VM Blackwood

Last modified by geosens on 2025/03/18 22:24

The VitiMeteo black wood disease tool is designed to assess the risk posed by the glassy-winged planthopper (Hyalesthes obsoletus), the primary vector of the Black Wood Disease. During the flight period of this insect, it is crucial to avoid controlling its host plants—bindweed (Convolvulus arvensis) and nettle (Urtica dioica). The graphs provided help users make informed decisions regarding this.

This wiki will guide you on how to interpret and use the graphs effectively for managing risks. Note: This guide explains how to use the graph, not the underlying calculations. You can find images of the disease here: https://rebschutz.hs-geisenheim.de/schadbilder-wein/schadbilder.php?Auswahl=Bois

1. Understanding the Risk Overview Table

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Purpose

The Risk Overview Table shows the risk levels for Hyalesthes obsoletus on bindweed and nettle over an 11-day period. Key components include:

  • Date Row: Grey-highlighted cells indicate the forecast period.
  • Percentage Values: Represent the risk level starting from specific dates (March 15 for bindweed and April 1 for nettle).

Key Threshold

When the risk level reaches 100%, it is recommended to halt weed control (e.g., mowing) to prevent disturbance to host plants.

Graph Components

  1. Risk and Temperature Curves

    • These curves depict the percentage progression of temperature sums toward the threshold values for bindweed and nettle.
    • Once the risk curve reaches the end of the flight period, it resets to 0%.

  2. Risk Bars

    • Labeled as "Risk A." for bindweed and "Risk B." for nettle.
    • Colored bars represent the calculated risk levels, corresponding to the legend provided in the tool.

  3. Weather Data

    • Shown at the bottom of the graph, this section includes:
      • Daily average temperature
      • Precipitation levels
      • Air humidity
      • Leaf wetness (displayed as raw data)

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3. Practical Application

To use the graphs effectively:

  1. Check the Risk Values: Identify if the percentage for either host plant has reached 100%. If so, avoid controlling these plants.
  2. Analyze the Trends: Use the risk curves to predict when the risk levels will peak or decline.
  3. Monitor Weather Conditions: Assess the environmental factors like temperature and humidity, which influence the planthopper's activity and the risk progression.