- Author: Deborah M Mathews
One of California's most adored flowering plants, impatiens, is being threatened by a serious pest. You may have noticed the common garden impatiens missing from nurseries, retail store shelves, and landscapes, parks, and gardens this year.
Impatiens are dying from a relatively new plant disease called impatiens downy mildew, caused by the fungus-like, oomycete pathogen Plasmopara obducens. The pathogen primarily affects varieties of Impatiens walleriana, or hybrids with an I. walleriana parent and wild impatiens (I. balsamina). Note that this pathogen does not affect New Guinea impatiens (Impatiens hawkeri) or other bedding plant genera. This disease develops rapidly, with a few leaves on apparently healthy impatiens beginning to show slight yellowing and stunting followed by development of white, powdery spores on the undersides of leaves, and later, by leaf and flower drop. Plants are likely to become completely defoliated within several weeks. The pathogen produces airborne spores, which can travel for many miles, as well as swimming zoospores and oospores, which can survive within soil and plant debris for long periods and infect healthy plants when replanted in the same area.
Early detection is especially critical for this disease since chemical control has been shown to be ineffective once sporulation begins. Scout routinely to identify and remove diseased plants before epidemics can result. Removing infected plants may limit spread to other areas of the landscape.
Consider growing alternative bedding plants that will grow well in shady areas of the landscape but that will not be affected by the disease. Some examples include Bergenia hybrids, Caladiums, Coral bells, Lobelia, New Guinea impatiens, Sweet alyssum, and wax begonias.
This article was originally published in the December 2013 issue of the UC IPM Green Bulletin. Read the entire article at http://www.ipm.ucdavis.edu/greenbulletin/
- Author: Karey Windbiel-Rojas
Do you know how to check your hotel room for bed bugs before you settle in for the night? Can you tell the difference between yellowjackets, paper wasps, and other common wasps? What’s in that bottle of pesticide you are thinking of using on your plants? New videos from UC IPM can help answer these questions!
Thanks in part to funding from the Western IPM Center, the UC Statewide Integrated Pest Management Program has recently created a series of short, 2-3 minutes videos to help you identify, monitor, manage or prevent some pests from becoming problems around your home and garden!
Find out how to use a bed bug detector and inspect your bedroom or hotel room for bed bugs. Protect yourself from mosquito bites and West Nile virus by eliminating mosquito-breeding sites around your yard. Watch how you can hose aphids off plants instead of spraying pesticides. Discover the difference between yellowjackets and other wasps and find out how to find, trap, and treat yellowjackets around your yard or property.
You can also learn about common garden spiders and how to catch them or clean up webs. Are snails and slugs eating your plants? Learn how to recognize whether plant damage was caused by snails or insects with similar feeding habits, and how to trap snails or apply baits. If ants have invaded your home, find out why they are there, how to get rid of them, and how to prevent future infestations.
Watch all our videos by visiting UC IPM’s YouTube channel or by going to the video library page on the UC IPM web site, where you can find these as well as other videos covering pests and related topics.
- Author: tunyalee martin
UC IPM’s new Pest Alert helps you identify Bagrada bug, an invasive stink bug spreading through western Arizona and southern California causing severe crop, nursery, and landscape losses. In agriculture, Bagrada bug is a pest of cole crops and other mustard family plants. In home gardens it feeds on these same vegetables and on ornamental plants such as sweet alyssum and candytuft.
Bagrada bugs use their needlelike mouthparts to pierce and feed on plants and their seeds. Damage includes leaf spotting, wilting, stunting, multiple branches or crowns, and death of the whole plant.
The Pest Alert was produced by UCCE advisors Eric Natwick and Surendra Dara, John Palumbo from the University of Arizona, and the UC IPM team.
Preliminary agricultural management information is also available.
- Author: Mary Louise Flint
Eye gnats are small nuisance flies that are attracted to people’s eyes, noses and mouths or sweating skin and open sores. They breed in moist soil that is high in decaying organic matter, often in agricultural operations. When breeding sites are near urban or recreational areas, eye gnats can become a major problem. Most problems with eye gnats in California have been in southern California, especially in San Diego County and the southern desert areas. A new Pest Note: Eye Gnats, written by James Bethke, Bryan Vander May and Loretta Bates of UCCE San Diego, provides information on identification, biology and management of these annoying pests around homes.
Find the Pest Note: Eye Gnats at
- Author: Cheryl Reynolds, UC Statewide IPM Program
Do you have snails and slugs chewing up your favorite garden plants? Are spiders hanging out in and around your home? How can you get rid of those pesky webs?
The UC Statewide IPM program has just released six short videos to help you find answers to these questions. Find the videos on the UC IPM YouTube channel or linked from the specific Pest Notes publications on Snails and Slugs or Spiders.
Snails and slugs chew holes in leaves and fruit of many different types of plants, but they aren’t always present when the damage is discovered. Caterpillars, earwigs, grasshoppers, weevils, and others cause similar damage. How can you identify the culprit? The short video clip “Did a snail eat my plant?” shows damage caused by various pests and can help you identify snail or slug damage by looking for their characteristic slime trails and excrement.
If you do have snails and slugs in the garden and want to control them without using pesticides, learn how to combine trapping with other nonchemical methods for best results in the clip “Trapping snails and slugs.” If you decide to use a pesticide, check out the video on ”How to apply snail and slug bait.” You’ll learn what types of baits are best, which ones to avoid, and how and when to apply them for best results.
Although many people fear them, most spiders you encounter during the day are harmless and can be beneficial in your garden and landscape by eating pest insects.. You can see different kinds of spiders in the short clip “Common garden spiders.” However beneficial they may be, you might not want them inside your home. Even though the easiest method of getting rid of a spider is to kill it, why not trap it and let it loose outdoors to eat those garden pests? “How to catch a spider” shows several ways to easily trap a spider and let it go, including two types of nifty spider catchers that catch spiders in hard-to-reach places. Now what about those sticky webs? “How to clean up spider webs” shows practical methods for removing webs from around your home such as vacuuming, sealing holes in cracks or screens, hosing them off, or using a Webster tool. These methods can also help to keep spiders out of your home.
For more information on snails, slugs, spiders, and other home and garden pests, visit the UC IPM web site.