South American Palm Weevil (saPW)
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The South American Palm Weevil (SAPW) originates from Central and South America, being found from southern Mexico southward to Argentina, and in the Caribbean from Puerto Rico southward to the Lesser Antilles. Previously, the furthest recorded northern distribution was 50 miles north of Cabo San Lucas, in Baja California Sur, Mexico. SAPW is considered a major pest of oil and coconut palms because infestations often result in the death of the tree. Adults are completely black, sometimes appearing velvety, and large in size often up to 1 ½ inches to 2 inches in length (see image above). Males possess a characteristic patch of stiff hairs on the top of the rostrum. Females deposit eggs into holes made by their rostrum, often where the plant surface is damaged or near leaf bases in the crown. The holes are sealed by the female with a brown waxy secretion. Females lay an average of 245 white eggs over their lifetime, but may lay as many as 700. Eggs hatch in about three days. Upon hatching, the creamy white larvae begin to feed on surrounding palm tissues. The larval period requires an average of about two months to complete. Mature larvae pupate in an oval-shaped cocoon about 3 inches long made of palm fibers inside the destroyed tree tissues. The pupal stage typically lasts two to three weeks. After hatching into an adult, the weevil emerges from the pupal case, but remains in the fibrous cocoon for several days before exiting. Adult weevils live for about 40 days.
SAPW causes economic damage during the larval stage, when larvae feed on the growing tissues in the crown of the palm, often destroying the apical growth area and subsequently causing death of the palm. Populations of only 30 larvae have been reported as sufficient to cause the death of an adult coconut palm. In addition, SAPW is an important vector of the red ring nematode Bursaphelenchus cocophilus (Cobb) (Aphelenchida: Aphelenchidae), which is the causative agent of red ring disease of coconut. This disease can kill palm trees within five months of inoculation. The captured San Ysidro weevil specimen was examined for this nematode by USDA Research Plant Pathologist Dr. Lynn Carta; however, no evidence of the nematode was found.
Males of SAPW produce an aggregation pheromone, which attracts other adult weevils to the infested host. Dispersal can occur through powered flight of the beetle as well as the movement of propagative material including trees and cuttings.
SAPW is reported as a pest of several palm species. Palm hosts include: date, Canary Island date, coconut, African oil palm, sago and Washingtonia fan palms. SAPW has also been recorded feeding on sugar cane. Adults are known to feed on ripe fruits such as avocado, citrus, guava, mango and papaya; however, the feeding damage is not considered economically significant.
Prepared by Kevin Hoffman, 6/29/11