Epidemiology of bacterial wilt disease on Eucalyptus pellita F. Muell. in Indonesia

Productivity of forest plantation such as Eucalyptus pellita in Indonesia is strongly decreased by bacterial wilt disease (Ralstonia solanacearum Smith). However, studies of bacterial wilt disease on E. pellita in Indonesia is still inadequate, so several comprehensive research are required. This research was aimed to analyse the dominant silviculture factors and soil properties which can contribute to disease epidemiology. Observation on disease incidence was conducted by the transect method on 40 observation plots selected by the purposive random sampling in 4 provinces in Indonesia. Nine silviculture factors were collected by tracking the identity and the history of plot maintenance, while soil properties were analysed from soil samples. The correlation among disease incidence to silviculture factors and soil properties was carried out by chi-square and multiple regression analysis, respectively. Planting age, Eucalyptus clones, and root malformation were the top 3 of silviculture factors which has shown significant correlation to disease incidence. Early growth of Eucalyptus sp. plant was a critical period of the disease epidemic, especially in the susceptible clone. On the other hand, soil texture (percentage of sand, clay, and silt) were the dominant variables of soil properties which strongly affected the disease incidence.