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50 result(s) for "Ellsworth, Peter C."
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Spatial scale of non-target effects of cotton insecticides
Plot size is of practical importance in any integrated pest management (IPM) study that has a field component. Such studies need to be conducted at a scale relevant to species dynamics because their abundance and distribution in plots might vary according to plot size. An adequate plot size is especially important for researchers, technology providers and regulatory agencies in understanding effects of various insect control technologies on non-target arthropods. Plots that are too small might fail to detect potential harmful effects of these technologies due to arthropod movement and redistribution among plots, or from untreated areas and outside sources. The Arizona cotton system is heavily dependent on technologies for arthropod control, thus we conducted a 2-year replicated field experiment to estimate the optimal plot size for non-target arthropod studies in our system. Experimental treatments consisted of three square plot sizes and three insecticides in a full factorial. We established three plot sizes that measured 144 m 2 , 324 m 2 and 576 m 2 . For insecticide treatments, we established an untreated check, a positive control insecticide with known negative effects on the arthropod community and a selective insecticide. We investigated how plot size impacts the estimation of treatment effects relative to community structure (27 taxa), community diversity, individual abundance, effect sizes, biological control function of arthropod taxa with a wide range of mobility, including Collops spp., Orius tristicolor , Geocoris spp., Misumenops celer , Drapetis nr. divergens and Chrysoperla carnea s . l .. Square 144 m 2 plots supported similar results for all parameters compared with larger plots, and are thus sufficiently large to measure insecticidal effects on non-target arthropods in cotton. Our results are applicable to cotton systems with related pests, predators or other fauna with similar dispersal characteristics. Moreover, these results also might be generalizable to other crop systems with similar fauna.
Genetically Engineered Crops: Importance of Diversified Integrated Pest Management for Agricultural Sustainability
As the global population continues to expand, utilizing an integrated approach to pest management will be critically important for food security, agricultural sustainability, and environmental protection. Genetically engineered (GE) crops that provide protection against insects and diseases, or tolerance to herbicides are important tools that complement a diversified integrated pest management (IPM) plan. However, despite the advantages that GE crops may bring for simplifying the approach and improving efficiency of pest and weed control, there are also challenges for successful implementation and sustainable use. This paper considers how several GE traits, including those that confer protection against insects by expression of proteins from (Bt), traits that confer tolerance to herbicides, and RNAi-based traits that confer resistance to viral pathogens, can be key elements of a diversified IPM plan for several different crops in both developed and developing countries. Additionally, we highlight the importance of community engagement and extension, strong partnership between industry, regulators and farmers, and education and training programs, for achieving long-term success. By leveraging the experiences gained with these GE crops, understanding the limitations of the technology, and considering the successes and failures of GE traits in IPM plans for different crops and regions, we can improve the sustainability and versatility of IPM plans that incorporate these and future technologies.
Effects of Local and Landscape Factors on Population Dynamics of a Cotton Pest
Many polyphagous pests sequentially use crops and uncultivated habitats in landscapes dominated by annual crops. As these habitats may contribute in increasing or decreasing pest density in fields of a specific crop, understanding the scale and temporal variability of source and sink effects is critical for managing landscapes to enhance pest control. We evaluated how local and landscape characteristics affect population density of the western tarnished plant bug, Lygus hesperus (Knight), in cotton fields of the San Joaquin Valley in California. During two periods covering the main window of cotton vulnerability to Lygus attack over three years, we examined the associations between abundance of six common Lygus crops, uncultivated habitats and Lygus population density in these cotton fields. We also investigated impacts of insecticide applications in cotton fields and cotton flowering date. Consistent associations observed across periods and years involved abundances of cotton and uncultivated habitats that were negatively associated with Lygus density, and abundance of seed alfalfa and cotton flowering date that were positively associated with Lygus density. Safflower and forage alfalfa had variable effects, possibly reflecting among-year variation in crop management practices, and tomato, sugar beet and insecticide applications were rarely associated with Lygus density. Using data from the first two years, a multiple regression model including the four consistent factors successfully predicted Lygus density across cotton fields in the last year of the study. Our results show that the approach developed here is appropriate to characterize and test the source and sink effects of various habitats on pest dynamics and improve the design of landscape-level pest management strategies.
Large-scale, spatially-explicit test of the refuge strategy for delaying insecticide resistance
The refuge strategy is used worldwide to delay the evolution of pest resistance to insecticides that are either sprayed or produced by transgenic Bacillus thuringiensis (Bt) crops. This strategy is based on the idea that refuges of host plants where pests are not exposed to an insecticide promote survival of susceptible pests. Despite widespread adoption of this approach, large-scale tests of the refuge strategy have been problematic. Here we tested the refuge strategy with 8 y of data on refuges and resistance to the insecticide pyriproxyfen in 84 populations of the sweetpotato whitefly (Bemisia tabaci) from cotton fields in central Arizona. We found that spatial variation in resistance to pyriproxyfen within each year was not affected by refuges of melons or alfalfa near cotton fields. However, resistance was negatively associated with the area of cotton refuges and positively associated with the area of cotton treated with pyriproxyfen. A statistical model based on the first 4 y of data, incorporating the spatial distribution of cotton treated and not treated with pyriproxyfen, adequately predicted the spatial variation in resistance observed in the last 4 y of the study, confirming that cotton refuges delayed resistance and treated cotton fields accelerated resistance. By providing a systematic assessment of the effectiveness of refuges and the scale of their effects, the spatially explicit approach applied here could be useful for testing and improving the refuge strategy in other crop–pest systems.
Transgenic cotton and sterile insect releases synergize eradication of pink bollworm a century after it invaded the United States
Invasive organisms pose a global threat and are exceptionally difficult to eradicate after they become abundant in their new habitats. We report a successful multitactic strategy for combating the pink bollworm (Pectinophora gossypiella), one of the world’s most invasive pests. A coordinated program in the southwestern United States and northern Mexico included releases of billions of sterile pink bollworm moths from airplanes and planting of cotton engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). An analysis of computer simulations and 21 y of field data from Arizona demonstrate that the transgenic Bt cotton and sterile insect releases interacted synergistically to reduce the pest’s population size. In Arizona, the program started in 2006 and decreased the pest’s estimated statewide population size from over 2 billion in 2005 to zero in 2013. Complementary regional efforts eradicated this pest throughout the cotton-growing areas of the continental United States and northern Mexico a century after it had invaded both countries. The removal of this pest saved farmers in the United States $192 million from 2014 to 2019. It also eliminated the environmental and safety hazards associated with insecticide sprays that had previously targeted the pink bollworm and facilitated an 82% reduction in insecticides used against all cotton pests in Arizona. The economic and social benefits achieved demonstrate the advantages of using agricultural biotechnology in concert with classical pest control tactics.
Quantifying Conservation Biological Control for Management of Bemisia tabaci (Hemiptera: Aleyrodidae) in Cotton
Conservation biological control can be an effective tactic for minimizing insect-induced damage to agricultural production. In the Arizona cotton system, a suite of generalist arthropod predators provides critical regulation of Bemisia tabaci Gennadius (MEAM1) (Hemiptera: Aleyrodidae) and other pests. Arthropod predator and B. tabaci populations were manipulated with a range of broad-spectrum and selective insecticide exclusions to vary predator to prey interactions in a 2-yr field study. Predator to prey ratios associated with B. tabaci densities near the existing action threshold were estimated for six predator species found to be negatively associated with either adult and/ or large nymphs of B. tabaci [Misumenops celer (Hentz) (Araneae: Thomisidae), Drapetis nr divergens (Diptera: Empididae), Geocoris pallens Stäl (Hemiptera: Geocoridae), Orius tristicolor (White) (Hemiptera: Anthocoridae), Chrysoperla carnea s.l. (Neuroptera: Chrysopidae), and Collops spp. (Coleoptera: Melyridae)] with the first three most consistently associated with declining B. tabaci densities. Ratios ranged from 1 M. celer per 100 sweeps to 1 B. tabaci adult per leaf to 44 D. nr. divergens per 100 sweeps to 1 large nymph per leaf disk. These ratios represent biological control informed thresholds that might serve as simple-to-use decision tool for reducing risk in the current B. tabaci integrated pest management strategy. The identification of key predators within the large, flexible food web of the cotton agro-ecosystem and estimation of predator to B. tabaci ratios clarifies the role of key predators in B. tabaci suppression, yielding potential decision-making advantages that could contribute to further improving economic and environmental sustainability of insect management in the cotton system.
Screening of insecticides for management of the invasive Oxycarenus hyalinipennis Costa (Hemiptera: Oxycarenidae) population sourced from urban southern California
Cotton seed bug, Oxycarenus hyalinipennis (Hemiptera: Oxycarenidae), was discovered in southern California in 2019. Surveys have found it within 160 km of cotton producing areas. While often only a minor pest in its native range, there are justified concerns that O. hyalinipennis could become a major pest of US-grown cotton. To proactively prepare for this possibility, 12 US-registered formulations and 1 experimental formulation were assessed in the laboratory for efficacy against O. hyalinipennis, using both contact and ingestion bioassays. Six formulations, consisting of acephate, dinotefuran, flupyradifurone, and imidacloprid with initial efficacy against O. hyalinipennis were used for subsequent dose-response bioassays. These compounds had LC50 values well below maximum labeled rates, although LC99.9 values often exceeded maximum label rates. Results indicate that if O. hyalinipennis infests cotton production regions, both selective and broad-spectrum options will be available for management.These findings establish a baseline for developing an integrated pest management program that can reduce potential damage from O. hyalinipennis, preserve natural enemies, and contribute to resistance management in cotton production areas.
Suppressing resistance to Bt cotton with sterile insect releases
Adaptation of insect pests to tolerate Bacillus thuringiensis (Bt) insecticidal proteins threatens to reduce the efficacy of Bt crops. Evidence from an extensive four-year field trial indicates that the release of sterile pink bollworm moths suppresses the emergence of resistance to transgenic Bt cotton, while helping to eradicate the pest. Genetically engineered crops that produce insecticidal toxins from Bacillus thuringiensis ( Bt ) are grown widely for pest control 1 . However, insect adaptation can reduce the toxins' efficacy 2 , 3 , 4 , 5 . The predominant strategy for delaying pest resistance to Bt crops requires refuges of non- Bt host plants to provide susceptible insects to mate with resistant insects 2 , 3 , 4 , 5 , 6 , 7 . Variable farmer compliance is one of the limitations of this approach. Here we report the benefits of an alternative strategy where sterile insects are released to mate with resistant insects and refuges are scarce or absent. Computer simulations show that this approach works in principle against pests with recessive or dominant inheritance of resistance. During a large-scale, four-year field deployment of this strategy in Arizona, resistance of pink bollworm ( Pectinophora gossypiella ) to Bt cotton did not increase. A multitactic eradication program that included the release of sterile moths reduced pink bollworm abundance by >99%, while eliminating insecticide sprays against this key invasive pest.
Inferring Biological Control Potential of Adult Predatory Coccinellids Using Life History Traits and Putative Habitat Preference
Aspects of the nutritional ecology and life histories of five predatory coccinellids (Coleoptera: Coccinellidae)—two arboreal predator species, Oenopia conglobata contaminata (Menetries) and Adalia bipunctata (Linnaeus), and three herbaceous dwelling predator species, Coccinella undecimpunctata aegyptica (Reiche), Exochomus nigripennis (Erichson), and Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae)—were compared when fed either Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Aphalaridae), the key psylla pest of pistachio trees, or Aphis gossypii Glover (Hemiptera: Aphididae), a common aphid on herbaceous plants in pistachio orchards.The putative habitat preferences of four of the five coccinellids studied were consistent with their performance on the major herbivore present in those two habitats in terms of net reproductive rate. Oenopia conglobata contaminata and Ad. bipunctata showed higher net reproductive rates when fed on pistachio psylla prey, whereas C. undecimpunctata aegyptiaca and E. nigripennis had better reproductive output on aphid prey. Moreover, E. nigripennis was the most specialized of these generalist predators, eating more and reproducing better when fed aphids. Hippodamia variegata was relatively unaffected by the diet offered, suggesting greater ability to switch among herbivore prey and perhaps better potential as a biocontrol agent with abilities to exploit Ag. pistaciae without large life history tradeoffs.
Integrated pest management: state infrastructure status after 50 yr of Federal support (1973 to 2023)
Abstract Integrated pest management uses a variety of tools coupled with historical, current, and projected information for economical pest protection of crops and other resources while accounting for risk to humans and the environment. Following the 1972 US Federal IPM Policy, funding for integrated pest management programming has continued for 50+ yr. However, multifaceted changes during this time have significantly affected state-level integrated pest management infrastructure, prompting a comprehensive survey to assess conditions, limitations, and growth potential of US integrated pest management programs. A survey was sent to 50 US states and 3 territories with integrated pest management programs in November 2022. Questions assessed integrated pest management-related staffing, funding, challenges, and other subjects. Information on invasive and emerging pests and barriers to providing integrated pest management to underserved populations was also requested. Results indicated 1,000+ integrated pest management specialists exist across state integrated pest management programs. integrated pest management programs involve diverse networks and stakeholders including university-based, federally funded, and society-based entities. The survey identified a clear need for a robust integrated pest management programmatic network containing trained multidisciplinary integrated pest management specialists to address the challenges caused by a changing climate, invasive species, pest and pesticide resistance, regulatory changes, and technological advances. A strong and collaborative group of integrated pest management specialists must be maintained and strengthened to address pressing and pervasive threats to food security and human health and wellbeing caused by existing, new, and emerging pests. A unified vision and stable support are needed to enhance and empower multistate integrated pest management programs, creating a national system so all can access the information, services, and tools for protection of health, home, and livelihood.