Occurrence and Damage of Broad Mites (Polyphagotarsonemus latus Banks) in Sweet Pepper (Capsium annuum L.) in Samoa

Abstract

Broad mites regularly infest sweet pepper crops in the tropics. A survey was carried out to assess the incidence broad mite infestation in sweet pepper crops in Upolu, Samoa. The population density of broad mites was related to plant development stages with the highest number of broad mites per leaf recorded at the early fruiting stage; no broad mites were recovered from plants at the seedling and vegetative stages. In a separate experiment, 3 sweet pepper varieties were artificially infested with 2 gravid female mites per seedling. At 7 days after infestation, a significant difference was observed in the 3 varieties with Yellow having the highest number of broad mites per plant followed by Giant Bell and Yolo Wonder at 62.0, 37.0 and 19.7, respectively. At 10 days, there was a significant difference in the mean population of broad mites on the varieties namely, Yellow (59.1 mites/plant), Giant Bell (32.4/plant) and Yolo Wonder (24.3/plant). The highest population of broad mites was observed on plants that had damage index level of 3 which corresponds to slight curling in the top leaves. This damage index was more common in Giant Bell and Yolo Wonder while leaf necrosis and defoliation were common on Yellow. Typical damage injuries observed on seedlings included distorted cupped leaves with zigzag veins, elongated petioles, and bronzed leaves and stem that later became necrotic and died. Farmers can use a severity index scale to help them recognize the presence of broad mites in their farms so that timely management can be done.