HOST PLANTS: Common in tomatoes, peppers, and eggplant.
SYMPTOMS: Blossom end rot may occur at any stage of growth in the development of the fruit, but, most
commonly, are first seen when the fruit is 1/3 to 1/2 full size. As
the name of the disease suggests, signs of infection appear only at the blossom end of the
fruit. At first a small, water-soaked lesion appears, which expands and darkens
rapidly as the fruits develop. The spot may grow until it covers as much as 1/3 to 1/2 of the entire surface of the fruit, or the spot may remain small
and superficial. Large lesions soon dry out and become flattened, black, and leathery
in appearance and texture.
FAVORED ENVIRONMENT: Low salt levels, droughts, and moisture shock (sudden change in moisture level) will cause this disease. Also rapid growth from excessive fertilizer application can promote the development of this disease.
BLOSSOM END ROT CONTROL: Control of blossom end rot is dependent upon maintaining adequate supplies
of moisture and calcium to the developing fruits. They should be planted in well drained,
adequately aerated soils. Tomatoes planted early in cold soil are likely to develop
blossom end rot on the first fruits, with the severity of the disease often subsiding
on fruits set later. Planting tomatoes in warmer soils helps to alleviate
the problem. Irrigation must be sufficient to maintain a steady growth rate
of the plants. When cultivation is necessary, it should
not be too near the plants nor too deep, so that valuable feeder roots remain
uninjured and viable. In home gardens, shading the plants is often helpful when
hot, dry winds are blowing, and soil moisture is low. Use of fertilizer low in
nitrogen, but high in superphosphate will do much to
alleviate the problem of blossom end rot. In emergency situations, foliage can
be sprayed with calcium chloride solutions. However, extreme caution must be exercised
since calcium chloride can be phytotoxic if applied too frequently or in excessive
amounts. Foliar treatment is not a substitute for proper treatment of the soil
to maintain adequate supplies of water and calcium.
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