Distribution of the premature stages of the whitefly, Bemisia tabaci (Gennadius) on melon leaves

Abstract

The present studies were carried out on melon crop in the experimental fields of the Faculty of Crop Protection, Sindh Agriculture University, Tandojam. When the plants were fully grown, a 30- leaf sample from the third and fourth node of randomly selected creepers from the field were plucked. The leaves were tentatively subdivided into four Sectors (A, B, C and D). The sector A and D were presenting the proximal half of the leaf whereas B and C the distal half of the leaf. The whitefly egg and nymphs were separately counted on these sectors. The overall mean eggs of 30 leaves on sector A (32.88±2.55), B (20.76±1.82), C (17.10±1.30) and D (24.58±1.71) were recorded. Egg-density on the proximal leaf Sectors A and D was 34.49% and 25.78%, respectively, which was higher than sector B (21.78%) and C (17.93%). The population percentages of nymphs on sectors A, B, C and D were 21.09, 26.92, 29.35 and 22.62%, respectively. The overall mean number of nymphs on sector A was121.73±9.29, B 155.37±10.71, C 169.41±11450 and D 130.59±11.39, respectively. The Analyses of variance showed that the distribution of whitefly eggs varied significantly (P<0.001) on leaf sectors. However, the nymphs were significantly more in number on Sector B and C than on A and D (P<0.05). It was also confirmed by DMR test.