Agrarforschung Schweiz

Author: Tamara Baumann

  • Curative Control of Wireworms (Agriotes spp.) in Potatoes

    Curative Control of Wireworms (Agriotes spp.) in Potatoes

    When wireworm damage to potato tubers is excessive the crop ceases to be marketable. Various control options were explored in an effort to remedy the problem.

    Wireworm damage to potatoes

    Wireworms – also known as click-beetle larvae – are highly polyphagous pests capable of causing major damage in various crops, including potatoes. The larvae tunnel into the tubers, adversely affecting the quality of the harvest. When the proportion of potato tubers damaged by this pest becomes excessive, the harvest fails to achieve its proper value, leading to major economic losses for producers.  Although various plant protection products were used in the past to control wireworms, their authorisations have been revoked. Currently, an effective solution is no longer available to farmers in Switzerland.

    Control efficacy of plant protection products

    Agroscope conducted pest control trials from 2015 to 2019 to study the efficacy of various chlorpyrifos-, spinosad-, spirotetramat-, tefluthrine-, fipronil-, Metarhizium brunneum- and Beauveria bassiana-based plant protection products in controlling wireworm damage in potato tubers. Three different application periods were studied: that of the catch crop preceding the potatoes, the potato-planting period itself, and the six weeks post-planting.

    The results obtained show that, regardless of the period of application, the tested products failed to significantly reduce wireworm damage to the potato tubers compared with the untreated control. However, the fipronil-based reference product, which exhibited a high level of efficacy, was an exception to this rule.

    The importance of application period for the fipronil-based treatment

    The control period played a key role in the level of efficacy of the latter product. When fipronil was applied in autumn in the catch crop preceding the potatoes, the proportion of tubers with wireworm damage was markedly lower than that of the ‘control during potato planting’ modality. Moreover, the rate of damaged tubers was 7% lower than the threshold of acceptability for the marketing of the crop.

    Conclusions

    • Wireworms cause major damage in potato crops.
    • Apart from the fipronil-based reference product, which is banned in Switzerland and in Europe, the anti-wireworm products tested failed to demonstrate efficacy in reducing damage to the tubers.
    • The period of implementation of the control measures plays a key role in their success and must be taken into consideration in future research. The said period may vary according to the nature of the plant-protection product.  
    • The option of control measures over the entire rotation is an interesting prospect to explore, particularly in the case of entomopathogenic fungi.
  • Grass-Clover Mixtures: High Yields, Low Nitrate Leaching

    Grass-Clover Mixtures: High Yields, Low Nitrate Leaching

    The advantages of grass-clover mixtures in ley farming are manifold. An Agroscope study now shows that their highly efficient use of available nitrogen also keeps the risk of nitrate leaching low.

    Grass-clover mixtures offer major advantages in ley farming: they supply high-quality feed, promote soil structure and fertility, use resources efficiently and provide the rotation with nitrogen from symbiosis which the clover fixes from the air.

    In collaboration with the ETH Zurich, an Agroscope team investigated the effects of clover-nitrogen fertiliser combinations on yields and the risk of nitrate leaching. Researchers tested the influence of different quantities of nitrogen fertilisers on pure grass swards, grass-clover mixtures and pure clover swards. Among others, they analysed soil nitrate levels and nitrogen balance, recording the risk of nitrate leaching both during the growth of the temporary leys and after tilling of the leys for the follow-on crop in the rotation.

    Pure clover and pure grass swards both have their drawbacks

    Pure grass swards with either very low or moderate nitrogen fertilisation (50 and 150 kg N, respectively) are not at risk of nitrate leaching, but were low-yielding. They require very high nitrogen fertilisation to achieve similar productivity to mixtures. This very high fertilisation rate can lead to a time-lagged risk of nitrate leaching.

    Even at the very low fertilisation rate, pure clover swards exhibited an increased risk of nitrate leaching. The similarly high nitrate-leaching risk of pure grass swards at high fertilisation rates and pure clover swards at low fertilisation rates suggests that leaching risk is influenced more by the nitrogen balance (total input minus nitrogen in harvested plant mass) than by the source of the nitrogen, i.e. fertiliser or symbiosis.

    Grass-clover mixtures use nitrogen efficiently…

    By contrast, grass-clover mixtures maximised biomass production at a low risk of nitrate leaching. This was accomplished by the efficient use of nitrogen from symbiosis, fertilisers and soil. Even after the tilling of the mixtures, nitrate leaching remained comparable to or even lower than after the tilling of pure grass swards.

    … and yield more forage with lower nitrate leaching

    The study reaches the conclusion that moderately fertilised grass-clover mixtures are markedly higher-yielding than pure grass swards. At the same time, the mixtures regulate symbiotic nitrogen fixation according to the needs of the plants and the availability of nitrogen in the soil, leading to a nitrogen balance of close to zero. As a result, they do not increase the risk of nitrate leaching compared to pure grass stands.

    Conclusions

    • In ley farming, moderately fertilised grass-clover mixtures are markedly more productive than pure grass swards and do not increase the risk of nitrate leaching.
    • In mixtures, symbiotic nitrogen fixation is regulated according to the needs of the plants and the availability of nitrogen in the soil, leading to a nitrogen balance of close to zero. This keeps the risk of nitrate leaching low.
    • The risk of nitrate leaching in grass-clover mixtures is no higher than for pure grass swards, even after tilling for the follow-on crop.
  • How are Plant-Based Alternatives to Dairy Products Perceived and Who Consumes Them?

    How are Plant-Based Alternatives to Dairy Products Perceived and Who Consumes Them?

    The range of plant-based alternatives to milk continues to rise. Agroscope and the SMP (Swiss Milk Producers) conducted an online survey to find out what products are being consumed and how they are perceived.

    The consumption of high proportions of animal products contributes significantly to harmful greenhouse gas emissions and ultimately to climate change. A more plant-based diet could counteract this. The wide range of plant-based alternatives to milk and dairy products supports this transition. Consumption of these products has increased in recent years.

    Survey on the consumption of plant-based alternatives to milk

    An online survey conducted in the German- and French-speaking parts of Switzerland aimed to examine in detail which products are consumed by whom and for what reasons. A total of 1204 people were asked about their consumption or non-consumption of plant-based alternatives to milk, yoghurt and cream products.

    Flexitarians frequently consume plant-based alternatives to milk

    The survey showed that consumers of plant-based alternatives tended to be young, well-educated, urban flexitarians – in other words, people who are interested in eating less meat. The findings suggest that plant-based alternatives to dairy products are often consumed in conjunction with animal products.

    Taste, health, sustainability and animal welfare are the main reasons

    The most frequently consumed plant-based alternatives to cow’s milk were soya, almond and oat drinks. The main reasons given by participants for consuming these products were taste (26%), health (34%, including allergies and intolerances), dietary variety (12%) and animal welfare and sustainability (16%). People who did not consume plant-based dairy alternatives cited a lack of interest in these products (38%) or stated that they did not like the taste (25%).

    The results of this survey have important implications for research and practice and provide a better understanding of the growing group of consumers who use plant-based alternatives to support a more sustainable diet.

    Conclusions

    • Consumers of plant-based dairy alternatives tend to be young, well-educated, urban flexitarians.
    • The most frequently consumed alternatives to cow’s milk are soya, almond and oat drinks.
    • Main reasons for consuming plant-based dairy alternatives are their taste, contribution to health (including allergies and intolerances) and positive impact on the environment.
    • Plant-based dairy alternatives are often consumed in combination with animal products.