Feb 11, 2010
Scientist Warn Farmers To Continue Monitoring Rust In Their Fields
Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.
Even though the soybean crop in Mato Grosso is approaching 20% harvested, farmers in the state are being advised to stay alert to the presence of soybean rust. Scientists are concerned that farmers are not giving the disease the importance that it deserves because the last severe outbreak of the disease in Mato Grosso was three years ago. Most of the early maturing soybeans have already been harvested, but seventy percent of the soybeans in the state are medium to late maturing varieties which are the most susceptible to the disease due to their longer life cycle. Another concern this year is the fact that the fungicides are now less effective in controlling the disease.
The last severe outbreak was in 2006 and at that time a farmer could apply fungicides after the disease had a foothold in his soybean field. The disease has since evolved and that strategy no longer works. Fungicides now must be applied at the earliest possible moment after the disease has been observed in the field. For early maturing soybeans it is recommended that fungicides be routinely applied every 25 days. For medium maturity soybeans the interval should be reduced to every 15 days and for late maturing soybeans even less. Farmers are being advised to inspect their fields at least every two days.
The rust situation on Mato Grosso is not as bad as it is in the neighboring states of Goias and Mato Grosso do Sul where the rainfall has been heavier and the number of confirmed rust cases is much higher.
Scientists are also advising their clients to consider applying fungicides even as the crop approaches maturity in order to hold down on the spread of the spores during the harvesting process.
The last severe outbreak of rust in Mato Grosso occurred in 2006. During that year, farmers in Primavera do Leste, which is located in southeastern Mato Grosso, needed ten applications of fungicides in order to control the disease. This year, the early soybeans in the same region received 1.5 applications of fungicides and the medium and later maturing soybeans will be sprayed four to five times.