Ecology, Infestation Levels, and Populations of AnthonomusWeevils (Coleoptera: Curculionidae) on Malpighia glabrain Mexico

Abstract

The ecology, infestation levels, and populations of Anthonomus weevils were documented in a diflubenzuron (Dimilin)-treated Malpighia glabra (L.) grove in El Trapiche, Mexico, from January 1995 to March 1998 and in an untreated grove in El Petacal (≈42 km away) from June 1997 to April 1998. Anthonomus caracasius (Faust) comprised 50-87% of the adult weevils from July 1997 through March 1998 in El Trapiche. A. sisyphus Clark comprised 3-25% of the weevils during the same period and A. alboscutellatus Champion 0-22%. A. caracasius was not found in El Petacal, and A. sisyphus represented 38-100% of adults at this site from June 1997 to April 1998. A. alboscutellatus represented 0-50% of adults during this period in El Petacal. A. unipustulatus Champion was rare at both sites. A. sisyphus developed only in fruits. A. unipustulatus developed inside wild Malpighiaceae fruit. A. caracasius and A. alboscutellatus developed only in flower buds. Up to 30 and 15% of fruits from El Trapiche and El Petacal, respectively, were positive for weevil eggs in 1997. Eggs normally occurred singly on the lower half of fruits. Up to 74 and 97% of fruits from El Trapiche and El Petacal, respectively, were infested with larvae, pupae, and adults in 1997. A. sisyphus, A. caracasius, and A. alboscutellatus were found throughout the year on M. glabra, but numbers were highest during the rainy season, from June to November, in El Trapiche from 1995 to 1998. M. glabra fruit production was highest from April to June, before the time when weevils were most abundant. There were no correlations between adult weevil population densities and fruit yields during these 3 yr, probably because of unnatural flowering cycles caused by year-round irrigation.