Response of cassava (Manihot esculentaCrantz) genotypes to natural infestation by scale insect pest Stictococcus vayssiereiRichard (Hemiptera: Stictococcidae)

•A comparative study out on six cassava varieties (two local and four improved) to determine their resistance levels against S. vayssiereiwas studied.•Infestation of plants with scale insects reduces growth and productivity and triggers the production of biochemical compounds.•Biochemical compounds can be used in varietal improvement to reduce the number of scale insects infesting cassava plants as part of IPM.•The linear regression model performed from the biochemical data variables in the cortex (CAT and HCN) and in the pith (TPC and CAT) have a negative linear relationship with the scale insect density.