An ecophysiological approach to crop losses exemplified in the system wheat, leaf rust and glume blotch

Abstract

A climate chamber experiment is reported in which were investigated the growth and transpiration of uninfected wheat plants (C), plants infected with either Puceinia recondita (leaf rust) alone (R), Septoria nodorum (glume blotch) alone (S), or with both pathogens together (I). The rust inoculation was at the 75 ~ heading stage, and was followed four days later by the glume blotch inoculation; re-infection was prevented. Effects of disease on axial development were not observed. The rate of total dry weight increase of the plants was reduced in S and I, mainly because of smaller dry weight increase of the heads. Kernel weight and kernel number in I were lower than in C, R, and S. Stems in S and I were shorter than those in C and R, and their weights were lower. Rapid root deterioration was observed in I. The transpiration was greater in R than in C, in S smaller. Transpiration in I was initially equal to that in R, but the transpiration rate decreased rapidly after the glume blotch symptoms became visible. The increase in the percentage of infection by rust in I was lower than in R, and the sporulation came almost to a stop soon after the appearance of glume blotch flecks. The percentage of infection by glume blotch in I increased faster than in S. Regression equations for growth and transpiration are given.Neth. J. Pl. Path. 80 (1974) Addresses Laboratorium voor Fytopathologie, Landbouwhogeschool, Binnenhaven 9, Wageningen, the Netherlands.