Lavender's main enemy is Stolbur phytoplasma, a bacterial disease that causes lavender plants to decay. It is transmitted by leafhoppers (Hyalesthes obsoletus), different species of flying and sucking insects of the Hemiptera order that feed on the sap of plants through their rostrum. As soon as the leafhoppers appear between June and August, the lavender plants must be watered above and below their foliage, and the attacked parts must be cut to prevent the spread of this disease.