Agricultural Pests

Pest-crop interactions play a crucial role in agro-ecosystems. Pest problems are very likely to be exacerbated under changing climate conditions since pests tend to thrive in warmer conditions (Rosenzweig et al., 2001). This is due to the lengthening of the frost-free seasons, allowing for more generations of pests; the extension of overwintering ranges with warmer winters; and the potential for new pests to emerge and spread, such as has occurred with the soybean cyst nematode and the soybean sudden death syndrome caused by Fusarium solani f. sp. alycines (Figure 10.8). Even in the current climate, warmer temperature and increases in rainfall tend to increase average per acre pesticide usage costs for many

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10 15 20

% Change to yield

Figure 10.7 (A) Demand met (monthly average percentage of water demand met) and reliability (percentage of years in which water demands are met) for the Lower Missouri Water Region for the present and for the Max Planck (MPI) climate change scenario for the 2010s, 2020s, and 2050s. (B) Runoff in the water regions supplying the U.S. Cornbelt for current climate, and the Geophysical Fluid Dynamics Laboratory, MPI, and Hadley Center (HC) climate change scenarios. (C) Number of events causing damage to maize yields due to excess soil moisture conditions, averaged over all study sites, under current baseline (1951-1998), and the HC and Canadian Climate Centre climate change scenarios. Events causing a 20% simulated yield damage are comparable to the 1993 U.S. Midwest floods. (From Strzepek, K.M., D.C. Major, C. Rosenzweig, A. Iglesias, D.N. Yates, A. Holt, and D. Hillel. 1999. J. Am. Water Resour. Assoc., 35:1639-1655; and Rosenzweig, C., F.N. Tubiello, R. Goldberg, E. Mills, and J. Bloomfield. 2002. Global Environ. Change, 12:197-202. With permission.)

10 15 20

% Change to yield

Figure 10.7 (A) Demand met (monthly average percentage of water demand met) and reliability (percentage of years in which water demands are met) for the Lower Missouri Water Region for the present and for the Max Planck (MPI) climate change scenario for the 2010s, 2020s, and 2050s. (B) Runoff in the water regions supplying the U.S. Cornbelt for current climate, and the Geophysical Fluid Dynamics Laboratory, MPI, and Hadley Center (HC) climate change scenarios. (C) Number of events causing damage to maize yields due to excess soil moisture conditions, averaged over all study sites, under current baseline (1951-1998), and the HC and Canadian Climate Centre climate change scenarios. Events causing a 20% simulated yield damage are comparable to the 1993 U.S. Midwest floods. (From Strzepek, K.M., D.C. Major, C. Rosenzweig, A. Iglesias, D.N. Yates, A. Holt, and D. Hillel. 1999. J. Am. Water Resour. Assoc., 35:1639-1655; and Rosenzweig, C., F.N. Tubiello, R. Goldberg, E. Mills, and J. Bloomfield. 2002. Global Environ. Change, 12:197-202. With permission.)

Figure 10.8 Spread of agricultural pests under current climate conditions: (top) Spread of soybean cyst nematode, 1971-1998; (bottom) Spread of soybean sudden death syndrome. (From Rosenzweig, C., A. Iglesias, X.B. Yang, P.R. Epstein, and E. Chivian. 2001. Global Change Hum. Health, 2:90-104. With permission.)

Figure 10.8 Spread of agricultural pests under current climate conditions: (top) Spread of soybean cyst nematode, 1971-1998; (bottom) Spread of soybean sudden death syndrome. (From Rosenzweig, C., A. Iglesias, X.B. Yang, P.R. Epstein, and E. Chivian. 2001. Global Change Hum. Health, 2:90-104. With permission.)

crops (Chen and McCarl, 2001). The emergence of new pests could produce situations for which agricultural systems may not be prepared.

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