Koa (Acacia koa Gray) Pest and Disease Image
Gallery
Online quick reference for
Scot Nelson, University
of Hawaii at Manoa, College of Tropical Agriculture and Human Resources
(CTAHR), Department of Plant and Environmental Protection Sciences (PEPS) snelson@hawaii.edu
J. B. Friday,
University of Hawaii at Manoa, College of Tropical Agriculture and Human
Resources (CTAHR), Department of Natural Resources and Environmental
Management (NREM) jbfriday@hawaii.edu
More
than 100 digital photos of pests and diseases of koa (Acacia koa Gray) in Hawaii are provided here to help koa growers
diagnose their pest or disease problems.
For most images, the resolution and size is set at 150 DPI and (500 x
375) pixels, respectively, to provide sufficient clarity and size to enable the
recognition of the more subtle disease characteristics with confidence. Users of this site may request or submit high-resolution images
of koa problems by email.
How
to use this site:
Pests and koa health problems are listed in brown
font below in alphabetical
order. Browse and click on an image
associated with a particular problem.
View, save or print the image. Click
on your browser’s “back arrow” to return to this page. If you would like
more information, please contact the
Basal stem damage and decay: | in landscape setting 1 2 | text |
Black twig borer (Xylosandrus
compactus): | dieback of
twigs and branches 1
2 | beetle entry and exit hole in twig 1 2 3 | adult beetle 1 | internal stem damage 1 | text |
Cattle browsing injury: | in forest setting, damage to stem 1 2 | text |
Coccinellids (lady beetles, beneficial insects): | larvae and adults on leaves of Acacia koa 1 2
3 | adult on leaves of Acacia koa 1
| text |
Conks (fungal fruiting bodies): | on trunks of A.
koa 1 2 |
Fallen tree: |
in forest setting 1
| text |
Hardpan: |
row of koa trees planted in hardpan 1 | basal stem decay 1 | roots after encountering hardpan 1 | text |
Large koa specimens: | in forest setting 1 |
Leafhoppers (probably a cicadellid): | adults 1 2 | damage to leaves 1 2 3 4 | damage plus sooty mold on leaves and phyllodes 1 2 |
Lichens: |
on branches of Acacia koa 1 2
3 4
| text |
Mistletoe (Korthlalsella
complanata): | as parasite on
limbs of Acacia koa 1 2 3 4 5
6 7 | text |
Powdery mildew (Oidium
sp.): | 1 2 | text |
Pruning wound: |
on koa stem 1
| text |
Psyllids [the Acacia psyllid (Psylla uncatoides)]: | adult 1 | immature 2 3
| text |
Root-knot nematodes (Meloidogyne
sp.): | young root
galls 1
| advanced root galls 1
2 3
| root-knot nematode galls compared with Bradyrhizobium
nodules 1
| nematode
life cycle diagram
| text |
Rust #1 (Atelocauda
digitata): | witches’ broom
symptom 1
2 3
4 5
| rusted phyllode with fungal uredinia 1 2 | rusted inflorescence 1 2 | rusted seed pods 1 2
3 | teliospores 1 2
| urediniospores 1
2 | Tuberculina maxima hyperparasite
of rust (purple colored fungus) 1 2
3 | Tuberculina
maxima (rust mycoparasite) spores 1 2 | Tuberculina
maxima mycoparasitism of a koa rust spore 1 | text |
Rust #2 (Atelocauda koae): |
on phyllodes 1
2 3 | text |
Scale (cottony-cushiony scale, Icerya
purchasi): | on
koa stem 1 | text |
Seedworms (the koa seedworm, Crytophlebia illepida): | on koa seeds 1 2
|
Self girdling (roots): | roots girdling the tree | text |
Sheep grazing injury: | on koa stems 1 2 |
Stem-boring beetles (Xyloborus
spp. and Xylosandrus compactus): | damage to stem and associated rotting of stem 1 2
3 4
| text |
Whiteflies (spiraling
whitefly, Aleurodicus dispersus):
| adults, pupae
and flocculent on koa phyllodes 1
2 3
| text |
Wilt (Acacia koaia, Fusarium oxysporum f. sp. koae): | wilting tree 1 2
| compare diseased foliage vs. healthy foliage 1 | leaf yellowing 1 | root rot 1 | internal stem necrosis 1 | stem canker 1 2 | text |
Wilt: (Acacia koa, Fusarium oxysporum f. sp. koae): | decline of mature trees 1 2
3 | decline of koa tree stand 1 2 3 4 5 | internal stem
necrosis 1
2 | stem canker 2 | internal branch necrosis and/or staining 1 2 3
4 | necrotic xylem elements 1 | juvenile reversion 1 2 | stem bleeding 1 | walling off 1 | text |
Wood decay (general): | decay of main stem | decay stain | text |
Links: | The Farmer’s
Bookshelf
| Crop Knowledge Master | Hawaii Pesticide Information Retrieval System | CTAHR homepage | UH-CTAHR Hawaii
Forestry Extension
| UH-CTAHR Koa Wilt Page | Don Gardner Koa Diseases |
More Pest & Disease Image Galleries: | Coffee (Coffea arabica) | Kava (Piper methysticum) | Palms | Papaya (Carica papaya) | Noni (Morinda citrifolia) |
Photo credits: J. B. Friday, Scot Nelson, Wayne Nishijima, Mark
Wright and Thom McEvoy
Site
design: Scot Nelson (2006)
Last site
update: 1.Oct.2007
Copyright Notice. These photographs may be freely used for educational
purposes. Please contact snelson@hawaii.edu if you wish to
duplicate any photographs for presentations, websites or publications. Written
permission is required for any commercial use of any images on this site.