Optimizing Plant Disease Management in Agricultural Ecosystems Through Rational In-Crop Diversification

Abstract

Biodiversity plays multifaceted roles in societal development and ecological sustainability. In agricultural ecosystems, using biodiversity to mitigate plant diseases has received renewed attention in recent years but our knowledge of the best ways of using biodiversity to control plant diseases is still incomplete. In term of in-crop diversification, it is not clear how genetic diversity per se in host populations interacts with identifiable resistance and other functional traits of component genotypes to mitigate disease epidemics and what is the best way of structuring mixture populations. In this study, we created a series of host populations by mixing different numbers of potato varieties showing different late blight resistance levels in different proportions. The amount of naturally occurring late blight disease in the mixture populations was recorded weekly during the potato growing seasons. The percentage of disease reduction (PDR) in the mixture populations was calculated by comparing their observed late blight levels relative to that expected when they were planted in pure stands. We found that PDR in the mixtures increased as the number of varieties and the difference in host resistance (DHR) between the component varieties increased. However, the level of host resistance in the potato varieties had little impact on PDR. In mixtures involving two varieties, the optimum proportion of component varieties for the best PDR depended on their DHR, with an increasing skewness to one of the component varieties as the DHR between the component varieties increased. These results indicate that mixing crop varieties can significantly reduce disease epidemics in the field. To achieve the best disease mitigation, growers should include as many varieties as possible in mixtures or, if only two component mixtures are possible, increase DHR among the component varieties.

Potato bacterial wilt in Ethiopia: history, current status, and future perspectives

“…Agronomic activities like topsoil amendment with 5% to 10% farmyard manure suppressed bacterial wilt severity and pathogen survival in soil as well as improved tomato yield in Ethiopia ( Yadessa, van Bruggen & Ocho, 2010 ). Other agronomic practices such as crop rotation and mixing crop varieties had also significant effect on bacterial wilt incidence in potato ( Kassa, 2019 ; Wang et al, 2021 ). In the study conducted by Lu et al (2016) with two different biochar made from peanut shell and wheat straw were added to R. solanacearum infested soil and the results showed that both treatments significantly reduced disease severity by 28.6% and 65.7% respectively in tomato fields.…”

What Can Be Learnt by a Synoptic Review of Plant Disease Epidemics and Outbreaks Published in 2021

“…From a broader perspective, disease management is increasingly seen as a multifunctional issue involving the securing of food supplies while safeguarding ecosystem health and reducing dependency on natural resources (He et al 2021), including the extended use of within-crop diversification (Wang et al 2021b) as shown for Zymoseptoria tritici in intraspecific mixed stands of wheat varieties (Orelana-Torrejon et al, 2021;Electronic Supporting Information, S5). Integrated crop management in both low-and high-input cropping systems is seen as an instrument for maintaining yields while reducing reliance on synthetic inputs such as pesticides and fertilizers (Richard et al 2021).…”

“…The balance between yield gains and infection risk in relation to climate change and variability makes the consequences for food security uncertain. A process-based simulation model was used to predict the incidence and severity of rice blast disease under different time scenarios and climate change scenarios (Wang et al 2021b; Electronic Supporting Information, S5). Little change was predicted by 2030, with a slight decline by 2070.…”

Emerging Extraction and Diagnostic Tools for Detection of Plant Pathogens: Recent Trends, Challenges, and Future Scope

“…A 13–22% loss is observed among the major food crops, including wheat, rice, soybean, potato, and many others. This loss is a major threat to food security, adding to the global burden and food scarcity . Plant pathogen infected diseases can prove to be fatal in the global scenario.…”

“…This loss is a major threat to food security, adding to the global burden and food scarcity. 2 Plant pathogen infected diseases can prove to be fatal in the global scenario. One such instance is the potato famine that occurred in the 19th century wherein the potato crop was ruined by Phytophthora infestans leading to the Irish famine with the death of over 2 million people.…”