Resistance induction in wheat plants by silicon and aphids

Abstract

The pest greenbug Schizaphis graminum (Rondani) (Hemiptera: Aphididae) stands out among the factors limiting Brazilian wheat production. Chemical control is predominant in aphid management making the production dependent on insecticides. The effect of silicon and previous infestation with aphids on the induction of resistance to the greenbug was evaluated in wheat plants. Treatments consisted of control; fertilization with calcium silicate; plant infestation with aphids; fertilization with calcium silicate + plant infestation with aphids. A free-choice preference test was performed 35 days after seedling emergence; the aphid's intrinsic rate of population increase (r m) was also determined, and the activities of three enzymes (peroxidase, polyphenoloxidase, and phenylalanine ammonia-lyase) involved in plant defense were quantified. Silicon fertilization and the previous infestation with aphids induced wheat plant resistance to the greenbug.