Manejo de Colletotrichum spp. en mango (Mangifera indica L.) mediante metodos quimicos y biologicos

Leaf samples were collected from various research and commercial mango (Mangifera indica L.) farms from south and western regions of Puerto Rico. The purpose of this study was to isolate, identified and characterized the species of Colletotrichum spp. associated with typical anthracnose lesions in mango leaves. All Colletotrichum isolates were identified as C. gloeosporioides and were virulent to mango leaves. Three fungicides:azoxystrobin, benomyl, and tebuconazole, were evaluated in vitro to determine the sensitivity of C. gloeosporioides isolates collected from mangoes in Puerto Rico and C. acutatum isolates collected from lemon (Citrus limon L.) in Mexico. Azoxystrobin reduced significantly the germination of conidia of C. gloeosporioides to dosages 0.1 to 1 ppm, but not of C. acutatum. The fungicide, benomyl reduced significantly the mycelia growth in both species to dosage 3 ppm. The fungicide, tebuconazole reduced significantly the mycelia growth of C. acutatum to dosages 10 ppm. The induction of systemic resistance was effective 24 h after the inoculation of an hipovirulent isolate (HV-165) of C. gloeosporioides on detached mango leaves. Reduced mean lesion size was observed on the upper and lower portions of the leaves treated with a virulent isolate. These reduction was significant at P < 0.05 using Turkey's test. However, the experiments tree mango seedlings were not well concluding since the pathogen was not able to establish on the tissues under greenhouse conditions (27°C and 80% relative humidity).