| Leaf spots on English ivy are caused by either a
bacterium, Xanthomonas campestris, or a fungus,
Colletotrichum trichellum. Both can cause
defoliation, but the fungal leaf spot is more active in
causing stem infection.
Symptoms and Diagnosis
Bacterial leaf spot first begins as light green, watersoaked
spots that enlarge and become brown or
brownish black in the center. On mature leaves the
margin of the spot may be red. An infection in the
leaf petiole causes the petiole to become black.
Infection can move into the stem causing tips to turn
black and die.
The fungal leaf spot produces large tan to brown
spots on the leaves. They do not have a red margin.
Black specks, fungal fruiting bodies, may be visible
in the dead tissue, giving the spots a speckled
appearance. The fungus can also infect stems,
resulting in tip dieback.
Integrated Pest Management Strategies
1. Remove and destroy infected leaves and stems.
Regardless of whether the spots were caused by a
bacterial or fungal pathogen, removing diseased
leaves will slow the spread of the disease.
2. Avoid wetting the foliage. Wetting the foliage,
especially in late afternoon or evening, facilitates
the development and spread of leaf spot
organisms. Water early in the morning so the
foliage dries before night.
3. Prune out and destroy all diseased plant parts in
the fall. Thin the planting to allow better air
movement and promote drying.
4. Live with the disease. The above cultural
practices are generally sufficient to keep the
disease from becoming a major problem.
5. Use fungicides. Sprays can be effective against
both bacterial and fungal leaf spot diseases. They
must be applied on a regular schedule and
reapplied if rainfall is prevalent. copper
fungicides are generally effective in controlling
both leaf spots. | 
