Biotypes of the castor bean whitefly Trialeurodes ricini (Misra) (Hom., Aleyrodidae) in Egypt: biochemical characterization and efficiency of geminivirus transmission

Abstract

The newly introduced castor bean whitefly (CBW) Trialeurodes ricini (Misra) has become an important pest which is widely spread all over Egypt. Biochemical studies were conducted to distinguish the different T . ricini biotypes and to determine the biotype economic threshold based on its ability to transmit plant viruses. Forty-five samples of T. ricini adults were collected from castor bean (Ricinus comrnunis) at different geographical locations representing the Egyptian Delta and Nile valley governorates. Esterase banding patterns were investigated to evaluate the extent of variation among the tested populations of the castor bean whitefly. Electrophoresis of homogenates of individual T. ricini females showed that there are five different biotypes (C,-CJ. The predominant biotype (C, type) was found in about 80% of the tested locations. In transmission studies, the polymerase chain reaction (PCR) was used to detect geminiviruses in nucleic acid extracted from the different castor bean whitefly biotypes. PCR revealed that the five biotypes of T . ricini are viruliferous. To evaluate the efficiency of the predominant T . ricini biotype for transmitting the tomato yellow leaf curl virus (TYLCV), acquisition and inoculation access periods were determined. PCR indicated that 50% of whitefly adults collected from castor bean, acquired the virus after 10 h exposure to TYLCV infected tomato. Experimentally, the rate of transmission increased as the inoculation access period was lengthened and reached a maximum after 4 h. The obtained symptomatological results were also confirmed by PCR.

Repellency Effect of Some Biochemical Extracts of Castor Bean Leaf on Two Sap-Sucking Insect Pests

“…Seed yield may be reduced in castor due to sooty moulds (Patel et al, 1986). As well as T. ricini was not known to be a virus vector until Idriss et al (1997) who reported this whitefly as a vector of tomato yellow leaf curl virus (TYLCV) in Egypt.…”

Expression of the Full‐length Coat Protein Gene of Tomato leaf curl Taiwan virus is Not Necessary for Recovery Phenotype in Transgenic Tomato

“…1999), where it causes up to 100% yield loss (Nakhla et al. 1994; Idriss et al. 1997; Nakhla and Maxwell 1998; Moffat 1999).…”

“…Tomato yellow leaf curl virus disease (TYLCVD), whitefly-transmitted geminivirus is an important devastating disease of tomato (Solanum lycopersicon) in many tropical, subtropical and temperate regions of the world (Cohen and Antignus 1994;Czosnek and Laterrot 1997;Navas-Castillo et al 1999), where it causes up to 100% yield loss (Nakhla et al 1994;Idriss et al 1997;Nakhla and Maxwell 1998;Moffat 1999). Recently, the distribution of Tomato leaf curl Taiwan virus (ToLCTWV) and Tomato yellow leaf curl Thailand virus (TYLCTHV) in Taiwan was well documented (Tsai et al 2011).…”

Morphological and molecular evidence supporting the validity of Trialeurodes lauri and T. ricini (Hemiptera: Sternorrhyncha: Aleyrodidae)

“…Trialeurodes ricini is a polyphagous, multivoltine species, which is difficult to control and is a serious pest of tomatoes (Idriss et al, 1997). In Egypt, T. ricini has been reported as a vector of the begomovirus Tomato yellow leaf curl virus (TYLCV) (Idriss et al, 1997) although other researchers have as yet been unable to duplicate these findings (Jones, 2003). TYLCV is listed in the plant health legislation of the EU (Smith et al, 1997).…”