Plant Pests and Climate Change

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Plant Pests and Climate Change

Climate change has become one of the biggest challenges facing plant health, and the most common cause of food production disruption in the world. It is a phenomenon that affects the entire world and various aspects of life, hence, the natural world along with its species are among the most affected.

According to new studies conducted by the Food and Agriculture Organization of the United Nations, climate change is promoting the spread of pests and threatening plants and agricultural crops. These pests have increasingly become more harmful to crops and pose an increasing threat to global food safety.

All the conclusions agreed upon by most experts and specialists warn that the impact of climate change on plant pests will become more detrimental and widespread in the world. To top it off, small farmers are by reason considered to be the most affected and harmed community on that level.

How does climate change affect plant pests?

Climate change causes extreme weather phenomena. It makes the plant more vulnerable and therefore empowers the pests. The continuous change in the Earth’s climate will also act as a catalyst for the colonization of new and invasive pests which will eventually lead to the loss of biodiversity. Abnormal high temperatures in the winter and early spring will lead to more pests and the early appearance of lesions.

The increasing risks of pests will pose a threat to workers in the agricultural sector and the reluctance of investors from this sector, which will negatively affect global food security.

What's the impact of climate change on insects?

Insects are classified as cold-blooded organisms whose temperature is almost identical to the surrounding environment. Temperature is considered one of the factors that most affects their life cycle, behavior, and survival.

Experimental studies show that elevated CO2 level often exacerbates the effects of temperature on plant diseases.

The hot climate will increase the growth rates of the insect community and increase the number of generations for species that reproduce for many generations. The duration of the growing and reproductive season will lengthen, and the ability of insects to survive the winter will increase. The hot climate will help insect pests to overcome danger stages during their life cycles, which may reduce the chance of parasitism and natural predation.

Regarding migratory pests: their geographical distribution, migration path, and risks of entering new areas will change.

How does climate change impact plant pathogens?

High temperature weakens the plant’s immunity, making it easily susceptible to infection, and at the same time leads to the emergence of generations of pathogens that are more resistant to high temperatures and more virulent. Plant pathogens have become more capable of infecting crops because of their ability to change their genes to adapt to the surrounding environment, and they have been able to invade new environments due to global warming, and this portends a global health disaster.

With climate change, plant pathogens are becoming more dangerous because they spread easily, can travel long distances, and some species have the ability to remain dormant in the soil for decades and then reactivate their life cycle.

Higher temperatures may cause the plant to become sick earlier than usual, shorten the incubation period so it produces more individuals in the same season, or increase the possibility of the plant being exposed to disease due to extreme weather fluctuations, such as hurricanes and strong winds.

Impact of climate change on weeds

Weeds have short life cycles and produce large quantities of seeds during their growing season. They compete with major crops for water, food and light, causing reduced yields, reduced quality, increased crop stress, reduced resilience to climate change, and may become a refuge for many harmful pests.

Climate change affects weeds as much as it affects cultivated crops, but weeds excel in having great genetic variation, which increases their ability to resist climate change.

The impact of climate change on pesticides

To fight pests, farmers often use chemical pesticides, which are responsible for about 1 to 4% of the greenhouse gas emissions that make climate change worse.

In a hot climate, some pesticides become less effective, such as pyrethroids and systemic pesticides, due to the weak ability of the stressed plant to absorb these compounds. High heat also breaks down the pesticide’s structure and decomposes it, which reduces its effectiveness on the targeted pest, and increases the degree of toxicity of the pesticide to the plant.

Antifungals have been weakened by climate change, and it is no longer appropriate to use compounds that target a single component in the fungus, simply because resistance to the compound will quickly develop and renders it ineffective.

How can the effects of climate change on plants and crops be mitigated?

The effects of climate change and its growing impact on plant health have obligated many countries and organizations to develop intensive plans and programs to manage this issue, and a number of recommendations have been suggested to mitigate the effects of climate change on plant health.

At the forefront of these recommendations is the consolidation of international cooperation, especially since the effective management of plant pests by one farmer or one country is usually unsuccessful and expensive, however, improving measures to limit the spread of pests on an international scale and making amendments to plant protection regulations prove to be more successful.

There is a need for more research on the effects of climate change on pests and, consequently, on plant health.

One must rely on plant varieties that are resistant and tolerant to heat stress, adopt integrated pest control methods, and a smart agriculture method that aids the effective use of resources such as land, fertilizers, water, seeds, etc. to improve the quality and quantity of agricultural products.

Since prevention is better than cure, developing methods for detecting the pest at the early stages will contain the infestation, reduce the resources required to overcome it, and employ modern technology (prediction devices – satellites – artificial intelligence – sensors) to monitor plant pests, analyze and study data, and intensify communication processes with the concerned parties.

The use of chemicals to combat fungi should be reconsidered, and natural enemies of fungi can be used, such as the Trichoderma fungus, which hinders plant fungi by competing with them for food and space or parasitizing them. Genetics can also be used to control the spread of plant pathogens by developing disease-resistant plants by introducing genes that give them resistance to the pathogen and cultivating varieties that carry different resistance genes together, because the genetic diversity in the plant makes it difficult for fungi to invade it. However, the latter remains unacceptable to some people.

Maryse Bou Zeid

mbouzeid@debbaneagri.com

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