Application of salicylic acid induces antioxidant defense responses in the phloem of Picea abies and inhibits colonization by Ips typographus

▶ Changes in the antioxidant defense system during bark beetle attack are significantly triggered by salicylic acid-treatment. ▶ Moderately-affected salicylic acid-treated bark is characterized by an earlier acclimatization stage. ▶ Salicylic acid-treated severely affected trees show a strong increase in total salicylic acid contents and higher antioxidant concentrations. ▶ The degradation of antioxidants within salicylic acid-treated bark is significantly delayed and alleviated. ▶ Salicylic acid-treatment results in a surprisingly long-term inhibition of bark beetle colonization.