A fungus is heading your way. The caterpillars are on the march. So are viruses and any number of insects and nematode worms, and since 1960 they have been shifting north and south at an average speed of 3km a year as the world warms, according to researchers at Exeter University in the UK.
Sandra Gurr and colleagues report in Nature Climate Change that they looked at more than 26,000 observations of 612 well-known crop pests and had access to observations made much earlier, including the first record of fungus attack on oilseed rape in the UK in 1822, Climate News Network reported Sunday.
Crop pests can cause famine, devastation and economic ruin. The 19th century Irish potato famine was caused by the pathogen Phytophthora infestans and the Great Bengal Famine of 1943 was blamed on the fungus Helminthosporium oryzae. French winegrowers have never forgotten nor forgiven the Phylloxera aphid that destroyed the vineyards.
But losses to crop pests are a quiet disaster now: they routinely destroy between 10% and 16% of all crops – a lost harvest that would otherwise feed more than 8% of the planet’s people.
And, warn Gurr and her co-authors, crop pests are still a threat to food security. The spread of pests towards the poles is certainly helped by human activity and they believe the most effective agency is international freight transport.
But global warming is certainly making it a little easier every year for the pests to find comfortable homes and easy pickings in previously unsuitable regions.
The mountain pine beetle Dendroctonus ponderosae has destroyed large areas of pine forest in the US Pacific Northwest. Rice blast fungus has now reached 80 countries, has had a dramatic effect on agricultural economies and on local ecosystems, and ominously has evolved to develop a taste for wheat. Wheat blast is now a big problem in Brazil.