Print version ISSN 0102-0536
AZEVEDO, Francisco Roberto de and BLEICHER, Ervino. Vertical and sectorial distribution of whitefly nymphs on melon leaves. Hortic. Bras. [online]. 2003, vol.21, n.3, pp. 464-467. ISSN 0102-0536. http://dx.doi.org/10.1590/S0102-05362003000300010.
The spatial nymphs distribution of Bemisia argentifolii Bellows & Perring (Hemiptera: Aleyrodidae) among and within melon leaves was observed. The vertical distribution among leaves was done, selecting randomly leaves from node 5th through 20th. The counting of nymphs was performed on a weekly basis, at 49; 56 and 63 days after planting, using a circular leaf disc with an area of 2.8 cm2. Higher nymph concentration was observed from the 8th to the 10th leaf counted from the top to the bottom of the melon plant. These leaves were considered the best ones to be sampled. The distribution of nymphs over the leaf sectors was performed, selecting randomly leaves and dividing them into four sectors (distal left, proximal left, distal right, and proximal right). The number of nymphs was similar in both proximal sectors, however in the proximal sectors the number of nymphs was greater than those found in distal sectors. From the total nymphs found, 13.70% were found on distal left sector, 35.70% on proximal left sector, 36.70 on proximal right sector and 14.25% on distal right sector. Sampling nymphs close to the central leaf rib is more effective.
Keywords : Bemisia argentifolii; sampling; melon.