Lesser Bulb Flies of Flowering bulbs

Disease Information

Lesser Bulb Flies


Lesser bulb flies (Eumerus species) range in size from 3/16 to 3/8 inch in length. They are dark blue with a metallic bronze sheen. The larvae (maggots) range in size from 1/16 to 3/8 inch and in color from white to grayish yellow.

Symptoms and damage

The maggots enter and then tunnel through the bulb. The bulbs begin to decay and fill with a semi liquid material. They may be killed outright or damaged so that only very small leaves are produced the following year. The maggots survive the winter in the bulb and the following spring they emerge into the soil where they pupate (transform to a nonfeeding stage where the larva changes to an adult form). The adults emerge, mate and the female crawls down through openings in the soil such as those left by leaves as they die to lay eggs on or near bulbs as well as on the soil surface and on the leaves at the neck of the bulb.


Cultural control of this pest includes mowing leaves as soon as they dry in the spring. Lightly tilling the soil after mowing destroys the soil openings that the adult females use to locate the bulb.

When bulbs are dug for dividing, any soft bulbs should be destroyed. Treating slightly damaged bulbs by placing them in hot water (109.4 °F to 111.2 °F) for 3 hours can control these pests. Be sure to keep an eye on the temperature and not let it go over the recommended temperature range as higher temperatures can damage the bulbs.


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