How to Manage Pests
UC Pest Management Guidelines
Bulb mites are white with large amber spots, brown legs, and are 0.55 to 0.75 mm long when fully grown. They are slow moving and oval shaped, so are sometimes mistaken for insect eggs. These mites can be found in hollowed out and decomposing portions of bulbs.
Bulb mites enter the bulb and feed in protected cavities, where fungi and bacteria may cause extensive decomposition of the bulb. They are associated with the spread of Fusarium, Stromatinia, and Pseudomonas diseases of bulbs. Species of bulbs attacked include freesia, hyacinth, lilies, narcissus, and onions, as well as underground peony rhizomes. Freesias are particularly affected because they require high temperature storage to break dormancy, which allows rapid growth of bulb mite populations. Lilies are attacked below ground, which stunts growth. Feeding at ground level causes the plants to topple.
Thoroughly clean bulbs, dip them in a sulfur fungicide solution, and dry them following harvest. The sulfur will control bulb mites as well as fungal diseases if the bulbs are being held at high temperatures. However, high rates of sulfur may be phytotoxic. Abamectin (Avid), dicofol (Kelthane), some pyrethroids, pyridaben (Sanmite), and endosulfan* (Thionex) are possibly effective, but have not been evaluated.
* Restricted-use pesticide. Permit required for purchase or use.
UC IPM Pest Management Guidelines: Floriculture and Ornamental Nurseries