- 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...
San Luis Obispo County has seen more than 20 detections of Asian citrus psyllid (ACP) since January 2018, according to Citrus Insider. The majority of these invasive insects have been found in the backyards of residential properties in the city of Nipomo.
If you haven't yet heard about this insect, Asian citrus psyllids can carry and spread the incurable citrus disease huanglongbing, also called HLB or citrus greening disease. Citrus trees infected with HLB develop mottled leaves and produce misshapen fruit that stays green and tastes bitter. There is currently no treatment for the disease, which usually kills trees within three to five years.
Due to these ACP finds, citrus growers in SLO County are on high alert,...
- Author: Janet Hartin
[From the Spring issue of the UC IPM Retail Nursery & Garden Center News]
Most disorders impacting landscape trees result from abiotic (non-living) disorders rather than attacks from biotic (living) pests like plant pathogens, insects, and vertebrates. Damage caused by abiotic and biotic disorders can appear similar, making diagnosis difficult at times. For example, discolored leaves on a Ficus nitida tree could be due to drought stress, a fungus, or a nutrient toxicity or.../span>