Poplar  - Disease information and Management Recommendations.

HOST PLANT DISEASE SYMPTOMS MANAGEMENT Poplar  Populus spp. Cankers, Valsa sordida (Cytospora chrysosperma), Phompsis sp., Hypoxylon sp., Mycosphaerella populorum, Cryptodiaporthe populea Fungi infect young twigs or wounds creating cankers on branches and trunks. Fruiting bodies commonly form on the face of cankers. Widespread and common on poplar, cottonwood, aspen and willow. Especially serious on Lombardy and silver leaf poplars. Maintain plant vigor. Remove cankered branches during dry weather. Avoid wounds. Avoid planting in areas with poor air circulation. Trees prone to many cankers should be replaced with another tree species. CHEMICAL: None. Leaf rust, Melampsora medusae and other species Yellow to orange pustules break through the surface on both leaf surfaces in mid to late summer. Angular yellow lesions may occur on the opposite leaf surface. Lesions turn black in autumn. Some defoliation may occur. Alternate hosts include hemlock, Douglas-fir, larch, and pine depending on rust species. Choose a poplar clone with resistance. Keep susceptible conifers 500 yards away from poplar stock. CHEMICAL: Seldom necessary in landscape settings. Triadimefon or triforine. Marssonina leaf spot, Marssonina populi Small brown leaf spots with yellow margins. Infection may advance into stem tissue. May be severe during wet seasons resulting in defoliation. Collect and destroy leaves. Plant in areas with good air circulation. CHEMICAL: Fungicides seldom warranted in landscape plantings. NURSERY: Chlorothalonil at bud break and every 7-10 days if necessary. Shoot blight, Venturia tremulae on Populus sp. and hybrids; V. populina on black cottonwood and balsam poplar Brown to black leaf spots rapidly expand on succulent tissue to cause shoot blight. Affected tissues dry out and become brittle. Remove and destroy infected shoots. Increase air circulation. Rake and remove leaves in the fall. CHEMICAL: Seldom necessary in landscape settings.

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