The larvae of many species of leafrollers (tortrix), feed on the leaves and fruits of apples and pears. The leafrollers are polyphagous, meaning they can feed on various kinds of food. Most species hibernate as larvae and damage flowers and fruitlets in May and fruits short before harvest.
Solution
Pheromone disruption can decrease the reproduction of leafrollers and prevent damage to fruits. However, not all relevant species are included in the pheromone, these species larvae must be controlled on a warm, dry, cloudy day just before or during flowering using Bt-products. To control the summer fruit tortrix, the selective granulovirus (Capex 2) can be used in combination with disruption to reduce the infestation pressure.
Description
Pheromone disruption, eventually in combination with Bt-products (Bacillus thuringiensis) or Capex, are important to reduce fruit damage by leafroller larvae and thereby increase the saleable yield and storability of the fruits.
Practical recommendations
• Look at the level of damage on harvested fruit from the previous season to estimate the potential damage (Picture 3).
• Establish 800-1000 Isomate dispensers/ha as high in the orchard as possible. The high location is important for an optimal distribution of the pheromones by the wind in the orchard, and thereby optimises the effect of the treatment.
• The optimal distribution of the dispensers in the orchard are evenly in a square pattern of 3.5 x 3.5 meters over the entire treated area.
• In the outermost twenty meters of the orchard, the distribution of pheromones is especially affected by the wind. Therefore, it is necessary to conduct an edge treatment by hanging one dispenser in each end tree in each row, as well as to double the number of dispensers in the outermost rows.
• When treating areas that are smaller than 3-4 ha, there is a considerable risk of the infestation from mated females from untreated neighbouring areas.
• If the initial infestation with summer fruit tortrix is high, use additional application of Capex in spring.
• Monitor the occurrence of the leafroller species in spring. If you find relevant species that are not covered by the pheromone disruption Isomate CLR, such as Hedya nubiferana and Spilonota ocellana, apply Bacillus thuringiensis.
In order to use the comment function, you must register with the third-party provider "Disqus".
When you activate this function, your browser establishes a direct connection with the servers of the third-party provider. We would like to point out that data is transmitted to the third-party provider after activation, and the latter may set cookies that can also be used for analysis and marketing purposes. For more information, please refer to our privacy policy.
Disqus
In order to use the comment function, you must register with the third-party provider "Disqus".
When you activate this function, your browser establishes a direct connection with the servers of the third-party provider. We would like to point out that data is transmitted to the third-party provider after activation, and the latter may set cookies that can also be used for analysis and marketing purposes. For more information, please refer to our privacy policy.
Activate