Plants are humans’ best friends and main allies in life on earth. Plants are responsible for 98 percent of the oxygen we breathe and make up 80 percent of our daily calorie intake. However, we often take them for granted, not realizing the importance of keeping them healthy.
Every year up to 40 percent of food crops is lost to plant pests and diseases. These losses in both yields and income have a devastating effect on the poorest communities who base their livelihoods on agriculture.
Plant pests and diseases know no boundaries. In a highly globalized and interconnected world, it is not surprising that these can travel and colonize new areas. Climate change is exacerbating this spread, creating favourable conditions for these pests and the survival of specific plant diseases in new areas. For example, climate change has already had a hand in expanding the host range or distribution of pests such as the red palm weevil, Fall armyworm, fruit fly, desert locust and emerald ash borer. An increase in pests poses a significant threat to the environment because pests, particularly invasive ones, can cause a major loss in biodiversity. Plant diseases are equally devastating, wreaking havoc on harvests and slashing incomes for farmers.
So, what are the some of the most invasive plant diseases and how is climate change contributing to their spread?
Here are just five increasingly dangerous plant diseases threatening plant health:
1) Potato late blight
Late blight is a disease that attacks potatoes and tomatoes and is caused by the fungus Phytophthora infestans. In tomatoes, the disease causes lesions on leaves, petioles and stems, while potato tubers develop a rot up to 15 millimetres deep. The fungus has a great ability to adapt to changing conditions, preferring warm and wet seasons. Climate change is creating favourable conditions for this fungus at different times and places than before. For example, in Egypt, increasingly warm and wet weather is promoting potato late blight epidemics, allowing the pathogen to accumulate earlier in the growing season.
2) Coffee leaf rust
This fungal disease, also known as Hemileia vastatrix, affects the leaves of the coffee plant. It begins to show up as yellow spots and then turns into a yellow-orange powder that easily spreads to other coffee plants. Coffee leaf rust is one of the biggest challenges for global coffee production because the disease is able to adapt to different climates. Global warming seems to help to reduce the incubation period of the pathogen, meaning that more generations of the pathogen can develop in a growing season.