Giant Palm W eevil or Palm etto W eevil (Rhynchophorus cruentatus)

Introduced: The giant palm weevil is with the cocoon, the larvae will pupate. native to Florida. The adult weevils are approximately 3/4 Current Infestation: It has been to 1 ³ inches (1.9 to 3.0 cm) long and reported from coastal South Carolina vary in color from solid black to red with a south through the Florida Keys, and west variable black into coastal Texas. pattern. Adults are active fliers Description/Biology: The giant palm and when not weevil is the largest North American flying will hide weevil. The entire life cycle, from egg to between the leaf bases and stems of adult, takes about 84 days. Eggs are laid healthy palms presumably to conserve in the bases of palm fronds or in pruning water within their bodies. wounds on host palms. Eggs hatch in about three days. Larvae, or grubs, are Seasonality: The immature stages are legless and creamy found year-round in Florida but adults are to yellowish in color. usually more noticeable in the late spring Their prominent and early summer months. head is dark brown and hard. Mature Hosts: The most susceptible hosts are larvae can be quite the Canary Island date palm (Phoenix large and feed canariensis) and sabal palm (aka cabbage palmetto, Sabal palmetto). voraciously Other reported hosts include: fishtail inside the palm palm (Caryota spp.), coconut palm on the soft (Cocos nucifera), latan palm (Latania plant tissue, spp.), date palm (Phoenix dactylifera), primarily in the royal palm (Roystonea sp.), saw palmetto palm heart (Serenoa repens), Florida thatch palm (growing bud). (Trinax radiate), and washingtonia palm (W ashingtonia spp.). Mature grubs migrate to Cocoons the periphery of the Stressed, damaged and recently stem or leaf petioles transplanted host palms are the most and prepare a cocoon susceptible. Palms struck by lightning from palm fibers. After have been found with subsequent weevil surrounding themselves infestations.

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Giant Palm W eevil or Palm etto W eevil Im portance: The damage from this by larval feeding is readily heard. weevil is lethal since an infestation is rarely found in the early stage and Treatment of recently transplanted palms infested palms are difficult to treat. with insecticides (imidacloprid) is an option but the costs can quickly become Dam age: The symptoms of a weevil prohibitive unless only a few palms are to infestation vary, but commonly involve a be protected. general decline of younger palm fronds. In palm species with upright leaves, such Grower - Palms should be grown using as the Canary Island date palm, the older cultural practices that promote vigor leaves begin to droop during the early (proper fertilization and irrigation). Palms stages of infestation but quickly collapse such as the Canary Island date palm are thereafter. As the infestation progresses, not adapted for the south Florida climate, the larval feeding damage and associated so great care should be taken to ensure rot is so severe that the top of the palm the health of these palms. W ounding of falls over which is termed "popped neck". palms, such as by pruning, should be If the palm is pulled apart at this stage, avoided. Insecticides that may offer larvae, cocoons, and even adults may be some control include acephate (Orthene), found within the crown region. chlorpyrifos (Dursban, DuraGuard), or imidacloprid (Marathon, Discus), Managem ent: Early detection of a however, results are inconsistent. weevil infestation is difficult, and treatment even in the early stages of If palms are infested with the giant palm infestation weevil, there is little chance of saving An infested palm that has been cut into them. Therefore, sanitation, as in may be pieces showing internal dam age too late to removing and destroying infested plant save the material is crucial in preventing or palm. If a reducing subsequent Infestations. palm is Decline due to the giant palm weevil is known to fairly rapid (3 to 5 weeks). Decline due to be disease generally take much longer and infested, for lightning strikes, plant death is almost the best overnight. decision is to cut it down and dispose of it before adults emerge from the palm. W ebsites: http://creatures.ifas.ufl.edu/orn/ Homeowner and Professional - All efforts palmetto_weevil.htm should be made to keep palms as healthy as possible. Avoid pruning susceptible palms during the adult weevil flying Authors: Kim Gabel, UF/IFAS, Monroe Extension season (spring to fall). The resulting Adrian Hunsberger, UF/IFAS, Miami-Dade Extension wounds are attractive to the weevil. If a Catharine Mannion, UF/IFAS, TREC Homestead palm is suspected of being infested, an Photo Credits: UF/IFAS, Holly Glenn, Adrian automotive mechanics stethoscope can Hunsberger, and Robin Giblin-Davis; and DPI be used for detection. The sound made August 2006

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