EFFECT OF GREENBUG (HOMOPTERA, APHIDIDAE) FEEDING ON CARBOHYDRATE-LEVELS IN WHEAT

The effect of biotype E greenbug, Schizaphis graminum (Rondani), feeding on nonstructural carbohydrate profiles in susceptible 'TAM W-101' winter wheat seedlings was investigated. Although greenbugs caused significant reductions in plant biomass, soluble carbohydrates (expressed as percentage dry weight) were not depleted and partitioning patterns were not altered, suggesting that reduced growth rates result from decreased photosynthetic capacity caused by toxicosis induced by greenbug. Total furanose levels were significantly reduced and did not recover after aphids were removed. Moreover, stem fructans showed a lower degree of polymerization in infested plants. These results may help to explain findings from previous reports that greenbug infestations predispose winter wheat to increased injury from cold temperature.