Leyland Cypress Diseases

Needle Blight

Cercospora needle blight, caused by the fungus Cercosporidium sequoiae (syn. Asperisporium sequoiae; Cercospora sequoiae), is a relatively new disease on Leyland cypress. However, it a common disease on species of Juniperus, Thuja, Cupressus, Taxodium, Cryptomeria, Sequoia and other genera. The first symptom of Cercospora needle blight is a browning of the needles in the lower crown next to the stem. The disease slowly spreads upward and outward until, in severe cases, only the needles at the tips of the upper branches remain green. In a general way, these symptoms mimic those caused by severe stress where the interior needles turn yellow and fall off. Fruiting bodies of the fungus appear as tiny, greenish pustules on the upper surface of the needles or on small twigs. Spores (conidia) are present throughout the spring and summer and are spread by wind. Infection usually occurs during periods of wet weather.

Cercospora needle blight can be controlled by spraying with copper-containing fungicides. There are no fungicides registered specifically for the disease on Leyland cypress, but Kocide is registered for general use on ornamentals. Spray plants at 10-day intervals from bud break until new growth matures.

Kocide -

Kocide 2000 is an advanced copper product. It utilizes a patented formulation to improve copper bioavailablity in order to optimize performance at lower usage rates. Kocide 2000 is dry flowable and disperses well in solution. It is as effective as other copper products, however, the volume of copper needed is reduced by up to 25%. Contains 53.8% cupric hydroxide (metallic copper equivalent: 35%).

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