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.