Defoliación artificial para estimar pérdidas por daños foliares en frijol (Phaseolus vulgaris L.)

Abstract

Bean diseases such as rust (Uromyces phaseoli var typica), web blight (Than:cucumeris), and angular leaf spot (Isariopsis griseola), among others, not only destroy plant foliage but also cause physiological damage. To determine yield losses, the cultivars “ICA-Guali” and "Porrillo Sintético'' were artificially defoliated to simulate disease attack Twenty, 40, 60, 80, or 100 per cent of the leaf surface area was removed at one of the following plant development stages formation of first trifoliate leaves, initiation of flowering, pod formation, or initiation of maturation (60 days after planting) From 3 replications yield losses from 100% defoliation were greater at the growth stages initiation of flowering and pod formation. At those stages losses were 59 and 77 per cent respectively for "ICA-Guali”, for “Porrillo Sintético '' losses were 60 and 73 per cent in the same period. During the formation of fist ni foliate leaves, 100 per cent defoliation decreased yields of 'ICA-Guali' 34% and those of “Porilla Simárico'' 49 per cent Total defoliation in stage of initiation of maturation decreased yields 20 per cent in both cultivars.