Plant architecture as a tool to mitigate late blight: significant but variable contributions of erect, aerated potato canopies over six years of field trials

Research into alternative methods to control late blight in potatoes has led to an investigation into the role of plant architecture, specifically canopy formation, in mitigating the spread of the disease. Late blight, caused by the pathogen Phytophthora infestans, thrives in humid conditions and temperatures, making canopy architecture a potential lever against the infection and development of the pathogen.

Two commercial potato cultivars, Monalisa and Bintje, were compared in replicated field trials over six years (2011-2016) under irrigation, and over three years also without irrigation. Monalisa, characterized by an erect and ramose (branching) structure, consistently showed a slower disease progression compared to Bintje, a semi-erect and leafy cultivar.

This difference was significant in every non-irrigated trial, but only in half of the irrigated trials. No single canopy trait, such as height, closure, leaf area, or stem number, explained this suppression across all years and conditions.

However, the most consistent correlate of disease suppression was canopy closure at the time of inoculation, suggesting a microclimate-mediated effect. While disease reduction using Monalisa rarely resulted in a yield benefit, it occasionally outyielded Bintje under irrigation conditions. The study concludes that canopy architecture can complement other levers within integrated late blight management strategies.

Yet, its significant year-to-year variability and dependence on environmental conditions must be considered when using it as a reliable control method.