Fungicide Sensitivity among Isolates of Colletotrichum truncatum and Fusarium incarnatum-equiseti Species Complex Infecting Bell Pepper in Trinidad

Bell pepper is an economically important crop worldwide; however, production is restricted by a number of fungal diseases that cause significant yield loss. Chemical control is the most common approach adopted by growers to manage a number of these diseases. Monitoring for the development to resistance to fungicides in pathogenic fungal populations is central to devising integrated pest management strategies. Two fungal species, Fusarium incarnatum-equiseti species complex (FIESC) and Colletotrichum truncatum are important pathogens of bell pepper in Trinidad. This study was carried out to determine the sensitivity of 71 isolates belonging to these two fungal species to fungicides with different modes of action based on in vitro bioassays. There was no significant difference in log effective concentration required to achieve 50% colony growth inhibition (LogEC(50)) values when field location and fungicide were considered for each species separately based on ANOVA analyses. However, the LogEC(50) value for the Aranguez-Antracol location-fungicide combination was almost twice the value for the Maloney/Macoya-Antracol location-fungicide combination regardless of fungal species. LogEC(50) values for Benomyl fungicide was also higher for C. truncatum isolates than for FIESC isolates and for any other fungicide. Cropping practices in these locations may explain the fungicide sensitivity data obtained.