Occurrence and intra-specific variation of sweetpotato weevil (Brentidae: Coleoptera) in relation to its potential spread in southern United States of America and the Caribbean

• Published in: Acta horticulturae no. 703; pp. 197 - 203
• Main Authors: Jackai, L.E.N, Sosinski, B, Jackson, D.M, Sorensen, K.A, Bonsi, C.K, Addo-Bediako, A, Ali, R, Tameru, B, Quarcoo, F, Alvarez, M.N
• Format: Journal Article
• Language: English
• Published: 01.01.2006
• Subjects: Cylas formicarius; insect pests; Ipomoea batatas; pest monitoring; plant pests; sweet potatoes; Caribbean; United States
• ISSN: 0567-7572
• DOI: 10.17660/actahortic.2006.703.24

The sweetpotato weevil, Cylas formicarius, causes severe damage to roots and other parts of the sweetpotato crop in the field as well as in storage, resulting in losses worth millions of dollars in revenue and food calories each year around the world. In the U.S.A., quarantine measures are in force in most southern States where the weevil is a problem. However, this has not stopped the spread of the weevil, nor the crop devastation it causes. In a USDA-funded project we have begun to study the factors that lead to weevil spread to non-infested areas and the genetic variation within the Cylas formicarius populations in the U.S. and the Caribbean. Preliminary results show that sufficient polymorphism exists among weevil populations to suggest important differences in these populations. Risk analysis studies also show the probability of weevil introduction into a new area without any mitigation measure to be 0.2667; that of weevil introduction following a pre-harvest mitigation effort was determined as 0.1175, and that of introduction following post-harvest mitigation 0.000517. The calculated overall risk of weevil introduction was 0.0000162, a low but nonetheless important risk level in a country where a single weevil could lead to the rejection of an entire crop and the imposition of strict quarantine measures with severe economic impact to growers. There are locations where no weevil infestations have ever been reported; GIS-aided studies will determine the environmental conditions that foster weevil establishment and thus provide a means of identifying “high risk” areas for weevil spread. We propose the formation of a network to conduct similar studies in other parts of the world.