dependence on broad-spectrum insecticides is particularly important to the continued profitable production of cotton in the higher rainfall areas of the cotton belt. Research in recent years has resulted in the development of a number of technologies useful in dealing with the boll weevil. Included are (1) modified cotton cultures using short-season cottons, (2) pheromone traps for detection and survey, (3) insect growth regulators such as Dimilin, (4) pheromone traps for suppression of low density populations, (5) mass production of usable sterile boll weevils, and (6) improved field scouting and population prediction methods. These new technologies have been integrated into cotton insect management programs which were placed into use on a trial basis for 3 years in an optimum pest management trial in Panola County, MS, and in a boll weevil eradication trial in North Carolina and Virginia. Both trials, completed in 1980, were highly successful as evidenced by substantial reductions of in-season use of insecticides for control of both the boll weevil and the bollworm/budworm complex. The participation of 99 to 100 percent of the producers in both trials and extensive monitoring with pheromone traps and by field scouting over large areas resulted in highly effective use of diapause control, insecticide applications and other control technologies. Although a number of new technologies are ready for expanded use, additional research is needed to (1) develop more effective insect growth regulators and sterile insects; (2) search for new chemicals such as feeding deterrents antifertility agents and insecticides; (3) to continue the search for resistant host plants and biological control agents; (4) to define the geographical races of boll weevils; and (5) to improve survey, detection, and prediction capabilities. Bollworm (corn earworm) and tobacco budworm The cotton bollworm or corn earworm and the tobacco budworm are the most destructive insect pests of American agriculture, causing losses in excess of $1 billion each year. In addition to losses to cotton, these insects are serious pests of corn, soybeans, tomatoes, sorghum, peanuts, lettuce, and other crops. The budworm, because of its development of resistance to insecticides, was responsible for the collapse of a 750,000-acre cotton industry in northern Mexico in the 1960's. Also, the cotton industry was seriously threatened in the mid-South and southern California in the mid-1970's by the tobacco budworm because effective control measures were not available. Because of resistance to three classes of insecticides by the budworm, only one class of insecticides is currently highly effective for its control. Therefore, other control methods are desperately needed to insure that crops that are attacked by the bollworm/budworm complex can be produced economically. Progress in developing new controls have been made; some of these new controls are being utilized while others are still under development. Included are (1) resistant crop cultivars, particularly in corn; (2) attractants in traps for survey and prediction; (3) new synthetic pyrethroid and organophosphate insecticides; (4) improved formulations and new strains of microbial agents such as Bacillus thurgiensis and a nuclear polyhedrosis virus; (5) mass production and release methods for an egg parasite; and (6) improved field scouting techniques. In addition to these new technologies that are in use at least to a limited extent, exciting discoveries of potential practical use include the hybrid sterility trait in the tobacco budworm, the identification of the components of the sex pheromones for both the bollworm and tobacco budworm, and the development of a large number of resistant breeding lines of plants. The advances that have had the most impact on control of the bollworm/budworm in recent years have been the development of predictive population models and survey methods which have saved the farmer in Texas alone $5 million and the development of the synthetic pyrethroid insecticides. However, the future prospects for control of the boll weevil without in-season use of broad spectrum insecticides provides an opportunity for increased use of selective methods of control and of naturally occurring beneficial insects for control of the bollworm/budworm complex. Many promising methods of control for the bollworm/budworm complex are on the horizon. However, development of practical use for these methods is complex. Since there are two species of insects involved that feed on a wide range of cultivated and wild host plants, such techniques as hybrid sterility, mating disruption with pheromones, and perhaps mass releases of parasite or predators may require a community or larger area approach Additional research is needed in a wide range of areas including (1) search for hybrid sterility in the bollworm (corn earworm), (2) nutrition, rearing, and behavior of bollworms and budworms for use in biological control (sterility, parasites, pheromones), (3) large scale field studies on mating disruption with pheromones, (4) improved rearing of egg and larval parasites, (5) continued search for host plant resistance, and (6) survey and prediction with particular emphasis on micro-meterological factors. Pink bollworm The pink bollworm is a foreign insect pest that became a very serious pest of cotton in the irrigated West in about 1965. Use of broad spectrum insecticides for its control led to the development of insecticide resistance in other insects such as the tobacco budworm in southern California and Arizona. The potential establishment of the pink bollworm into the San Joaquin Valley of California threatens the cotton crop in that area that is valued at over $1 billion. Improved methods of controlling the pink bollworm with reduced dependence on broad spectrum insecticides is needed to protect the cotton crop in Arizona, southern California, and Mexico and to reduce the threat to the cotton crop in the San Joaquin Valley of California. Research advances in recent years have included (1) the commercialization of nectarless varieties of cotton that reduce populations of the pink bollworm by about 50 percent; (2) new synthetic pyrethoid and organophosphate insecticides; (3) development of the mating disruption technique using the pink bollworm pheromone; (4) rearing and release of sterile insects to prevent infestation of cotton in the Imperial Valley of California; (5) discovery of plant growth regulators for potential use in cultural control; and (6) improved survey, particularly with pheromone traps, and population prediction. Although a number of these advances are in practical use, there is a need for improved methods of using pheromones for mating disruption, for methods of producing more competitive sterile insects, and for additional plant growth regulators. In addition, more information is needed on the genetics, physiology, and behavior of the pink bollworm. Improved population models, including studies of migration are also needed to design improved programs. The influence of pink bollworm populations in Mexico on those in the U.S. needs to be determined. Southern Pine Beetle The Southern pine beetle (SPB) is the most destructive of the eastern species of bark beetles and occurs throughout the Southeastern and Southern States. It causes significant pine mortality every year somewhere in the South. Outbreaks have been reported as far back as the 1750's. About 800,000 thousand cubic feet (MCF) of pine timber has been killed since 1968; an annual loss averaging about 72,500 MCF. Since 1974, populations of the southern pine beetle have declined to a low in 1978 when about 7,800 MCF of pine timber were killed. Now on the rise again, about 125,200 MCF of timber is estimated to have been killed in 1979, equivalent to the lumber needed to build about 55,000 average-size houses. The losses in 1980 were also high and were particularly severe in Mississippi, Alabama, Georgia, and South and North Carolina. Such losses upset management plans, reduce potential yields from managed stands, and devastate the forest holdings of small, private nonindustrial land owners the principal owners of commercial forest land in the South. In years of peak SPB damage, a glut of beetle-killed timber is created that exceeds the processing capacity of local mills. Major accomplishments from the Expanded Southern Pine Beetle Research and application program (ESPBRAP) were as follows; (1) Stand risk-rating systems developed to determine susceptibility to beetle attack. It allows foresters to identify stands that need special attention when beetle populations increase and to set priorities for silvicultural treatments (2) Sawmill operator's guide prepared to show possibilities for profit in limber from SPB killed trees. (3) Damage prediction model developd to estimate future tree mortality over large areas. Effects on other forest resources can also be estimated. (4) A stand-growth model for plantations allows simulation of the effects of management practices on tree growth. (5) Dursban 4E insecticide approved by EPA for bark beetle control (6) Methods for sampling SPB populations developed and tested. (7) Spotgrowth model to predict tree mortality in "spots" over large areas developed and being tested. (8) Aerial survey and navigation systems developed to estimate size and number of infestations and volume of dead trees over large areas. (9) Progress toward use of behavioral chemicals (pheromones or sex attractants) to disrupt normal attack behavior of SPB. A current research program is underway with emphasis on the following problems: (1) The combined effects of the SPB insect natural enemies (parasites and predators) and associated mite and nematode complex on SPB population trends. (2) The role of symbiotic microorganisms associated with SPB in reproduction and development. (3) Biological and physiological characteristics of stressed pine trees that render them attractive and susceptible to SPB attack and survival. (4) Evaluate existing hazard-rating systems and silvicultural treatments developed for reducing losses from SPB. (5) interrelationships amoung SPB populations, natural enemies, associated microbes, and individual tree and stand characteristics (population dynamics). (6) Evaluate candidate chemical insecticides for protection of individual trees from SPB attack. (7) Effects of insecticides on SPB parasites and predators. (8) Effects of insecticides on soil and aquatic organisms. Major research studies on Southern Pine Beetle with priority for early attention are: (1) pilot test of models for estimating impacts and spot growth of SPB infestations. (2) Develop methods for measuring the cost and benefits or cost effectiveness of selected treatment tactics applied under forest conditions. (3) Test and refine the sawmill decision model in two geographic locations. (4) Simplify field and office procedures for estimating SPB populations in trees, spots, and areas. (5) Develop models for describing and predicting host susceptibility to SPB attack. (6) Pilot test SPB stand-rating systems in several geographic locations in the southeast. (7) Develop and test formulations of pheromones for supression. (8) Integrate findings for ESPBRAP into SPB management systems. Much new technology has been developed by the program is now in need of validation, pilot testing, and transfer to users. General areas of need are to validate and refine pest management decision making processes and to further analyze and synthesize the large amount of knowledge on SPB to properly design integrated SPB management and treatment strategies. Specfically, future needs & major knowledge gaps to be filled are: Cooperative Research and its cooperators in the State agricultural experiment stations and forestry schools have participated in an expanded southern pine beetle program since 1975. SEA/Cooperative Research received $844,532 in fiscal year 1980 from the forest service and $1,080,000 in fiscal year 1981 for use in the jointly planned Forest Pest Research and Development Program on Southern Pine Bark Beetle and the Canada/U.S.A. Spruce Budworms Research, Development and Application Program. In Fiscal Year 1981, $633,000 is available from the Forest Service for research and development on Southern Pine Bark Beetles. Research by the State agricultural experiment stations and forestry schools in Georgia, New Hampshire, North Carolina, Texas, and Virginia contributed to developing techniques for evaluating the impact of southern pine beetle populations; insect sampling and population dynamics; mortality and competition factors; soil, tree, stand and climatic characteristics; development of behavioral chemicals; evaluation of toxicants; and stand manipulative practices. This information has been provided to forest managers. Currently the State agricultural experiment station and forestry school researchers are contributing in the areas of characterizing flight dispersal by the Southern Pine Beetle, dynamics of endemic Southern Pine Beetle populations, development of a pheromone system, development of sampling procedures and statistical models and decision-support system development for Southern Pine Beetle Management. Douglas-Fir Tussock Moth The Douglas-Fir Tussock Moth (DFTM) is a defoliator of major importance in the interior Douglas fir and true fir forests of western North America. Occasionally, its populations increase catastrophically, causing extensive mortality, top- kill, and growth loss in trees of all ages within various parts of its range. The deleterious effects of the moth have been severe from the interior of British Columbia to Mexico, and from the Rocky Mountains to the Cascade and Siskiyou Ranges of Washington, Oregon, and California. Damage inflicted by the DFTM can adversely affect local forest operations and regional forest management objectives. The last major outbreak of DFTM occured from 1971-1974 in Oregon, Washington, and northern Idaho in which timber and growth losses reached 200,000 thousand cubic feet (MCF), creating major problems in salvage and forest regeneration. The insect has remained at low levels since the 1971-1974 outbreak collapsed. Major outbreaks tend to occur every 8-10 years which suggests that the next outbreak can be expected in the early 1980's. The Expanded Tussock Moth Research Program was successful and major research accomplishments have resulted in (1) Increased understanding of biology, nutritional requirements, and genetic variation among populations of DFTM. (2) Increased understanding of DFTM population ecology, including the role of natural enemies in the decline of outbreaks and in maintaining low-density populations. (3) A stand outbreak model was produced that predicts tree mortality, top-kill, and growth reduction. |