Pathogenicity of Moniliophthora roreri isolates from selected morphology groups in harvested cacao pods and in vitro sensitivity to compost tea.

Abstract

Moniliopthora roreri is the frosty pod rot disease (FPD) and one of the most devastating cacao pathogens worldwide. However, M. roreri pathogenicity on harvested cacao pods and sensitivity to compost tea have not been fully described. Monosporic cultures of M. roreri from different morphology groups were obtained. The isolates’ pathogenicity was tested by inoculation onto harvested cacao pods, and symptoms were evaluated at 3-day intervals during 16 days before estimating the area under the disease progress curve (AUDPC). The sensitivity of M. roreri to compost tea was evaluated on potato dextrose agar (PDA) amended with 1 to 5 % compost tea. All morphology groups could infect harvested cacao pods during the 16 days with a disease severity index abode 75 %. Compost tea completely inhibited the growth of M. roreri when used at 4.5 % or higher. Results suggest a shortened biotrophic phase during the infection in harvested pods and a medium to high sensitivity of M. roreri to compost tea.

Chemical Characterization of Trichoderma spp. Extracts with Antifungal Activity against Cocoa Pathogens

“…The typical symptoms include abnormal shoots that display stem swellings, bud proliferation, and vegetative brooms, which inspired the name witches’ broom disease in cocoa [ 5 ]. The results of recent studies from the major cocoa-producing provinces of Ecuador showed that Moniliophthora species possess high morphological and genetic diversity [ 6 , 7 , 8 , 9 ]. For this reason, some alternatives such as cacao agroforestry systems [ 1 ] and biological controls using products based on endophytic organisms, including the combined application of natural or chemical products [ 10 ], have been used to reduce the impact of diseases, minimize the utilization of fungicides, and improve the yield of cocoa production.…”