Traits of farming practice affecting vascular streak dieback disease on cacao in Central Sulawesi

Abstract

Vascular streak dieback (VSD) caused by the basidiomycete Ceratobasidium theobromae is one of the most important cocoa diseases in Central Sulawesi, causing branch dieback with an infection can kill seedlings and mature trees on susceptible cocoa varieties. This objective of this study is to examine the disease incidence of VSD in cacao in the field, determine the factors that influence the disease, and distinguish the characteristics of cocoa stomata from healthy plants and those infected with C. theobromae. All environmental variables tested were rainfall, wind speed, temperature, elevation, fertilizer; insecticide, herbicide, and fungicide applied; pruning, age of cacao trees, number of trees per plot (population); agricultural farming systems (monoculture or polyculture) sanitation of the plantation, number of stomata, diameter stomata, stomatal density. This study was carried out at the cacao plantations in center of cocoa plantation in Central Sulawesi districts by using generalized linear models. The study showed that C. theobromae infected all of the plantations on the study sites selected. Off all variable tested, fungicide, sanitation, number of stomata and the density of stomata were the significantly influence the disease incidence of VSD in cocoa plantation.