Papaya (Carica papaya, Brassicales: Caricaceae) is not a Host Plant of Tomato Yellow Leaf Curl Virus (Tylcv; FamilyGeminiviridae, GenusBegomovirus)

Abstract

Tomato is an important crop in Florida with a 2009 farm value of $520,000,000 (USDA-Agricul tural Statistics Service, 2010). Biotype B of the sweetpotato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a principal pest of to mato both in Florida and in tropical/subtropical regions globally (Oliveira et al., 2001). This in vasive insect vectors many plant viruses, among of the most detrimental of which are a group of begomoviruses collectively referred to as toma to yellow leaf curl virus (TYLCV) (Moriones & Navas-Castillo 2000; Glick et al., 2009). Typical symptoms of tomato infected with TYLCV include chlorosis and leaf curling. A banker plant system has been developed for management of B. tabaci in greenhouses and is presently under evaluation (Xiao et al. 2011). The banker plant system relies on papaya (Carica pa paya L.) and its host-specific whitefly, Trialeurodes variabilis Quaintance to support populations of Encarsia sophia (Girault & Dodd) parasitoid wasps. The parasitoids, in turn, search greenhouse crops such as poinsettia and tomato where they control B. tabaci. However, papaya is a document ed host of B. tabaci (Costa et al. 1993; Anderson et al. 2005), so it is crucial to establish that papaya is not also a host plant for TYLCV. If papaya harbors TYLCV, this could be perceived as an unacceptable risk, impeding adoption by tomato growers of the papaya banker plant strategy. TYLCV infectivity of papaya plants was tested in 60 cm x 60 cm x 60 cm screened laboratory cages. Whitefiy adults used in the experiment originated from non-viruliferous and virulifer ous B. tabaci biotype B colonies maintained on tomato at the USDA-Horticultural Research