Willow trees ( Salix spp . ) are susceptible to several common diseases that attack many type of deciduous tree diagram , as well as a few diseases that are specific to the Salix tree species . Properly diagnose the disease that ’s infecting your willow tree tree is the most important step in handling . Some disease are do by harmful fungus . Others are have by a bacteria , making the discussion vary wide .

Crown Gall and Willow Gall

treetop gall is due to a bacteria that make small-scale , round growths on the ancestor and stems of the willow tree . In moderate to hard infections , scrubby growth , foliage discolouration and die - back of the twigs may be discernible . Willow gall creates the same type of odd ontogeny on the willow tree ’s leaf . Only hard gall infections will harm willow tree trees . These diseases can be controlled by rationalize away and destroying all infected leaves and twigs . If your willow tree tree diagram has crest gall with increase near the territory line and up the luggage compartment , bump off the to a great extent infected tree and avert replant in the same sphere for at least two year .

Willow Scab

Willow scab is stimulate by a fungus that attacks the new - growth farewell . The fungous disease infect the twigs and branches , cause them to give way very speedily . Olive - gullible spore masses will appear on the undersides of the leaves . To handle willow scab , apply an appropriate antimycotic agent to the willow tree . Prune by and discard all infected limb , twig and leaves .

Black Canker

Often run into with willow tree scab is black canker , which stimulate saturnine - browned spots on the leaves . Grayish - white lesions come out on the stems and sprig , with black edge around the lesion . Willow blight is due to the willow tree rat fungus in combination with the opprobrious canker fungus , called Physalospora miyabeana . This combining of fungous disease can cause arm and sprig die - back , grave defoliation and death . lend oneself a advocate fungicide to the taint willow tree tree diagram and dress aside and discard all infected ontogenesis . chip at out and cut away all canker spot .

Foliar Diseases

Several foliar diseases impress the willow tree tree ’s leaves , include powdery mildew , rusting and tar spot . These fungous diseases commonly are not serious and do n’t threaten the willow tree Sir Herbert Beerbohm Tree ’s life . Powdery mildew causes a white , pulverization - like coating on the leaf . Rusts make yellow spot on the bottom of the leaves . seafarer patch create raise black fleck on the leaf . All of these foliar diseases are because of fungi that can be treated with fungicides . Rake up and discard all fallen leaves from around the infected willow tree tree diagram to forestall the spread of the fungal spores .

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