William K Heve1, Fahiem E El-Borai1,2, Daniel Carrillo3, Larry W Duncan1. 1. Institute of Food and Agricultural Science, University of Florida, Citrus Research and Education Centre, Lake Alfred, FL, USA. 2. Plant Protection Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt. 3. Institute of Food and Agricultural Science, University of Florida, Tropical Research and Education Centre, Homestead, FL, USA.
Abstract
BACKGROUND: Caribbean fruit fly (Caribfly) is a serious economic insect pest because of development of larvae that hatch from eggs oviposited into fruits by female adults. This study assessed the virulence of twelve entomopathogenic nematode (EPN) isolates to Caribfly in laboratory bioassays as a starting point toward evaluation of management strategies for the fruit-to-soil-dwelling stages of A. suspensa in fields infested by Caribfly. RESULTS: Inoculation of A. suspensa with 1 mL of ca 200 IJs larva-1 killed Caribfly at either larval or pupal stage. Pupae were more resistant to EPN infections than larvae. Adult emergence from inoculated pupae in soil microcosms was significantly lower than that observed in filter paper assays. Longest or largest steinernematids suppressed emergence of more adult Caribfly from pupae in soils, whereas shorter heterorhabditids were more infectious to Caribfly larvae. The highest mortalities of A. suspensa were caused by exotic nematodes Steinernema feltiae and Heterorhabditis bacteriophora, followed by the native Heterorhabditis indica and the exotic Steinernema carpocapsae. CONCLUSION: Entomopathogenic nematodes reduced the development of Caribfly larvae and pupae to adult in our bioassays, suggesting that EPNs have potential for biological control of A. suspensa. Future work will assess management strategies, using the virulent EPNs, in orchards infested by A. suspensa.
BACKGROUND:Caribbean fruit fly (Caribfly) is a serious economic insect pest because of development of larvae that hatch from eggs oviposited into fruits by female adults. This study assessed the virulence of twelve entomopathogenic nematode (EPN) isolates to Caribfly in laboratory bioassays as a starting point toward evaluation of management strategies for the fruit-to-soil-dwelling stages of A. suspensa in fields infested by Caribfly. RESULTS: Inoculation of A. suspensa with 1 mL of ca 200 IJs larva-1 killed Caribfly at either larval or pupal stage. Pupae were more resistant to EPN infections than larvae. Adult emergence from inoculated pupae in soil microcosms was significantly lower than that observed in filter paper assays. Longest or largest steinernematids suppressed emergence of more adult Caribfly from pupae in soils, whereas shorter heterorhabditids were more infectious to Caribfly larvae. The highest mortalities of A. suspensa were caused by exotic nematodes Steinernema feltiae and Heterorhabditis bacteriophora, followed by the native Heterorhabditis indica and the exotic Steinernema carpocapsae. CONCLUSION: Entomopathogenic nematodes reduced the development of Caribfly larvae and pupae to adult in our bioassays, suggesting that EPNs have potential for biological control of A. suspensa. Future work will assess management strategies, using the virulent EPNs, in orchards infested by A. suspensa.
Authors: William K Heve; Fahiem E El-Borai; Evan G Johnson; Daniel Carrillo; William T Crow; Larry W Duncan Journal: J Nematol Date: 2018 Impact factor: 1.402