Symptoms
Spindle-shaped silk cases (bags) hanging from fronds. Larvae feed inside cases causing defoliation. Severe infestations result in frond skeletonization. Mass outbreaks can defoliate entire palms.
Prevention
Monitor fronds regularly for early bags. Hand-collect bags before mass outbreak. Encourage natural parasitoids. Maintain tree vigor through good nutrition.
Treatment
Organic
Apply Bacillus thuringiensis (Bt) when larvae are young and still moving outside bags. Release Apanteles parasitoid wasps. Hand-collect and destroy bags before adults emerge.
Chemical (last resort)
Apply chlorpyrifos or triazophos by trunk injection or foliar spray during early instar stage. Timing is critical — large larvae inside bags are protected from sprays.
Affects 1 crop
Sources
MARDI Palm Pest Guide; DOA Extension Bulletin