Bulb mite

Systematic position: The bulb mite Sancassania berlesei is a member of the family Acaridae, order Acariformes. It is a cosmopolitan mite, frequently found in soils rich in organic matter and in stored agricultural commodities, often causing significant economic losses in bulbous crops.

Host plants: This pest primarily targets Allium species, such as onions and garlic, as well as ornamental bulbous plants like tulips, gladioli, and hyacinths. It can also colonize the seeds of cereals and legumes, or the roots of other vegetables, especially when the plant tissue is already compromised or decaying.

Biology and life cycle: The development of Sancassania berlesei is highly correlated with humidity and temperature. Under favorable conditions, the life cycle is rapid. A key feature of its biology is the presence of a mobile deutonymph stage, known as a hypopus, which allows the mite to withstand harsh environments and hitchhike on insects or rodents to colonize new areas.

Nature of damage: The mites feed on the basal plate of the bulb, causing it to hollow out and decay. Infested bulbs often show stunted growth, yellowing leaves, and root loss. The injury caused by the mites serves as a gateway for secondary fungal and bacterial pathogens, leading to the rapid rotting of stored bulbs or failed germination in the field.

Control measures: Successful management involves rigorous sanitation, including the removal and destruction of infested plant material. Ensuring dry storage conditions (low humidity and cool temperatures) is critical to preventing outbreaks. For chemical control, soaking bulbs in acaricidal solutions prior to planting can effectively reduce population levels and protect the developing plants.