Submitted to: Archives of Phytopathology and Plant Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/22/2008
Publication Date: 9/1/2010
Citation: Abd-Rabou, S., Simmons, A.M. 2010. Augmentation and Evaluation of a Parasitoid, Encarsia inaron, and a Predator, Clitostethus arcuatus, for Biological Control of the Pomegranate Whitefly, Siphoninus phillyreae. Archives of Phytopathology and Plant Protection. 43:1318-1334. Interpretive Summary: The pomegranate whitefly is also called the ash whitefly. It is an insect pest of several economic plants. It feeds by sucking on leaves of plants such as apple, ash, pear, and pomegranate. It is found in several countries including the United States, United Kingdom, and Egypt. Encarsia inaron is a parasite (a small wasp) that attacks whiteflies. Clitostethus arcuatus is a predator (a lady beetle) that eats whiteflies. A study was conducted on the use of the predator and parasite for the control of the pomegranate whitefly. Field tests were conducted during 11 years (1996-2006). About a million each of the predator and parasite were reared and released in fields of pomegranate in Egypt. Whitefly kill was highest during the summer and fall. Up to about 90% of the whiteflies were killed. Findings from this study help in the understanding of the usefulness of these natural enemies after multiple releases in the field.
Technical Abstract: The pomegranate whitefly, Siphoninus phillyreae (Haliday) (Homoptera: Aleyrodidae), attacks at least 60 plant species of economic importance including pomegranate (Punica granatum), apple (Malus domestica), pear (Pyrus communis) and ash trees (Fraxinus spp.). A study was conducted to evaluate the biological control potential of this pest with a parasitoid, Encarsia inaron (Walker) (Hymenoptera: Aphelinidae), and a predator, Clitostethus arcuatus (Rossi) (Coleoptera: Coccinellidae). Both species were mass reared and monthly releases were made in fields of pomegranate during each of 11 consecutive years (1996-2006). About 1,155,000 En. inaron and 990,000 C. arcuatus were released in fields in Assuit governorate in Egypt on pomegranate which was naturally infested by S. phillyreae. Populations of the natural enemies and parasitism were much higher in field plots where releases were made as compared with where no releases were made. The maximum rate of parasitism reached 93% (88% by En. inaron) in the field treatment where releases were made, while parasitism peaked at 36% in plots where no releases were made. The population of En. inaron was significantly correlated with the build-up of the whitefly population during the field season. Additional parasitism was by natural infestations by Eretmocerus parasiphonini Evans and Abd-Rabou. The maximum number of C. arcuatus ranged from 13 to 44 beetles per 100 leaves, and there were more predators in the release plot than in the control plot. These observations enhance the understanding of the usefulness of these natural enemies after augmentation in the field.