R. E. Stinner

A potential influence of rhizobium activity on the availability of nitrogen to legume herbivores

SummaryEvidence is presented which supports the hypothesis that allantoin, a ureide that is a major storage form of nitrogen (N) in legumes whose N is derived from N-fixation, is not utilizable by at least some insect herbivores. We suggest that the nutritive quality of soybean foliage for Mexican bean beetles is influenced by soil nitrogen level through its impact on rhizobial activity which indirectly alters the proportion of ureide-nitrogen to amino acid-nitrogen without affecting total Kjeldahl-nitrogen. This may provide a basic mechanism for protecting the nitrogen stores of legumes from herbivory while avoiding the metabolic burden of secondary compound production.

Temperature-dependent development and parasitism rates of four species of Pteromalidae (Hymenoptera) parasitoids of house fly (Musca domestica) pupae.

Abstract. Parasitoid development, parasitoid‐induced host mortality and parasitoid progeny emergence were determined at five constant temperatures for Muscidifurax raptor Girault and Sanders, Muscidifurax zaraptor Kogan and Legner, Spalangia earneroni Perkins and Spalangia endius Walker using pupae of the house fly, Musca domestica L., as hosts. At temperatures of 20, 25, 30 and 35oC the median development times (days from oviposition to adult emergence), respectively, were M.raptor (28.4, 20.7, 14.3, 14.5), M.zaraptor (30.6, 22.8, 14.1, 14.2), S.cameroni (55.6,35.2, 21.8,25.0) and S.endius (52.4, 31.5,16.3,14.6). All species failed to emerge at 15oC. Using densities of five parasitoids and 100 hosts and a 24 h exposure period, Muscidifurax species oviposited at a greater rate over a wider range of temperatures than Spalangia species. At 15, 20, 25, 30 and 35oC the mean number of pupae killed per parasitoid were, respectively, M.raptor (1.4, 7.4,10.5, 13.7,14.1), M.zaraptor (0.0, 3.3, 8.9,14.4,15.0), S.cameroni (0.0, 7.8, 11.0, 11.9, 7.4), S.endius (0.6, 4.0, 7.5, 12.0, 11.7), and means of the number of parasitoid progeny per parasitoid were, respectively, M.raptor (0.2, 5.2, 7.9, 11.8, 11.6), M.zaraptor (1.3, 4.4, 8.2, 13.0, 13.7), S.cameroni (0.0, 2.4, 4.7, 5.1, 1.0), S.endius (0.0, 0.9, 3.4, 7.5, 4.9). Development and ovipositional activity in S.cameroni was strongly inhibited at 35oC. The model by Sharpe & DeMichele (1977) was used to describe temperature‐dependent development and the number of parasitoid progeny produced per parasitoid at temperatures of 15–30oC in all species.

Parasitism of house fly (Musca domestica) pupae by four species of Pteromalidae (Hymenoptera): effects of host-parasitoid densities and host distribution.

Abstract. Parasitoid‐induced mortality of house fly, Musca domestica L., pupae and parasitoid progeny emergence by four species of pteromalid parasitoids, Muscidifurax raptor Girault & Sanders, M.zaraptor Kogan & Legner, Spalangia earneroni Perkins and S.endius Walker, were determined for a 24 h exposure period using parasitoid: host ratios ranging from 1:2 to 1:50. When the number of parasitoids was held constant (n=5) and the numbers of hosts varied, and when the number of hosts was held constant (n=100) and the number of parasitoids varied, both the number of pupae killed per parasitoid and the number of parasitoid progeny per parasitoid increased with increasing parasitoid:host ratios to reach an upper limit asymptotically. Maximum values were, respectively: M.raptor (14.7, 11.1), M.zaraptor (12.3, 9.3), S.cameroni (16.9, 5.5), S.endius (14.8, 9.7) with no consistent effects attributed to parasitoid interference.

Decision analysis as a tool for integrating simulation with expert systems when risk and uncertainty are important

Abstract Risk and uncertainty are important components of agricultural decision making. The methodology of applied decision analysis is especially useful in addressing such problems, but has not been widely integrated with expert systems. One problem has been the difficulty of handling uncertainty within the expert system framework in a way which is logically consistent with rational decision criteria. An additional problem in agriculture is the need to combine uncertain or incomplete information from simulations and statistical studies with the subjective knowledge of one or several experts. In this paper, it is argued that Bayesian probability theory provides a natural approach, and a methodology is developed for combining diverse sources of information within the framework of an expert system. The methodology is developed within the context of an expert system for protection of soybeans against corn earworm, using information from HELSIM, a heliothis population model (R. Stinner) and from the SOYGRO soybean crop model (G. Wilkerson).

Temperature-dependent Development of Immature Carcinops pumilio (Coleoptera: Histeridae), a Predator of Musca domestica (Diptera: Muscidae)

The development rates of the immature stages of Carcinops pumilio (Erichson), a predator on eggs and first instar larvae of the house fly, Musca domestica L. were determined at six constant tempera...

Applications Of Information Technology In IPM

This chapter discusses the impacts and applications of information technology (IT) in pest management. A brief review will be given to the history of IT applications in pest management with an emphasis on recent developments. The discussion will focus on two IT technologies, the World Wide Web (the Web) and databases, within the context of their applications to pest management. Some of the applications will be highlighted to illustrate the potential impacts of the IT technologies in pest management in the near future. Finally, a detailed consideration of the application of these technologies in a decision support system for plant disease management will be presented.

Agricultural chemicals use data access using coldfusion markup language and a relational database

Abstract A relational database was developed for the agricultural chemical use data collected by the US Department of Agriculture, National Agricultural Statistics Service since 1990. coldfusion Markup Language was used for the client-side interface and server side process programming. The database is accessible from the Web at URL: http://www.pestmanagement.info/nass . Users can obtain information about agricultural chemical use in the database by search of crop, year, region, and active ingredient. Various agricultural chemical usage statistics are provided as Web tables, dynamically generated US maps, charts and graphs, and downloadable Excel files. We used a centralized software architecture in this project, which is suitable for projects with moderate programming complexity. A distributed approach might be more appropriate for the more complex projects. The current database information, spanning 1990–2001, will be augmented in the future, possibly using an automated updating scheme.

Sexually differentiated flight responses of the Mexican bean beetle to larval and adult nutrition

SummaryFlight of male and female Mexican bean beetle adults was examined in laboratory tests. The experimental design made it possible to examine flight behavior not only with respect to different types of hosts (young vs senescent common bean foliage) but also with respect to effects due to their utilization during particular stages of beetle development. The median flight time of males was significantly affected by the adult host, but not by the juvenile host; whereas, the median flight time of females tended to be more affected by the juvenile than by the adult host. These different effects of hosts on the flight times of males and females resulted in sexual dimorphism in flight when the sexes were fed senescent foliage as adults. Although age significantly affected the flight time of both males and females, the reproductive status of females did not affect their flight times. The significance of these results are discussed with respect to the influence of the nutritional complexity of habitats on life history strategies and population dynamics.

Uncertainty in pest control thresholds: Application to chemical control of corn earworm on soybean

Abstract Uncertainty and risk are important components of chemical spray decisions. In this paper, we define an action threshold using the decision analytic approach (based on axioms of rational choice under uncertainty) of minimizing expected loss. The concept of loss is defined in terms of the cost of making an incorrect treatment decision. Expected loss implies integrating the loss function over probability distributions used to describe the relevant uncertainties. This concept of the action threshold is applied to control of corn earworm on soybean crops, using a time-dependent threshold function previously developed (Yu et al. , 1992). The main source of uncertainty in this application is the time of onset of influx of adult moths. This approach to defining the threshold provides a framework for explicit consideration of uncertainties and also, through the use of multi-attribute loss functions, inclusion of cost factors other than monetary.

A model for a time-dependent economic threshold for chemical control of corn earworm on soybean

Abstract A model was developed for the economic threshold for chemical control of corn earworm on soybean. The methodology involves development of analytic and piecewise analytic models, based on simulation experiments with mechanistic process level models, supplemented with field observations and laboratory data. The model for the corn earworm population describes the population as a vector, whose elements represent age groups within each developmental stage. The economic threshold was initially derived as a time-dependent surface and operationalized by projecting to a single dimension (medium size larvae or medium plus large size larvae). The resulting threshold is time dependent. Sensitivity analysis indicates that the threshold curve is most sensitive to errors in the description of moth influx and of crop phenology.