VIRTIGATION partners LIST (Luxembourg Institute of Science & Technology) and INRAE have assessed the impact of climate change on the spread of viral diseases in European agriculture.
Article by Tiziana Centofanti from the VIRTIGATION project
A serious threat to European food security
Preparing for the impacts of climate change is crucial in preserving European agriculture. In a recent report, scientists from VIRTIGATION partners LIST and INRAE have investigated how rising temperatures and shifting environmental conditions could alter the dynamics of viral diseases in tomato and cucurbit crops. This research delves into the effects of future climates on pest behavior, the efficacy of biocontrol agents, and the spread of ToLCNDV. They focus in particular on the Bemisia tabaci whiteflies, which are a significant global agricultural pest, comprised of multiple cryptic species that vary in their ability to transmit plant viruses. Notably, they can spread over 500 viruses apart from ToLCNDV, including also e.g. TYLCV. The rapid reproduction, wide host range, and increasing resistance to insecticides of the Bemisia tabaci whitefly complex makes it a serious threat to European food security.
How climate change impacts viral spread
The VIRTIGATION LIST group has examined how a projected mid-future Central European climate (2061-2070) will affect Bemisia tabaci MED whiteflies and their natural biocontrol agents. The MED species within the B. tabaci complex is particularly problematic due to its high resistance to chemical controls and exceptional efficiency in transmitting viruses. This species thrives in warm climates, making it especially sensitive to environmental changes. To understand how climate change impacts the whitefly Bemisia tabaci MED’s ability to acquire the ToLCNDV virus, LIST researchers conducted experiments with zucchini plants, using present and projected future climate scenarios.
One of the central findings of this study is that the projected future climate of Europe (based on 2061-2070 scenarios) may amplify the challenges already faced by farmers. Under warmer conditions, the plant pest Bemisia tabaci MED becomes more efficient at spreading ToLCNDV in zucchini plants. Experiments showed that increased temperatures lead to higher virus acquisition and transmission rates, suggesting that growers may face more severe outbreaks of ToLCNDV in the future.
The role of biocontrol agents in a warming climate
The use of biocontrol agents, like Encarsia formosa and Eretmocerus eremicus, has been a cornerstone of sustainable pest management. However, the LIST research highlighted that these natural enemies of whiteflies may struggle to survive in the warmer climates of the future. While their reproduction rate increases, their shorter lifespans could necessitate more frequent introductions, making pest control costlier and potentially less effective over time.
New innovative tools for plant disease monitoring
To accurately measure the amount of ToLCNDV virus in infected samples, LIST developed a droplet digital PCR (ddPCR) method. ddPCR is a highly sensitive technique that allows for the precise counting of viral DNA without needing standard references. The development of precise tools such as droplet digital PCR (ddPCR) allows for the absolute quantification of viral loads, enabling scientists and growers to closely monitor and respond to the spread of ToLCNDV. Accurate data means better-targeted measures and the potential to reduce the devastating impacts of viral diseases like ToLCNDV on tomato and cucurbit crops. The ongoing work of LIST will now focus on refining this ddPCR method for publication, providing a new tool for absolute ToLCNDV quantification.
How temperatures & drought affect ToLCNDV in melon
In a second part of the recent VIRTIGATION report, INRAE scientists conducted a study on how temperature and drought affect ToLCNDV in melons. The INRAE researchers looked at two versions of the virus: one that causes severe sickness and another that seems to “recover”.
They found that even when temperatures were higher, like those expected with climate change, the ToLCNDV virus didn’t get stronger or spread more. In fact, hotter temperatures helped the melon plants grow, even if they were infected. Interestingly, the version of the virus that causes severe sickness had less of an impact at higher temperatures. And for added reassurance, melon varieties that are naturally resistant to ToLCNDV stayed resistant even when it was hot or dry.
These INRAE research results are encouraging news for melon growers, because it suggests that rising temperatures may not make ToLCNDV a bigger problem. Furthermore, melon varieties bred for resistance should continue to be effective even in climate change conditions.
A new climate change reality for European agriculture
The implications of the recent VIRTIGATION report are clear: to ensure food security and a sustainable European agricultural sector, Europe must develop climate-resilient crop protection strategies. This includes further investment in innovative monitoring tools, exploring genetic resistance in plants, and adapting integrated pest management techniques to align with the changing climate. Growers, scientists, agricultural extension services and policymakers must strengthen their collaboration to prepare for a future where climate change influences how we grow our tomato and cucurbit crops.
Read here the deliverable “Report on the effects of climate change on the current and future spread of viral diseases in Europe” produced by VIRTIGATION partners LIST and INRAE, which describes their research made in more detail.
Watch also here LIST lead scientist Matteo Ripamonti describe the project’s research on viral disease spread under climate change conditions in our VIRTIGATION “Research in Brief” video series.
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