Pest Management Problems Research Articles

Computer-aided technology for regional pest management: Towards agricultural sustainability

Sustainable agriculture is commonly accepted in China and is practised by means of agro-ecological engineering. Large scale agricultural production, supported by advanced technology and the dissemination of eco-agricultural knowledge, will be more important in the future. With the development of integrated pest management, increasing evidence suggests that, large- and very-large-scale ecological engineering techniques must be developed and used. Also, computer-aided techniques such as geographical information systems and expert systems offer a more effective way to resolve new problems in pest management. As a pilot investigation using computer-aided technology for regional pest management in China, a vegetable production information and decision system, BJ-CABBAGIS, has been developed. Design of the system, supporting software and hardware for its development, and its function and preliminary application are presented in detail.

Air-tower sprayers increase spray application efficiency in mature citrus trees

Summary. Conventional pesticide spraying in citrus crops with low-profile sprayers results in pest management problems because of the poor distribution of pesticide throughout the tree. Pesticide losses, particularly drift, are a concern with this type of sprayer especially in orchards situated in or near urban areas. The spray deposit on citrus leaves and fruit and off-target losses (canopy run-off and drift) were determined for air-assisted low-profile sprayers and air-assisted sprayers fitted with tower air conveyors (air-towers). The air-tower sprayers produced even distribution of leaf spray deposits through the full height of the tree canopy while the low-profile sprayers produced decreasing leaf spray deposits with increasing height in the trees. The Metters tower sprayer and Cropliner low-profile sprayer resulted in increasing deposits from the 0˚ axis through to the 90˚ axis to sprayer travel while the Barlow tower sprayer and the Hardi low-profile sprayer produced a more even distribution of deposits through the axes to sprayer travel. Fruit deposits were not significantly different between sprayers. The Barlow tower sprayer produced significantly less canopy spray run-off compared with the low-profile sprayers. The Barlow tower sprayer resulted in a significant reduction in spray drift in the above tree zone compared with the Hardi low-profile sprayer. Better distribution of pesticides in citrus tree canopies will improve pest control especially in the top sections of the tree as this is where the greatest increase in pesticide deposit is achieved with air-tower sprayers. Both ground and air contamination from pesticides can also be reduced by using sprayers fitted with air-tower conveyors designed to produce even airflows for the full height of the citrus trees being sprayed.

Optimizing Complex Bioeconomic Simulations Using an Efficient Search Heuristic

For simulation to be truly useful for investigating many problems in agricultural economics, non-simplifying optimization techniques need to be employed. General methods for simulation optimization that do not inhibit system characterization or analysis are available, and they would appear to provide much of the mathematical and optimizing rigor demanded by economists. This paper describes the theory and algorithm of a robust and efficient simulation optimization approach, the Complex Method. An example of implementing the algorithm is illustrated using a pest management problem.

Integrated Approach to an Improved Citrus Production and Marketing System in Benue State of Nigeria

The commercial production and handling systems in Benue State was undertaken under a World Bank assisted project to identify and seek solution to constraints facing citrus farming in some rural parts of Nigeria. Selected areas noted for intensive fruit cultivation like Gbako,Yandev,Katsina-ala, and Aliade was covered in a survey by citrus agronomists and postharvest specialists. The study looked into processes and activities at farmers plots, agriculture department extension plots and nurseries, local markets and processing plants. Key production constraints identified include pest management and weed problems,bush burning, and high labor costs for farm operations. Lack of organized marketing outlets, high transport costs, and fruit decay at collection centers were the main bottlenecks facing the postharvest operations. Local processors face the problems of poor-quality raw material supply and the unstable price regimes every season. Investigation revealed that improved extension linkages that emphasize appropriate orchard management skills, integrated pest management, and careful handling should be introduced.

The role of public policy in implementing IPM

The implementation of IPM has been hindered in many cases by a lack of policies aimed at promoting it. IPM technology has been developed but not fully implemented, either because of a lack of understanding of its potential to meet social needs or a lack of will to introduce necessary supporting policies. In other cases, IPM technology has not even been developed because of a lack of policy support. The role and potential of policies to promote IPM are examined, particularly in the context of pest management problems in Central America.

Periodic Plowing Effects on Soil Properties in a No‐Till Farming System

AbstractSoils in no‐tillage management are often plowed for crop rotation or to correct a pest or soil management problem. This study determined whether soil properties created by no‐tillage were retained or reestablished after plowing and return to no‐tillage. The study was conducted on a Capac loam (fine‐loamy, mixed, mesic Aeric Ochraqualf) in East Lansing, MI. In 1986 and 1987, one each of three treatments in no‐tillage since 1980 was plowed and subsequently returned to notillage (NTP86 and NTP87) and compared with conventional tillage (CT) and long‐term no‐tillage (NT). In all treatments, plowing, compared with NT, decreased bulk density by 0.17 to 0.28 Mg m−3, increased total porosity from 0.03 to 0.10 m3 m−3, increased macroporosity by 0.05 to 0.13 m3 m−3, and decreased microporosity by 0.03 to 0.05 m3 m−3. Wheel traffic increased bulk density 0.14 to 0.18 Mg m−3 in the plowed soils but only 0.04 Mg m−3 in the NT soil. Soil surface P, K, and organic C (OC) were redistributed in the surface 200 mm by plowing, but plowing did not eliminate stratification of chemical properties in the surface 50 mm. The NTP87 treatment enhanced mineralization of N over both CT and NT by 9.8 to 18.4 g N m−3 in the surface 50 mm in 1987. Residual effects were evident 1 yr after plowing. However, 4 to 5 yr after plowing, most soil properties had returned to levels of NT, although reestablishment of C and N in the surface remained lower than NT.

THE NORTHEAST SARE (LISA) APPLE PRODUCTION PROJECT

Developing sustainable production systems based on the disease resistant apple cultivars (DRACs) and IPM techniques is a key objective of this multidisciplinary project involving 19 principle investigators across 5 cooperating institutions. Cultivar selection is a crucial decision for an apple grower which will impact the farm's competitiveness and profitability for many years. Factors that growers consider when deciding what cultivars to plant include consumer acceptance and marketability; winter hardiness; yield potential; fruit storage qualities, color, taste, and size; and potential pest management problems. These factors are being researched in this project. Disease resistant orchards will undoubtedly present new economic considerations to growers, wholesalers, and processors. A further objective is to provide economic analyses of alternative techniques and to forecast the impact of changes in production systems on the Northeast apple industry. Apple growers must have access to research-generated information that addresses the critical issues facing them Rapid information dissemination is a high priority of this project. The Northeast Sustainable Apple Production Newsletter has over 1200 active subscribers across the United States and in 7 foreign countries. The Management Guide for Low-Input Sustainable Apple production has been well received and continues to be requested world-wide.

One-Sided Shift Trellising Addresses Harvest, Pest Management and Cultural Problems in Rubus

Static-V trellis increases raspberry yield, but fruiting shoots grow toward its center making harvest difficult. Shading causes early leaf abscission and it favors fungus diseases inside the V. Static training of floricanes and primocanes to opposite sides of a V trellis prevents neither harvest difficulty, nor primocane injury during harvest. In 1988-89 harvest difficulties were reduced by bloom-time shifting of floricanes on a V-trellis. Over 90% of fruiting shoots were oriented to the trellis ' exterior, but primocane shading and early leaf abscission continued. The 'bent fence' trellis was designed and tested in 1989. It shifts floricanes from horizontal orientation to an upright position on one side of a V-shaped trellis, thus retaining outward display of fruiting shoots and achieving unobstructed display of primocanes on the opposite side. Harvest efficiency, disease reduction, accurate deposition of pesticides, avoidance of solar injury (sun scald), and adaptation of mechanical pest control procedures are potentiated by this system. It also reduces impediments to studies of carbohydrate partitioning, photosynthetic efficiency, yield efficiency, and intraplant competition.

Harvesting discrete nonlinear age and stage structured populations

A natural extension of age structured Leslie matrix models is to replace age classes with stage classes and to assume that, in each time period, the transition from one stage class to the next is incomplete; that is, diagonal terms appear in the transition matrix. This approach is particularly useful in resource systems where size is more easily measured than age. In this linear setting, the properties of the models are known; and these models have been applied to the analysis of population problems. A more applicable setting is to assume that the reproduction, survival, and transition parameters in the model are density dependent. The behavior of such models is determined by the form of this density dependence. Here, we focus on models in which the parameters depend on the value of an aggregated variable, defined to be the weighted sum of the number of individuals in each stage class. In forestry models, for example, this aggregated variable may represent a basal area index; in fisheries models, it may represent a spawning stock biomass. Current age structured nonlinear stock-recruitment fisheries models are a special case of the models considered here. Certain results that apply to age structured models can be extended to this broader class of models. In particular, the questions addressed relate to the minimum number of age classes that need to be harvested to obtain maximum sustainable yield policies and to managing resources under nonequilibrium and stochastic conditions. Application of the model to problems in fisheries, forestry, pest, and wildlife management is also discussed.

Social problems in pest management in the tropics

Use of synthetic organic chemical pesticides introduced after World War II has resulted in a number of health, environmental, and socioeconomic problems discussed here. Both developed and developing countries have been affected. The problems in the developing countries of the tropics came about largely because of an error in transfer of technology. Pesticide technology developed by and for use in the developed countries was exported to countries with cultures and social structures that were not prepared to absorb this technology. Integrated pest management (IPM), an approach that reduces pest damage to tolerable levels through a variety of techniques, including natural enemies, genetically resistant crops, environmental modifications, and, when necessary and appropriate, chemical pesticides, represents an important trend toward rational management of crop pests in the developing countries. However, simply exporting IPM ‘packages’ from developed to developing countries would also be an error in transfer of technology. Each situation must be evaluated individually under actual farming conditions, and the IPM program must be tailored for the particular group of intended beneficiaries. Some of the interrelated social, attitudinal and institutional factors that should be evaluated are discussed.

Feedback control for a class of pest management problems modeled by a noninteractively distributed system

A class of distributed-parameter optimal control problems whose system dynamics are more akin to those of systems of ordinary differential equations is presented together with a set of necessary conditions for optimality. It is shown that certain insect pest management problems fall within the ambit of this theory, which is then used to investigate the properties of the optimal pesticide application schedule and to synthesize a part-feedback control strategy. This latter strategy is presented in a way which makes it applicable to devising strategies for the application of pesticides in agricultural systems that are too complex to be easily modeled, but for which correlations are available between pest levels at certain points during the growing season and yield losses.

Economic Benefits of Kalman Filtering for Insect Pest Management1

The efficiency and potential economic gains of filtering techniques for pest management problems are demonstrated by applying them to a life cycle model of the bean leaf beetle, Cerotoma trifurcate (Forster) (Coleoptera: Chrysomelidae). The Kalman filter estimator utilized combined information from sample data with a model of a dynamic system to obtain estimates of the current state of the system. The sample data were obtained by a two-stage sampling scheme. Specifically, the west-southwest district of Illinois was the area of concern. Four primary sampling units (PSU) were chosen, and from each PSU, 10 samples were drawn. This process was repeated four times throughout the 1980 growing season. For the particular data set considered, use of a model of bean leaf beetle dynamics results in substantial gains in estimate efficiency and a reduction in the number of fields required to be sampled.

Optimal Integrated Control of Alfalfa Weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae)1)

AbstractThe use of optimization methods to determine single and multidimensional economic thresholds for insect pests in discussed. A review of previous applications of optimization methods to pest management problems is followed || by a detailed description of an application to alfalfa weevil management. This model uses dynamic programming to determine the best combination of chemical, cultural and biological means for control of the alfalfa– weevil. The model includes stochastically varying weather patterns, seven weevil age–classes, three parasite age–classes, and five alfalfa plant components. The decision variables include times of harvest and insecticide applications over a three–year period. The multi–dimensional economic thresholds calculated depend upon parasite density and weather, as well as upon alfalfa–weevil density. Results for central New York, USA, are presented.

Engineer-Entomologist Cooperative Research Programs Needed to Solve Problems in Pest Management

The professional crop protection consultant practicing in today's agriculture is frequently frustrated with problems which can only be solved by engineering know-how. These problems are brought about by many factors, but the most common one relates to the rapidly changing agricultural scene, where farmers have become family corporations handling large acreages, monster equipment, and managing hundreds of thousands of dollars each year. Early planting, no-tillage or reduced tillage, high plant populations, changing varieties, modern irrigation, multiple cropping, massive harvesting techniques, and variable storage conditions all play a part in this changing kaleidoscope.

Pine and Montane Vole Age Estimates from Eye Lens Weights

Lens weights were a satisfactory basis for estimating ages of 124 pine voles (Microtus pinetorum) and 517 montane voles (M. montanus) of known age. Other body and cranial measurements were of little added value for estimating ages when considered over a full two-year age range. Analyses of covariance showed no differences attributable to sex, season of birth, or laboratory generation in the lens weight-age regressions. Montane voles from small (1-4), medium (5-6), and large (7-10) litters had significantly different regressions, although pine voles from small (1-2) vs. large (3-4) litters did not differ. J. WILDL. MANAGE. 39(3):550-556 Various species of microtine rodents are central problems in both ecological theory (Krebs et al. 1973) and pest management (Forbes 1972, Federal Cooperative Extension Service 1959), and age specific data are needed to understand their basic population processes (e.g., Schaffer and Tamarin 1973). In pest management situations age specific birth and death rates are frequently the essential basis for accurately estimating effects of proposed or actual management decisions. If, as seems possible, reproductive inhibitors should replace toxic mortality agents in vole management programs (Richmond and Stehn, unpublished data), then data on age specific rates and age structure will be even more important, because in general birth rate perturbations will have a greater impact on population age structure (and thereby on potential rate of increase) than death rate changes. For these and other applications we sought to develop age estimation formulae for pine and montane voles. Our data are established mammalian aging criteria: eye lens weights and several morphologic measurements from known-age series of laboratory animals. Morris (1972) thoroughly reviewed this field, and Friend (1968) reviewed the lens weight technique sp cifically. We thank M. E. Richmond for assistance throughout the project and S. G. Fisher and D. Q. Thompson for reviewing the manus ript. R. Stehn, J. Jannett, J. Stone, and K. Tonnessen provided essential technical assistance. R. H. Foote kindly lent the electrobalance. The Cornell University Office of Computer Services and the University of Massachusetts Computing Center supplied machine time. METHODS AND MATERIALS The pine voles used here were of the first through fourth laboratory generations from animals originally collected near New Paltz, Ulster County, New York. The montane voles were first through third or fourth generation laboratory descendants of animals collected near Moran, Teton County, Wyoming. The pine voles were born between 1 February 1969 and 12 January 1 Supported by U.S. Department of Interio Award Contract 14-16-0008-1037 and a Ford Foundation Grant to the Cornell Program in Pest Management Ecology. A contribution from the New York Cooperative Wildlife Research Unit (U.S. Fish and Wildlife Service, Cornell University, New York State Department of Environmental Conservation, and Wildlife Management Institute, cooperating). 2 Present address: Division of Biological Sciences, University of Missouri, Columbia 65201. 550 J. Wildl. Manage. 39(3):1975 This content downloaded from 157.55.39.96 on Sun, 02 Oct 2016 06:40:27 UTC All use subject to http://about.jstor.org/terms VOLE AGE ESTIMATES ? Gourley and Jannett 551