The mites go through two larvae phases during their development. Their very short pincer-like mandibles prick the tissue only on the surface. As a result, only severe infestation will leave visible damage on the leaves, which will twist slightly and stick to each other when unfurling. The mites are mainly found in the central veins, the midribs, of the leaves.
The mites are also often found in the plant’s inflorescence, from which they can easily migrate to the bulblis. As a result, the growth of heavily infested tree onions will be affected, causing the bulblis to vary greatly in size.
Once the plant’s leaves die, the mites will move to the bulblis and the cloves in the ground, where they sit well protected between the clove and the surrounding leaf. If the temperature is warm enough, they will start to reproduce and will be found in a small hole below the tip of the clove. Light infestation is basically undetectable, thus it may occur that lightly infested cloves might be stored after harvest. Should the cloves be stored at too warm temperatures (summer temperatures, not cooled), the mites will multiply rapidly and the cloves will dry out as a result of the pricks.
Minute pirate bugs (Orius species) and predatory mites from the Tydeidae family have been found on heavily infested inflorescences in the wild as natural predators.