Treatment Plans
Monitor and manage galls
Why is my plant developing these strange growths?
The problem
A gall is an abnormal growth, a kind of benign tumor, produced by the plant itself. It is a very localized defense response and rarely threatens the plant's survival, especially on a mature plant. Most often, the problem is mainly cosmetic. These structures can appear on leaves, stems, or buds and take many forms: round, pointed, smooth, or even hairy.
- Caused by feeding punctures or egg laying by outside organisms.
- The culprits are often insects, such as gall wasps and gall midges, or mites, and less often fungi or bacteria.
- A gall provides shelter and food for the larva developing inside.
- A heavy infestation on a young plant can slow growth by diverting some of its resources.
The plant is not “sick” in the usual sense; another organism has manipulated it into creating this structure.
How galls form
Gall formation is a fascinating process. It starts when an insect or mite pierces plant tissue to lay an egg. At the same time, it injects chemicals that act like plant growth hormones. The plant responds by changing normal cell development at that exact location. Tissue then multiplies in an organized way around the egg or larva.
| Stage | Estimated duration | Details |
|---|---|---|
| Egg laying | Immediate | An insect or mite chooses young, tender tissue, such as a bud or young leaf, and deposits its egg. |
| Induction | A few days | Injected substances reprogram plant cells, which begin multiplying abnormally. |
| Growth | Several weeks | The gall grows along with the larva inside, providing food and protection. |
| Maturity | Variable | The larva becomes an adult and leaves the gall, often through a small exit hole. The empty gall then dries on the plant. |
This is a highly developed form of parasitism in which the parasite forces its host to build a custom home.
What to do now
- Inspect the entire plant carefully to assess how many galls there are. One or two are not a problem.
- Cut off the most affected leaves or stem sections cleanly with disinfected pruners. This is the most effective method because it removes the organism before it becomes an adult.
- Immediately discard cut parts in the trash, not your compost, to keep larvae from completing their cycle and spreading.
- Monitor the plant closely over the next 2 to 3 weeks for new galls.
- Avoid all chemical treatment. Insecticides are ineffective because the gall completely protects the pest inside.
Prevention
- Carefully inspect every new plant before bringing it into your home.
- Maintain good air circulation around plants to discourage flying insects.
- Regularly check leaf undersides and young shoots, favored egg-laying sites.
- Keep plants healthy with suitable watering and light to make them more resistant to attacks.
Common problems
- Galls · Abnormal growths of various shapes on leaves, stems, or roots.
- Natural aging · Normal aging of the oldest leaves.
FAQ
Are galls dangerous to my plant?
Generally, no. On an established plant, galls are mainly a cosmetic problem and do not threaten its life. A heavy infestation on a young plant or seedling can, however, weaken it by diverting its energy.
Do I have to cut off affected parts?
Not if the gall’s appearance does not bother you. Pruning is, however, the simplest and most effective way to remove the pest before it reproduces. If you do nothing, the adult insect will emerge and may create new galls.
What exactly is inside a gall?
Most often, one or more insect or mite larvae. The larva feeds on the gall’s nutrient-rich internal tissue while remaining protected from predators and outside conditions.
Can galls spread to my other plants?
The gall itself does not spread. The organism causing it, the adult insect or mite, can move to other plants to lay eggs. This is why removing affected parts is recommended to interrupt the cycle.
How can I tell a gall from another problem, such as a fungal disease?
A gall is a solid growth that forms an integral part of the plant’s tissue. In contrast, diseases such as powdery mildew appear as a powdery coating on the leaf surface. Other fungi cause spots or dead areas rather than new raised structures.
Where did the insect that caused this come from?
It may have entered through an open window, or, more commonly, it was already on a new plant you brought home. Inspecting new purchases is the best prevention.