headerphoto

Bulb Thrips



There are several different bulb Thrips species that bother our flower garden bulbs but luckily for most of us, a well fed (compost) and adequately watered garden (mulch) will make the bulbs healthy enough that most attacks aren't a major problem. I note that the recommendation to feed and water your bulbs is taken straight from commercial production manuals.

The Pest

Adult bulb thrips are slender, tan to dark brown in color and about 1/20 to 1/16 inch in length with fringed wings. This really tiny fly hides successfully inside leaf crinkles or under bulb scales; in fact, you'll never likely see one before you see the damage.

Both the adult fly and nymph (little larva) scrape away at the surface cells of bulbs or flower buds to feed.

In the case of bulbs, this may result in some stunting. Flowers wind up streaked or in severe cases, refuse to open or open in distorted ways. The flowers die quite quickly as well.

The Control

Our friends the ladybird beetle and green lacewings feed on this pest so do everything you can to encourage these in your garden. Any insecticides that kill off these pests are not doing you any good.

Bright blue or yellow sticky traps work nicely on bulb thrips with blue being the colour of choice for commercial greenhouses. Paint cardboard or plastic and then coat with a non-drying horticultural glue (heavy grease or vaseline works too if thick enough to get the insect stuck). Place these around your garden approximatately 10-feet apart.

Spraying with insecticidal soap is possible but you have to do it every 3-5 days once you see the streaks on the damaged leaves. Insecticidal soap will kill the adult flies if you hit them (but they're so tiny it is tough to see).

Neem sprayed at 3/5 day intervals will also kill adult flies.

Dusting leaves and young buds with Rotenone has also been suggested to kill off the adult flies. Dusting with sulfur and diatomaceous earth is also recommended. Try to remove bulb tunics (tulip) or other dirt and covering (glad) before treating. In other words, remove the hiding spaces for the larvae

If the larva are doing the damage, soaps aren't really a good option. Dipping the bulb in a weak chlorox solution has been recommended to destroy overwintering eggs.

Read and follow directions on the label for best results to control bulb thrips. In this case, chemical insectides are no more effective than organic controls.





Click here to ask a question about bulb thrips.





Loading













Doug's Facebook Page


Sponsorship Opportunities