The spring rain earlier this week has lawn and landscapes looking the best I have observed in years. Cool weather and high moisture produce perfect growing conditions for cool season turf and cool weather annuals.
However, the cool weather can bring problems to other plants. Cool, wet weather in early spring can often cause problems with landscape plant materials, namely camellias and Bradford pears.
Camellias throughout the county are now infested with leaf gall. This foliar disease is caused by overwintering fungi which is able to survive the winter in leaf buds, infecting newly developing leaves. The infested leaves become thickened and succulent and are often larger than normal leaves.
These young, diseased leaves are grossly distorted with a pinkish-green color on the top leaf surface and a white color on the under leaf surface.
Fungal spores of the disease are dispersed by strong wind currents and splashing water. The weather experienced over the past few weeks was perfect for spreading the disease. The diseased camellia leaves eventually dry up, turning brown to black later this month.
Fortunately, leaf gall causes little damage to the overall health of the shrubs or to camellia flowering, but may be unsightly in the landscape or garden.
You can prevent future infestations by removing and discarding diseased leaves as they appear. Fungicide applications are seldom necessary and provide only limited disease control.
Cool, rainy weather also produces an environment favorable for fireblight in Bradford pears, edible pears and apples. Fireblight is caused by a bacteria spread with splashing rain, insects or sometimes introduced by infected pruning tools. The weather was cool and rainy during the bloom period this spring, conducive to spreading the disease.
Unlike camellia leaf gall, fireblight does not manifest itself until later in the spring and early summer. At this time most will have forgotten about weather conditions conducive for the diseases. Controlling fireblight with sprays is generally not practical. Commercial apple or pear producers often spray with streptomycin sulfate during bloom as a control, however most orchardists grow fireblight resistant cultivars.
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Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. For archived garden columns or other information, visit the Rowan County Master Gardener web site at www.rowan mastergardener.com, e-mail Darrell_Blackwelder@ncsu. edu; call 704-216-8970.