Spring is here and if you are like us, you can't wait to get outside and see how your plants and garden are doing! As usual, UC IPM has useful tips for the month of April to prevent pests in the garden and landscape. To see more tips specific to your region, visit the Seasonal Landscape IPM Checklist on the UC IPM website. Here are some general tips to get you started:
- Cover fruit trees with netting to exclude birds and other vertebrate pests.
- Aphids are out already so look for them and their natural enemies such as predaceous bugs like lacewings, lady beetles, and syrphid flies. On sturdy plants, spray aphids off with a strong stream of water or apply insecticidal oils or insecticidal soaps to kill them.
- Manage ants. Plants infested with honeydew producing insects like aphids, whiteflies, and mealybugs may attract ants who take that honeydew back to the nest to feed the colony. Manage ants around landscape and building foundations using insecticide baits and trunk barriers.
- Whitewash tree trunks to deter borers and prevent sunburn. Apply to young trees or older bark on susceptible trees newly exposed to sunlight.
- Look for signs of clearwing moths boring in ash, birch, pine, poplar, and willow.
- Check for signs of powdery mildew on apple, crape myrtle, grape, rose, and stone fruits. Take preventative measures, like pruning, to provide better air circulation between plants.
- Watch for yellowjackets and other wasps building nests in undesirable locations. Knock down newly started nests and use lure or water traps to control populations.
- Prevent mosquitoes by eliminating standing water in gutters, drain pipes, flowerpots, etc. Place Bt “dunks” (Bacillus thuringiensis subspecies israelensis) in birdbaths and ponds to selectively kill mosquito larvae.
- Adjust watering practices as rainfall decreases. Check irrigation systems for leaks and broken emitters and perform maintenance as needed. Consider upgrading the irrigation system to improve its water efficiency.
- Monitor stone fruit trees for pests such as aphids, borers, brown rot, caterpillars, powdery mildew, and scale insects.
Don't see your county on the checklist or want to provide feedback? Let us know!
- Author: Karey Windbiel-Rojas
After all the winter rains you may find yourself dealing with weeds and struggling to control them. The first step in successfully controlling weeds is knowing what weed you have. Well, you're in luck: the UC IPM website contains many useful resources to help you identify and manage weeds in the garden or landscape.
A great place to start is the Weed Gallery, which contains images and identification tips for more than 150 common weeds.
If you think you know the name of your weed, you can use the common or scientific name to view photos to confirm identification. Just use the “List of All Weeds” link from the main weed gallery page.
If you don't know what the weed is, the gallery will help you identify the plant using visual characteristics. First, narrow your search by choosing “identification” in the weed category—broadleaf, grass, sedge, or aquatic plant. That will show you a collection of photos in that category.
Select the photo of the plant form or leaf characteristic that resembles your weed (Figure 1) to see another sub-menu of weeds that exhibit more traits of your weed. Scrolling over a thumbnail image on this sub-menu will bring up several photos of the weed—as a seedling and mature plant, its flower, and seeds—to further help you identify it.
Once you think you've identified the weed, click on the linked weed name, which will take you to a photo gallery page. Here you will find details about the weed's habitat, growth characteristics, and life stages. For many weeds, there is a link to the Pest Notes that will give you information about its management, both chemical and nonchemical. Each page in the gallery also links to the Calflora website to show where the weed grows in California.
The gallery contains other features as well:
- Want to know more about plants and their parts? Illustrated tutorials distinguish among broadleaf, grass, and sedge plants and define plant parts used in characterizing certain plant species.
- Need to find out what weeds are in your lawns? The broadleaf and grass categories link to an identification key for common turf weeds.
- Didn't find your weed? See the weed identification tool under “More information” to search the UC Weed Research & Information Center (WRIC) technical weed key.
You can find the weed gallery page on the left-hand column of the main Home & Landscape page on the UC IPM web site or from the many weed-related pages. To access the weed gallery directly, visit https://ipm.ucanr.edu/PMG/weeds_intro.html.
Visit UC IPM's Weeds library page to find general weed management tips, individual weed-related Pest Notes, the weed gallery, key to weeds in turf, and other useful resources. https://ipm.ucanr.edu/PMG/menu.weeds.html
[Originally featured in the Spring 2024 edition of the Home & Garden Pest Newsletter]
Follow these general tips for the month of February to prevent pest in the garden and landscape. To view more tips specific to your region, visit the Seasonal Landscape IPM Checkliston the UC IPM website.
- Protect sensitive plants from freezing and frost damage.
- Check grapes for pests like powdery mildew, Eutypa dieback, Phomopsis cane and leaf spot, and others.
- Paint or varnish and seal wood to deter carpenter bees. If intolerable, treat tunnels during early spring.
- Prevent mosquitoes by eliminating standing water in gutters, drain pipes, flowerpots, etc. Place Bacillus thuringiensis subspecies israelensis in birdbaths and ponds to selectively kill mosquito larvae.
- Apply a preventive spray for peach leaf curl once or more during late fall through bud break in spring if leaf curl has been a problem on nectarine or peach.
- Prune evergreen, summer-flowering shrubs.
- Manage weeds using nonchemical methods such as cultivation, handweeding, or mowing. Control young weeds as soon as they pop up.
- Whitewash tree trunks to deter borers and prevent sunburn. Apply to young trees or older bark on susceptible trees newly exposed to sunlight.
- Apply organic mulches where thin or soil is bare under trees and shrubs to prevent weeds and regulate soil moisture and temperature. Keep mulch back from trunks and at a depth of 2 to 4 inches, depending on the mulch type.
Don't see your county on the checklist or want to provide feedback? Let us know!
- Author: Lauren Fordyce
Mark your calendars and register now for these free IPM webinars! Learn about pest identification, prevention, and management in and around the home, garden, and landscape. Webinars are open to all members of the public and we encourage you to share them with anyone who may be interested in joining!
The UC Statewide IPM Program Urban and Community Webinar Series occurs on the third Thursday of every month from 12:00-1:00pm PST. All webinars are recorded and posted to the UC IPM YouTube channel– so don't worry if you can't attend!
January 18, 2024 – Peach Leaf Curl & Springtime Fruit Tree Diseases
Winter is a great time to control many fruit tree pests. In this webinar presented by plant pathologist Dr. Akif Eskalen, you will learn to identify and manage fruit tree diseases such as peach leaf curl, fire blight, and others.
Register at https://ucanr.zoom.us/webinar/register/WN_fE6ncJItThyHQhjb24rAGA
February 15, 2024 - Controlling Springtime Weeds
With winter rains, come springtime weeds! In this webinar, weed scientist Clebson Goncalves will show you how to identify common weeds that emerge in the spring and how you can prevent or control them from popping up in your landscape.
Register at https://ucanr.zoom.us/webinar/register/WN_igafr6JISpanuVeKxP7aYg
March 21, 2024 - Insect Egg Identification (Easter egg hunt!)
What are those weird eggs you found? UC IPM's Karey Windbiel-Rojas will cover different types of insect eggs you might encounter in the garden and landscape—are they pests, beneficials, or just interesting visitors?
Register at https://ucanr.zoom.us/webinar/register/WN_FtjvMNOFRnui0hdP5zjTpA
April 18, 2024 - Mosquitoes & Ticks of Public Health Concern
Mosquitoes and ticks are important vectors that can spread diseases and threaten public health. In this webinar presented by Mary Sorensen from the Placer County Mosquito & Vector Control District (MVCD), you will learn about the health risks these pests pose, how you can manage them and protect yourself, and how MCVDs in California are preparing for new threats like invasive mosquitoes.
Register at https://ucanr.zoom.us/webinar/register/WN_E4X0cA8WSWqAoQwtVWR4pA
May 16, 2024 - Moles, Voles, and Gophers!
Burrowing rodents like moles, voles, and gophers can wreak havoc in the garden and landscape by eating seedlings and plant roots, damaging tree bark, and making lawns unpleasant with their mounds and tunnels. Join Human-Wildlife Conflict Resolution Specialist Roger Baldwin to learn how best to manage these pests.
Register at https://ucanr.zoom.us/webinar/register/WN_y8DfmVuxQhCkFpJPRoEi4A
June 20, 2024 - Flea Control & Diseases: Starting from Scratch
Fleas are small but mighty insects that are important medical and veterinary pests. They can vector pathogens and parasites, and their bites cause discomfort and irritation. In this webinar presented by Laura Krueger from the Orange County Mosquito & Vector Control District you'll learn how to keep yourself and pets safe from fleas and flea-borne diseases.
Register at https://ucanr.zoom.us/webinar/register/WN_Ni_preUtTna4XyOq1FD_gA
Webinars for July through November will be announced later in 2024. Follow us on Facebook or Instagram to stay up to date on new webinars, pest management tips, and more!
- Author: Belinda Messenger-Sikes
Have you been seeing a lot of defoliated sycamore trees recently? Sparse foliage and early leaf drop on sycamore trees might be due to anthracnose. The cool, wet spring in many parts of California provided the perfect conditions for this disease. Anthracnose is a common fungal disease sometimes called leaf, shoot, or twig blight. It can cause twisted, distorted branches in American sycamore, some varieties of London plane trees, and California sycamore trees. Sycamore anthracnose is primarily an aesthetic concern since it usually doesn't kill established trees.
Symptoms
Take a close look at the fallen leaves for the characteristic irregular blotches caused by this disease. Anthracnose can cause leaf spots, cankers, and wilting of young leaves in the spring (Figure 1). Emerging leaves turn brown and die. On older leaves, irregular spots or brown blotches begin on either side of the main leaf vein. The lesions spread, covering much of the leaf surface. Extensive twig or shoot blight occurs when young, growing shoots are killed. New shoots grow back from lower on the branch, eventually causing the branch to look gnarled with a “shepherd's hook” appearance (Figure 2).
Springtime disease
The fungus overwinters on infected sycamore twigs and dead leaves., The disease is most severe during wet years when temperatures during the leafing-out period are below 55°F. The disease is not a problem in hot, dry weather. While the first flush of leaves might be lost to the disease, the canopy will regrow as the second flush of growth matures.
Management
Sycamore anthracnose is best managed by cleaning up fallen infected leaves to prevent the spread of the spores to the following year's new growth. Rake and dispose of fallen leaves and twigs during the growing season and in the fall. Prune and dispose of infected twigs and branches in the fall or winter. Avoid sprinkler irrigation that keeps trees wet. When planting sycamore trees in gardens and landscapes, choose resistant cultivars.
Fungicides do not reliably control sycamore anthracnose in California. By the time you see symptoms, it's too late to treat since fungicides effective against the disease are preventive (before the symptoms appear), not eradicative (after the disease symptoms appear). In landscape and residential settings, chemical spray applications are usually not practical due to the size of the trees and the high potential for pesticide drift.
Most sycamore trees will fully recover from defoliation caused by anthracnose, so the best option could be to just rake up the fallen leaves to reduce disease inoculum for the following year.
For more information about anthracnose, see the UC IPM Pest Notes: Anthracnose.
[Originally published in the Summer 2023 Issue of the UC IPM Green Bulletin Newsletter]
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