Relationship of Broad Mite (Acari: Tarsonemidae) to Host Phenology and Injury Levels in Capsicum annuum

Abstract

The responses of broad mite, Polyphagotarsonemus latus Banks (Acarina: Tarsonemidae), were studied on four phenological stages of pepper plants: vegetative (V), blossoming (B), early fruiting (EF) and late fruiting (LF) stages. All stages of the mite preferred the undersides of the leaves to the uppersides. Plants in V, B, and EF stages had higher numbers of mites per cm 2 of foliage than plants in the late fruiting stage. A damage index scale (0-6) was developed to assess broad mite injury to pepper plants. Eight to nine cumulative mite days/cm 2 were needed to reach a damage index equal to 3 for V, B and EF plant stages. The damage index was also used to relate broad mite injury to leaf area, height, water content, number of leaves, flowers, buds, fruits and fruit weight of plants infested at four different phenological stages. Plants infested when 14 weeks old (late fruiting stage), had less damage, significantly higher number of fruits and fruit weight than plants infested at earlier plant stages, i.e., vegetative, flowering or early fruiting. The relationship between the damage rating (x) and fruit numbers per plant (y1) and fruit weight in grams (y2) was given by y1 = 2.83-0.45x and y2 = 232.5-37.234x, respectively.