The yield loss of maize (Zea mays L.) grown for grain when the plants are mechanically damaged

Deficit of water, oxygen and a low temperature are the main stress factors in crop fields. From biotic stress factors, pathogenic microorganisms, but also many species of animals as evolutionary advanced herbivores, cause serious plants damage. The impact of three different intensities of leaf damage (not damaged, damaged by 25% and 50%, also by 75% in 2005) on the maize yield of hybrid varieties Reseda and Ribera was monitored in a field experiment founded in 2004 and 2005 in locality Žabčice (corn production region, zone K2, average altitude 184). The rising intensity of the leaf area reduction negatively influenced the economic grain yield. However, the yield differences were not statistically significant. Decisive differences in TGW values were not established among individual variants, nor were observed significant changes in the weight of cobs and the grain ratio