Correlation of Mottle Disease Severity and Insect Vector Abundance on Black Pepper Yield

Abstract

Insect-borne viral diseases epidemics are influenced by interaction among host plants, viruses, their vectors, and environment. Two species of mealybugs i.e. Planococcus minor and Ferrisia virgata are known as virus vectors that cause mottle disease on black pepper (Piper nigrum). Research was conducted to determine the main factors affecting mottle disease spread in the field. Study was conducted by observing 30 productive black pepper plants at the experimental field in Sukabumi, West Java. The parameters involved abundance of mealybugs, severity of mottle disease, and yield of black pepper plants. Disease severity and plant yield was assessed for three consecutive harvest seasons, while mealybug abundance was observed every two months for a year. The results showed that abundance of mealybugs did not have significant affect to disease severity and plant yield, indicating the vectors in the field does not play as a prominent role in disease spreading. Simple linear regression between disease severity and plant yield showed coefficient determination of R2 value about 0.4351 with negative correlation, indicating opposite effect between severity and plant yield. Increasing disease severity affect moderately plant yield decrease. Therefore, planting virus free seed stocks and applying good cultivation practices in the field will inhibit disease development and spreading which in turn will affect continuous optimal plant yields.