The Fire blight is the most serious bacterial disease of rosaceae, caused by the bacterium Erwinia amylovora. It affects more than 150 plant species, mainly pear and apple trees, quince, medlar and ornamental plants such as hawthorn. It first appeared in Italy in 1991 and is now present in most pome fruit growing areas. The symptoms caused byErwinia amylovora involve the entire plant throughout the vegetative cycle and are as follows:
- Flowers and shoots wither and blacken by folding into a hook shape.
- The woody parts have cankers that emit droplets of bacterial exudate; infected branches and trunks are olive-red in colour when stripped of their healthy parts.
The spread of the bacterium occurs mainly through wind and rain: the infection penetrates the plants through wounds (fallen leaves, broken buds, various injuries) and flowers.
How can one defend oneself against this dangerous bacterium?
For this type of infection, prevention is much more important than phytosanitary measures; therefore, the following preventive measures must be observed:
- Careful and constant monitoring of the plants to detect any symptoms as soon as possible.
- In the event of symptoms, immediate removal of affected organs (by cutting 70 cm from the symptom, using tools disinfected with quaternary ammonium salts).
- Waste must be burnt (the bacterium also lives in cut branches) and affected plants at the stem must be completely uprooted.
- Correct management of plant development: avoid nutritional imbalances and excessive pruning.
- Manual removal of secondary blooms (which are the most natural route of penetration for Erwinia amylovora).Erwinia amylovora).
- It is also advisable to install anti-hail nets and under-canopy irrigation systems.
- Once these preventive measures have been followed, it is also possible to proceed with complementary phytosanitary interventions, again of a preventive nature (given that there are no post-infection cures) based on copper.
An alternative prevention medium to copper is Bacillus subtilis. The Bacillus genus belongs to the PGPR (Plant Growth Promoting Rhizobacteria) group and comprises species of bacteria isolated from the rhizosphere with numerous beneficial activities. They help plants overcome stresses in the aerial and root system caused by various fungi and bacteria, and promote plant growth through the production of
The products Botrimax and Biotyl, biostimulants of the Microtech line, , are fundamental allies in the preventive action of damage caused by 'fire blight', given the high concentration of Bacillus subtilis in their formulation!
Their use is approved under organic farming regimes, as well as being ideal tools for 'zero residue' farming.