What is Armillaria Root Rot?
Armillaria root rot is a severe fungal disease that affects trees, woody plants, and some herbaceous plants including palms and succulents.
Also known as oak root fungus, Armillaria root rot can rapidly kill trees and presents a challenge to management since infected woody roots can persist for years underground. No plants are completely immune to Armillaria root rot, so prevention is key. Deeply planted trees are often more susceptible to this disease.
The distinctive “honey mushrooms” growing from the base of a tree signals an infection, but they may not always be present. Other visible symptoms include flat cankers on the trunk, wilting, and canopy...
Landscape trees provide welcome shade, fruit, homes for wildlife, and even a place for kids to climb. But if the wood is damaged, disease-causing fungi can infect the tree. A number of fungal diseases decay wood in both tree branches and trunks, weakening and sometimes killing the tree. Wood decay can be hazardous when infected branches and trunks fall.
Shot hole borers are tiny insects the size of a sesame seed that don't look particularly harmful, but don't let their diminutive size fool you. Two of these borers are invasive—the polyphagous shot hole borer and the Kuroshio shot hole borer. They carry pathogens and are spreading them throughout southern California. Together, the borers and the fungi are a deadly combination that are killing many trees. Trees affected include avocado, sycamore, white alder, box elder, cottonwood, and willow.
The two shot hole borers are nearly identical in appearance, and both have a symbiotic relationship with several pathogenic fungi. The female borers lay eggs which introduces fungi into trees. The fungi grow and provide food for...
- Author: Michelle Le Strange
- Author: Carol A Frate
- Author: R. Michael Davis
![Newly emerged inky cap mushrooms, Coprinus comatus. [R.M.Davis]](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/41367small.jpg)
Wet weather is favorable to mushrooms, which are sometimes called toadstools. Mushrooms are the visible reproductive (fruiting) structures of some types of fungi. Although the umbrella-shaped fruiting body is the most common and well known, mushrooms display a great variety of shapes, sizes, and colors. Some other fruiting bodies encountered in lawns include puffballs, stinkhorns, and bird's nests, descriptive names that reveal the diversity of forms among mushrooms. But regardless of shape, the purpose of all fruiting bodies is to house and then disseminate spores, the reproductive units of fungi.
Many people become concerned when mushrooms appear in their lawns; however, most mushroom-producing fungi in lawns are merely...
![Healthy red apple ice plant. [H. Schenk]](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/36348small.jpg)
[From the April-May 2016 issue of the UC IPM Green Bulletin]
A downy mildew caused by the fungus Peronospora mesembryanthemi has recently been confirmed by the USDA-APHIS from a red apple ice plant (Aptenia cordifolia) sample collected in San Diego. Since this first finding in San Diego County in summer 2015, the disease has spread to Orange, San Bernardino, and Ventura counties and is now found in the Goleta area in Santa Barbara County.
Peronospora mesembryanthemi was first reported from South Africa and...
