{"id":2349,"date":"2026-10-21T00:35:07","date_gmt":"2026-10-20T23:35:07","guid":{"rendered":"https:\/\/koczoradam.hu\/?p=2349"},"modified":"2026-10-21T00:35:07","modified_gmt":"2026-10-20T23:35:07","slug":"elorejelzo-novenyek-rozsa-cekla","status":"publish","type":"post","link":"https:\/\/koczoradam.hu\/en\/elorejelzo-novenyek-rozsa-cekla\/","title":{"rendered":"A rose at the head of the vine row, beetroot in the sugar beet: do indicator plants work?"},"content":{"rendered":"

A rose bush at the head of every vine row, a few beetroot plants in the middle of a sugar beet field.<\/strong> Both rest on the same idea: a more sensitive plant shows disease symptoms earlier than the crop, so you can protect it in time. A nice idea, and logical at first hearing. In crop protection, however, logical and effective are not always the same thing.<\/p>\n\n

\"No-till
A no-till sugar beet field. Can you spot the beetroot?<\/figcaption><\/figure>\n

Where does the idea come from?<\/h2>\n

In German wine regions, roses planted at the head of the rows are still a common sight: tradition has it that rose powdery mildew appears before grapevine powdery mildew, so the rose signals when to spray. And in a no-till sugar beet field I came across the practice of mixing a small share of beetroot into the seed, because Cercospora leaf spot (Cercospora beticola<\/em>) shows up on it sooner.<\/p>\n

The two cases are not the same. Rose and grapevine powdery mildew are caused by two different pathogens (Podosphaera pannosa<\/em>and Erysiphe necator<\/em>), whereas sugar beet and beetroot are two varieties of the same species, infected by the same fungus. In one case even the biological basis is questionable; in the other it is at least promising.<\/p>\n

Where an indicator plant can fail<\/h2>\n

Even if we accept that the indicator plant is more sensitive, in practice several conditions must be met at once: the susceptibility of the varieties, the presence of an infection source and the environmental needs of the pathogens all matter. The indicator plant also has to be found in a large field, and it\u2019s worth thinking through what happens to it if the spraying fails.<\/p>\n

Four questions before you try it<\/h2>\n
    \n
  1. Does the same pathogen attack the indicator plant and the crop?<\/li>\n
  2. How susceptible is your variety, and how susceptible is the indicator plant\u2019s variety?<\/li>\n
  3. How will you find and monitor the indicator plants in the field?<\/li>\n
  4. What happens if the indicator plant itself becomes a source of infection?<\/li>\n<\/ol>\n

    In some places a method like this is a cheap and useful addition; in others it is just pretty. Which one it is for you depends on local conditions.<\/p>\n

    In detail<\/h2>\n

    I wrote about both cases, and how promising I think the method is, in Parasztvak\u00edt\u00e1s: Esettanulm\u00e1ny: n\u00f6v\u00e9nyv\u00e9delmi el\u0151rejelz\u0151 n\u00f6v\u00e9nyek<\/a> (for subscribers).<\/p>\n

    How I can help<\/h2>\n

    I work as an independent plant doctor: I don\u2019t sell plant protection products and I take no commission from distributors. My advice is guided by one thing only: what pays off for your farm.<\/p>\n