The Invasion Of The South American Palm Weevil
California palms are being attacked by a variety of weevils. One of the most notorious weevils as of late is the South American Palm Weevil (SAPW). The SAPW crossed the border from Mexico into southern California seven years ago and has been on the move ever since. SAPWs bring the potential for widespread destruction of palm trees and millions of dollars in damage.
Where Are They?
According to San Diego County officials, the South American Palm Weevil can be found as far east as Texas and as far north as Orange County (as per a recent report in May 2018). Experts believe these weevils will be much harder to eradicate than other weevil species because of the close proximity of the source in Mexico.
What Do They Look Like?
South American Palm Weevils are jet black insects with extended snouts. They have hard bodies and small heads. They can grow up to 2-3″ in length. One infected tree can have as many as 1,000 weevils housed in it.
What Are Signs Of Damage?
South American Palm Weevil infestation is difficult to detect in its early stages. Early signs of damage include truncated or cut-off leaf tips or chewed off mid-blade pinnae. This damage usually occurs first in the top or center leaves of the canopy and then spreads. Another sign of infestation is reduced growth of the newest leaves emerging from the top or center of the canopy. This gives the top of the canopy a flat or depressed look. Once the leaves in the center or top of the canopy are infested, they will turn brown and may eventually collapse. They are also easy to pull off.
What Other Threats Do They Cause?
The South American Palm Weevil also hosts a nematode called the Bursaphelenchus cocophilus which is the leading cause of red ring disease (RRD). Control of RRD can only be accomplished by controlling the South American Palm Weevil.
How Do You Get Rid Of Them?
Management of both the South American Palm Weevil and red ring disease require the use of an integrated pest management program. This comprehensive program should include monitoring and trapping, field sanitation, prophylactic treatment, removal of infested and diseased palm trees, quarantine, training, and education. In some circumstances the use of pesticides may also be warranted.