Tropical Agricultural Research (Oct 2015)
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
Abstract
Incidence and types of insect-transmitted virus diseases of plants vary with the environmental factors, which have direct or indirect relationships on population dynamics of vectors. Alternative indirect strategies are essential to mitigate the environmental and health hazards of pesticide usage, which is the most predominant method of vector management used at present. The present study was conducted to determine the variation of virus disease incidence and the population of insect vectors in field grown tomato (Solanum lycopersicum L.) cv. Thilina in different environmental conditions using two crop management systems namely, existing management system with pesticide applications and an integrated management package (IMP) with less reliance on pesticides. Incidence and types of virus diseases, their abundance and types of both insect vectors and beneficial insects were recorded over one cropping season, together with mean day temperature and rainfall data. Peroxidase activity in tomato tissues was quantified spectrophotometrically to determine the effects of the location and management practices on build-up of defence related enzymes in plant tissues. Relationships between the virus disease incidence, vector and beneficial insect populations and climatic parameters were also analyzed. Results revealed that there was no significant (p=0.05) difference between the two types of management systems in terms of virus disease incidence indicating the equal efficiency of the tested IMP treatment and existing pest control method on virus disease management. Abundance of insect vectors and beneficial insect populations were significantly (p0.05) influenced by the interaction effect of the management system and location. The mean day temperature was weakly related with the virus disease incidence at different locations. Peroxidase activity of tomato tissues was significantly (p0.05) different among locations and did not significantly vary between the plants treated with IMP and the existing management systems.Tropical Agricultural Research Vol. 25 (3): 376-395 (2014)
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