Every seven days after whitefly exposure, entries in both trials were scored for disease severity using a 1–6 severity scale, where: 1 = healthy, no observable symptoms; 2 = very mild with slight yellowing and mosaic on top leaves and no Leaf curling; 3 = mild yellowing, mosaic and/or slight leaf curling on youngest leaves, severe symptoms; 4 = moderate yellowing and/or leaf curling on the youngest (top) leaves; 5 = severe yellowing and blistering
and/or severe leaf curling plus some leaf size reduction on the youngest leaves of the main stem and/or at least one branch; 6 = very severe yellowing, blistering and/or very severe leaf curling, leaf deformation, leaf size reduction and stunting.