Journal of Insect Science (2008) 8 (4), p. 37 (Ortega-Arenas et al.)

Laura D. Ortega-Arenas, D.A.A. Miranda and M. Sandoval-Villa (2008)
Greenhouse whitefly eggs and nymphs density on Gerbera jamesonii under different nitrogenous fertilizer regimes
Journal of Insect Science 8 (4), 37-37
in P. A. Stansly and C.L. McKenzie, organizers: Fourth International Bemisia Workshop - International Whitefly Genomics Workshop, December 3-8, 2006, Duck Key, Florida, USA
Abstract: The objective of the study was to evaluate the influence of nitrogenous fertilization in three varieties of gerbera (Gerbera jamesonii H. Bolus), on the oviposition rate and population density of whitefly nymphs, Trialeurodes vaporariorum (West.). An evaluation was also made of the effect of nitrogen concentration on indicators of flower quality (diameter of capitulum, diameter of peduncle and length of penduncle), yield and post-harvest life. Three varieties of gerbera were used (Tzigana, Fallela and Marisol) and three concentrations of nitrogen (8, 12 and 16 me L⁻¹), in a completely random design with factorial arrangement of treatments. The effect of the treatment was determined registering every two days, the population density of whitefly eggs and nymphs, per cm² of leaf, in two experiments: 1) free choice and 2) no choice. The population density of eggs and nymphs was higher in free choice assays. In these, the number of eggs and nymphs increased significantly (p<0.05) as the supply of nitrogen increased. In the no choice assays, however, the oviposition rate and nymphs density were not notably influenced by the nitrogen supply. In the three varieties, the highest density of eggs and nymphs was related to the nitrogen content in the leaves. The nitrogen supply did not effect the diameter of the capitulum, the length and thickness of the peduncle and the yield, but it did have an influence on the post-harvest life of the flower. In the varieties Fallela and Marisol, the post-harvest life was longer as the nitrogen supply was increased; on the other hand, in the Tzigana variety, the duration of the flower did not show a direct relationship with the nitrogen content.
Database assignments for author(s): Laura D. Ortega-Arenas

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Trialeurodes vaporariorum	Gerbera (crop)