Relationship between Tomato Yellow Leaf Curl Viruses and the Whitefly Vector

Abstract

Tomato yellow leaf curl is prevalent in tomato growing districts of Uganda. The disease is known to be spread by a whitefly (Bemisia tabaci) in a persistent manner. Some of its symptoms are leaf curl, marginal leaf yellowing, malformation of fruits, stunting and dieback (in case of primary infection at early seedling stage), so the disease is economically important. Therefore, this study delved into the relationship between the disease and the vector in selected agro-ecosystems in the Country. The influence of weather and seasonality on the incidence of the disease and the vector was also investigated through a series of field experiments across a period of two years. New methods for trapping the vector were developed and applied to estimate its populations on individual plants and in the overall field environment. The findings were that whereas incidence of the disease is low at seedling stage, the whitefly population is highest at this stage. It was also found that the vector population is favoured by drought, so rainy conditions reduced it tremendously.

Screening of Tomato Varieties for Resistance to Tomato Leaf Curl Viral Disease under Field Conditions

“…There was non-significant relationship of vector insect with both incidences as well severity of tomato leaf curl disease, r 2 = 0.07068, P= 0.8272 and r 2 = 0.2869, P= 0.3660, respectively. Such findings are previously reported by Ssekyewa et al (2007) who assessed a negative relationship between number of plants infected with tomato yellow leaf curl virus and percentage marketable tomato yield. Tomato maturity was inversely proportional to whitefly infestation.…”

“…Tomato maturity was inversely proportional to whitefly infestation. Later on, Ssekyewa et al (2010) reported that inci-dence of tomato yellow leaf curl disease was lower, whereas the vector population was higher at seedling stage. It is well documented that a single individual of insect vector can transmit the virus to a single or dozen of susceptible plants.…”

Variations of Incidence, Types of Virus Diseases and Insect Vector Populations of Tomato (Solanum lycopersicum L.), Grown in Different Agroecological Regions of Sri Lanka under Two Crop Management Systems

“…Rahman et al (2006), Mehta et al (1994), Gupta (2000), Paul (2002) and Parvin (2002) have reported an increase of whitefly population and its positive correlation with the spread of TYLCVD under field conditions. However, Ssekyewa et al (2007) reported that virus occurrence varied in space and time, and with management practices, crop development stage, and weather conditions based on field experiments conducted on TYLCV and tomato leaf curl virus (ToLCV) using two crop management systems (i.e. chemical pesticide and non-pesticidal application).…”

Appraisal of Genetics and Heterosis of Important Traits in Chilli Pepper Cultivated under the Influence of Chilli Leaf Curl Virus Disease

“…[41]. The differential response of genotypes to ChiLCV incidence and symptom expression could be attributed to the fact that the disease incidence and its spread are influenced by the occurrence and population dynamics of the vector whitefly and the weather conditions in the agro-ecosystem [42].…”