- Author: Elaine Lander
If you're planning to get a holiday tree for your home, you may find unexpected guests have already made their home in your evergreen selection. Common holiday trees such as firs, pines, and spruces can host pests such as aphids, scales, mites, bark beetles, or even praying mantis egg cases. These pests may be present regardless of whether you select your tree from a local tree lot or go to cut your holiday tree at a nearby tree farm or forest. But...
Anthracnose is a group of fungal diseases that infect many trees and shrubs, causing dark lesions on leaves and cankers on twigs and stems. In some areas of California, vegetables and turfgrass can also be infected with anthracnose.
Symptoms of anthracnose vary by plant host and weather conditions. High humidity and dense canopies can exacerbate this common disease. Management relies on planting resistant cultivars of landscape plants along with careful maintenance of susceptible cultivars, such as pruning and removal of fallen leaves and twigs.
Authors Jim Downer (UCCE Ventura County), Steven Swain (UCCE Marin County), and Amanda Crump (UC Davis Plant Sciences) recently revised
- Author: Elaine Lander
Mistletoe is a familiar sight of the season, often found wrapped in ribbon and hung for certain festivities this time of year. But did you know it is actually a parasitic plant that grows on a number of landscape trees in California?
There are two types of mistletoe in California. Broadleaf mistletoes attack certain broadleaf trees and some conifers while dwarf mistletoes attacks only conifers. Broadleaf mistletoes have green stems with thick, oval leaves. Dwarf mistletoes are smaller, with short stems and yellow scaly leaves.
Both types of mistletoe grow through tree bark and into the tree's tissue, living off the host tree. Healthy trees can typically tolerate a few mistletoe infections although individual branches may...
We hope by now most people have heard about and are aware of the Asian citrus psyllid (ACP), a small brown insect that carries a deadly citrus disease called huanglongbing (HLB), threatening all backyard citrus trees as well as the statewide citrus industry.
This insect feeds on newly developed leaves of all varieties of citrus trees and can spread the bacteria that causes HLB. The HLB disease can kill a citrus tree in as little as 5 years and there is so far no cure or remedy.
Learn more about ACP and HLB by joining the free UC Ag Experts Talk on December 5 from 3:00pm to 4:30pm. Dr. Elizabeth Grafton-Cardwell, Director of Lindcove REC and Research...
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...