Bulb mite

The bulb mite, known scientifically as Rhizoglyphus callae, is a destructive pest belonging to the family Acaridae. It is a tiny, translucent, yellowish-white arachnid that thrives in high-humidity environments, primarily infesting the subterranean parts of various bulbous crops. Its presence is often overlooked until significant damage has occurred.

This pest primarily attacks bulb and corm plants, including calla lilies (Zantedeschia), tulips, hyacinths, and gladioli. In agricultural settings, particularly in greenhouses and cold storage facilities, it can cause devastating economic losses by rendering planting materials unmarketable or completely destroying the growth potential of the bulbs.

The biological cycle of Rhizoglyphus callae is characterized by rapid development, often completing a generation in as little as two weeks under warm conditions. A critical survival strategy for this mite is the formation of a hypopus stage—a non-feeding, highly resistant nymph form. This stage allows the species to endure harsh environmental conditions and survive periods of starvation.

The damage caused by the mite is internal, which makes detection difficult. The mites penetrate the basal plate of the bulb and feed on the inner tissues. This activity leads to the degradation of the bulb, resulting in stunted growth, yellowing foliage, and eventually total plant collapse. Furthermore, the feeding sites become entry points for secondary fungal and bacterial infections.

Management strategies for Rhizoglyphus callae require an integrated approach:

• Rigorous inspection and culling of infested planting stock.
• Maintaining proper storage temperatures below 5°C and low humidity.
• Hot water treatment of dormant bulbs before planting.
• Systemic acaricide application when infestations are detected.