Soybean rust increased by 220% in Brazil, costs BRL2 billion per season

Date:03-10-2023

Since its introduction in Brazil in 2001, Asian soybean rust, caused by the fungus Phakopsora pachyrhizi, has been the most serious disease that affects soybean crops, causing losses of up to 80% if not controlled.

According to surveys conducted by the Antiferrugem Consortium, which brought together some 100 laboratories in Brazil, the total cost of the disease exceeds US$2 billion per harvest in the tropical country, considering the purchase of fungicides and the productivity losses it causes.

The Antirust Consortium also said that the recent number of cases of Asian soybean rust in the 2022/23 harvest exceeded 119 in nine Brazilian states, adding that compared to the same period last year, between November 2022 and January 2023, this was an increase of more than 220% in just one season.

According to the Brazilian Association of Soy Producers (Aprosoja), the hot and humid climate favored the spread of the fungus, Phakopsora pachyrhizi.

Management strategies are centered on practices such as the ″sanitary void,″ which is having live soybean plants in the field for at least 90 days to reduce the spread of the fungus inoculum.

The use of cultivars with an early cycle and sowing at the beginning of the recommended period, as well as the adoption of resistant cultivars, respecting the sowing calendar, and the use of fungicides can also help control the disease.

Currently, P. pachyrhizi has mutations that confer resistance to the three main groups of site-specific fungicides, and new mutations can be selected over time.

″The fungus that causes the disease can adapt to some of the control strategies, either by losing sensitivity to fungicides or by 'breaking down' the genetic resistance of soybean cultivars,″ said Cláudia Godoy.

(Editing by Leonardo Gottems, reporter for AgroPages)