Argentina corn harvest faces more deep cuts from stunt disease spread

By Maximilian Heath

BUENOS AIRES, April 17 (Reuters) - Argentina's corn harvest, already cut sharply due to a stunt disease spread by leafhopper insects, is "likely" to be slashed significantly further, a Rosario grains exchange analyst said on Wednesday, a potential knock to global supplies.

Argentina, the world's No. 3 corn exporter, once expected a record haul of corn, but since March the crop has been hit by an unprecedented outbreak of the bugs, which led the exchange to slash its forecast by 6.5 million tons to 50.5 million tons last week.

Leafhoppers are insects that carry the harmful spiroplasma disease and whose population tends to spread in hot and dry conditions. They have badly dented 2023/24 corn, which started its harvest a few weeks ago and is now 15.3% complete.

"Corn is very affected and this is something we fear and that worries us," Cristian Russo, head of agricultural estimates at the Rosario Stock Exchange, told Reuters.

"It is likely that this will be a factor in further losses, which will not be minor losses."

Russo said that in the worst-hit northern provinces such as Chaco, Santiago del Estero and Tucumán, the losses caused by the disease ranged between 40% and 50%, when normally the figure reached only 5% at worst.

He added that severe cases of leafhoppers, which thrive in humid and warm conditions, were also being seen in regions where they usually did not appear, a reflection of the unusual nature of this year's damaging outbreak.

"It has reached areas where it never reached before. It took the technicians by surprise. It hit the center and north of (the province of) Santa Fe and (the province of) Córdoba very hard and reached the (agricultural) core region," Russo said.

Cold weather outlook?

In response to the outbreak, the government announced last week it was accelerating approval procedures for two insecticide products recommended to combat the spiroplasma disease, though that comes largely too late for the current harvest.

Another factor that will determine how the outbreak progresses is the arrival of low temperatures, because the insect cannot resist temperatures below 4 degrees Celsius, Russo said. Argentina is in early autumn.

However, scientists at the University of Buenos Aires (UBA) said that a rapid decrease in temperatures was not expected in northern Argentina, the location of the worst outbreaks.

"The northern provinces have already had very warm temperatures since the summer," Matilde Rusticucci, an academic at the university's Department of Sciences of the Atmosphere and Oceans, said in a report on Wednesday.

"In the coming months they continue to have the possibility of suffering very high maximum temperatures."

However, rainfall is likely to subside due to the weakening of the El Niño climate phenomenon, which in Argentina translates into an increase in the rainfall pattern.

(Reporting by Maximilian Heath in Buenos Aires; Writing by Adam Jourdan; Editing by Matthew Lewis)