Black olive caterpillar (Characoma nilotica) feeds on flowers and leaves of black olive trees. The larvae’s droppings can also be a nuisance. Low populations of black olive caterpillar do not cause extensive damage. However, high populations, skeletonizing feeding of late instars can ‘brown out’ trees, and cause them to defoliate. Multiple years of damage can negatively affect the health an already stressed tree.
Treatment Strategy
Work by Davey tree (Dr. AD Ali) showed trunk injection of Aracinate prior to bloom worked very well controlling both black olive caterpillar and the gall forming eriophyid mite. Dr. Ali has promoted these findings through out Florida
Other Treatment Practices
- Adequate water is a key factor in maintaining stress free plants. A slow, deep watering event once every few weeks during dry conditions will help maintain soil moisture levels and minimize stress.
- Mulch is very beneficial for all trees because it reduces competition with turf and moderates soil temperature and moisture levels. The addition of 3 inches of wood chips or shredded bark under the drip line can have a very beneficial effect by holding in moisture and promoting healthy fibrous roots.
- Cambistat can also be used to promote tree health and reduce the incidence and severity of stress mediated diseases and insect problems on trees growing in urban areas.
Trunk Injection Using Aracinate
Soil Application Using Lepitect
Foliar Spray Using Tengard
Foliar Spray Using Acelepryn
Expected Results
Soil injections of Lepitect will begin efficacy within 3-10 days for most pests. Control on larger trees will not occur as quickly (2-3 weeks). Lepitect soil applications last for 30 days after treatment. Repeat applications may be necessary if pest activity persists for longer than 30 days. Trials by Davey displayed excellent season long control with the use of Aracinate.
Signs of Damage
- Flowers of black olive are consumed followed by skeletonization of canopy
- Staining due to frass under affected trees
Photo: Caldwell, D.
University of Florida Extension Service, IFAS
Photo: Stephanie Sanchez
butterflies.heuristron.net
Photo: Wikimedia Commons
Trees At Risk
- Black Olive (Bucida buceras)
- Also reported on buttonwood (Conocarpus erectus), though less of an issue
Biology
- Young caterpillars emerge with flowers of black olive (Bucida buceras), and begin feeding on the petals.
- After flowers have been consumed the caterpillars move to skeletonizing the leaves.
- Petioles are clipped and the leaves are used to hide cocoons.
- Moths emerge after about 3 weeks.
- Some years, eggs of a second generation are deposited on 4 to 12 inch long, string bean like galls which develop from the flowers.
- Galls are created by an eriophyid mite (Eriophyes buceras).
References
University of Florida
http://entomology.ifas.ufl.edu/pestalert/black_olive_caterpillar.pdf
Dr. AD Ali, Davey Tree Expert Company Presentation at Trees FL 2018
Always refer to product label for rates and approved uses. Some images courtesy of forestryimages.org or Wikimedia Commons. Use of the images does not imply endorsement of treatments.
