MECHANICAL TRANSMISSIBILITY AND EFFECTS OF WATERMELON MOSAIC VIRUS AND CUCUMBER MOSAIC VIRUS ON TWO WATERMELON CULTIVARS

A screen house experiment was used to evaluate the mechanical transmissibility and effect of Watermelon mosaic virus (WMV) and Cucumber mosaic virus (CMV) on virus infection, growth, yield of Kaolac and Sugar dragon watermelon cultivars. The treatments consisted of each cultivar mechanically inoculated with a virus and a buffer control; making 6 treatment combinations each replicated 6 times with a total of 36 pots. The results indicated that Kaolac and Sugar dragon watermelon cultivars were susceptible to mechanical inoculations with WMV and CMV, with consequent diminutions in plant growth, number and weights of pods produced. The significantly highest percentage infection was in Kaolac cultivar inoculated with CMV (3.6 – 23.6%). Kaolac cultivar inoculated with CMV also produced the significantly dwarfed plants (37.3cm) and lowest average number of leaves per plant (49.4). The significantly lowest average number of pods/plant (1.8) and weight of pods/plant (1.7Kg) were equally in Kaolac cultivar inoculated with CMV. The significantly highest average number of pods/plant (5.4 – 5.6) and average weights of pods/plant (4.9 – 5.2 kg) were however realized in the control treatments. On the overall, pathogenicity was greater in Kaolac watermelon cultivar infected with CMV compared with other treatments. Since genetic resistance is considered the most effective and most economical form of viral disease control; the screening of cultivars for their natural resistance to virus infection is essential for the development of control and management strategies for improvements in watermelon cultivation.