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4 Technological and Biological Changes and the Future of Pest Management
Pages 144-209

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From page 144...
... We also examine how human activities have effected changes in the ecological milieu within which pest-crop interactions take place and the selection regime under which pests evolve, and we relate the changes to prospects for pesticide use in the future. GLOBAL PESTICIDE MARKET TRENDS Chemical-Pesticide Market The global chemical-pesticide market is about $31 billion.
From page 145...
... Biopesticide Market 145 Biologically based pesticide products (also known as biorational products) generate sales of about $700 million per year (including transgenic crops)
From page 146...
... Microbial 65 66 67 72 7.5 Transgenic plants 405 429 455 610 34.1 Miscellaneous 180 184 188 208 10.6 Total 650 679 710 890 25.4 aestimated Source: Eppes, in press. pesticides are the Bacillus thuringiensis-based (Bt-based)
From page 147...
... Source: Panna 1998. Major trends in the agrichemical industry today include · Consolidation of multinational agrichemical companies.
From page 152...
... , and Novartis and AstraZeneca have merged to form Syngenta. Another major trend in the market is the rapid growth of biotechnology products compared with chemical pesticides, stimulating the vertical integration of agrichemical companies with seed and food companies.
From page 153...
... Large agrichemical companies are therefore aligning themselves with generic suppliers of chemical pesticides to reduce erosion in sales of the products that were formerly proprietary products. Several agrichemical companies have purchased outright or partially own generic companies.
From page 154...
... . The consolidation of distribution and agrichemical companies has created some concern for farmers.
From page 155...
... · . Term~hc~ae Fungicide Herbicide Fungicide Bird repellent Insecticide Insecticide Herbicide Insecticide Insecticide Insecticide Trifloxystrobin Fungicide ornamental Corn Various seed treatments Potato Below-ground bait station Above-ground bait station Sugar beets Soybeans Ornamentals, citrus, nuts, fruit trees Food crops 1994 Potato, cucurbit, tomato, 1999 tobacco Cotton Corn, soybean, peanut Cotton Walnuts Pome fruit, cotton, leafy vegetables, cole crops, sugarcane, pecan, forestry, 1995 pending 1997 1994 1997 1995 1997 1996 pending 1999 1997 1995 pending fruiting Vegetables, Ornamentals Pome fruit, grape, cucurbit, 1999 peanut, turf, banana aNew uses of existing active ingredients.
From page 156...
... Because of the lower cost and shorter time to develop a biopesticide, as opposed to synthetic chemicals or transgenic crops, as seen in Figure 4-2, small biopesticide companies are able to enter this market. New startup firms develop alternative technologies for smaller markets that are neglected by larger agrichemical companies.
From page 157...
... ct 6o a) ~ 4F 2OTime to Market Cost of Development Transgenic Chemical Pharmaceutical Crops Pesticides Natural Products Biocontrol Pesticidal Agents Natural Products FIGURE 4-2 Cost to develop and time to market of various products.
From page 158...
... The diamondback moth, Plutella xylostella, which has evolved resistance to all chemical classes and also to Bt, can be managed with IPM (Metcalf 1989~. In Taiwan, two larval parasitoids, pheromone traps, and Bt reduced pest population densities on cauliflower and broccoli to less levels than in neighboring, conventionally sprayed plots (Asian Vegetable Research and Development Center 1991~.
From page 159...
... The system enhances predators and manages pesticide resistance in potatoes through the use of "soft" chemicals and Btt, and rotation of pesticides in different chemical classes. Although Btt has commercial promise for control of Colorado potato beetle, the advent of the pesticide imidacloprid has reduced the use of Btt substantially.
From page 160...
... New genetically engineered and improved Bt products might provide more opportunities and choices for growers who use IPM programs. The most successful Bt products are ones that provide efficacy, ease of use, and consistency approaching traditional chemical pesticides.
From page 161...
... nuclear polyhedrosis virus (NPV) was the first baculovirus to be marketed in the United States.
From page 162...
... On head lettuce in California, a beet armyworm NPV was field-tested for 3 years and compared with chemical insecticides (Gelernter et al. 1986~; results indicated comparable control with methomyl and permethrin.
From page 163...
... To enable development of more economical and effective products, R&D efforts should focus on making improvements in baculovirus production, formulation, and application technologies in conjunction with genetic engineering of the viruses to enhance their kill rates and broaden their host range. Entomopathogenic Fungi Over 500 fungi are regularly associated with insects; some cause serious disease in their hosts, but few have been used commercially as control agents.
From page 164...
... It should be noted that public research agencies have played an important role in the development of gypsy moth pest-management strategies. In fact, the use of Entomophaga maimaiga with Bt and NPVs exemplifies the trend toward biologically based pest management in gypsy moth control in the last 10 years.
From page 165...
... can be used in rotation with chemical products or stand-alone in conjunction with disease-forecasting models. Natural products are organic compounds produced by microorganisms, plants, and other organisms.
From page 166...
... The use of Bacillus subtilis as a fungicidal treatment has been demonstrated on a number of diseases, including cornstalk rot (Fusarium roseum) (Kommedahl and Mew 1975)
From page 167...
... Many of the new chemistries in fungicides, insecticides, and herbicides can trace their origins to natural products. For example, glufosinate is a derivative of bialophos, a natural product derived from Streptomyces viridachromogens (Leaven et al.
From page 168...
... Hypovirulence has achieved its widest success in combating chestnut blight, a disease that radically altered the eastern forest landscape after introduction of an invasive fungus (NRC 1996~. Transgenic Crops Choice of crop variety has always been a cornerstone of crop protection, especially for disease and insect control.
From page 169...
... Industrial leaders anticipate that plants containing chitinase genes and other genes for fungal and bacterial plant-pathogen control will be on the market in the near future; many of these newer genetically engineered plant varieties are already undergoing field tests (Figure 4-3~. Transgenic plants, whether engineered to contain an insecticidal protein, such as an endotoxin protein from Bt or a chitinase gene to control root rot pathogens, appear to have the same advantages as traditionally bred pest-resistant crop varieties.
From page 170...
... Cholesterol oxidase, an enzyme from the microorganism Streptomyces and discovered by Monsanto Company, is toxic to cotton boll weevils and has been engineered into cotton plants; the enzyme is not effective on other insect pests. The current choices of transgenic plants that contain single Bt genes are "first-generation" plants and will be followed by more sophisticated "second-generation" and "third-generation" plants with greater flexibility for use in IPM systems.
From page 171...
... Strategies designed to limit the development of resistant pests on the basis of understanding of pest population dynamics (such as studies on pest population establishment and growth, genetics, movement, behavior, number of generations required to develop resistance, and generation time) are critical for optimal and sustained use of transgenic plants in IPM systems.
From page 172...
... Unlike biological control agents, synthetic pesticides cannot respond evolutionarily to pest adaptation. That response is the responsibility of modern agriculture.
From page 173...
... Genetic Engineering of Pests Most research aimed at pest management based on genetic engineering has focused on genetic manipulation of crop plants, economically important tree species (Carozzi and Koziel 1997; Raffa 1989) , and biocontrol agents (Hoy et al., 1997, Bonning and Hammock 1996~.
From page 174...
... Although replacement of a native population with insects that had translocations required release of huge numbers of laboratory-reared insects (at least as many as in the native population if there was one translocation and no relative fitness reduction) , it seemed theoretically possible to release a relatively small number of insects that had transposable elements (about 10% of the native population)
From page 175...
... 1997~. In addition to its use to develop novel control strategies based on transposons and microorganism-based incompatibility, genetic engineering could be used to improve the efficiency of classical genetic control strategies, such as introduction of conditional lethal genes or sex-ratio distortion genes (Gould and Schliekleman, in prep.~.
From page 176...
... In most cases the molecular targets are ones that are peculiar to the pest and are not found in nontarget organisms (for example, essential amino acid biosynthetic pathways)
From page 177...
... Combinatorial Chemistry Combinatorial chemistry encompasses systems in which a large number of chemical compounds are made via multiple parallel synthesis. In this system, a set of building blocks (N)
From page 178...
... 1997~. Tests are also conducted early in the discovery process to assess the toxicity of potential leads to nontarget organisms, such as fish or aquatic invertebrates.
From page 179...
... The reasons for the low rate of interception are many, including the distribution of the pest, the size of the pest population at the time of application, uncertainty as to how and when the pest will encounter the pesticide, the use of broadcast sprays, and drift. One way to reduce the risk posed by pesticides is to increase the amount of pesticide that reaches the target pest while decreasing the total amount of pesticide applied to the field.
From page 180...
... However, the technology is limited by the lack of charging nozzles suitable for the commercial market (Carlton et al., 1995~. In addition, the effectiveness of electrostatic sprayers depends on environmental factors, such as temperature and relative humidity, height of the spray boom over the canopy, and distribution of the pesticide spray throughout the canopy (electrostatic sprayers tend to deposit most of the pesticide material in the top of the canopy)
From page 181...
... Precision-agriculture techniques are new technologies under development that can vary the amount of herbicide application. In the future, users might map a field to identify locations of various weed populations and then select the amount and type of herbicide spray that match the weed density and population for that area of the field (Paice et al.
From page 182...
... Many of these technologies rely on space-age communication and incorporate the use of global positioning systems. Modern irrigation technologies that adjust input use according to variability in soil and weather conditions and rely on weather stations and moisture-monitoring equipment are also examples of precision technologies.
From page 183...
... In addition, airborne sensors that detect multispectral reflectance differences between crop and other vegetation canopies can identify crop-vigor variation in response to insect pests and plant pathogens (UC Davis, 1997; Baldy et al., 1996; Hill et al., 1996; Kline et al., 1996; Liedtke, 1997; Vickery et al.; 1997; Ustin et al., 1997~. As this technology is improved, it is likely that pesticide use will decrease with the change from whole-field to pest-location-specific applications.
From page 184...
... Work by basic and applied scientists led to the careful dissection of the population dynamics involved in successful biological control of the citrus red scale (Murdoch et al. 1995, Murdoch and Briggs 1996~.
From page 185...
... Studies of population dynamics of plant pathogens have been hampered by our inability to monitor fungi, bacteria, and viruses when they are at low densities. Decision-Support Systems for Pest Management A wide array of issues including crop productivity, environmental protection, and profitability creates a complex background against which agricultural producers or professional managers are expected to make decisions about optimal pest management.
From page 186...
... The low representation of alternative tactics in DSSs is a result of inability to predict the outcome of these tactics. Cultural and biological pest-management tactics rely on more subtle influences on pest populations; so more environmental factors play a role in determining population dynamics and there is greater variability in success rates.
From page 187...
... Increased carbon dioxide also has the ability to affect plant-pest relationships through by affecting global temperatures. Through the "greenhouse effect", increased carbon dioxide is predicted to increase average global temperatures by 1.5-4.5°C.
From page 188...
... At present, for example, the red imported fire ant (Solenopsis invicta) , accidentally introduced into North America from Brazil, is effectively restricted to southern states, where they cause considerable damage (Callcott and Collins 1996~.
From page 189...
... Increased Ultraviolet-B Radiation As a result of stratospheric ozone depletion, due principally to emissions of chlorofluorocarbons, levels of ultraviolet-B-radiation (UV-B)
From page 190...
... or by competing with crop plants for water, minerals, or light for photosynthesis. Introduced species can also cause problems by altering trophic dynamics and ecosystem structure.
From page 191...
... As for the impact of biological invasions on the future of pesticide use in the United States, suffice it to say that some of the most controversial examples of pesticide use in the last half-century have involved attempts to eradicate introduced species. An ill-fated campaign launched in 1957 to eradicate Solenopsis invicta, the red imported fire ant, culminated in expensive failure, public concern, and political concern about the safety of the chemical control agents used (Kaiser 1978, Hinkle 1982~.
From page 192...
... ever, potential effects include loss of critical germplasm for crop improvement, breakdown of such mutualistic associations as those between pollinator and plant and between plant and mycorrhizae, and decrease in availability of natural enemies for use in biological-control programs. With respect to direct effects of extinctions on pesticide use, in that natural products have often provided leads for development of chemical control agents (or have themselves served as control agents)
From page 193...
... Many pests are documented to have become resistant to new pesticides in less than 3 years (Forgash 1984, Shelton and Wyman 1991, Sun et al.1992, Schwinn and Morton 1990~. Unlike biological control agents, synthetic pesticides cannot respond evolutionarily to pest adaptation.
From page 194...
... Organophosphates and pyrethroids attack components of the nervous system common to all insects, but some of the newer insecticides affect target sites that are only found in specific groups of insects. For example, the toxins from Bt are effective at very low concentrations when a target insect has a midgut receptor to which the
From page 195...
... The new field of pesticide-resistance management, which has interwoven the disciplines of IPM and population genetics, concedes that pests have the potential to adapt to almost all control tactics. If future synthetic compounds are more prone to pest adaptation than older compounds, resistance management could become more critical.
From page 196...
... If genes that decrease such fitness costs have general buffering impacts on pests with other resistance genes, pest populations might accumulate traits that allow them to withstand metabolic changes caused by major resistance genes.
From page 197...
... They contend that as genetically engineered crops are released into the environment, genes from these crops will spread into weed and pathogen populations and will cause increased crop losses. Rigorously derived data prove that genes can be transferred between some crops and their weedy wild relatives, for example, sorghum and Tohnsongrass, cultivated rice and wild rice, wild radish and cultivated radish (Klinger et al.
From page 198...
... 1982. Potential for biological control of plant disease on the phylloplane.
From page 199...
... Pp. 115-138 in New Directions In Biological Control: Alternatives For Suppressing Agricultural Pests And Diseases, R
From page 200...
... 1974. The Genetic Control of Insect Pests.
From page 201...
... 1989. Toxicity of a new strain of Bacillus thuringiensis to Colorado potato beetle (Coleoptera: Chrysomelidae)
From page 202...
... 1988. Isolation and identification of iturins as antifungal peptides in biological control of peach brown rot with Bacillus subtilis.
From page 203...
... 1996. Contributions of ecology to biological control.
From page 204...
... 1999. Microbial pesticides and natural products as alternatives.
From page 205...
... 1995. Regulation of an insect population under biological control.
From page 206...
... 1991. Evolution and management of resistance in the Colorado potato beetle, Leptinotarsa decemlineata.
From page 207...
... 1987a. Nuclear polyhedrosis virus for control of Spodoptera exigua larvae on glasshouse crops.
From page 208...
... Pp.57-83 in Food, Crop Pests and the Environment, the Need and Potential for Biologically Intensive Integrated Pest Management, Zalom F.G.
From page 209...
... 1988. Biological control of soilborne plant pathogens in the rhizosphere with bacteria.


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