Incidence and varietal preference of whitefly, Bemisia tabaci Genn. on sunflower
2002
Afghan, S.S.
Leaves of 6 sunflower varieties SC-83, SC-92, Abina, Amita, HO-1 and Record were observed after germination till harvest to record whitefly population and trichomes density/leaf a factor of resistance to whitefly attack. Thirty Leaves from each variety (from top, middle and bottom portion of 30 plants) were randomly selected to observe whitefly population. 5 leaves from each variety were also observed for trichomes density. The results show that the overall mean population of whitefly on SC-83, SC-92, Record, Amita, Albina and HO-1 were 4.52 plus-minus 0.93, 4.41 plus-minus 0.90, 3.13 plus-minus 0.53 2.95 plus-minus 0.60, 2.88 plus-minus 0.64, and 1.62 plus-minus 0.44 per leaf respectively in relation to trichomes density per 2 cm-2 on SC-83 44.40 plus- minus 6.63, SC-92 42.2 plus-minus 4.96, Record 36.4 plus-minus 6.03, Amita 35.8 plus-minus 5.98, Albina 34.4 plus-minus 5.86 and Ho-1 30.00 plus-minus 5,47 respectively. The result also reveal that two peaks in whitefly population were recorded. 1st during 3rd week of February and 2nd during 4th week of March. The highest mean population was recorded during 1st peak i.e. 12.45 plus-minus 2.43, 11.74 plus-minus 1.95, 6.25 plus-minus 1.90, 6.65 plus-minus 0.66, 6.74 plus- minus 1.03 and 4.47 plus-minus 0.44 per leaf on SC-83, SC-92, Record, Amita, Abina and HO-1 respectively. Whitefly, Bemisia tabaci appeared on the sunflower varieties from seedling upto the harvesting of the crop. The response of all varieties towards the attack of whitefly was more or less identical. However, varieties SC-83 and SC-92 were more preferable than Albina, Amita and record, HO-1 was least preferable. Trichomes density on leaf was proved to be a factor attributing whitefly attack. The lesser the density of trichomes on leaf harbours lesser the population of whitefly.
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