Fighting Fungus: How Pruning Cuts Impact Apple Trees in Chile

You might not think much about it, but when apple trees get pruned, they're not just left to heal on their own. Researchers in Chile's Maule region have been studying how pruning cuts affect trees' susceptibility to fungal infections. They focused on four types of fungi: Diplodia mutila, D. seriata, Lasiodiplodia theobromae, and Neofusicoccum arbuti. These guys can cause serious damage to trees, leading to cankers and dieback.The study found that fresh pruning wounds, those just a day or two old, are like a buffet for these fungi. They're much more likely to get infected than older wounds. The research also showed that certain fungi, like Neofusicoccum arbuti and D. seriata, are real troublemakers. They're more aggressive and can cause bigger problems earlier on. Interestingly, the time of year when trees get pruned also matters. Early pruning, done in June, led to bigger fungal lesions. This suggests that pruning later, in August, might help reduce the risk of infection. Rainfall plays a big role too. Most fungal spores (conidia) were released during rainy periods between June and August. That's something to keep in mind when planning pruning schedules to minimize fungal risks.