Abundance of Icerya purchasi Maskell (Hemiptera: Margarodidae) and its parasitoid Cryptochaetum iceryae (Diptera: Cryptochaetidae) in Argentina blueberry crops

ROCCA MARGARITA; GRECO NANCY; MAREGGIANI GRACIELA

ENVIRONMENTAL ENTOMOLOGY

Entomological Society of America

Lugar: Lanham; Año: 2009 vol. 38 p. 380 - 386

0046-225X

Icerya purchasi Maskell is a polyphagous scale pest of ornamentals and several other crops. It hastwonatural specialist enemies that maintain its populations atlowlevels: Rodolia cardinalis (Mulsant) and Cryptochaetum iceryae (Williston). I. purchasi was recently observed in blueberry crops (Vaccinium corymbosum L.) in Argentina. Seven blueberry Þelds located in different agricultural landscapes were sampled from July 2006 to September 2008. I. purchasi was present only in the citrus areas of Gobernador Castro, San Pedro, and Concordia. In the last locality, it was present in January 2007, and the abundance was very low. In Buenos Aires, I. purchasi was more abundant in Gobernador Castro where it was present throughout all study period. In San Pedro, it was only registered in August 2007 and March, April, and June 2008. In Gobernador Castro, where the abundance was highest, the dominant crop near blueberries is citrus. The low abundance in San Pedro and Concordia Þelds may be attributable to the replacement of citrus crops by nonhosts. In Concordia and San Pedro Þelds, no parasitized I. purchasi were found. In Gobernador Castro, the proportion of adults parasitized was 0.805 _ 0.286. When the risk of parasitism was analyzed for three density categories, there were no signiÞcant differences. R. cardinalis was present only in Gobernador Castro, and very few individuals were observed. The presence and abundance of I. purchasi in blueberry crops in Argentina seems to be linked to the structure of the landscape at the regional level, and the variable incidence of C. iceryae suggests major constraints to the scaleÕs population growth.