European canker (Neonectria ditissima): Direct control with lime water (BIOFRUITNET Practice Abstract)

Summary

Less infected parts of the tree requires less manual work for excising cankers, a healthier tree and a better yield with higher quality.
Practical recommendations
Direct measures
• Lime water is a basic substance in Europe. It is a fine suspension of lime in water. The average particle size is 3µm (Akdolit).
• Two products are described in the registration as basic substance. The product Neccal (Akdolit) contains 24% active ingredient (a.i.). The product Ulmer Kalkmilch contains 33% a.i. (36 % Münsterkalk with a.i. 92 %) and is used at the same rate as the lime water Akdolit.
• Application time for spray and sprinkler application is leaf drop starting at the end of October until the end of December. For brush application the application time is during the winter period till March.
• Infection occurs in autumn during prolonged wet periods and are common on wounds, such as leaf scars.
• Lime water should be used preventively, just before an infection period in autumn. Its high pH (11-13) prevents the germination of European canker spores. On the tree, calcium carbonate (pH 6-7) is formed with the CO2 from the air soon after application.
• With three treatments, a reduction of 50-75% can be achieved on the amount of newly formed cankers in June. The effectiveness can even reach 90% when up to seven sprays are applied. The more often, the better – dependent on the weather.
• Even with the use of lime water, preventive measures remain necessary, like manual labour for excising canker spots.
Spraying treatment
• Dosage 63-104 l/ha (maximum 728 l/ha) (24%) and 45-76 l/ha (maximum 532 l/ha) (33%), 2-7 times.
• Remove the pre-filter; the nozzles filters do not need to be removed. Turn on the pump and agitator and let it run. Spray everything all at once. Do not use more lime water than 10% of the water volume. So, at 1000 l/ha of water, maximum 100 l lime water can be added.