Soybean Rust Stopped in its Tracks

soybean rust

Soybean Rust Pustules

Asian soybean rust (ASR) was first detected in the continental U.S. in 2004 in Louisiana. Before the discovery in the U.S., the yield losses caused by ASR in many parts of the world were devastating. In South America, especially in Brazil, yield losses ranged from 10 to 80%. Funding was made available for a network of ASR sentinel plots that would serve as an early-warning system for the presence of the disease. Sentinel plots are planted two to three weeks earlier than commercial fields. If ASR is found in a sentinel plot, this is a signal to scout surrounding fields. The growth difference in sentinel and commercial fields allows growers and farm advisors time to make decisions. If conditions are optimal for the rapid spread of ASR (warm and humid), the solution is treatment with fungicides.

“Soybeans and wheat made an awesome economic combination for growers in the Southeast this year, creating plenty of optimism for profits from this year’s beans and optimism for planting more of the crop in 2013.

Even the earliest appearance on record of Asian Soybean Rust did little to slow down what is shaping up to be one of the best soybean crops on record in some parts of the Upper Southeast.

Rust was detected along a southern tier of North Carolina counties on Sept. 12, but Mother Nature, a well-coordinated system of sentinel plots, and timely actions by growers stopped rust in its tracks.

Though the disease was documented on Sept. 12, in North Carolina, the earliest on record by three days, it appears there will be little damage to the state’s 1.65 million acre soybean crop.

Duplin County, N.C., Extension Agent Curtis Fountain says once the disease was detected in counties less than 100 miles from his county, growers quickly reacted and applied fungicides when needed.

North Carolina State University Plant Pathologist Steve Koenning and Soybean Specialist Jim Dunphy issued timely updates on movement of the disease and provided virtually day-to-day observations on when and what to spray to best manage ASR.”

Author: Roberson, R.
Affiliation: Farm Press, Editorial Staff
Title: Rapid Grower Response, Weather Stop Early Soybean Rust Outbreak
Publication: Southeast Farm Press, December 5, 2012.

Italian Farmers Realize Profits from Herbicide Applications

In Italy, herbicides to kill weeds in crop fields have been routinely used on almost all the acres for the past 30 years. Is the cost of the herbicide application justified considering the levels of weed infestation? Italian researchers examined the record…

“The frequency distribution of yield loss due to weeds in winter wheat, sugar beet, maize and soybean has been studied using the available data of weed control trials undertaken in north-central Italy in the last 30 years. The breakeven yield loss and the probability of obtaining a positive net return from chemical weed control were calculated, considering different treatment options and different weed-free yields.”

“In winter wheat the probability of a positive net return from chemical weed control is high, between 80.5 and 97.3%. … As far as other crops analysed are concerned, the probability of a chemical treatment being profitable is >80% in maize and soybeans and >95% in sugar beets.”

“The profitability of chemical weed control depends on the density, composition and time of emergence of the weed flora, on the competitiveness of the crop and on the chemical used. In most cases, however, it is profitable to spray; in other words in the Po Valley there is a high degree of probability that the weed density is sufficient to bring about a yield loss greater than the treatment cost.”

Authors: G. Zanin¹, A. Berti² and M. Giannini³
Affiliation: ¹ Instituto di Agronomia Generale e Coltivazioni Erbacee, Padova, Italy; ² Centro per lo Studio dei Diserbanti del CNR, Padova, Italy; ³ ESAV, Venice, Italy
Title: Economics of herbicide use on arable crops in north-central Italy.
Publication: Crop Protection. 1992. 11:174-180.

Sustainable Ag Pioneers Learn Value of Modern Herbicides

Dick and Sharon Thompson of Boone, Iowa are pioneering giants of the sustainable agriculture research agenda in the U.S. They helped found Practical Farmers of Iowa. Since 1986, the Thompsons have conducted on-farm research trials and have produced an annual report. The Thompson farm is not organic; however, they generally do not use herbicides, preferring to use a rotary hoe to destroy weeds. In most years, the mechanical control works well, but then came the very rainy 2008 growing season…

“2008 was not a good year for soybeans because of weather, rain and more rain. This was the first year that we lost money on a soybean field. We could not rotary hoe. The beans were good size when we cultivated the first time (June 24). The cultivator threw soil in and around the bean plants, looked like an excellent job. It rained 1.25 inches two days later on June 26 starting all the weed seed we pushed into the row. We had grass in the row, which is not the norm, along with broadleaf weeds. … The field was a mess. The rope wicks attached [to] our old hyboy filled with round up [herbicide] went up and back on the same rows to kill the weeds so that our small combine could harvest the field. The rope wick killed the weeds and the combine was able to handle the dead weeds. The yield was 37 bushel per acre, 7 bushel below county average of 44 and we lost $49 per acre. The field was sprayed for aphids adding more expense.”

“We could not manage weeds in the end rows of corn and soybean fields without herbicides.”

Authors: Dick and Sharon Thompson
Publication: Thompson Agriculture Alternatives 2009 Report
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