New World palm/Palmetto; Palm (coconut palm, oil palm, etc.)

Not known to transmit any human or animal pathogens.

Rhynchophorus ferrugineus is not currently known to vector any plant pathogens, but it could carry the red ring nematode, Bursaphelenchus cocophilus, that causes red ring disease of palms.

At least three other palm weevils from the subfamily Rhynchophorinae, including R. palmarum, are reported to vector the red ring nematode, and now that the geographic area of the nematode-carrying weevils overlaps with the distribution of R. ferrugineus in the Caribbean, there is an increased possibility of R. ferrugineus coming into contact with the red ring nematode.

Traps should be placed at least 100 feet from host trees.

Palm weevil cone traps are now approved for use and are available.

Bucket traps are suspended above the ground while palm weevil cone traps are placed on the ground. Both types of traps use the same propylene glycol-water solution, lures and food baits. For home-made traps, the bucket may range in size from one to five gallons.

Visual surveys may be used to detect larval populations before adults emerge. A trap and lure combination may be used to detect adult populations. See the Survey Design section for survey instructions.

Climate Suitability Map
A Climate suitability map is now available. This survey should only be considered in the states with appropriate climate conditions and suitable hosts for this insect.

The map was produced by the SAFARIS Team. SAFARIS is a modeling framework that enables PPQ to quickly respond to emergencies, efficiently survey for pests, and assess potential pest impacts by collecting critical geospatial data and developing predictive models. SAFARIS is developed and maintained by the NC State University, Center for Integrated Pest Management (CIPM) with support from PPQ PPRA.

All three attractants (commercially available aggregation pheromone, synergist, and food bait) are required in traps to report negative data (absence) for R. ferrugineus.

The length of effectiveness of all three palm weevil lures (Rhynchophorus ferrugineus Aggregation Lure; Rhynchophorus palmarum Aggregation Lure; and Palm Weevil Lure, Ethyl Acetate) is 42 days. The release rates and longevity of the lures are based on temperature (i.e., the release rate increases at higher temperatures). Lures may need to be changed more frequently in hot, dry regions such as Arizona, Florida, Texas and California.

At the present time, it appears that placing pheromones for both R. ferrugineus and R. palmarum in the same trap is an acceptable practice. Therefore, if both pests are targets, the trap should be baited with the pheromone lures for R. ferrugineus and R. palmarum, ethyl acetate, and the food bait.

Food baits in either type of trap should be placed in the bottom of bucket traps and covered with liquid. Water is necessary for bait to ferment. Food baits can be placed in separate aerated containers that are placed inside traps. These containers allow fermentation to occur by protecting bait, water, and yeast from propylene glycol that is often added to traps to drown and preserve weevils.

Infested trees often have no visible symptoms because feeding larvae are concealed within the interior of the palm. The most common visible symptoms of R. ferrugineus infestations are drooping fronds, distorted or offset growth in the canopy, and small holes in the trunk/crown at the base of damaged fronds. See the Pest Datasheet for more details and images of infested palms.

Damage caused by larval feeding can resemble symptoms caused by other palm pests and it may be difficult to definitively diagnose the damage until weevil eggs, larvae, or pupae are found inside the palm.

Trapping and visual surveys can be conducted year-round. Modeling of flight probabilities based on a Mediterranean climate suggests most flight activity takes place from June through September with activity beginning as early as April and extending into December in southern locations like Israel (Rochat et al., 2017). In humid subtropical climates in Japan, adults were found outside the tree as early as March with flight trap captures recorded from June into December (Abe et al., 2009).

Multiple generations can be completed within the same host, so larval populations are likely to be present year-round (Milosavljevi? et al., 2019).

Visual Survey
Visual surveys may be used to find weevils in palms with highly suspect damage or clear signs of infestation. If permission can be obtained from the property owner, remove palm fronds by pulling the fronds to the ground or cutting the frond at the base with a pole cutter. Once the frond has been removed, inspect the base of the frond for tunneling, larvae, pupae, or adults (See the Pest Datasheet for images of infested fronds).

Another visual inspection method entails cutting a "window" in the crown of a highly suspect tree. Based on the size of the tree, multiple fronds are cut from one side of the crown from near the tip to the start of the trunk to reveal any tunneling occurring in the crown. This method will affect the appearance of the palm and access to the canopy may be difficult. Therefore, only highly suspect trees should be used for examination and permission must be obtained from the property owner. Due to the long life cycle of the weevil, this type of inspection may detect the larval and pupal stages of the pest before adult weevils would be able to be detected in traps.

Trapping Survey

Trap Placement
Note: it is important to hang the traps from non-host trees. Palm weevils can be attracted to the food bait may not be trapped and may attack the palm instead if traps are hung in host trees.

For surveys in the urban environment, bucket traps should be suspended from trees or poles. Traps should be hung approximately 6.6 feet above the ground to reduce the possibility of disturbance by people, pets, and wild animals. Hang the traps from non-host trees or telephone poles, at least 100 feet from host palms that may be attractive to R. ferrugineus.

Palm weevil cone traps are placed on the ground and use the same liquid and baits as the bucket trap. These traps should also be placed at least 100 feet from a host tree.

Note: if traps will be placed in a unique environment (i.e., non-urban, palm nursery or production areas, etc.), please contact Amy Roda for instruction on trap placement.
Amy Roda, PPQ-S&T
305-278-4900
amy.l.roda@.usda.gov

Trap Servicing
Collect insect specimens from the trap and replace food baits every seven to nine days. Replace pheromone and ethyl acetate lures every six weeks (42 days). Lures may need to be changed more frequently in hot, dry regions such as Arizona, California, Florida, and Texas. To ensure fermentation of baits, it is crucial importance to keep food bait covered with water.

Surveys should target date farms or palm production areas like nurseries, natural environments where native palms occur, and urban environments where palms have been planted as ornamental trees.

Weevils captured by hand from infested trees or found in traps should be submitted for confirmatory identification and red ring nematode screening following the protocol outlined in Floyd (2012). See the References section for detailed instructions and guidance.

Morphological. Identification should be verified by an identifier with expertise in the Rhynchophorus genus. A microscope with x50 magnification is needed.

EPPO Diagnostic: Rhynchophorus ferrugineus and Rhynchophorus palmarum (See link in references)

Rhynchophorus palmarum (native the Caribbean and established in California) and R. cruentatus (native to the southeastern United States)