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Title: RECOGNITION OF INSTARS AND ADULT TRAP CATCHES OF COSMOPOLITES SORDIDUS (COLEOPTERA:CURCULIONIDAE) FROM PLANTAINS IN PUERTO RICO.

Author
item PANTOJA, ALBERTO
item SALAZAR, AMPARO - UNIV OF PR - MAYAGUEZ
item MACCHIAVELLI, RAUL - UNIV OF PR - MAYAGUEZ

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/13/2006
Publication Date: 9/20/2006
Citation: Pantoja, A., Salazar, A., Macchiavelli, R. 2006. Recognition of Instars and Adult Trap Catches of Cosmopolites sordidus (Coleoptera: Curculionidae) from Plantains in Puerto Rico. Annals of the Entomological Society of America. 99(5):875-878 (2006).

Interpretive Summary: Worldwide the banana weevil (BW), Cosmopolites sordidus (Germar), is the most important insect pest of banana and plantain. The weevil has been implicated in the decline and disappearance of highland banana in central Uganda and western Tanzania , while in Puerto Rico, C. sordidus is considered the most important pest of plantains and bananas. Larval damage affects plant growth and development, reduces bunch weight and quality, and in heavy infestations may cause the plant to snap at ground level before harvesting. In the Caribbean basin marketable yield from C. sordidus damage may be reduced up to 90%; worldwide yield reductions range from 0 to 100%. There is no consensus on the number of instars for the banana weevil; reports vary from five to a variable number of instars ranging from 5 to 8. The variable number of larval instars is attributed to developmental polymorphism and the presence of biotypes. In spite of the economic importance of the BW in the Caribbean, there is a paucity of information on the biological aspects of C. sordidus in the region. Reports on developmental polymorphism and/or biotypes underline the need to study BW biology on the Caribbean basing. Knowledge of BW biology and population density is of utmost importance in developing IPM programs. In 1996 we initiated a research project to study the population dynamic and biology of the BW in Puerto Rico. From this work we report the number of instars of C. sordidus and adult abundance in the field. C. sordidus was found to have five instars. Adult C. sordidus densities reached a peak in January with 2.4 adults per trap, the lowest density recorded was during the month of April with 0.7 adults per trap. Adults captures seems to be influenced by precipitation with higher captures after precipitation events.

Technical Abstract: On the basis of head capsule widths of field collected larvae, C. sordidus was found to have five instars. The mean head capsule widths are 0.44, 0.71, 1.04, 1.48, and 1.85 mm for the first to fifth instar larvae, respectively. The greatest growth ratio was recorded between the first and second instar. Adult C. sordidus densities reached a peak in January with 2.4 adults per trap, the lowest density recorded was during the month of April with 0.7 adults per trap. Adults captures seems to be influenced by precipitation with higher captures after precipitation events.