Other non-parasitic causes

- Hail injuries

After heavy rains accompanied by hail, it is not uncommon to observe in the most exposed parts of the stems and peduncles, small bursts of brownish grey, corresponding to impact of hailstones (figure 1). The leaves are also particularly affected (see Perforated, cut, shredded leaves ...).
 

- Chemical injuries

Some suckercides, when overdosed or applied under certain conditions, can burn the stem epidermis by runoff. In the days following the application numerous, irregular, necrotic lesions of light brown colour appear (figure 2).