Using virtual 3-D plant architecture to assess fungal pathogen splash dispersal in heterogeneous canopies: a case study with cultivar mixtures and a non-specialized disease causal agent

Abstract

The results show agreement with previous data obtained using experimental approaches. They demonstrate that in order to maximize the potential mixture efficiency against a splash-dispersed pathogen, optimal susceptible/resistant cultivar proportions (ranging from 1/9 to 5/5) have to be established based on host resistance levels. The results also show that taking into account dispersal processes in explicit 3-D plant canopies can be a key tool for investigating disease progression in heterogeneous canopies such as cultivar mixtures.

Contrasting plant height can improve the control of rain-borne diseases in wheat cultivar mixture: modelling splash dispersal in 3-D canopies

“…Here we focused on individual dispersal events and not on the whole epidemic, in order to better understand mechanisms related to canopy architecture. Other studies have investigated the effect of cultivar mixtures on epidemics, and shown that mixture effects can be amplified by successive dispersal cycles (Gigot et al, 2014).…”

“…Cultivar mixtures consist of growing different cultivars together in the same field. This cultural practice can provide a reduction of disease propagation if mixtures are adequately designed, in particular if chosen cultivars have contrasting levels of resistance to the targeted disease (Finckh and Wolfe, 2006;Gigot et al, 2014). Moreover, it makes it possible to grow cultivars having interesting qualities (e.g.…”

“…On the other hand, spores are intercepted by resistant plants which are not or little affected by disease, and part of the inoculum is therefore prevented from reaching susceptible plants (barrier effect). The reduction of disease propagation in cultivar mixture can be optimized by using an adequate proportion of resistant and susceptible cultivars within the mixture (Jeger et al, 1981;Garrett and Mundt, 1999;Xu and Ridout, 2000;Cox et al, 2004;Dai et al, 2012;Gigot et al, 2014). For example, Gigot et al (2013) obtained reductions of STB severity up to 42 % in wheat cultivar mixtures containing 75 % of partially resistant plants and 25 % of susceptible plants.…”

Warming affects foliar fungal diseases more than precipitation in a Tibetan alpine meadow

“…Understandably, fungal pathogens are likely to benefit from increased moisture, which can promote fungal spore germination, mycelium growth, and initiation of infection (Woods et al ., ; Strengbom et al ., ). In addition, the dispersal of spores could be affected by precipitation over short distances both positively (dispersal through rain‐splash droplets) and negatively (removing spores from air and leaf surfaces before they have attached) (Gigot et al ., ). For host plants, altered precipitation can alter fungal infections.…”

Disease risk perception and diversity of management strategies by farmers: The case of anthracnose caused by Colletotrichum gloeosporioides on water yams (Dioscorea alata) in Guadeloupe

“…The protective effect of varietal admixture was nevertheless lower when admixture grain was too fine. Indeed, while use of varietal admixture or multi-lines can decrease pathogen epidemics, especially with regard to soil-borne diseases or splash dispersed fungi (Mundt, 2002;Trutmann et al, 1996), a too fine grain in admixture can translate in inefficient plant protection when admixture is at the individual plant level, since susceptible plants may thus grow within pathogen average dispersal distance (Gigot et al, 2014;Skelsey and Newton, 2014;Garett and Mundt, 1999), and our results suggest that fine scale varietal admixture are indeed associated with increased reports of anthracnose (Farmers' experience of anthracnose is lower when admixture is practiced in blocks and rows compared to when varieties are planted haphazardly or alternated one after the other). Admixture and cultivation of other species were rather expected effects of acknowledged beneficial practices (Mulumba et al, 2012), and they definitely seem to fit in a set of potentially sustainable strategies against the disease, provided the admixture grain be greater than dispersal ability of Colletotrichum.…”