Nitrogen Fertilization Effects on the Composition of Foliar Amino Acids of Russet Burbank Potato
Wen, G., Cambouris, A.N., Ziadi, N., Bertrand, A., Khelifi, M. (2019). Nitrogen Fertilization Effects on the Composition of Foliar Amino Acids of Russet Burbank Potato. American Journal of Potato Research, [online] 96(6), 541-551. http://dx.doi.org/10.1007/s12230-019-09743-6
Plain language summary
Colorado potato beetle (CPB) is a notorious defoliating pest of potato crops. The CPB populations are generally suppressed by chemical insecticides. However, the CPB has the capability to rapidly develop resistance to registered chemicals. With the aim of reducing chemical applications to control the CPB, efficient integrated pest management (IPM) has to be implemented. As an herbivorous pest, the CPB lives mainly on potato foliage. Thus, the chemical composition of potato leaves, such as sugars, amino acids and glycoalkaloids, could play an important role in determining the feeding behavior and physiology of CPB. For instance, it has been shown that potato foliar sugars and amino acids promote CPB feeding while glycoalkaloids inhibit CPB development by adversely affecting the central nervous and digestive systems. Here we tested in a greenhouse experiment the effects of different nitrogen (N) fertilization rates (0, 60, 120, 180, and 240 kg N ha−1) on the chemical composition of potato leaves in relation with their potential impact on CPB. We found that N fertilization had no significant effect on leaf glycoalkaloid concentrations. However, the concentration of foliar sugar and amino acid concentrations increased under low N fertilization (0 to 120 kg N ha−1), decreased under 180 kg N ha−1 and re-increased at 240 kg N ha−1. The relatively low sugar and amino acid concentrations observed at 180 kg N ha−1, suggests that this N rate may be effective for CPB management while maintaining a high tuber yield. These findings support the implementation of an IPM strategy to control CPB by identifying management factors inducing changes in leaf chemical composition.
Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is an important pest of potato crops. Potato foliar amino acids play essential roles in CPB growth. In this study, amino acids were classified into four groups according to their different roles in promoting CPB growth. Then, nitrogen (N) rate effects on the concentrations of amino acid groups were investigated under field conditions. Experiments were carried out with five N rates of 0, 60, 120, 180, and 240 kg N ha−1 in a randomized complete block design. Twenty leaves were collected at 40, 54, 68, and 82 days after planting (DAP) for amino acids analysis. Results showed that N rate had no significant effect on concentrations of each amino acid group at 40 DAP. However, their concentrations linearly increased as N rate increased at 54, 68, and 82 DAP, suggesting that higher N rates could potentially favor CPB growth after potato enters tuber initiation stage.