Influence of Host Nitrogen Levels on Development, Survival, Size and Population-Dynamics of Sugarcane Mealybug, Saccharicoccus-Sacchari (Cockerell) (Hemiptera, Pseudococcidae)

Abstract

Nitrogen levels in commercial plots of sugarcane varied over the cane-growing season. However, when adjusted for seasonal effects, nitrogen did not have a detectable effect on the size of mealybug populations on cane. In laboratory experiments, the survival of immature Saccharicoccus sacchari and the size attained at the onset of the oviposition period was influenced by the level of nitrogen fertiliser applied to potted sugarcane. Survival of S. sacchari increased to a maximum at 320 mg L-1 soluble nitrogen in sugarcane and decreased at higher levels, while size increased with increased nitrogen over the whole range of concentrations tested. Nitrogen-driven changes in the abundance of S. sacchari predicted from laboratory data indicate that normal variations in nitrogen concentrations of field-grown sugarcane have little effect on the population dynamics of S. sacchari.