Sticky leaves and crumpled new shoots on tulips in spring usually point to clusters of tiny insects feeding on the fresh growth. Aphids go after spring bulbs both in the ground and in storage, and cool spring weather suits them. Knowing what they look like, what they leave behind and how to move them off the plants keeps the bulbs healthy for next year.
Aphids: What You See
Look first at the newest growth, because that is where the colonies settle.
- Small clusters of soft-bodied, pear-shaped insects sit packed together on emerging leaves, shoots and buds.
- Leaves and flowers come out curled, twisted or deformed where the insects have been sucking sap.
- The foliage turns sticky and shiny from honeydew, a sugary liquid the insects excrete as they feed.
- Dark, sooty splotches appear on that sticky surface when a fungus grows on the honeydew.
- Some adults have wings and some do not, and young nymphs of every size share the same cluster.
Heavy colonies that stay for a long stretch can leave shoots and buds wilted, and sometimes the tips die back.
From the almanac
Bulbs in your state
The dates on this page depend on where you live. Your state's page carries its frost dates, its USDA zones and the year laid out month by month.
Northeast
Southeast
- Alabama
- Arkansas
- Delaware
- Florida
- Georgia
- Kentucky
- Louisiana
- Maryland
- Mississippi
- North Carolina
- South Carolina
- Tennessee
- Virginia
- West Virginia
Midwest
Southwest
West
Pacific Northwest
Canada
Aphids or Something Else?
Several other problems leave sticky, distorted or speckled growth on bulbs. The insect itself, and where it sits on the plant, settles the question quickly.
Check the undersides of leaves and the tips of shoots with a close look, or a hand lens if the insects are hard to see.
| Looks like | How to tell them apart |
|---|---|
| Thrips damage | Thrips are slender insects that rasp the surface, so you see streaked, silvery or distorted petals, but the insects are not pear-shaped and the foliage is not coated in a sticky film. |
| Mite damage | Mites are far smaller than aphids and cause stunted, deformed growth, yet you do not find clusters of visible, soft-bodied insects sitting on new shoots. |
Sooty mold alone can also fool you, since it looks like a dark dusting on leaves. It only forms on honeydew, so look for the sticky surface and the insects that made it.
What Causes Aphids, and Where It Is Worst
Aphids feed by sucking plant sap, and they multiply fast because for much of the year they give birth to live nymphs that mature into wingless or winged adults. Essentially all of them are females. In Colorado, males appear only in late summer or early autumn, during the last outdoor generation.
Bulbs can carry the problem in before you plant them. Tulip bulb aphids feed on tulip bulbs and other bulbs and corms in storage as well as in the field, and they also infest leaves, shoots, buds and flowers once the plants are growing. In North Carolina, planting infested bulbs can lead to distorted, stunted new growth.
Spring is the busy season, because aphids are typically more of a problem during cool weather. The pest is not tied to one region. It can turn up anywhere spring bulbs grow.
How to Treat Aphids
Start with the gentlest methods, since natural enemies are already working in your favor.
- Inspect new spring growth regularly, so that you catch small colonies before they spread.
- Spray the clusters with a hard stream of water, which knocks the insects off the plant and leaves leaves and buds intact. In Utah, this is the suggested first move.
- Switch to insecticidal soap if the insects keep returning, because it is another soft option that works on contact with the pests.
- Leave ladybugs, lacewings, syrphid flies, damsel bugs and wasps alone, since these feed on or parasitize aphids and generally keep them under control.
For anything stronger, ask your state’s cooperative extension office what is approved where you live, since registrations differ from state to state.
How to Prevent Aphids Coming Back
Prevention follows the bulb year, starting before the bulbs ever go in the ground.
- In fall, before planting, look over each bulb and set aside any that look infested, because stored bulbs can carry aphids into the bed.
- In early spring, begin looking at emerging shoots, since cool weather favors the insects and colonies start on new growth.
- As leaves open, rinse any small clusters with a hard stream of water before they build up and curl the foliage.
- Through bloom and after, leave the beneficial insects in place and avoid anything that would clear them out.
- After flowering, let the leaves yellow naturally, then clear the bed of debris.
Healthy, undisturbed beds give the natural enemies of aphids a steady place to work.
Where This Comes From
This information draws on university extension guidance on bulb pests. Your own state’s cooperative extension office can confirm timing and approved treatments for your area.
Common Questions
Can Aphids Travel on Stored Bulbs?
Yes. Tulip bulb aphids infest tulip bulbs and other bulbs and corms during storage, so inspect them before you plant.
Why Are My Tulip Leaves Sticky?
Sticky leaves usually come from honeydew excreted by feeding aphids. Look for clusters on new growth to confirm.
Do Aphids Kill Bulbs?
Their feeding mainly distorts leaves and flowers. Very high numbers over an extended period can cause wilting and sometimes dieback of shoots and buds.