Herd immunity in food crops: promoting efficient and durable use of biocontrol and chemical fungicides

Herd immunity is a form of indirect protection from disease that occurs when a sufficient percentage of a population becomes immune to infection through e.g. vaccination thereby reducing the likelihood of infection for individuals who lack immunity.

The concept of herd immunity developed within the science of human epidemiology and has never been fully explored in relation to crops.The first aim of this project is to investigate whether herd immunity can be obtained in crop plantations through speckled use of 1) resistant cultivars, 2) biological control (Aureobasidium pullulans), and 3) chemical fungicides (Switch®).

The second aim is to investigate whether use of these speckled measures creates selection mosaics with evolutionary micro-refuges for the pathogen, thereby preventing it from evolving counter-resistance.

Garden strawberry infected by Botrytis cinerea (causing grey mould) will be used as a model system.If herd immunity can be obtained in plantations and at the same time create evolutionary refuges, then this concept comes with two game-changing advantages.

First, lower amounts of plant protection products can be used, leading to economic savings and reduced environmental risk.

Second, the evolution of counter-resistance will be delayed, thus enabling prolonged durability of plant protection products and resistant cultivars.

These novel achievements would drastically increase cropping security as well as the economic and ecological sustainability for farmers.