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.
Commercial corn today is 100% hybrid corn. This means that the seed corn is produced by cross-pollinating two inbred lines. Because corn plants have both male (tassels) and female (silks) reproductive parts, a seed corn field has to be altered in order to keep the plants from pollinating themselves and therefore just producing more inbred seeds. This is done by detasseling the 'female' rows of corn.