Invasive insects will destroy thousands of trees in the coming years, according to a new study published by the British Ecological Society. Experts say that by mid-century, invasive insects like the emerald ash borer could kill 1.4 million street trees in the United States, at a cost of more than $900 million.
The study presents the first national prediction of street tree death due to invasive insects. To investigate, a research team led by McGill University analysed the data from some 30,000 urban areas in the United States.
Estimates suggest that emerald ash will be the most destructive of the invasive insects. Experts estimate that emerald ash bora is responsible for 90 percent of the death of 1.4 million trees. Significantly, the blight is expected to kill all ash trees in more than 6,000 urban areas.
According to the survey, the effects of invasive insects will not be evenly distributed across the country. Experts found that less than a quarter of the US community would be affected, including 95 percent of street tree deaths. Some areas between New York, Chicago and Milwaukee will be severely affected.
The researchers noted that their findings could help urban tree managers predict which tree species, in which areas, will be most at risk from invasive insects.
“These results can hopefully provide a cautionary tale against planting a single species of the tree throughout entire cities, as has been done with ash trees in North America,” said study lead author Dr Emma Hudgins. “Increasing urban tree diversity provides resilience against pest infestations. While we know this more intuitively for monocultures of crops, many cities continue to plant what are essentially monoculture urban forests.”
Along with Iran and Pakistan, India in the Southwest Asia region has been identified by the United Nations FAO as one of three hotspots for locust swarms. Of the three, the Horn of Africa has been hit the most by locust swarms, to the point that the FAO has described it as “an unprecedented threat to food security and livelihoods”.
Ethiopia, Kenya and Somalia are among the 17 countries that witnessed the locust attacks in the Horn of Africa. In the Red Sea region, locusts have destroyed vegetation in Saudi Arabia, Oman and Yemen.
In India, about 1.7 lakh hectares of agricultural land has been affected by locust swarms, which arrived from Pakistan through the border areas of Rajasthan and Gujarat.
Farmers in Rajasthan and Gujarat have faced locust outbreaks since December 2019, when the insects entered Pakistan from Jalore and Jaisalmer in Rajasthan and then spread to Banaskantha, Patan and Mehsana districts of Gujarat.
Out of the total 1,68,548 hectares of damaged agricultural land, over 88 per cent of the crop was severely damaged, resulting in a loss of lakhs of rupees.