Spatial Temporal Pattern of Chili Virus Disease in Bogor and Its Relation with Yield Loss

Diseases caused by viruses are a major constraint in the production and productivity of chili peppers (Capsicum annuum) in Indonesia. Several viruses infect chili peppers, making viral infections complex. Viral infections in plants are systemic and potentially cause total yield loss. The spatial and temporal patterns of viral disease development in the field need to be studied to determine disease control decisions and estimate crop losses. The study was conducted in two chili pepper production fields owned by farmers in Bogor, treated with and without mulch. Observations and analysis were based on the incidence and severity of disease, as well as crop yields. The temporal development of viral diseases in chili peppers showed a sigmoid curve for both incidence and severity of disease in the two types of fields. The level of disease in fields without mulch was relatively higher than in mulched fields. The spatial development of viral diseases based on heatmap analysis showed that the virus spread evenly in both unmulched and mulched fields. The severity of viral diseases significantly affects the quality and quantity of harvested fruit, as indicated by a negative correlation between the level of disease and the harvest yield and the harvest price obtained per plant. The higher the disease severity, the greater the yield loss. In seven harvests, the unmulched plot yielded 5.3 kg of chilies, while the mulched plot yielded 6.7 kg of chilies (grades A–C). Thus, the use of mulch resulted in lower disease intensity and better yields compared to the unmulched plot.