nutrient excess or toxicity (general)
Host: burley tobacco (Nicotiana tabacum (burley type)
Description: Visual symptoms of Mn toxicity may develop when soil acidity reduces the soil pH to near 5.4 or less. Under these conditions, the lower leaves take on a mottled or chlorotic appearance. Light, greenish-yellow to pale white mottles occur between dark green areas along the veins. Also, leaves may appear to have a hard semi-glossy surface. If the soil pH continues to drop, mottles may be spread over the entire plant and growth will be stunted. Under extremely acid conditions, the availability of Mn increases and plants take up the nutrient to the extent that it becomes toxic, and plants may eventually die. Plants exhibiting Mn toxicity symptoms usually occur in spots or streaks within the field. Seldom will the entire field be affected. The problem is corrected with the proper use of lime.
Image type: Field
Image location: United States
Name: R.J. Reynolds Tobacco Company Slide Set
Organization: R.J. Reynolds Tobacco Company
Country: United States