Even if enough Fe is in the soil, deficiency can occur under the following conditions: poorly drained soil, high Ca, high Mn, high pH, high P, high heavy metals, oxygen deficiency. Deficiency symptoms General: Yellow or white areas on youngest leaves. Older leaves remain green.
Bt corn is a variant of maize that has been genetically altered to express one or more proteins from the bacteria Bacillus thuringiensis. The protein is poisonous to certain insect pests and is widely used in organic gardening. The European corn borer causes about a billion dollars in damage to corn crops each year.
They seem to think that our carefully-tended plants and vegetables were planted for their benefit alone. Bt, or Bacillus thuringiensis, is an organic insecticide that is a useful addition in the gardeners' arsenal against many of these plant-eating insects.