Single and combined effect of two fungal diseases on growth of moth plant, Araujia hortorum (Apocynaceae)

RAMÍREZ, GUSTAVO HERNÁN; BIANCHINOTTI, MARÍA VIRGINIA; ANDERSON, FREDA ELIZABETH

New Zealand Journal of Botany

RSNZ PUBLISHING

Año: 2021 p. 1 - 19

0028-825X

Araujia hortorum is a perennial, broad-leaved herbaceous climbernative to South America considered an invasive weed in NewZealand and several other countries where it has beenintroduced. Ascochyta araujiae and Septoria araujiae are thecausal agents of two of the most frequently encountered diseasesaffecting natural populations in Argentina, which on manyoccasions co-occur on the same plant. Host?pathogeninteractions generally result in a decrease in host fitness.However, when two or more pathogens occur simultaneously ona single host the outcome of the combined interaction might bedifferent from the sum of each acting individually. An experimentwas conducted to investigate the single and combined effect ofthe two pathogens on growth of the host plant as comparedwith healthy control ones. Each pathogen individually, as well asthe combination of both, had a significant effect on size andbiomass production of diseased plants. The interaction of bothdiseases resulted in biomass reductions similar to those ofA. araujiae acting alone. This is because A. araujiae, having ashorter latent period, induces earlier defoliation causing the lossof latent S. araujiae infections that never develop. Theimplications of these findings on the potential use of thesepathogens as biological control agents are discussed.