August 11, 2016
Two more trees have been confirmed positive for Huanglongbing (HLB), the plant disease carried by an invasive insect called the Asian citrus psyllid (ACP).
One tree is located in San Gabriel and the other is in Hacienda Heights, in very close proximity to the original HLB find from 2012. As always, the California Department of Food and Agriculture worked quickly to contact the homeowners and remove the infected trees. The tree in San Gabriel has already been removed, and the tree in Hacienda Heights is scheduled to be removed today.
The Citrus Pest & Disease Prevention Program outreach team has been active with HLB education in Los Angeles for many months....
[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...
/span>Summer is in full gear and along with warm weather comes the abundance of some seasonal insect pests such as flies. Of the thousands of fly species, only a few are pests in and around the home, the most common one being the house fly.
Flies can carry bacteria and viruses that cause conditions such as diarrhea and food poisoning. House flies pick up disease agents while feeding on materials like feces and then deposit them onto human food after contact with or feeding on human food.
The best way to deal with house flies is to use a combination of exclusion and sanitation practices. While humans commonly find adult flies to be the most bothersome life stage, the larval stage is the best target for management efforts....
- Author: Igor Lacan
In the December 2013 issue of the Green Bulletin, we looked at “Pruning and Tree Physiology: The Bad and the Ugly” for pruning and maintaining ornamental trees as well as some pruning pitfalls. However, pruning can also be highly beneficial for many landscape trees. In this article I will review some approaches to pruning which either directly suppress pests or which maintain tree health, and because impaired health predisposes trees to a number of diseases, these pruning measures could thus be considered a part of an integrated pest management program.
Formative pruning: A young tree arriving from the nursery or...
- Author: Mary Louise Flint
- Editor: Karey Windbiel-Rojas
We've been getting calls this summer from gardeners finding fire blight damage in backyards and landscapes. Fire blight is usually associated with wet springs. Although spring 2014 wasn't particularly wet, rain occurring when apples, pears, quince, cotoneaster, and pyracantha are in bloom can induce the disease even in dry years.
The malady is called fire blight because terminals of affected branches suddenly blacken and die as if they've been scorched by fire (Figure 1). The disease is caused by the bacterium Erwinia amylovora, which commonly enters trees and shrubs through blossoms in rainy weather. Ideal conditions for disease development are rainy or humid weather with mild daytime temperatures (75° to...