ARS | Publication request: VIRULENCE OF ENTOMOPATHOGENIC NEMATODES AGAINST DIAPREPES ABBREVIATUS IN AN OXISOL

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 9, 2007
Publication Date: June 4, 2007
Citation: Jenkins, D.A., Shapiro Ilan, D., Goenaga, R. 2007. Virulence of entomopathogenic nematodes against Diaprepes abbreviatus in an oxisol. Florida Entomologist. 90(2):401-403

Interpretive Summary: Diaprepes abbreviatus is weevil whose larvae feed on the roots of a broad range of hosts, including many important tropical fruit crops. Damage to the roots can suppress yield and result in the death of the tree. This pest is successfully combated with nematodes in Florida, where D. abbreviatus is a critical pest in citrus. The use of nematodes in Puerto Rico has not been as successful, largely due to the compact nature of the soils in Puerto Rico which are not easy for the nematodes to move in. However, new species and strains of nematodes have been discovered and there is some evidence that the ability to infect D. abbreviatus in heavy, clayey soils may vary with species or strains of nematodes. We assayed nine different species/strains of nematodes against D. abbreviatus larvae in an Oxisol from Puerto Rico with high clay content. This study revealed that all of the species/strains of nematodes reduced the survival of the larvae within 14 days of application when compared to untreated controls and that the number of larvae surviving did vary, with some strains even resulting in 100% mortality. This indicates that nematodes may be an effective form of control against D. abbreviatus and may reduce the use of pesticides in tropical fruit orchards established in an Oxisol.

Technical Abstract: Nine species/strains of entomopathogenic nematodes were assayed against larval Diaprepes abbreviatus in an oxisol. All species/strains demonstrated significantly lower mean larval survival compared to the untreated controls. All four strains of Steinernema riobrave assayed demonstrated larval survival at or close to zero. This study indicates that nematodes may be an effective means of controlling D. abbreviatus in the heavy Oxisols that are found in many tropical fruit growing regions.