Epidemiological study of Colletotrichum spp. associated with Enterolobium cyclocarpum (Jacq.) Griseb. and Platymiscium pinnatum (Jacq.) Dugand in the Colombian Caribbean Region

Abstract

Epidemiological analyzes of foliar diseases associated with Colletotrichum spp. in Enterolobium cyclocarpum and Platymiscium pinnatum  were performed under field  conditions and without any type of intervention. At the  Universidad del Magdalena (Santa Marta, Colombia), four trees for each species and four equidistant monitoring sites per tree were established. The incidence and severity were recorded for 33 weeks (March to November 2016), including two follow-up periods: dry and rainy season. Disease development curves were elaborated. Moreover, the  development rate (r) and the area under the disease  progress curve (AUDPC) were calculated for each follow-up period. The effect of the meteorological variables was  statistically analyzed by correlation and multiple regression. In E. cyclocarpum, the highest incidence and severity were recorded  between September and  November with 100 and 19.6%, respectively, showing a positive correlation with  relative humidity and negative with average temperature, solar radiation and wind speed. In P. pinnatum, the maximum values of incidence and severity were observed  between March and April with 68.9 and 1.3%, respectively. However, correlation analyzes did not support their relationship with the environmental factors. The r values during the dry months were 0.136 and 0.107 units week-1 and the AUDPCs were calculated at 51 and 4 units week-1 for E. cyclocarpum and P. pinnatum, respectively. In the rainy months, the r values were 0.187 and 0.016 units week-1 and the AUDPCs were 186 and 2 units week-1,  respectively. In conclusion, the development of the disease  varies according to the forest species, time of year and some meteorological variables.