Abstract
The disease of Vascular streak dieback (VSD) is a deadly disease of cocoa plants, because it attacks the vascular tissue of cocoa at growing point of the plant. In West Sumatra the disease was first reported in 2015 with an incidence of disease range 58.82% - 100% and an intensity of disease range 24.29% - 44.7%. The purpose of this study was to examine the effectiveness of dosage application of oil formula and nano emulsion of citronella formula against Vascular streak dieback (VSD) disease on cocoa plants in West Sumatra (in Padang Pariaman District and Limapuluh Kota District). The results showed that the percentage of VSD disease attacks in both testing sites was 100%. The oil and nano emulsion of citronella formulas can reduce the intensity of VSD disease on cocoa plants in West Sumatra, particularly in Padang Pariaman District and Limapuluh Kota District. The reduction of VSD intensity in Padang Pariaman district ranged from 8.32 to 21.13%; while in Limapuluh Kota district ranged from 4.33 to 11.80%. The nano emulsion of citronella formulation is effective to suppress the intensity of VSD disease on cocoa plants at doses 0.1% (≥ 30% of effectiveness level).
Highlights
VSD (Vascular streak dieback) disease is a deadly disease of cocoa plants, because it attacks the vascular tissue at growing point
The percentage of VSD disease attacks at both sites reached 100%. Both sites are used as research sites for the application of biopesticide citronella oil and nano emulsion of citronella formulation
In the observation of disease intensity of VSD that has been done every month in Limapuluh Kota district, some treatments still showed an increasing trend and it was decreasing trend of disease compared to with the control without treatment
Summary
VSD (Vascular streak dieback) disease is a deadly disease of cocoa plants, because it attacks the vascular tissue at growing point. The development and spread of the disease in Indonesia is very rapid, because VSD disease was first discovered in 1983 in Sebatik island (East Kalimantan), and in 2013 almost all cocoa plantations are infected with the disease [1]. In West Sumatra the disease was first reported in 2015 with disease incidence are 58.82% - 100% and an intensity of disease are 24.29% 44.7% [2]. In Indonesia, especially in West Sumatra the potential for loss of results has not been reported. Poor garden maintenance can accelerate the spread of disease in the field. Cocoa cultivation in Indonesia is generally a smallholder plantation, where in the management and maintenance has not done well.
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