Virulence of Entomopathogenic Nematodes Against Diaprepes Abbreviatus in an Oxisol.
Florida Entomologist 2007, June, 90, 2
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Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae) is an insect whose host range includes more than 270 species of plants, including many economic species (Martorell 1976; Simpson et al. 1996; Wolcott 1936). Damage to roots by larvae can reduce yield and impact the long term health of host plants. There is a need to identify biocontrol options for this pest that are efficacious in Puerto Rico. Entomopathogenic nematodes in the families Heterorhabditidae and Steinernematidae are lethal parasites of insects (Poinar 1990) and have proven effective against D. abbreviatus in Florida (McCoy et al. 2000; Shapiro-Ilan et al. 2002, 2005). However, these assays were conducted in the sandy soils typical of the regions where citrus is cultivated in Florida. For infective juvenile nematodes to successfully infect a host they must be able to move through the soil. Therefore, soil physical properties, such as those typical of sandy soils (porous and aerated), should facilitate nematode infectivity than denser soils, such as clays. Indeed a number of researchers have noted that the clay content of a soil is inversely proportional to the ability of nematodes to disperse in that soil (Georgis & Poinar 1983; Barbercheck & Kaya 1991; Barbercheck 1992). However, recent research has shown that the role of soil physical properties in nematode dispersal and survival is more complex, varying with species of nematode (Portillo-Aguilar et al. 1999; Koppenhofer & Fuzy 2006). Additionally, research shows that nematode virulence to D. abbreviatus can be significantly higher in certain high clay content soils (Shapiro et al. 2000). Greenhouse assays with Steinernema feltiae (=Neoaplectana carpocapsae) conducted in Puerto Rico against D. abbreviatus revealed limited mortality, but results were ambiguous and the soil type assayed was not identified (Roman & Figueroa 1985). Another study of the virulence of S. feltiae against D. abbreviatus in soils from various regions of Puerto Rico indicated that infection rates were higher in soils from regions that had a higher sand content, suggesting that increased infectivity was positively correlated with the porosity of the soil (Roman & Beavers 1983).
- 2,99 €
- Category: Life Sciences
- Published: 01 June 2007
- Publisher: Florida Entomological Society
- Print Length: 8 Pages
- Language: English