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.
Resistant strains of the European corn borer have developed in areas with defective or absent refuge management. In November 2009, Monsanto scientists found the pink bollworm had become resistant to first-generation Bt cotton in parts of Gujarat, India-that generation expresses one Bt gene, Cry1Ac.