Leonard B. Coop

Predicting effects of climate change on Swiss needle cast disease severity in Pacific Northwest forests

Abstract Swiss needle cast of Douglas-fir (Pseudotsuga menziesii) is caused by the ascomycete Phaeocryptopus gaeumannii. Symptoms are foliage chlorosis and premature needle abscission due to occlusion of stomata by the ascocarps of the pathogen, resulting in impaired needle gas exchange. Growth losses of 20%-50% due to Swiss needle cast have been reported for approximately 150 000 ha of Douglas-fir plantations in western Oregon since 1996. In the western Coast Range of Oregon and in New Zealand, winter temperature is strongly correlated with pathogen abundance. Models for predicting disease severity based on winter temperature account for 77% and 78% of the variation in 1- and 2-year-old needles, respectively, for western Oregon sites and approximately 80% for New Zealand. A trend of temperatures increasing by 0.2–0.4 °C during the winter months and spring precipitation increasing by 0.7–1.5 cm/decade since 1970 suggests that regional climate trends are influencing the current distribution and severity of Swiss needle cast disease. Continuing winter temperature increases predicted for the Pacific Northwest of approximately 0.4 °C/decade through 2050 suggest that the severity and distribution of Swiss needle cast is likely to increase in the coming decades as a result of climate change, with significant consequences for Pacific Northwest forests.

Decision support system for economic analysis of grasshopper treatment operations in the African Sahel

A decision support system for benefit/cost analysis of chemical treatment of the Senegalese grasshopper, Oedaleus senegalensis (Krauss) (OSE), was created to assist in the training, analysis, and management of grasshopper treatment programmes. The system, known as GHLSIM, has linked simulation models, databases, and a user interface. Millet and sorghum phenology and yields are estimated by an FAO (Food and Agriculture Organization, United Nations) soil water deficit model. Outputs from the PRIFAS (Programme de Recherches Interdisciplinaire Francais sur les Acridiens du Sahel) OSE biomodel, including daily grasshopper life stages and favourability for development, are converted to density estimates using survey data, oviposition rates, and natural and insecticide-caused mortality. Crop loss is estimated through crop injury units — a function of grasshopper stage densities, consumption rates, crop preference, crop stage susceptibility, and non-crop vegetation greenness. Second-year benefits of treatment are estimated from end-of-season egg-pod densities. The model was calibrated using published economic thresholds for four crop stages. Yield increases from a late-season grasshopper aerial treatment campaign, 22 September — 19 October 1987, at 13 sites in eastern Chad were estimated at 33%±20% (s.e.). Benefit/cost ratios were 2.6±0.5 for the first season, and 3.8±0.7 with second-year effects added. The analysis indicated that optimal timing was 5–10 days earlier than the actual treatments. Crop yield reports from treated and non-treated areas, a crop loss assessment conducted in Batha, Chad in October 1987 and a break-even analysis provide further evidence that the campaign was successful and cost-effective at most sites, as indicated by model results.

The consequences of photoperiodism for organisms in new climates.

A change in climate is known to affect seasonal timing (phenology) of the life stages of poikilothermic organisms whose development depends on temperature. Less understood is the potential for even greater disruption to the life cycle when a phenology shift exposes photoperiod-sensitive life stages to new day lengths. We present a conceptual framework and model to investigate the ways that photoperiod-cued diapause can interact with a change in climate or latitude to influence voltinism in poikilothermic organisms. Our degree-day phenology model combines detailed spatial climate data, latitude- and date-specific photoperiods, and development and photoperiod response parameters. As an example, we model the biological control beetle Galerucella calmariensis and map the number of generations expected following its introduction into diverse climates throughout the continental United States. Incorporation of photoperiodism results in a complex geography of voltinism that differs markedly from predictions of traditional phenology models. Facultative multivoltine species will be prone to univoltism when transported to either warmer or southern climates due to exposure of the sensitive stage to shorter day lengths. When moved to more northern locations, they may attempt too many generations for the season duration thereby exposing vulnerable life stages to harsh weather in the fall. We further show that even small changes in temperature can result in large and unexpected shifts in voltinism. Analogous effects may be expected for organisms from wide variety of taxa that use photoperiod as a seasonal cue during some stage of their life cycle. Our approach is useful for understanding the performance and impacts of introduced pests and beneficial organisms as well as for predicting responses of resident species to climate change and climate variability.

Integrated pest management (IPM) and Internet-based information delivery systems

The Internet enables collaboration and information sharing on an unprecedented scale. It has become a prime medium for research and extension communication. The World Wide Web (WWW) makes it possible to combine information from many different sites in a seamless fashion. The potential for using the web to integrate all types of static and interactive (dynamic) information is unique and unprecedented. The web provides excellent interfaces for all kinds of interactive network databases, and many kinds of online analyses and data processing. Web-based models and decision support systems (DSS) are becoming popular because little or no client software is required, thus reducing software management and distribution costs. No other medium offers such ability as simultaneous real-time weather information, multimedia, analytical processing and multi-way discussion and feedback. IPM is an information-intensive system. Both IPM research and implementation require the reliable supply of timely information. The Internet provides the means to establish communication links between IPM researchers and extension professionals and their clientele to expedite multi-way exchange of information and technology transfer. The Internet particularly the WWW, has opened up a rich array of data resources for IPM research, extension, teaching, and learning that was not as readily accessible before the advent of the Internet. The future of IPM delivery systems through the Internet is promising; internet-based information exchange is quickly becoming an absolute requirement for local, regional/areawide, and international implementation of IPM systems.