Gall mites rarely
cause serious plant damage, but are a concern among growers because of the
unsightly appearance of infested leaves. There are no reports on its impact on
yield, but is a major concern in Bicol Region, Philippines.
Galls with irregular sizes and shapes are formed on vines and leaves by
injecting a chemical into plant tissues during feeding. These chemicals cause
plant tissues to grow abnormally.
Mites in all stages of development live inside the same gall.
Mites are extremely small and difficult to see without magnification. The worm-like body is about
148-160 Ám long and 46 Ám thick. It is white, cylindrical and tapers
to the rear. The entire body surface has a large number of close-set fine
discontinuous lines giving the shield a wrinkled appearance. Forelegs are
moderately arched and the hind legs are shaped like the foreclaw. The
abdomen has about 67 rings.
Eggs are laid within the gall; nymphs mature within the gall and the emerging
adults infest new foliage.
It has also been reported on other Convolvulaceae like Ipomoae staphylina.
Presence of galls on the leaves makes it easy to diagnose the problem.
Control is not necessary but parts with unsightly galls may be removed.
Amalin, D.M. and Vasquez, E. A. 1993. A handbook on Philippine sweetpotato
pests and their natural enemies. International Potato Center (CIP), Los Ba˝os,
Philippines. 82 p.