Bi J L, Toscano N C, Madore M A
Department of Entomology, University of California, Riverside, California 92521, USA.
J Chem Ecol. 2003 Mar;29(3):747-61. doi: 10.1023/a:1022880905834.
The impact of urea nitrogen fertilization on silverleaf whitefly, Bemisia argentifolii Bellows & Perring, population dynamics was examined in field-grown cotton (Gossypium hirsutum L.). Five urea nitrogen treatments were tested, consisting of soil applications of 0, 112, 168, and 224 kg nitrogen per hectare, and acombined soil-foliar application of 112:17 kg nitrogen per hectare. A positive response was observed between N application rates and the measured levels of nitrate N in petioles from mature cotton leaves. Similarly, a positive response was observed between N application rates and the numbers of adult and immature whiteflies appearing during population peaks. To determine whether these positive responses were related, we measured the levels of dietary N compounds (proteins and free amino acids) that would be available for insect nutrition in cotton petioles at the different N application rates. Sampling dates and N application treatments affected levels of soluble proteins in cotton petioles, and interactions between sampling dates and treatments were significant. Across all sampling dates, the relationship between N application rates and levels of soluble proteins was linear. Sampling dates also affected levels of total and individual free amino acids. Fertilizer treatments only affected levels of total amino acids, aspartate, asparagine, and arginine plus threonine. Levels of aspartate or asparagine and the N application rates were linearly correlated. No significant correlations were observed between levels of dietary N compounds in cotton petioles and numbers of whiteflies, either adults or immatures, on the cotton plants.
在田间种植的棉花（陆地棉）中，研究了尿素氮肥施用对银叶粉虱（Bemisia argentifolii Bellows & Perring）种群动态的影响。测试了五种尿素氮处理，包括每公顷土壤施用0、112、168和224千克氮，以及每公顷112:17千克氮的土壤-叶面联合施用。在施氮量与成熟棉叶叶柄中测得的硝态氮水平之间观察到正相关。同样，在施氮量与种群高峰期出现的成虫和若虫粉虱数量之间也观察到正相关。为了确定这些正相关是否相关，我们测量了不同施氮量下棉花叶柄中可供昆虫营养的膳食氮化合物（蛋白质和游离氨基酸）水平。采样日期和施氮处理影响棉花叶柄中可溶性蛋白质的水平，采样日期与处理之间的相互作用显著。在所有采样日期中，施氮量与可溶性蛋白质水平之间的关系呈线性。采样日期也影响总游离氨基酸和单个游离氨基酸的水平。肥料处理仅影响总氨基酸、天冬氨酸、天冬酰胺以及精氨酸加苏氨酸的水平。天冬氨酸或天冬酰胺的水平与施氮量呈线性相关。在棉花叶柄中的膳食氮化合物水平与棉花植株上的粉虱（成虫或若虫）数量之间未观察到显著相关性。
