Detección de la forma sexual de la sarna del peral (Venturia pirina ADERH) en montes frutales del sur de la provincia de Mendoza, Argentina

Abstract

In view of the increasing damages produced by the pear scab (Fusicladium pirinum Lib.) in fruit groves in southern Mendoza, a study was designed to explain some aspects of the biology of the fungus in this region, and to establish the presence of the still undetected sexual form in the province. In the autumn of 2001, leaves with clear symptoms of the disease were collected in three fruit groves in the area, and placed in stratified form in the ground. Early in July and for 15 days, some of the leaves were sampled and examined under a stereomicroscope. By the end of July, the first black bodies were detected on the surface of the leaves and identified as Venturia pirina Aderh. pseudothecia. At that moment the asci were beginning to differentiate their ascospores. Fifteen days later a high percentage of the ascospores were perfectly differentiated in the asci, and some of them had undergone dehiscence, which may have resulted in the presence of the inocula in the field under favorable environmental conditions. This study confirms the presence of the teleomorphic form of the pear scab�s causal organism in the departments of San Rafael and General Alvear in southern Mendoza. This is of the utmost importance for the epidemiology of the disease, and it should be given due consideration in the strategy to control it.Ante la exaltación de los daños producidos por la sarna del peral Fusicladium virescens Bon. en montes frutales del sur de la provincia de Mendoza ,se programó un estudio a fin de aclarar la biología del hongo en la región y buscar la presencia de la forma sexual no detectada aún en nuestra provincia. En otoño de 2001, en montes comerciales de la zona, se recolectaron hojas con síntomas claros de la enfermedad y se colocaron estratificadas sobre el suelo. Al inicio de brotación se extrajeron estas hojas y una vez en laboratorio fueron observadas al estereomicroscopio en busca de cuerpos negros inmersos en el mesófilo de las hojas. Éstos se apartaron y fueron observados al microscopio óptico, determinándose que un gran número de ellos correspondían a pseudotecios de Venturia pirina Aderh. Este trabajo confirma la presencia de la forma teleomórfica del agente causal de la sarna del peral, en la provincia de Mendoza, de fundamental importancia en la epidemiología de la enfermedad y en las estrategias para su control