Dynamis borassi: an emerging pest of peach palm (Bactris gasipaes) in Colombia
Dynamis borassi (Coleoptera: Dryophthoridae) is widely distributed in South America and is an economic pest of commercially important palm species (Arecaceae), such as Cocos nucifera (coconut), Oenocarpus mapora and Bactris gasipaes (peach palm). It has been reported to cause damage to the inflorescence and crown tissue of palm trees and is also considered to be a vector of red ring disease caused by Bursaphelenchus cocophilus. According to the literature, D. borassi has been found on the following host plants (all Arecaceae): Astrocaryum carnosum, Astrocaryum chonta, Astrocaryum standleyanum, Bactris gasipaes, Cocos nucifera, Euterpe oleracea, Oenocarpus bataua, Oenocarpus mapora, Oenocarpus minor, Syagrus schizophylla, Syagrus vagans.
A tentative distribution list is as follows:
EPPO region: Absent.
South America: Argentina, Brazil (at least in Bahia, Espirito Santo, Para), Colombia, Ecuador, French Guiana, Panama, Peru, Venezuela.
In Colombia and since 2010, D. borassi has been associated with the death of more than 250 000 palm trees in B. gasipaes plantations along the Pacific coast and with a 75% reduction of the national production. B. gasipaes is also of significant socio-economic importance as it provides useful food resources to native people. In Colombia, it has been observed that damage was due to a complex of weevils involving Rhynchophorus palmarum (EPPO A1 List) and D. borassi. R. palmarum was initially thought to be the main cause of damage, but recent research has shown that D. borassi is the first weevil to attack peach palm trees (B. gasipaes), and that R. palmarum, acting as a secondary pest, can then successfully attack the palm trees. It is noted that both weevil species share similar morphological characteristics rendering diagnosis difficult, particularly in the larval stage, when damage occurs. D. borassi attacks the inflorescences and the crown of B. gasipaes. Larvae feed through the leaf stalk and bore tunnels towards the base of the crown, inflicting serious damage leading to plant death (toppling of the crown).
For the moment, the potential risks that D. borassi might present to palms grown in the EPPO region are difficult to assess as this species remains confined to tropical areas and is reported on palm species that are not widely grown in the EPPO region. However, considering the current level of damage observed in Colombia and past experience with the introduction of R. ferrugineus around the Mediterranean Basin, this weevil species should not be overlooked.
Sources
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