. thuringiensis are significantly more effective than the control, the dusting being more effective in most cultivars (Asyrtico, Sauvignon blanc, Debina, Athiri, Agiorgitico, Limnio, Syrah, and Cabernet sauvignon), and the spraying in a few cultivars (Xinomavro, Roditis, and Chardonnay). Dusting in the blue-black cultivars was found to be more effective than spraying, this not being the case in the yellow-green cultivars. This fact should be taken into consideration when cultivars of different color were planted in the same field. Single dusting proved to be better in cultivars with loose, average and dense berry cluster compactness, whereas double spraying gave better results in compact cultivars.
A new carbamate, RE-11775 (m-sec-butylphenyl N-methyl-N-(phenylthio) carbamate), has been found which has unusually high toxicity to mosquito larvae. Laboratory and field evaluations demonstrate that it has the potential of being used operationally for control of the larval and adult stages of susceptible and organophosphorus-resistant strains of Aedes nigromaculis (Ludlow). Preliminary studies indicate that RE-11775 also has the potential for controlling susceptible and organophosphorus-resistant strains of Culex spccies. This new carbamate is relatively safe and no adverse properties became apparent during the present tests.
In this study we evaluated the effects of the biorational pesticide, Spinosad (GF-120 formulation), on foraging behavior in the stingless bee Plebeia moureana (Ayala). Several foragers were individually trained to collect an unscented 1.0 M sucrose solution (31% sucrose wt:wt) from a blue plate in one arm of a Y-tube maze. The other arm offered plain water on a yellow plate. After 20-30 visits to the setup, the sucrose solution was exchanged for a sucrose solution mixed with one of five concentrations of GF-120 and 30 consecutive choices of each bee were recorded. Interestingly, the foragers collected the sucrose solution with GF-120 at all concentrations. Our results show that: 1) the GF-120 formulation, when applied at the recommended concentration and mixed with food, does not discourage engaged foragers and, 2) foraging behavior over time is not significantly impaired by the continuous collection of GF-120.
Effectiveness of GF-120 (Dow Chemical) Fruit Fly Bait containing the insecticide spinosad in controlling mango-infesting fruit flies (Diptera: Tephritidae) was assessed by comparing treated orchards with untreated orchards. Twelve mango, Mangifera indica L., plantations located in six villages (two similar orchards per village: one orchard treated and orchard untreated) scattered in the Borgou department (northern Benin) were monitored weekly with fly traps, and the fruit was sampled twice for larval infestation at the beginning and in the middle of May in both 2006 and 2007. The two main mango fruit fly pests are Ceratitis cosyra (Walker) and Bactrocera invadens Drew, Tsuruta & White, an invasive species that recently spread throughout West Africa. In both the 2006 and 2007 seasons, C. cosyra had the earliest peak of abundance, and the difference between treated and untreated orchards, in terms of mean number of flies trapped per week and per trap, was significant only in 2007. B. invadens populations quickly increased with the onset of the rains, from mid-May onward, with no significant difference between treated and untreated orchards. In 2006 and 2007, the larval infestation by B. invadens was significantly lower in plots treated with GF-120 than in untreated control plots. GF-120 provided an 81% reduction in the number of pupae per kilogram of fruit after weekly applications for 7 wk in 2006 and an 89% reduction after 10 wk of weekly applications in 2007. The possibility of integrating GF120 bait sprays in an integrated pest management package is discussed in relation to market requirements.
The objective of this study was to determine the relationship between residual time of GF-120 (spinosad) treatment and mortality in three species of Anastrepha Schiner. Concentrations of 96, 72, 48, and 24 ppm were aged on mango leaves under field conditions for 0, 3, 7, 10, 14, 17, and 21 d after application. We found that Anastrepha ludens, A. obliqua, and A. serpentina were highly sensitive to spinosad. The effects of spinosad were not reduced over the 4 d after the initial application, even at a concentration of 24 ppm. Mortality at 14 d after the application of 72 and 96 ppm of spinosad was similar in each of the three fruit fly species. In addition, we found that 24 ppm of spinosad was consumed the most by each species even though no direct relationship between the rate of consumption per female and the dose of the product was observed, in this test, higher consumption of active ingredient was observed at a concentration of 72 ppm, for A. ludens, 48 ppm for A. obliqua, and 96 ppm for A. serpentina. Our results suggest that a spinosad concentration of 72 ppm may effectively control these pests for at least 10 d under field conditions.
Effects of different concentrations of GF-120 NF Naturalyte Fruit Fly Bait on attraction and feeding responses, mortality, and control of the western cherry fruit fly, Rhagoletis indifferens Curran, were determined. In the laboratory, flies that had been exposed to sugar and yeast extract and then deprived of all food for 16-20 h were attracted to 40.0% GF-120, but not to 0.6 and 4.8% GF-120 (vol:vol). Nonstarved flies were not attracted to any concentration. Flies in the field were not attracted to 55.6% GF-120 on cherry leaves, and few flies fed on the bait. In the laboratory, males fed for shorter durations on and ingested lower amounts of 0.6% than 4.8 or 40.0% GF-120, but females fed equally on all concentrations. Spinosad in GF-120 was highly toxic to flies. Lethal concentrations50 (LC50 values) of spinosad for starved flies at 1-4 d were 1.5-0.7 ppm. When gravid flies were exposed to cherries treated with 0.6, 4.8, and 40.0% GF-120, mortality was greater at each higher concentration, but none prevented oviposition. Field spray tests comparing 0.6, 4.8, and 40.0% GF-120 in 225 ml of spray per cherry tree resulted in 79-94% lower larval infestations than in controls, but no differences were seen among the concentrations. Evidence from this study indicates that fresh 40.0% GF-120 was attractive in the laboratory but that flies were not attracted to fresh GF-120 from far distances within trees, suggesting that suppression of populations is caused in large part by flies finding the bait through normal movement over large areas.
A fruit fly bait to attract and kill adult fruit flies, GF-120, was tested in cages to determine effects of pretreatment diet and bait aging before use on cumulative mortality rates of Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae). Protein-starved and protein-fed, 9-d-old flies both experienced varying overall cumulative mortality at 4, 8, 24, and 48 h. Pretreatment diet had no significant effect on mortality. Overall mortality rates were below 10% for 4 h, 39-43% at 8 h, but mortality in all treatments increased to 89-93% by 24 h, and 99% by 48 h. In a second experiment, GF-120 baits were either freshly prepared or aged for 24 h. Subtreatments consisted of protein-fed and protein-starved flies. The 24-h-aged bait killed significantly more flies at 4 and 8 h than the freshly prepared bait. Protein-starved flies had significantly higher mortality at 4 h and marginally higher mortality at 8 h than protein-fed flies. At 24 and 48 h, there were no significant differences among treatments, and overall morality rose to 99-100% by 48 h. These results may explain differences noted in previous publications in which fruit fly mortality to GF-120 was reported as unusually low as well as reports of bait ineffectiveness for protein-fed flies. The overall impact of any initial repellency of GF-120 seems negligible as judged by overall cumulative mortality at later evaluation times.
GF-120 is a baited formulation of the insecticide spinosad containing 1% ammonium acetate, developed for control of economically important fruit flies. The response of feral cherry fruit flies, Rhagoletis cingulata Loew, to GF-120 augmented with 0, 5, or 10% ammonium acetate was evaluated under orchard conditions. Significantly more flies were observed within 30 cm of bait droplets with 10% ammonium acetate added compared with standard bait or to a water control. These fly visits to GF-120 enhanced with 10 or 5% ammonium acetate lasted an average of 263.2 +/- 85.2 and 337.6 +/- 72.6 s, respectively, compared with 50.3 +/- 36.4 s for standard GF-120. Droplets containing additional ammonium acetate also were contacted by more flies, and more flies fed upon these droplets than on GF-120 or the water control. Furthermore, the duration of feeding on GF-120 bait enhanced with either level of additional ammonium acetate was significantly greater compared with standard GF-120 or water. Feeding events lasted between 61.5 +/- 30.7 and 73.4 +/- 21.0 s on enhanced GF-120 compared with 6.8 +/- 5.7 s on standard GF-120. Collectively, these results indicate that the interaction of feral R. cingulata with GF-120 droplets and the toxicant spinosad can be increased by addition of ammonium acetate.
In a field study in Hawaii, color-marked protein-deprived and protein-fed female melon flies, Bactrocera cucurbitae Coquillett, were released within canopies of unsprayed sorghum plants (a nonhost of melon flies) outside of a border area of unsprayed or bait-sprayed sorghum plants or open space that surrounded cucumbers, a favored host of melon flies. Application of bait spray to sorghum or sugarcane surrounding host plants of melon flies is a common practice for melon fly control in Hawaii. GF-120 Fruit Fly Bait spray proved very effective in preventing protein-deprived females from alighting on cucumbers (23% of released females were observed dead on bait-sprayed sorghum; 0% were observed alive on cucumbers), but proved less effective in suppressing protein-fed females (14% of released females were observed dead on bait-sprayed sorghum; 11% were observed alive on cucumbers). No females were found dead on unsprayed sorghum. Compared with open space surrounding cucumbers, the presence of unsprayed sorghum as surrounding border area neither significantly enhanced nor significantly inhibited the ability of either type of female with respect to finding cucumbers. Greenhouse cage assays revealed that compared with droplets of water, droplets of GF-120 Fruit Fly Bait spray were highly attractive to protein-deprived females within 1 h of bait spray application to sorghum, but lost about half of their attractiveness within 5 h and all of it within 24 h under the dry greenhouse conditions used for maintaining baited-sprayed sorghum plants in these assays. Laboratory cup assays showed that bait spray droplets remained highly toxic to protein-deprived females 24 h after application, but lost nearly half of their toxicity within 4 d under laboratory exposure and nearly all of it after approximately 8 mm of rainfall. Combined findings suggest that application of GF-120 Fruit Fly Bait spray to nonhost plants for melon fly control either be made often enough to overcome loss of attractiveness of bait spray droplets to females or that bait spray be applied to nonhost plants that are themselves attractive to the females.
Bait sprays containing the toxicant spinosad (GF-120) were applied to citrus groves in the Rio Grande Valley of Texas where Mexican fruit flies were detected in surveillance traps. The sprays were applied as a supplement to a continuous sterile insect release program. Sterile fly captures were 47-63% lower in the treated groves compared with control groves. Eight of 10 secondary pest populations declined in the test groves subsequent to spray applications, but they also declined in the control groves, suggesting that the decline was a seasonal phenomenon rather than a result of the bait sprays. Citrus whitefly, Dialeurodes citri (Ashmead), populations increased modestly and citrus blackfly, Aleurocanthus woglumi (Ashby), populations remained unchanged compared with pretreatment levels. Thus, no outbreaks of secondary pests occurred as a result of the spinosad bait sprays in this instance, as has been reported for malathion bait sprays in citrus. The bait sprays had no detectable effect on populations of specific indicator species of parasitoids (including Aphytis spp. and Comperiella bifasciata Howard), or on numbers of beneficial insects in general, in the treated groves.
The metabolic fate of ¹⁴C-labe1ed GS-13005 (S- ((2- methoxy-5-oxo-Δ²-1,3,4-thiadiazolin-4-yl) methyl) O,O-dimethyl phosphorodithioate), the active ingredient of the insecticide Supracide® was followed in plants, soil, and animals. A rapid degradation of this insecticide in all investigated was observed. In addition to the hydrolysis of the ester bond, the heterocyclic moiety of GS-13005 was cleaved, and the fragments originating were oxidized to CO2 which represented the main metabolite. The pattern of metabolites in bean and alfalfa plants consisted of almost exclusively polar substances, approximately ⅓ of which liberated GS-12956 (2-methoxy-Δ²-1,3,4-thiadiazolin-5-one) after hydrolysis. Only trace amounts of the corresponding P-O derivative, GS-13007 (O-[(2-methoxy-5-oxo-Δ²-1,3,4-thiadiazolin-4-yl)-methyl] O,O-dimethyl phosphorothioate, and of G5-12956 were detected.
The pronounced degradation of GS-13005 in 2 types of soil was suppressed after steam sterilization emphasizing the role of the soil microorganisms.
Locusts metabolized the thiadiazole ring of GS-13005 resulting in the liberation of ¹⁴CO2 and an increasing amount of water-soluble metabolites.
Urine and expired air were the main routes for the excretion of metabolites of GS-13005 orally applied to rats. ro accumulation of GS-13005 or its metabolites was observed in any organ of the rat after feeding the insecticide for 10 days. In addition to ¹⁴CO2, the sulfoxide derivative, GS-28370 (2-methoxy-4-methylsulfinylmcthylorganisms Δ²-1,3,4-thiadiazolin-5-one), and the sulfone derivative, GS-28369 (2-methoxy-4-methylsulfonylmethyl-Δ²-1,3,4-thiadiazolin-5-one), were determined as the main metabolites of the urine. These metabolites are not cholinesterase esterase inhibitors and have acute toxicities in the range of only 1/15-1/50 of the parent insecticide. The metabolic fate of these metabolites and of GS-12956 was followed to determine the sequence of the metabolic reactions taking place in the course of the degradation of GS-13005 in the rat.
The mechanism of the degradation of GS-13005 in the rat was investigated in vitro systems demonstrating methionine as the methyl donor for the synthesis of the main metabolites.
Absence of GS-13005 and its oxidation product, GS-13007, in the milk of a goat was demonstrated. Only 0.6% of the dose orally applied was found in the form of polar metabolites.
CME 134, 1-(3,5-dichloro-2,4-difluorophenyl)3-(2,6-diHuorobenzoyl) urea, is very active against immature mosquitoes. The operational use rate appeared to be 0.0056 kg (AI)/ha (0.005lb/acre). When applied at the latter rate, the compound is safe to nontarget, aquatic organisms. CME 134 is stable in water under acidic conditions and less stable when temperature and pH increase simultaneously; sunlight has little effect on its aqueous stability. CME 134 might adsorb onto organic matter, thus affecting residual activity in field water. In highly polluted water, the chemical appeared to be lost because of microbial action as well as adsorption onto organic matter. In animal waste lagoons, biological activity persisted for several weeks during the fall and winter but only for a few days during early summer. Persistence in pasture water is limited to a few days when applied at levels up to 0.027 kg (AI)/ha (0.03 Ib/acre).
The feasibility of radiolabeling larval American dog ticks, Dermacentor variabilis (Say) with strontium-90 (Sr90) is demonstrated. The radioisotope was administered in inorganic form by inoculation of procreant females. Transov- arial transfer to larval progeny resulted in sufficient radioactivity to permit easy detection of labeling in individual larvae, Double labeling of D. uariabilis with both carbon-14 (C14Sr90 was done by inoculations of mix- tures of C14 glucose and inorganic Sr90 into the engorged parents, Detection of these double-labeled ticks and discrimination of such individuals from either C-14 or Sr90 labeled ticks was done with the aid of a 2-channel liquid scintillation detector. The advantages of increasing the variety of radioisotope labels available for radioecological research with ticks are discussed.
[14C]Noviflumuron uptake, clearance, rate of excretion, and transfer from treated to untreated termite workers were evaluated at 15,19, 23, and 27 degrees C. Feeding units were constructed from plastic containers provisioned with washed sand, distilled water, [14C]noviflumuron-treated feeding discs (0.05 or 0.5% [AI]), and Reticulitermes flavipes (Kollar) workers. Feeding units were held in environmental growth chambers preset at 15, 19, 23, and 27 degrees C. The amount of [14C]noviflumuron present within R. flavipes was measured by scintillation counting and subsequently quantified. Uptake of noviflumuron by R. flavipes workers at 15 degrees C was approximately 2.8 times less than at 19 or 23 degrees C and approximately 4.4 times less than at 27 degrees ighest uptake of [14C]noviflumuron occurred at 27 degrees C and 144 h. Most transfer of [14C]noviflumuron from treated to untreated termite workers occurred between 19 and 27 degrees C. [14C]Noviflumuron had a half-life in R. flavipes workers of approximately 31-45 d, dependent on temperature. A higher amount of [14C]noviflumuron was lost through excretion at > or = 19 degrees C (approximately 15-22%) compared with 15 degrees C (0.27%). Results indicated that increased uptake, transfer, and clearance of noviflumuron by R. flavipes occurred at warmer temperatures (19-27 degrees C), and all of these processes were significantly lower at 15 degrees C.
The potato leafhopper, Empoasca fabae (Harris), is a key pest of alfalfa, Medicago sativa L., in part because of the leafhopper's ability to disrupt upward translocation within phloem tissues. To determine if leafhopper injury also disrupts basal translocation necessary for regrowth and perenniality of alfalfa, we used radiolabeled 14CO2 to measure the basal transport of photoassimilates in injured and healthy plants. In one experiment, less 14C was transported to lower stem tissue of leafhopper-injured plants in comparison to the same tissue of healthy plants in early vegetative and early reproductive stages of alfalfa development. In a second experiment, less 14C was transported to lower stem, crown, and root tissues of injured plants in comparison to the same tissues of healthy, early reproductive plants. The disruption of basal transport caused by potato leafhopper may impact carbon storage and mobilization subsequent to defoliation, winter survival, and nitrogen fixation.
Comparisons of formulations of Bacillus thuringiensis (H-14) de Barjac and different application times were conducted in small streams against Simulium vittatum Zetterstedt in northeast Tennessee. Teknar liquid (wdc), Vectobac (WP), and Bactimos (WP) produced average mortalities of 85, 80, and 61%, respectively, at 10 mg/liter per 1 min (= 10 ppm) 10 to 400 m below the point of application. The efficacy of the 1-min application time of Teknar at 10 mg/liter was significantly higher in terms of mortality and effective carry than the 20-min application at 0.5 mg/liter. Doubling and trebling the concentration of Vectobac WP and Bactimos WP, respectively, increased mortality and carryover that of the rate of 10 mg/liter per min, but was not proportionate to increase in dosage.
The effect of temperature on [14C]fipronil uptake and transfer from donor (D) to recipient (R) Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) workers was evaluated. Test chambers used in the fipronil uptake study were constructed from petri dishes containing autoclaved soil treated with 1 ppm [14C]fipronil (1.14 microCi of total radioactivity per petri dish), distilled water, and R. flavipes workers. Test chambers were held in environmental growth chambers preset at 12, 17, 22, 27, and 32 degrees C. For the fipronil transfer study, donor termites stained with Nile blue-A were exposed to soil treated with 1 ppm [14C]fipronil for 2 h. Donors were then combined with unexposed recipient termite workers at either 1D:5R, 1D:10R, or 1D:20R ratios. Test chambers consisted of a nest and feeding chamber connected by a piece of polyethylene tube and held in growth chambers at 12, 17, 22, 27, and 32 degrees C. Worker termites were sampled over time and the amount of [14C]fipronil present was measured by scintillation counting. Some degree of uptake and transfer occurred at all temperatures and ratios in this study. The highest level of uptake occurred by termites held at 22-32 degrees C, followed decreasingly by 17 and 12 degrees C. Maximum transfer of [14C]fipronil occurred at the higher ratios (1:5 > 1:10 > 1:20) of donors to recipients. Data presented in this study suggest that temperature is one of the key factors affecting the rate of uptake and subsequent horizontal transfer of [14C]fipronil in subterranean termites.
Data from field collections of third- and fourth-stage larvae of Culex tarsalis Coquillett and pupae were used to calculate expected frequencies based on the negative binomial distribution. The data fit the negative binomial with a dispersion constant (kc) of 0.0525. The decision limits for a sequential sampling plan were then calculated. Aerial applications of Bacillus thuringiensis Berliner serotype H-14 toxin controlled C. tarsalis larvae without producing any detrimental effects to predators. The best control was obtained on a field treated with B. thuringiensis H-14 toxin and stocked with mosquito fish.
The Formosan subterranean termite, Coptotermes formosanus Shiraki, is an invasive species in many parts of the world, including the U.S. mainland. The reasons for its invasive success may have to do with the flexible social and spatial organization of colonies. We investigated the population and breeding structure of 14 C. formosanus colonies in Louis Armstrong Park, New Orleans, LA. This population has been the focus of extensive study for many years, providing the opportunity to relate aspects of colony breeding structure to previous findings on colony characteristics such as body weight and number of workers, wood consumption, and intercolony aggression. Eight colonies were headed by a single pair of outbred reproductives (simple families), whereas six colonies were headed by low numbers of multiple kings and/or queens that were likely the neotenic descendants of the original colony (extended families). Within the foraging area of one large extended family colony, we found genetic differentiation among different collection sites, suggesting the presence of separate reproductive centers. No significant difference between simple family colonies and extended family colonies was found in worker body weight, soldier body weight, foraging area, population size, or wood consumption. However, level of inbreeding within colonies was negatively correlated with worker body weight and positively correlated with wood consumption. Also, genetic distance between colonies was positively correlated with aggression levels, suggesting a genetic basis to nestmate discrimination cues in this termite population. No obvious trait associated with colony reproductive structure was found that could account for the invasion success of this species.
Spinosad was proposed as a potential chemical for control of lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), in Australian broiler houses after the detection of strong cyfluthrin resistance in many beetle populations. In 2004-2006, spinosad susceptibility of 13 beetle populations from eastern and southern Australian broiler houses and a cyfluthrin/fenitrothion-resistant reference population was determined using topical application, and was compared with the susceptibility of an insecticide-susceptible reference population. Comparisons of dose-response curves and baseline data showed that all populations, including the insecticide-susceptible population, were roughly equivalent in their response to spinosad, indicating no preexisting spinosad resistance. Two field populations, including the resistant reference population, which had confirmed cyfluthrin/fenitrothion-resistance, showed no cross-resistance to spinosad. There was no significant correlation between beetle weight and LC9.9. A discriminating concentration of 3% spinosad was set to separate resistant and susceptible individuals. Considering the levels of spinosad resistance that have been recorded in other insect pests, the sustained future usefulness of spinosad as a broiler house treatment will rely on effective integrated beetle management programs combined with carefully planned chemical use strategies.
The new Dursban® insecticide is effective in controlling mosquitoes. The active ingredient of this insecticide is O, O -diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate. In spraying Dursban to control mosquitoes, the chemical will come in contact with the fish, plants, and soil in the environment. In investigations with [14C] labeled insecticide, it was found that the Dursban is rapidly absorbed from the water by plants and soil particles, but very slowly metabolized. Fish absorb the compound at a much slower rate, but rapidly metabolize it. The detoxified products are then eliminated into the water. Under natural conditions the majority of the Dursban will be absorbed by the plants and soil particles thus limiting the amount which can be taken up by the fish.
Six different resistant and susceptible strains of M. domestica L. (Diptera: Muscidae), were reared aseptically on a synthetic diet containing cholesterol-4-14C as the only sterol source. The uptake of cholesterol was different for all the strains, but there was no correlation of cholesterol content between resistant and susceptible flies. The uptake of cholesterol by the females was higher than that for the males, indicating a greater requirement for the females because of oogenesis. Esterificntion of the 3-²-hydroxyl group accounted for an average of 28% with the free sterol fraction making up approximately 71% of the total sterols. Small amounts of radioactive polar compounds were recovered, indicating at least to a small extent, the metabolism or breakdown of cholesterol to other more polar derivatives. Analysis of the free and esterfied sterols by column chromatography, gas-liquid chromatography, and reverse isotope dilution demonstrated that unchanged cholesterol accounted for 96% of these fractions. Analysis by column chromatography and reverse isotope dilution showed that 0.9% behaved like 7-dehydrocholesterol.