Open access publications in the SLU publication database

Fungal diseases often lead to a greatly reduced productivity in organic apple cultivation compared with IP cultivation. This is mainly due to lack of chemical agents approved for the control of storage diseases before or after harvest. One of the objectives of this project has been to develop a preparation based on naturally occurring protective substances that can counteract fungal diseases, and which can also be used in organic fruit cultivation. A basic requirement for using and succeeding in organic plant protection is that knowledge about the biology, infectious agents and spread of harmful organisms is available. This project therefore also aimed at increasing today's insufficient knowledge of harmful pathogens and making this knowledge available to advisors and growers.

The results in the project showed that a mixture of the plant oils thymol and eugenol has good effect on the storage potential of organic apples during field treatment (once a month during the season). This treatment reduced natural fungal attack during storage without causing any adverse effect on the harvest or fruit quality (softness, taste and appearance). Furthermore, our findings showed that important sources of infectious spreading are mummified fruits left on the trees, as well as dropfruit and fallen unripe fruit lying on the ground under the trees. Rainwater, European canker, wind and insects are also likely to contribute to the spread of infection. Fruit from the top of the tree had better tolerance to fungal attacks.