25 February 2016
Potential Effects of Climate Change on Transboundary Plant Pests and Diseases: FAO’s Response and Contributions
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Climate change is expected to affect, where crops are cultivated, the distribution of plant pests, the introduction of new pests, the frequency of major pest outbreaks, and the risk of pesticide residues in food.

Approximately one-third of global crop production is lost every year to plant insects and diseases, including migratory insects and diseases, referred to as transboundary plant pests, which spread to a number of countries and can reach epidemic proportions in which control and management require cooperation between those countries. Climate change is expected to affect, where crops are cultivated, the distribution of plant pests, the introduction of new pests, the frequency of major pest outbreaks, and the risk of pesticide residues in food.

The consequences of climate change and its effect on plant pests could cause severe reductions in crop production, an increasing number of crops to fail, and a greater reliance on pesticides.

The primary drivers that influence a change in plant pest dynamics are climatic conditions such as increases in temperature, variability in rainfall intensity and distribution, change in seasonality, drought, carbon dioxide concentration in the atmosphere and extreme high rainfall events (e.g. hurricanes, storms, floods). Other factors such as pest characteristics (e.g. lifecycle, optimal growth conditions, and host interaction) and intrinsic ecosystem characteristics (e.g. monoculture, biodiversity) will affect these dynamics. This could lead to a greater number of emerging plant pests, which come into contact with new hosts that do not necessarily have an appropriate level of resistance, or are introduced in the absence of naturally occurring biological control agents. New more virulent and aggressive strains of plant pathogens are likely to develop as experienced recently on wheat, coffee and cassava.

So far, global warming has culminated in the spread and adaptation of insect vectors such as flies, thrips, and aphids, resulting in higher frequency and wider spread of diseases transmitted by these vectors and causing substantial damage to infested crops. Examples of these diseases are viral diseases of cassava (Mosaic virus, Brown Streak virus), banana bunchy top disease, and greening disease of citrus.

Other crop diseases that can be potentially influenced by climate change include potato diseases, diseases of wheat, maize and oil palm, and coffee leaf rust disease.

Although the specific implications of climate change on plant pests and diseases are difficult to predict, it seems possible to project future condition or occurrence of such pests and diseases.

For example, desert locust, which is one of the most dangerous and damaging of all migratory pests, has adapted to semi-arid or desert environments where rainfall is scarce and irregular. Potential changes in temperature, rainfall and wind patterns associated with climate change are expected to have dramatic effects on desert locust, such as causing locusts to mature soon and allowing seasonal breeding to commence earlier and last longer. Similarly, the increased El Niño events due to climate change are likely to have an impact on three other locust species (Italian, Moroccan, and Migratory) in the Caucasus and Central Asia.

The FAO Desert Locust Information Service (DLIS) operates an early warning system to monitor weather, ecological conditions and locust infestations on a daily basis since 1978. It is the global focal point and clearinghouse for all locust and locust-related survey and control data, which are analysed to produce monthly bulletins, six-week forecasts, alerts and warnings.

In Madagascar, a greater incidence of extreme rainfall events could cause more frequent and intense plagues of Migratory Locust and Red Locust. In Indonesia, an increase in the frequency of droughts could lead to greater swarm formation by the local Migratory Locust subspecies. In Peru, above-average rainfall associated with El Niño events is likely to favor outbreaks of Schistocerca interrita in the northwest desert that can spread to the Andean valleys.

Another example are the diseases of wheat, such as stem and stripe rusts, expected to be among those influenced most by climate change. They are especially serious in the Near East, Central Asia and Eastern and Northern Africa, creating severe epidemics and causing significant losses in wheat production. FAO, in partnership with ICARDA and CIMMYT in context of the BGRI (Borlaug Global Rust Initiative), works closely with countries affected or threatened by wheat rust, including Ug99, to better manage wheat rust in the face of climate change.

At the global level, FAO manages transboundary plant pests within the Food Chain Crisis Management Framework – Emergency Prevention System (FCC-EMPRES). The common strategy to address transboundary pests relies mainly on prevention, early warning, and early reaction and capacity development.

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