Two identical looking species of wood-boring beetles, collectively known as invasive shothole borers (ISHB), have killed thousands of trees in Southern California and pose an ongoing threat to California's urban and wildland forests. These beetles, which are not native to the United States, were first identified in Los Angeles County in 2012 and have since spread to six other counties: Orange, Riverside, San Bernardino, San Diego, Santa Barbara, and Ventura.
Beetles, Fungus, and Impact
The polyphagous shothole borer (Euwallacea fornicatus) (Figure 1) and the Kuroshio shothole borer (Euwallacea kuroshio) are small ambrosia beetles that have a symbiotic relationship with several species.../h2>
Like outdoor plants, houseplants can also experience pest problems. Did you know that too much or too little watering is the most common way that houseplants die? They can also suffer from too much or too little light, incorrect fertilization, and a variety of pests and diseases. Knowing the proper growing conditions for your houseplant and checking regularly for signs of pests or disease are the best ways to keep your houseplants healthy.
If your houseplant is looking unhealthy, our newest publication Pest Notes: Houseplant Problems can help you find out what may be wrong. Authored by UCCE Environmental Horticulturalists Dennis...
Peach leaf curl is a disease that affects peach and nectarine trees. Although you may not see symptoms right now in the dormant season in California, it's time to think about treatment, especially if your tree had the disease last year.
Symptoms of this fungal disease include distortion, thickening, and reddening of foliage as trees leaf out in the spring. As weather warms, damaged leaves that die and fall off trees are replaced with new, usually healthy leaves. However, after several years without treatment, peach leaf curl will cause tree decline and reduced fruit production.
Avoid peach leaf curl by growing varieties resistant to the disease. For nonresistant peach and nectarine trees, consider spraying with...
This time of year, you may notice a white, powdery looking growth on fruit, vegetable plants or ornamental plants in your garden. What is it? It could be powdery mildew.
Powdery mildew is caused by several different fungi that may attack plant leaf surfaces, shoots, fruits, and flowers. There are several species of powdery mildew; all are spread by wind and thrive in shady areas when temperatures are between 60-80 °F. The fungi attack both new and old foliage, and can be a problem on certain plants. The disease usually occurs first on new leaves, before spreading to older parts of the plant. This is why over fertilizing worsens powdery mildew.
Many woody and herbaceous...
[From the December 2016 issue of the UC IPM Green Bulletin]
The Polyphagous shot hole borer (PSHB) (Fig. 1) and Kuroshio shot hole borer (KSHB) are invasive wood-boring beetles that attack dozens of tree species in Southern California, including commercial avocado groves, common landscape trees, and native species in urban and wildland environments. Both beetles spread a disease called Fusarium Dieback (FD), which is caused by pathogenic fungi. Trees that are FD-susceptible may experience branch dieback, canopy loss, and tree mortality (Fig..../span>