Using epidemiological principles to explain fungicide resistance management tactics: why do mixtures outperform alternations?

Effect of azole fungicide mixtures, alternations and dose on azole sensitivity in the wheat pathogen Zymoseptoria tritici

114-130_Feb08 Techwell.indd

Fungicide resistance in dollar spot caused by Sclerotinia homoeocarpa is a common problem on golf courses in North America (Figure 1) (2), and managing fungicide resistance is a complex and controversial topic (1,4). With dollar spot, the question of whether to use the same fungicide until resistance develops or to rotate different chemistries and tank mixtures has not been defi nitively answer...

Epidemiological and evolutionary management of plant resistance: optimizing the deployment of cultivar mixtures in time and space in agricultural landscapes

The management of genes conferring resistance to plant-pathogens should make it possible to control epidemics (epidemiological perspective) and preserve resistance durability (evolutionary perspective). Resistant and susceptible cultivars must be strategically associated according to the principles of cultivar mixture (within a season) and rotation (between seasons). We explored these questions...

Coexistence, niches and biodiversity effects on ecosystem functioning.

General principles from coexistence theory are often invoked to explain how and why mixtures of species outperform monocultures. However, the complementarity and selection effects commonly measured in biodiversity experiments do not precisely quantify the niche and relative fitness differences that govern species coexistence. Given this lack of direct correspondence, how can we know whether spe...

Can high-risk fungicides be used in mixtures without selecting for fungicide resistance?

Fungicide mixtures produced by the agrochemical industry often contain low-risk fungicides, to which fungal pathogens are fully sensitive, together with high-risk fungicides known to be prone to fungicide resistance. Can these mixtures provide adequate disease control while minimizing the risk for the development of resistance? We present a population dynamics model to address this question. We...