Probability of occurrence of the mixed infection Canditatus phytoplasma sp. - Bean golden yellow mosaic virus (BGYMV) in Phaselous vulgaris L.

Abstract

The objective of this work was to determine the probable occurrence of the mixed infection phytoplasma - BGYMV in Phaselous vulgaris L. and the symptoms associated. This probability was calculated using classical probability and a smoothed adjustment of the series of not centered moving median was used to estimate the presence of a mixed infection in two close points. The conditional probabilities of a mixed infection knowing the a priori probabilities of phytoplasma and begomovirus were calculated using the classical formula of probability. The influence of present symptoms in the agricultural ecosystem on the probability of this mixed infection to increase and its association with the vector presence were evaluated using principal component analysis and canonical discriminate test. The occurence of a mixed infection was more probable when it was known a priori that the phytoplasma was present than when it was the begomovirus. Symptoms in the bean crop associated with the mixed infection were wrinkled leaves, mosaic, and reduced size of the leaves. Even in the presence of the vector, leaf chlorosis and deformation were associated with a low probability of mixed infection, which suggested the presence of a unique virus or another disease. We suggest that this association can be used in the prediction of mixed diseases as an initial prognosis leading to a rapid diagnosis with reduced costs due to a better selection of samples.