Impacts on Crop Protection - Climate Resilient Agriculture for Ensuring Food Security - page 106

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Impacts on Crop Protection

Abstract
Anthropogenically induced climatic change arising from increasing levels
of atmospheric greenhouse gases infl uences the ecology of agricultural
pests such as insect pests, diseases, nematodes, and weeds. Changes in
climate may trigger changes in geographical distribution, increased over-
wintering, changes in population growth rates, increases in the number of
generations, extension of the development season, changes in crop-pest
synchrony, changes in interspecifi c interactions, pest biotypes, activity and
abundance of natural enemies, species extinction, increased risk of inva-
sion by migrant pests, and effi cacy of crop protection technologies. Global
warming will also reduce the effectiveness of host plant resistance, trans-
genic plants, natural enemies, biopesticides, and synthetic chemicals for
pest management. Therefore, there is a need to generate information on
the likely effects of climate change on pests to develop robust pest man-
agement technologies that will be effective in future under global warming
and climate change.

Keywords
Climate change • Insects • Mites • Plant pathogens • Nematodes • Weeds

Crop plants live in a very complex ecosystem in
competition with neighboring plants including
weeds. Both are supported and/or attacked by
viruses, bacteria, fungi, insects, mites, spiders,
nematodes, amphibia, birds, mammals etc. All of
these species interact with each other. It is esti-
mated that globally 70,000 pest species, includ-
ing 9,000 insect and mites, 50,000 plant
pathogens, and 8,000 species of weeds, exist.
About 10 % of these 70,000 are considered major

pests. Climate change will increase the chal-
lenges from pests.
There have been several efforts to provide a
measure of global crop losses by weeds, insects,
and diseases. The most recent and comprehen-
sive of these estimates are those made by Oerke
( 2006 ) (Table 6.1 ). Estimates on potential and
actual losses despite the current crop protection
practices are given for wheat, rice, maize, pota-
toes, soybeans, and cotton for the period 2001-