Caution
This information was developed for North Carolina and may not apply to other areas.
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Table Legend
* Degree of importance of pest: I = Important pest, high probability of occurrence; II = Treat as needed; III = Occasional pest, treat when detected.
** Number of applications needed for most effective control. It is usually best to wait 10 to 14 days between applications in cool weather and 7 to 10 days between applications in warm weather.
G = granular; P = prune out infested twigs or branches; S = spray application.
Rhododendron Pest Management Calendar
Pests | Degree of Importance of Pest* | Number of applications** | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
azalea stem borer | II | 1 |
Spray Application |
Spray Application |
Spray Application/ prune out infested twigs or branches |
prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | ||||
black vine weevil | I | 3 | granular | granular | granular |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
||||
climbing cutworms | III | 1 |
Spray Application |
Spray Application |
||||||||||
Japanese weevil | II | 1 or 2 |
Spray Application |
Spray Application |
Spray Application |
|||||||||
lace bugs | II | 1 or 2 |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
Spray Application |
|||||
rhododendron borer | II | 1 |
Spray Application |
Spray Application |
Spray Application/ prune out infested twigs or branches |
prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | prune out infested twigs or branches | ||||
rhododendron gall midge | II | 2 |
Spray Application |
Spray Application |
|
Spray Application |
Spray Application |
* Degree of importance of pest: I=Important pest, high probability of occurrence, II=Treat as needed: III=Occasional pest, treat when detected.
** Number of applications needed for most effective control. It is usually best to wait 10 to 14 days between applications in cool weather and 7 to 10 days between applications in warm weather.
Other Resources
- Azalea Stem Borer. Frank, S. and J. R. Baker. 2020 (revised). Entomology Insect Notes, NC State Extension Publications.
- Black Vine Weevil. Frank, S. et al. 2020 (revised). Entomology Insect Notes, NC State Extension Publications.
- Caterpillars That Feed on Trees and Shrubs. Frank, S. and S. Bambara. 2009. Entomology Insect Notes, NC State Extension Publications.
- Rhododendron Borer. Baker, J. R. 2021 (revised). PDIC Factsheets, NC State Extension Publications.
- Rhododendron Gall Midge. Baker, J. R. 2019 (revised). PDIC Factsheets, NC State Extension Publications.
- Lace Bugs. Frank, S. 2019 (revised). Entomology Insect Notes, NC State Extension Publications.
- Twobanded Japanese Weevil. Frank, S. and J. R. Baker. 2019 (revised). Entomology Insect Notes, NC State Extension Publications.
- Insect and Related Pests of Shrubs. Baker, J. R. ed. 1980. NC Agricultural Extension Service publication AG-189. 199 pp.
- North Carolina Agricultural Chemicals Manual
- Extension Plant Pathology Publications and Factsheets
- Horticultural Science Publications
- Search for more information on insects from NC State Extension
For assistance with a specific problem, contact your local N.C. Cooperative Extension Center.
This Insect Note has not been peer reviewed.
Publication date: Feb. 4, 2019
Revised: Nov. 10, 2023
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