Predictive model for "Mal de Rio Cuarto" disease Intensity.

MARCH G.J; BALZARINI M; ORNAGHI J.A; BEVILACQUA J.E; MARINELLI A

PLANT DISEASE

The American Physiological Society

Lugar: St Paul; Año: 1995 vol. 79 p. 1051 - 1053

0191-2917

“Mal de Río Cuarto” (MRC) virus disease is the most important virus disease of maize (Zea mays L.) in Argentina with the rural areas near Chaján, Sampacho, and Suco (in Río Cuarto, province of Córdoba) being the most affected. A predictive model for MRC before planting a crop was developed based on the disease intensity over nine  agricultural years (1981-82 to 1989-90) and a series of weather variables for that period (such as minimum, mean, and maximum temperatures, number of frosts, and amount of rainfall). To build the model, agricultural years were divides into two groups according to the percentage of severely affected plants (intensity). A year was considered “mild” if the percentage of severely affected plants was less than 20% and “severe” if the percentage was higher.  A discriminates stepwise procedure was used to analyzed data. The average maximum temperatures in Junes, July and August, the average maximum temperatures in July and August, and total rainfall in June, July, and August were found to be significant forecasters of disease intensity. The model was validated in the agricultural years of 1990-91, 1991-92, 1992-93 and 1993-94. The relative intensity of the disease was adequately forecasted and confirmed for those years. Results support the feasibility of forecasting MRC intensity prior to planting maize in the area under study.