Yield Loss of Corn Hybrids to Incremental Defoliation

A yield loss model is needed to describe field corn's ( Zea mays L.) response to progressive defoliation caused by defoliating agents such as plant pathogens or insects. Defoliation was achieved by physical removal of leaves at different growth stages starting two weeks prior to tasseling (V14) and continuing through physiological maturity. These treatments created different corn defoliation progress curves (CDPC). Three hybrids responded similarly to defoliation over the five environments tested. The general yield loss model for the regression of percent yield and CDPC was: urn:x-wiley:15437833:media:crm2cm2005042701rs:crm2cm2005042701rs-math-0001 The regressions for the individual environments were very similar to the general model. Loss of leaves below the ear leaf at silking resulted in 11% yield loss. When defoliation was initiated at dent stage yields were not reduced. This model improves the accuracy of predicting yield loss in field corn to defoliation that becomes progressively severe over time such as foliar diseases.