- Author: Elizabeth E Grafton-Cardwell
Attention Pest Management Professionals!
Are you looking for continuing education units (CEUs) to complete your renewal application this year for the Department of Pesticide Regulation (DPR)? The UC Statewide IPM Program and the Lindcove Research and Extension Center have online courses available that can help you get those needed credits. All courses have moved to the pest management section of the national eXtension online campus system. Be sure to spend at least 1 hour on each unit to receive credit.
The online courses available from UC IPM that offer units for DPR license renewal include:
- Providing Integrated Pest Management Services in Schools and Child Care Settings (1 unit Laws and Regulations and 1 unit Other)
- Pesticide Resistance (2 units Other)
- Pesticide Application Equipment and Calibration (1.5 units Other)
- IPM – A Solution for Reducing Pesticides/Water Quality: Pesticide Properties (1 unit Other)
- The Impact of Pesticides on Water Quality/Mitigating Urban Pesticide Runoff (1 unit Other)
- Water Quality and Mitigation: Bifenthrin and Fipronil (1 unit Other)
- Herbicides and Water Quality (1 unit Other)
Six additional courses on key pests of citrus are also available for DPR units and were developed by Beth-Grafton Cardwell from the Lindcove Research and Extension Center. These include:
- California Red Scale (1 unit Other)
- Citricola Scale (1 unit Other)
- Citrus Red Mite (1 unit Other)
- Cottony Cushion Scale (1 unit Other)
- Forktailed Bush Katydid (1 unit Other)
- Citrus Peelminer (1 unit Other)
For a list of other approved online or in-person courses, visit the DPR website. UC IPM plans to add additional online courses in 2019.
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- Author: Elizabeth E Grafton-Cardwell
- Editor: Elaine Lander
[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 leafminer is a moth that arrived in California in 2000 and has invaded citrus throughout the state. This small moth lays its eggs on new, succulent citrus leaves. The larvae burrow through the soft leaf tissue, creating shallow meandering tunnels, or mines (Figure 1). Larval feeding causes the leaf to curl and distort. Mature citrus trees are less frequently attacked since most of their tough leaves are resistant to the leafminer, but very young trees with their higher proportion of young, tender leaves, are more susceptible. This can slow growth of young trees but even those with heavy leafminer damage are unlikely to die.
In home landscapes, citrus leafminers are killed by many natural enemies—other insects and spiders that attack pest insects. Insecticides don't work very well on this pest because it is inside the leaves. If you can, try to ignore leafminer damage since citrus can tolerate it. The leaves damaged by leafminers will continue to produce food for the tree, so they do not need to be removed. If you remove them, it will stimulate the tree to produce more new leaves, which will be attacked by the leafminer and more damage will appear.
For more information about management techniques, see the Pest Notes: Citrus Leafminer.
Looking for other citrus insect pests? Check out our related posts on mealybugs and cottony cushion scales, Asian citrus psyllid, and ant control for Asian citrus psyllid.
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- Author: Elizabeth E Grafton-Cardwell
- Editor: Elaine Lander
[This post has been modified from the article originally published in the Fall 2018 issue of the Retail Nursery and Garden Center IPM News.]
As a home gardener, you may find big white bugs clinging to the twigs and leaves of your citrus trees and need help with identifying and managing these pests. At first glance, they may look similar but in order to have effective pest management, it's important to first determine what they are. Mealybugs and cottony cushion scale are common pests on backyard citrus trees that can easily be mistaken for one another.
Mealybugs
Mealybugs (Figure 1) are soft, oval, wax-covered insects that feed on many plants in garden, landscape, and indoor settings. These insects suck plants juices as they feed and can produce abundant honeydew which can in turn lead to sooty mold. Mealybug feeding can also reduce tree vigor and damage fruit. Colonies of mealybugs hide in crevices so light infestations might be missed.
Mealybugs are very difficult to control with insecticides. Instead encourage, conserve natural enemies by reducing ant numbers and dust. As with citrus leafminers, many natural enemies feed on and kill mealybugs. Some include common predators such as mealybug destroyers, lacewings, and spiders.
Clusters of mealybugs can be physically removed by handpicking or pruning them out. A high-pressure water spray repeated daily can also reduce populations.
The Pest Notes: Mealybugs contains more information about citrus mealybugs and other common mealybugs.
Cottony Cushion Scale
Cottony cushion scale (Figure 2) is most easily recognized by the female's elongated, fluted white cottony egg sac which can be about ½ inch long. These insects can infest both citrus and some woody ornamentals. Like mealybugs, they suck plant juices and produce profuse amounts of honeydew which attracts ants and allows growth of sooty mold. Cottony cushion scale decreases the plant's health by sucking sap, and heavy infestations can cause branches to die.
In most regions of California, cottony cushion scale is well controlled by natural enemies; the red and black lady beetle called the vedalia beetle, or a parasitic fly. Insecticides don't control adult cottony cushion scale very well and may kill their natural enemies, allowing even more growth of the scale insect.
See the Pest Notes: Cottony Cushion Scale to learn more about this pest.
Looking for other citrus insect pests? Check out our related posts on citrus leafminer, Asian citrus psyllid, and ant control for Asian citrus psyllid.
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- Author: Edward Walbolt
As a native Californian, I grew up enjoying California grown oranges, limes, lemons, and other common citrus. In fact as an adult, these fruits have become a staple of my diet. I try to purchase citrus at farmers markets and I check to see that it is grown in California not only to keep our agricultural sector strong, but because I think we have some of the best quality citrus in the world.
I have recently been educating myself on the latest serious pest related disease to affect Southern California citrus crops and I am starting to get worried that our illustrious citrus industry could be in for some trouble in the near future. The disease damaging Southern California crops is called Citrus Greening; its technical name is Huanglongbing (HLB). The disease is bacterial-based and is being spread by a tiny pest known as the Asian citrus psyllid. This problem seems to have origins in China and was first detected in the Florida citrus crops in the early 2000’s. It has finally made its way to California and that is cause for concern because there is no known cure for the disease, and it kills citrus trees as rapidly as within 5 years once they have become infected. The Florida crops have been under Federal quarantine since the discovery of the outbreak but in spite of that, the disease has emerged in our state recently. It seems to be centralized in the Southern California area and there are several local quarantine orders to prevent the spread of it in our direction here to the North, but that will only slow the spread, not completely contain it. Our central valley farmers have expressed legitimate concern over this disease because it has the potential to wipe out their livelihood. I urge all of us to honor and respect the quarantines on citrus and together we can do our part in keeping containment on Citrus Greening in the foreseeable future.