Africa: Climate Change Brings Previously Unthinkable New Pest and Disease Pressures

Berlin — Temperate climate zones are home to most of the world’s richest countries, and they have until now been the world’s main breadbaskets for meeting international demands for grains, oilseeds and livestock.

However, climate change threatens to alter the course of history, allowing some native pests to reproduce more frequently and for longer periods of time, while invasive insects and pathogens become more widespread.

It is no coincidence that agriculture in temperate regions, such as northern Europe and much of North America, is characterized by high productivity.

Agricultural sectors in temperate zones are highly capital intensive with new technologies continuously being introduced; weather conditions during growing seasons are often predictably favorable; harsh winters and cold springs prevent many plant pests and pathogens from overwintering, all of which allow crops to approach their physiological ceilings while minimizing storage losses.

In a word

Pests and diseases may undergo rapid evolutionary changes through natural selection during climate change. As the climate warms, agricultural pests and diseases move northward and become more widespread.

Nevertheless, the science linking climate change to changes in the behavior of insect pests and pathogens is complex, given the multitude of biological responses of the latter and their interactions with changing environmental stimuli.

Invasive species, by definition, have succeeded in areas outside of their native range and are therefore more adaptable than native species. Evolution and adaptation are therefore intrinsic mechanisms that explain why pests and diseases pose consistent threats (both locally and transboundary) in a changing climate.

Natural selection also explains the resistance of an increasing number of insect pests to pesticides.

Why should richer economies worry? What science tells us

Rising temperatures in temperate zones are likely to attract new migrated pests, according to a recent report on the scientific links between climate change and pest and disease outbreaks by the TMG Think Tank for Sustainability and Climate and the Intergovernmental Authority on Development’s Implementation Center. from areas where heat stress is very severe.

However, with warmer winters in northern latitudes, migration is more likely, resulting in insect pest populations rising to harmful levels due to early emergence (shorter dormancy due to accelerated metabolic rates associated with higher temperatures).

While there is uncertainty as to whether invasive species can establish in new environments, much will depend on factors such as the rate of temperature rise, food supply and natural enemies, and whether they can maintain or adapt to synchrony with plant growth cycles. they feed

Warming will also have other harmful effects, such as increasing generations of native and invasive insect pests through more breeding throughout the year, encouraging population growth.

Finally, with a larger temperature window in which insects and pathogens can flourish and increased heat stress on plants in temperate zones, these zones may experience rapid increases in pest and disease outbreaks, increased pesticide use, increased costs to farmers, and lower yields.

In fact, transboundary and transoceanic expansion of invasive species is already northward due to climate change, including extreme events such as cyclones and storms, and is exacerbated by international trade and travel.

An example here is the recent spread of destructive lampreys to the United States, which demonstrate great adaptation to new environments and pose an imminent threat to viticulture-based economies. The researchers predict further expansion of the corn earworm, which destroys corn, cotton, soybeans and vegetables, into the U.S. corn belt.

According to UN estimates, at least 20 percent of all food grown in the world is lost to plant pests and diseases every year. As rich temperate countries become increasingly vulnerable, total losses will increase.

Consequently, as confirmed by the latest report of the Intergovernmental Panel on Climate Change (IPCC), while scientific theory is urgently needed to provide additional precision on pest-climate dynamics, action is needed now.

The use of technological breakthroughs in the field of artificial intelligence will be important for the control of plant pests and diseases, diagnosis through early warning systems, and epidemic prediction.

As with all pest and disease outbreaks, prevention is cheaper than dealing with full-blown crises, and moreover, once pests and diseases have established themselves, it is often impossible to eradicate them.