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PubMed2003

Geographical variation and sexual dimorphism of phenoloxidase levels in Japanese beetles (Popillia japonica).

Phenoloxidase (PO) production can be used as an indicator of pathogen defence in insects. The geographical mosaic of coevolution implies that traits associated with pathogen defence will vary across a geographical range. Bateman's principle implies that the benefit of increased defence levels is greater for females than males. To test both of these hypotheses, we sampled four populations of Japanese beetles, Popillia japonica, across Vermont: two were from locations using biological pest control, and two locations did not use biocontrol. We quantified defence levels (PO) and parasite resistance in males and females from each population. Populations from areas with biocontrol exhibited greater PO production, females produced more PO, populations with higher levels of PO suffered less mortality from pathogen exposure, and PO levels positively correlate with increased mortality in the absence of parasitism. Results support the geographical mosaic of coevolution and the implications of Bateman's principle.

Analysis of Variance↗
PubMed2005

Synergistic interaction between Beauveria bassiana- and Bacillus thuringiensis tenebrionis-based biopesticides applied against field populations of Colorado potato beetle larvae.

Commercial biopesticides based on the fungal pathogen Beauveria bassiana strain GHA and the bacterial pathogen Bacillus thuringiensis tenebrionis were applied alone and in combination (tank mixed) against larval populations of the Colorado potato beetle, Leptinotarsa decemlineata, in small plots of potatoes over three field seasons. Interactions between the two products were evaluated in terms of pest-control efficacy. B. bassiana (formulated as Mycotrol) was applied at low and medium label rates of 1.25 and 2.5 x 10(13) conidia/ha, and B. thuringienis (formulated as Novodor) was applied at low and high label rates of 40.3 and 120.8 x 10(6) Leptinotarsa units/ha. Two weekly applications of the bacterial pesticide alone provided 50-85% control of beetle larvae within 14 days after the initial application, while applications of the mycopesticide alone produced no greater than 25% control. Maximum control, in nearly all tests, was produced by the combination of the two products. The combined treatments produced a statistically significant 6-35% greater reduction in larval populations than would have been predicted had the two biopesticides acted independently. This low-level synergistic interaction was observed during all field seasons and resulted from combinations at all rates, including, in one of two tests, the low rates of each product. These results indicate that B. thuringiensis and B. bassiana have strong potential for integrated biologically based management of Colorado potato beetle.

Animals↗
PubMed1987

The biotechnology of Bacillus thuringiensis.

One of the challenges in the application of biotechnology to pest control is the identification of agents found in nature which can be used effectively. Biotechnology offers the potential of developing pesticides based on such agents which will provide environmentally sound and economically feasible insect control alternatives. Such an agent, the insect pathogen Bacillus thuringiensis, is the subject of intense investigations in several laboratories. Insecticides which use the entomocidal properties of B. thuringiensis are currently produced and sold worldwide; new products are currently in the development stage. Herein, the biology and genetics of B. thuringiensis and the problems associated with current products are critically reviewed with respect to biotechnology. Moreover, the economic and regulatory implications of technologically advanced products are evaluated.

Amino Acid Sequence↗
PubMed1988

Loss of Crown Immunity in the NHS; the effect on hotel services.

A less than "holy" combination of the Environmental Officers of Health (EHO) and the pest control industry had for some time been conducting a campaign for the removal of Crown Immunity from hospitals. They had not been so vociferous in their campaign to remove the same privilege from prisons and the armed services. I find it difficult to believe this was out of conviction that other institutions were trouble free. For in 1985 of the 191 Institutional outbreaks only 37 (19%) were in hospitals. The outbreak of Salmonella food poisoning at the Stanley Royd hospital provided enough public pressure to be generated for crown immunity to be removed from NHS premises. It remained in prisons and the armed services.

Accident Prevention↗
PubMed2003

Biopesticides.

The term 'biopesticide' encompasses a broad array of microbial pesticides, biochemicals derived from micro-organisms and other natural sources, and processes involving the genetic incorporation of DNA into agricultural commodities that confer protection against pest damage (plant-incorporated protectants). Some microbial pesticides, such as Bacillus thuringiensis, have a long history of safe and effective use as a biological insecticide. More recent developments in microbial pest control include the utilisation of other bacterial and fungal species that may competitively inhibit the growth of pathogenic and toxigenic micro-organisms on important agricultural commodities. The use of microbes and their gene products introduces additional considerations to the toxicological dose-response relationship, including a need to determine the plausibility of infectious and immunological effects in association with human exposure to these biopesticides in food or the environment. Studies of substantial equivalence suggest that foods currently derived from plant-incorporated protectants are not likely to differ from conventional foods. However, there is general consensus that the scientific methods to assess risks from genetically modified foods and micro-organisms will continue to evolve in the future.

Agriculture↗
PubMed2002

Laboratory fecundity as predictor of field success in Trichogramma carverae (Hymenoptera: Trichogrammatidae).

Laboratory fecundity assessments are routinely used to determine the quality of commercially reared Trichogramma egg parasitoids before release for pest control, but there is little information on the relevance of this trait to the field success of Trichogramma. Herein, we characterize the parasitism success of strains of Trichogramma carverae Oatman & Pinto in the laboratory on a factitious (Sitotroga cerealella Olivier) and a natural (Epiphyas postvittana Walker) host. Differences in fecundity of the strains in the laboratory were consistent with a heritability of approximately 10%, allowing ranking of the strains from highest to lowest fecundity. The strains with particularly high and low fecundities were tested for successful parasitism in the field. Results of the field releases show that strain differences in laboratory fecundity did not influence field performance. The implications of this result for fecundity as a quality indicator for commercial stocks are discussed.

Animals↗
PubMed2002

Deteriorated housing contributes to high cockroach allergen levels in inner-city households.

The high prevalence of childhood asthma in low-income, inner-city populations is not fully understood but has been at least partly attributed to the disproportionate exposures associated with socioeconomic disadvantage. The contribution of indoor allergens to asthma is well documented, but links between socioeconomic disadvantage and indoor allergen levels are not clear. We investigated levels of cockroach allergens (Bla g 2) in a sample of 132 Dominican or African American low-income households with young children in northern Manhattan in New York City (40% were receiving public assistance) to determine whether the distribution of allergens is a function of housing deterioration. Deterioration was measured by the presence and number of physical housing problems (holes in the ceilings and walls, water damage, etc.). More than 50% of the sample had two or more types of housing dilapidation, and 67% of the sample reported cockroach sightings in their homes. Samples of dust were collected from kitchen and bedroom surfaces. We hypothesized that the greater the dilapidation, the higher the allergen levels, independent of income, sociocultural factors, and pest-control methods. In addition, we hypothesized that the homes of families characterized by frequent moves (23.5%) would have higher allergen levels than more stable families. Results showed significant positive associations between housing deterioration and allergen levels in kitchens, after adjusting for income and ethnicity, with independent effects of residential stability (p< 0.05). Bedroom allergen levels were associated with housing instability (p < 0.01) and ethnicity (p< 0.01). Findings demonstrated that indoor household allergen levels are related to degree of household disrepair, after adjusting for individual family attributes, suggesting that social-structural aspects of housing may be appropriate targets for public health interventions designed to reduce allergen exposure.

Adolescent↗
PubMedDate not supplied

Educational and informational strategies to reduce pesticide risks. Council on Scientific Affairs.

BACKGROUND: In 1993, the American Medical Association (AMA) requested its Council on Scientific Affairs to investigate issues and concerns related to (1) improving public notification of pesticide applications and (2) improving educational programs for commercial and farm pesticide applicators and increasing enforcement of licensing examination requirements. This report was presented at the 1994 Interim Meeting of the AMA House of Delegates as Report 4 of the Council on Scientific Affairs. METHODS: Information for the report was derived from published literature and from personal communications with state and federal regulatory officials, physicians, and representatives of pest control, lawn care, and farm organizations. Some information about state certification and training programs was obtained from telephone conversations with pesticide applicator training program coordinators from California, Florida, Illinois, Iowa, Michigan, Missouri, Nebraska, New Jersey, New York, Texas, Washington, and Wisconsin. These states were selected because they contain large agricultural or urban populations that are likely to require the services of trained professional pesticide applicators. RESULTS: Current surveillance systems are inadequate to characterize potential exposure problems related either to pesticide usage or to pesticide related illnesses. The effectiveness of applicator certification and training programs and public notification programs could not be determined because of a lack of federal and state survey data for making useful assessments. CONCLUSIONS: Considering current data gaps, it is prudent for homeowners, farmers, and workers to limit pesticide exposures to themselves and others.

Certification↗
PubMed2006

Residue formations of phosphorus hydride polymers and phosphorus oxyacids during phosphine gas fumigations of stored products.

With the extent of international usage and the critical role phosphine gas (PH3) plays in commercial pest control, identification of the residual components deposited during fumigation is mandatory. It has been postulated that these infrequent residues are primarily composed of phosphoric acid or reduced forms of phosphoric acid [hypophosphorous acid (H3PO2) and phosphorous acid (H3PO3)], due to the oxidative degradation of phosphine. Using environmental scanning electron microscopy, gas phase Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy, the structural elucidation and formation mechanism of the yellow amorphous polyhydric phosphorus polymers (P(x)H(y)) that occur in addition to the lower oxyacids of phosphorus in residues deposited during PH3 fumigations of select tobacco commodities are explored. This research determined that nitric oxide gas (or nitrogen dioxide) initiates residue formation of phosphorus hydride polymers and phosphorus oxyacids during PH3 fumigations of stored products.

Drug Residues↗
PubMed2005

The toxicity and behavioural effects of neem limonoids on Cnaphalocrocis medinalis (Guenée), the rice leaffolder.

Meliaceae plant products have been shown to exert pesticidal properties against a variety of insect species. In agricultural pest control programs, such products may have the potential to be used successfully as botanical insecticides. The effect of the neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione and deacetylnimbin on the biology and mortality of rice leaffolder larvae was investigated. In laboratory experiments, treatment with neem limonoids suppressed leaf folding behaviour of C. medinalis. Biological parameters (larval duration, pupal duration adult longevity and fecundity) were also affected by the treatment. Azadirachtin, salannin, and deacetylgedunin showed high bioactivity at all doses, while the rest of the neem limonoids were less active, and were only biologically active at high doses. Azadirachtin was most potent in all experiments and produced almost 100% larval mortality at 1 ppm concentration. These results indicate neem limonoids affect the larval behaviour. These effects are most pronounced in early instars.

Animals↗
PubMed2006

Rodenticide grain bait ingredient acceptance by Norway rats (Rattus norvegicus), California ground squirrels (Spermophilus beecheyi) and pocket gophers (Thomomys bottae).

Vertebrate pest control in California is often accomplished through the use of rodenticide grain baits. These grain baits are composed of steam-rolled oats (SRO), a toxicant, an indicator dye and an oil combination. A series of tests were performed to determine the effects of various dye and oil formulations on acceptance of grain bait by Norway rats [Rattus norvegicus (Berk)], California ground squirrels [Spermophilus beecheyi (Richardson)] and pocket gophers (Thomomys bottae Eyd & Gerv). Seven different dyes, four oil formulations and clean (untreated) oats were tested for acceptance. The addition of the selected oils and dyes to grain resulted in no significant differences in consumption. This indicates that there is a wide variety of dyes that could be used in the formulation of rodenticides. These alternatives could aid in proper pesticide use, the deterrence of bait consumption by birds and possibly in ingredient adhesion to the finished bait.

Animals↗
PubMed1990

Synthesis of antifeedants for insects: novel behaviour-modifying chemicals from plants.

The need to protect our food supply from predatory insect attack using more ecologically acceptable methods has led to a rapidly growing interest in behavior-modifying chemicals from natural sources. Compounds which deter insects from feeding (antifeedants) are attracting special attention owing to their potential use in integrated pest control management systems. We have been studying the synthesis of plant-derived compounds that display antifeedant properties. The aim of the work is to understand more precisely the feeding mechanisms of insects at a molecular level so as ultimately to be able to design simpler compounds capable of mimicking the activity of the natural products. Our synthetic studies on the sesquiterpenoid antifeedants, polygodial and warburganal, and on the diterpenoid clerodane, ajurgarin I, have shown the promise of this approach. Current effort is directed towards structure-activity studies and synthesis of the extraordinarily potent antifeedant and growth-disrupting agent azadirachtin, isolated from the Neem tree, Azadirachta indica (A. Juss). This work has led to the correct structure assignment for azadirachtin and afforded many compounds for biological evaluation. It is of special significance that incorporation of the hydroxydihydrofuran portion of azadirachtin in a simple model system formed a compound with antifeedant activity comparable to that of the natural product.

Animals↗
PubMed2005

Life without methyl bromide: the Italian experience in replacing the fumigant.

Methyl bromide (MB) has been the most widely used chemical for the fumigation of soil, commodities, buildings and furniture for over seventy years. Since January 1st 2005, it has been phased-out in industrialized countries, where only critical uses are allowed, because of international regulatory measures designed to reduce substances that potentially deplete the stratospheric ozone layer. Italy ranked second in the world, after USA, in MB consumption, due to the importance of horticultural crop production. In order to replace the use of MB, research in Italy was aimed at: a) reducing the use of MB and its emission (short-term goal); b) developing alternative pest control methods, based on available technologies (mid-term goal); c) developing new MB alternatives (mid- and long-term goal). Italian growers switched to other fumigants, applied at reduced dosages, lowering their environmental impact and risk of worker exposure. Moreover, the adoption of non-chemical alternatives slowly but steadily increased as a result of the many activities (demonstration trials, seminars, etc.) carried out in the country. The gradual shift to MB alternatives over a 10 year period, as well as the use of half rates of MB under virtually impermeable plastic films (VIFs), has generally prevented the feared loss of competitiveness of Italian horticulture. Extension in cooperation with the fumigation companies was able to provide growers with a range of methods for soil disinfestation. The experience gained in Italy and how it can help developing countries to define strategies and training programmes needed to comply with the Montreal Protocol is discussed.

Crops, Agricultural↗
PubMed1997

CytA enables CryIV endotoxins of Bacillus thuringiensis to overcome high levels of CryIV resistance in the mosquito, Culex quinquefasciatus.

Cry proteins produced by Bacillus thuringiensis are selective biodegradable insecticides used increasingly in bacterial insecticides and transgenic plants as alternatives to synthetic chemical insecticides. However, the potential for development of resistance and cross-resistance in target insect populations to Cry proteins used alone or in combination threatens the more widespread use of this novel pest control technology. Here we show that high levels of resistance to CryIV proteins in larvae of the mosquito, Culex quinquefasciatus, can be suppressed or reduced markedly by combining these proteins with sublethal quantities of CytA, a cytolytic endotoxin of B. thuringiensis. Resistance at the LC95 level of 127-fold for a combination of three CryIV toxins (CryIVA, B, and D), resulting from 60 generations of continuous selection, was completely suppressed by combining sporulated powders of CytA in a 1:3 ratio with sporulated powders of a CryIVA, CryIVB, and CryIVD strain. Combining the CytA strain with a CryIVA and CryIVB strain also completely suppressed mosquito resistance of 217-fold to the latter toxins at the LC95 level, whereas combination of CytA with CryIVD reduced resistance in a CryIVD-selected mosquito strain from greater than 1,000-fold to less than 8-fold. The CytA/CryIV model provides a potential molecular genetic strategy for engineering resistance management for Cry proteins directly into bacterial insecticides and transgenic plants.

Animals↗
PubMed2004

Accurate determination of oosporein in fungal culture broth by differential pulse polarography.

A simple and accurate differential pulse polarographic method has been developed for the determination of oosporein in the culture broth of the fungus Beauveria brongniartii. This hydroxybenzoquinone derivative is the only major secondary metabolite secreted by this entomopathogenic fungus, which is used as biological pest control agent (BCA) against Melolontha melolontha larvae. It can be found in the host organism as well as in the formulated product. The polarographic behavior of oosporein was examined in various buffer systems over the pH range 3-10. In Britton-Robinson buffer/methanol solution (3:7 v/v, pH 5.5) the differential pulse polarograms exhibited reproducible peaks at E(p) = -0.18 V vs silver/silver chloride/potassium chloride (3 M). Under these conditions, a plot of peak height vs concentration of oosporein was found to be linear over the range 5.9 x 10(-)(7) to 2.5 x 10(-)(5) M (0.18-7.74 microg mL(-)(1); r = 0.9998). The detection limit was calculated to be 54 ng mL(-)(1). To evaluate the concentration of oosporein, the standard addition method was applied. The analysis of oosporein in the culture broth led to a mean value of 524.9 microg mL(-)(1) broth with a relative standard deviation (S(rel)) of +/-2.6%. The proposed polarographic method is accurate, not time-consuming, and it is of low cost because no separation steps are necessary.

Ascomycota↗
PubMed2026

Aphid symbiotic virus engineered for in vivo expression of insecticidal effectors.

Microbial pesticides are eco-friendly alternatives to chemical pesticides. However, few viral pesticides have been developed. Insects harbor diverse symbiotic viruses, which have the potential to be engineered for translational applications in pest control. Here, we engineered Acyrthosiphon pisum virus (APV), a symbiotic virus of the pea aphid, to deliver anti-aphid effectors using reverse genetics technology. A cytomegalovirus (CMV) promoter-driven APV infectious clone was successfully rescued in pea aphids with the assistance of nanocarrier star polymer (SPc). Based on this infectious clone, the protein coding sequence of chymotrypsin inhibitor variant 8 (Chy8) and the double-stranded RNA sequence targeting the aphid clip-domain serine protease (SPLP) were separately assembled into the APV genome to generate APV-Chy8 and APV-dsSPLP infectious clones, respectively. The recombinant APV clones reduced aphid relative survival rates by 34% and 17% by microinjection, respectively. To enhance the transcriptional efficiency, the APV-Chy8 and APV-dsSPLP clones were transcribed in vitro using the T7 promoter. The in vitro-synthesized APV-Chy8 and APV-dsSPLP clones reduced aphid relative survival rates by 48% and 45% by microinjection, respectively. These results demonstrate that engineered APV can deliver cargos and reduce aphid survival under injection-based experimental conditions, highlighting the potential of symbiotic virus-based vectors for delivering insecticidal effectors.

Animals↗
PubMed2005

Microbial synthesis of chitinase in solid cultures and its potential as a biocontrol agent against phytopathogenic fungus Colletotrichum gloeosporioides.

Antifungal activity of chitinase can be effectively utilized in biologic pest control strategies. Because solid-state cultivation has been termed a cost-effective means for fungal growth and metabolite production, chitinase production by Trichoderma harzianum was studied using wheat bran-based solid medium containing 1% colloidal chitin. Chitinase synthesis was found to be growth associated because maximum enzyme (5.4 U/g of dry substrate) and biomass production occurred at 72 h. Substrate moisture had a critical impact on chitinase production; five grams of medium having an initial moisture content of 68.4% when incubated for 72 h increased the enzyme yield to 9.3 U/g of dry substrate. Optimization of colloidal chitin concentration showed that improvements in chitinase yield and maximum activity were attained with a 2% (w/w) concentration. Supplementation of additional nitrogen sources also influenced enzyme production, and the best yield was obtained with yeast extract. The effect of crude chitinase on hyphal morphology of the phytopathogenic fungus Colletotrichum gloeosporioides was swelling as well as lysis of hyphal wall, depending on the age of the mycelium. Studies of pH and thermal stability showed that crude culture filtrate was active over pH 4.0-6.0 and retained about 48.2% activity after 40 min of incubation at 40 degrees C.

Biomass↗
PubMedDate not supplied

Effect of combined application of methyl isothiocyanate and chloropicrin on their transformation.

Combining several soil fumigants to increase the broad spectrum of pest control is a common fumigation practice in current production agriculture. In this study, we investigated the effect of combined application of chloropicrin and methyl isothiocyanate (MITC) on their transformations and persistence in the environment. In aqueous solution, no direct reaction between MITC and chloropicrin occurred and relatively slow rates of hydrolysis of these compounds were observed in aquatic environments free of suspended solids. The transformation of chloropicrin, however, was accelerated in aqueous solution with MITC because of a reduction reaction with bisulfide (HS(-)), which is a by-product of MITC hydrolysis. In soil, when fumigants were applied simultaneously, the degradation of MITC was suppressed under the bi-fumigant application due to the inhibition of soil microbial activity and a possible abiotic competition with chloropicrin for a limited number of reaction sites on the surface of soil particles. However, the degradation rate of chloropicrin was significantly enhanced in the bi-fumigant soil system, which was primarily attributed to the reaction of chloropicrin and HS(-). Two sequential application approaches were developed to investigate the feasibility of the combined application of metam sodium (parent compound of MITC) and chloropicrin in soil and assess their potential effects on environmental fate. For both application sequences, the degradation of chloropicrin was accelerated and that of MITC, as a major breakdown product of metam sodium, was inhibited in soil.

Chemical Warfare Agents↗