- Author: Lauren Fordyce
![Fuzzy-like white spots all over the green pad of a prickly pear cactus.](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/101738small.jpg)
It may be after Labor Day, but some of your plants may still be wearing white, breaking that long-standing fashion “rule”! While many of us don't adhere to this old rule for our wardrobes these days, you may care about white stuff on your plants this time of year.
There are several white colored pest insects and diseases that you could be noticing on your plants.
Scales
Several types of scale insects are white. Each has their own host preferences, or plants they feed on.
- Cochineal scales feed only on cacti, usually prickly pears. On the outside they are white and waxy but...
![This blotchy yellowing of citrus tree leaves is an early sign of Huanglongbing and will worsen as the disease develops in the tree. (Photo courtesy of CitrusInsider.org)](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/64892small.jpg)
The California Department of Food and Agriculture has declared a quarantine following the detection of Huanglongbing (HLB) in multiple residential citrus trees in Corona (Riverside County). This is the first time HLB has been detected in Corona.
The 107-square mile quarantine area will link up with the east side of the existing quarantine in Los Angeles, Riverside, Orange and San Bernardino counties, creating a contiguous 1,127-square-mile area. The new portion is bordered on the north by Chino Airport, on the south by Black Star Canyon, and on the east by Interstate 15.
The quarantine prohibits the movement of all citrus nursery stock or...
![Brown adult, yellow nymphs, and white wax of Asian citrus psyllids.<br>(Credit: M Rogers)](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/64359small.jpg)
(Credit: M Rogers)
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...
- Author: Karey Windbiel-Rojas
![pest-04-ACP-waxy-tubules-002-Rogers](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/64374small.jpg)
A quarantine has been declared following the detection of the citrus disease Huanglongbing (HLB), or citrus greening, in a single citrus tree in an unincorporated area of San Bernardino County, near Montclair. This is the first time the plant disease...
- Author: Elizabeth E Grafton-Cardwell
![Three brown mottled Asian citrus psyllid adults feed on young citrus leafs alongside their small yellow orange eggs.](https://ucanr.edu/blogs/UCIPMurbanpests/blogfiles/58277small.jpg)
(Credit: M. Lewis, CISR)
[This post has been modified from the article originally published in the Fall 2018 issue of the Retail Nursery and Garden Center IPM News.]
Citrus trees remain a popular choice for home gardeners in California, largely due to their ease of care, beauty, and functionality for food and shade. However, backyard citrus can also be plagued by pests such as psyllids, leafminers, cottony cushion scale, and mealybugs.
Longtime readers of this blog will know that we have covered the
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