EFFECT OF NITROGEN-FERTILIZER SOURCE AND LEVEL ON OVIPOSITIONAL CHOICE OF POINSETTIA BY BEMISIA-ARGENTIFOLII (HOMOPTERA, ALEYRODIDAE)

The nitrogen content of poinsettia, Euphorbia pulcherrima Willdenow, was varied using different levels of calcium nitrate or ammonium nitrate fertilizers. Plants were exposed to female Bemisia argentifolii Bellows & Perring adults. Although females were found randomly on the treated plants, the number of eggs laid on ammonium nitrate-treated plants increased linearly with the level of nitrogen applied to plants. The protein-nitrogen content of the leaves increased linearly with the level of nitrogen applied to plants, despite the nitrogen source. The amino nitrogen content of ammonium nitrate-treated plants increased linearly with the level of nitrogen applied to plants. For calcium nitrate-treated plants, a 3-degree regression response was significant between the amino nitrogen content of the phloem and the level of nitrogen applied to plants. Selection of a host plant for oviposition is related to the nitrogen content of the host plant.