Dark brown to angular black spots on the upper leaf of V. suspensum are typically less blotchy and more distinct. This disease can be seen colonizing the underside of diseased leaves and appears whitish gray and downy-like on Viburnum ‘Awabuki’ and V. suspensum leaves. As the disease progresses leaves begin to drop off, and large portions of the canopy can become defoliated. Physical Appearance Downy Mildew of Viburnum Diagnostic Guide Is this answer helpful?Thanks!Give more feedbackThanks!How can it be improved?How can the answer be improved?Tell us how Viburnum Awabuki Pests & Diseases | Garden Guides wwwenguides›FlowersPESTSLEAF SPOTSOTHER DISEASESDamage caused by pests that feed on the foliage of Viburnum awabuki affects the appearance of the plant but normally does not harm it. Curled or rolled leaves are symptoms of aphid or thrip infestations. Thrips also cause purplish-red spots on the underside of the leaves, where they scrape the cells and suck the sap. Spider mites are active in the cool weather of spring and fall when they pierce the foliage and feed on the sap. The leaves turn grayish-brown, the leaf tissue collapses and the..See more on gardenguides ENH817/ST660: Viburnum odoratissimum var. awabuki - EDIS Common name(s): Awabuki Sweet ViburnumFamily: CaprifoliaceaeUSDA hardiness zones: 9A through 11 (Fig. 2) Shoot blight causes grayish to brown decayed spots on the leaves. The spots first appear at the leaf margins, then spread to the rest of the leaf. Infected flower clusters or twigs are killed.