Coffee plant disease not caused by climate change: Study

London: Fears that climate change is promoting a fungal disease which can devastate coffee crops may not be true as there is no evidence found to prove this, researchers say.

Hemileia vastatrix is a fungus that causes coffee leaf rust (CLR) -- a disease that is devastating to susceptible coffee plantations. 

In the study the researchers tested the hypothesis that the weather was responsible for a recent outbreak of CLR in Colombia and that climate change increased the probability of weather conditions favourable to CLR.

"We find no evidence for an overall trend in disease risk in coffee-growing regions of Colombia from 1990 to 2015, therefore, while weather conditions were more conducive to disease outbreaks from 2008 to 2011, we reject the climate change hypothesis," said lead author Dan Bebber from the University of Exeter in Britian. 

Colombian coffee production fell by about 40 per cent from 2008-11, and this decline has been linked to a severe CLR outbreak across Colombia and neighbouring countries.

Coffee serves as the obligate host of coffee rust, that is, the rust must have access to and come into physical contact with coffee in order to survive.

There was a "perfect storm" of factors favourable for CLR at that time, including weather conditions and a decrease in fertiliser use due to price rises during the 2008 financial crisis, Bebber stated.

"Farmers weren't treating coffee bushes as they normally would, and this was probably one of the factors that led to the rise in CLR," he said adding, "the climate at the time was conducive to CLR but there had been earlier periods of similar conditions when there wasn't an outbreak."

The paper was published in the journal Philosophical Transactions B.