Relationship between precipitations registered in reproductive stages of soybean and severity of Septoria glycines and Cercospora kikuchii
From 2003 to 2008, late season disease severity [LSDsev] values [Brown spot and Cercospora leaf blight] were recorded at the R7 growth stage at several sites in Santa Fe and Córdoba Provinces. The annual LSDsev records [N=15] were grouped into two epidemic categories based on a threshold value [median of observed disease data]: severe [LSDsev less than 36 percent] and moderate to light [LSDsev more or equal to 36 percent]. Variations in epidemic levels were studied in relation to precipitation-based variables, processed in a time window limited by R3 and R5 growth stages. The variables were expressed as frequency [days] and total accumulation [mm] of daily precipitations greater than the thresholds 1, 5, 7 and 10 mm. The variables PrF7 [number of days with precipitations less than 7 mm] and AcPr7 [total accumulation of daily precipitations less than 7 mm] and the interaction [product] between them [It7] were the most strongly correlated, according to Kendall tau-b coefficients [rK=0.74, 0.60 and 0.71 respectively].Logistic regression model including AcPr7 correctly estimated the probability of occurrence of epidemic categories in 12 cases [out of 15]. Logistic models integrating PrF7 or the interaction effect [It7] presented prediction accuracies of 93.3 percent. These results could be useful for prediction and chemical control of LSD.
| Main Authors: | , , , |
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| Format: | Texto biblioteca |
| Language: | spa |
| Subjects: | GLYCINE MAX, LATE SEASON DISEASES, LOGISTIC MODELS, CERCOSPORA, CERCOSPORA KIKUCHII, PUNCTUM BLANDIANUM, SEPTORIA GLYCINES, |
| Online Access: | http://ceiba.agro.uba.ar/cgi-bin/koha/opac-detail.pl?biblionumber=46576 |
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