Leaf nutrients content of tomato and incidence of insect pests and diseases following two foliar applications

The leaf plays key roles in plant functions. In this study, we evaluated major nutrients (Nitrogen (N), phosphorous (P), and potassium (K)) contents of the leaves of tomato (Solanum lycopersicum) following applications of two foliar nutrients sources. Pest population dynamics as well as disease incidence and severity of the crop were also evaluated. The study was conducted at the Plantation Crops Section of the Kwame Nkrumah University of Science and Technology, Ghana in two consecutive cropping seasons. Two tomato varieties were treated with two foliar nutrients sources viz. Herbagreen and Sidalco liquid fertilizer in a split-plot layout. A conventional (granular) NPK fertilizer and a control (no application) were also evaluated. The foliar applications generally increased leaf N concentration of tomato more than the conventional NPK fertilizer and the control. Sidalco liquid fertilizer significantly (p < 0.05) increased foliar K concentration in the major season while Herbagreen increased K concentration by 108% over the NPK fertilizer in the minor season. However, leaf P concentrations were similar (p > 0.05) among the foliar and soil applications. The foliar applications (p < 0.05) reduced the densities of Bemisia tabaci (Gennadius) than the NPK fertilizer and the control in both seasons of cropping. In the minor season, Herbagreen (p < 0.05) reduced both incidence and severity of late blight. Herbagreen treated plants produced fruit yield comparable to the conventional NPK fertilizer and registered lower disease incidence and severity as well as lower insect pest populations possibly due to its silicon content.