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Top 10 pests in gardens and landscapes and how to control them

Download the free booklet at the bottom of the page!

1. Ants

Most people deal with ants around their home at some point. Because most ants live outdoors, focus efforts on keeping ants from entering buildings by caulking entryways. Follow good sanitation practices to make your home less attractive to ants. Spraying ants inside the home will not prevent more ants from entering. Use baits to control the ant colony. Pesticide baits work by attracting worker ants who then take the poison back to the nest where the entire colony, including queens, can be killed. In the landscape, ants protect honeydew-producing pest insects from predators, so use sticky barriers or insecticide baits to keep ants out of trees and shrubs.

 

2. Aphids

Aphids can curl leaves and produce sticky honeydew, but they rarely kill plants and you usually can wash them off with water. When aphid numbers get high, natural enemies such as lady beetles (lady bugs), lacewings, syrphid fly larvae, soldier beetles and others frequently feed on them, eliminating the need for pesticides. Protect these good bugs by avoiding the use of insecticides that can be toxic to a broad variety of insects. Ants protect aphids from these natural enemies, so keep ants away from your garden as well. When pesticides are necessary, use less toxic products such as insecticidal soaps and oils.

 

3. Asian citrus psyllid and Huanglongbing disease

The Asian citrus psyllid (ACP) and the deadly bacterial disease it spreads, Huanglongbing (HLB), threaten citrus trees in backyards and on farms. There is no cure or effective control method for HLB disease.  All types of citrus—including oranges, grapefruit, lemons, and mandarins—are affected as well as a few closely related ornamentals. ACP and HLB have already devastated the Florida citrus industry, and now that it is in the Western U.S. it is threatening the California citrus industry as well.

 

4. Gophers

Gophers are small burrowing rodents that feed on roots of many types of plants. A single gopher can ruin a garden in a short time, and gopher gnawing can damage irrigation lines and sprinkler systems. In lawns, their mounds are unsightly and interfere with mowing. Early detection is critical to prevent damage. Use both traps and underground fencing to manage gopher problems. Toxic baits are available but can pose threats to wildlife, pets, and children, especially in backyard situations.

 

5. Leaf-feeding caterpillars

Caterpillars, which are the larvae of butterflies and moths, damage plants by chewing on leaves, flowers, shoots, and fruit. Caterpillars in fruit or wood can be difficult to manage because they are hidden most of their life and can cause serious damage even when numbers are low. However, many plants, especially perennials, can tolerate substantial leaf damage, so a few leaf-feeding caterpillars often aren't a concern. Handpicking and beneficial predators and parasites often provide sufficient control. Look for feeding holes, excrement, webbed or rolled leaves, caterpillars, eggs, and good bugs.

 

6. Peach leaf curl

Peach leaf curl is a fungal disease that affects only peach and nectarine trees. Distorted, reddened foliage in the spring is a distinctive symptom. New leaves and shoots thicken and pucker and later may die and fall off. An infection that continues untreated for several years can lead to a tree's decline. To prevent peach leaf curl, treat peach and nectarine trees with a copper fungicide every year after leaves fall. After symptoms appear in the spring, any treatment will not be effective. When planting new trees, consider buying peach tree varieties that are resistant to the disease.

 

7. Rats

Rats eat and contaminate food, garden produce, and fruit, and transmit diseases to humans and pets. Manage rats by removing food and shelter, eliminating entryways into buildings, and trapping. Snap traps are the safest, most effective, and most economical way to trap rats. For Norway rats, place traps close to walls, behind objects, in dark corners, and in places where you have found rat droppings. For roof rats, place traps in off-the-ground locations such as ledges, shelves, branches, fences, pipes, or overhead beams. Ensure traps are out of reach of children and pets.

 

8. Scales

Scale insects suck plant juices and are pests of many trees and shrubs. Infestations can cause yellowing or premature dropping of leaves, sticky honeydew, and blackish sooty mold. Plant parts can distort or die back, depending on the species and abundance of scales. Most plants tolerate low to moderate numbers of scales. Provide plants with proper cultural care, especially irrigation. Encourage scale predators such as lady beetles or lacewings and look for parasite emergence holes in scale covers. Use sticky barriers or insecticide baits to selectively control scale-tending ants. Consider replacing problem-prone plants because most scales are highly specific to certain plants.

 

9. Snails and slugs

These slimy mollusks emerge from hiding at night and chew holes in leaves and flowers of many succulent garden plants and fruit. Management requires a vigilant and integrated approach that includes eliminating moisture and hiding spots, trapping, setting up barriers, and handpicking. Regularly remove snails from shelters you can't eliminate such as low ledges on fences, undersides of decks, and meter boxes. Place traps in your garden and dispose of trapped snails and slugs daily. Reduce moist surfaces by switching to drip irrigation or watering in the morning rather than later in the day. Consider snail-proof plants such as impatiens, geraniums, begonias, lantana, nasturtiums, and many plants with stiff leaves and highly scented foliage such as sage, rosemary, and lavender.

 

10. Weeds in landscapes

Prevent weed invasions in new beds with good site preparation. Keep weeds out with an integrated program that includes competitive plants, mulches, and hand removal. Be particularly vigilant about removing aggressive perennial weeds. You rarely should need herbicides in established landscape plantings. Mulches prevent weed seed germination by blocking sunlight. Remove small weeds by hand before they flower and set seed. Use shallow cultivation or hoeing to remove annual weeds from ornamental plantings. Only use herbicides for special-problem situations before establishing new plantings or for difficult-to-control perennial weeds.

 

To see all of the University of California's Statewide Integrated Pest Management Program's information on home, garden, and landscape pests, visit http://www.ipm.ucanr.edu/PMG/menu.homegarden.html

For other short pest “Quick Tips” like the ten above, see http://www.ipm.ucanr.edu/QT/

 To read even more in-depth, peer-reviewed information on many other common home and landscape pests in California, see the Pest Notes series at http://www.ipm.ucanr.edu/PMG/PESTNOTES/index.html

Download your free UC IPM Quick Tips Booklet of the Top Ten Pests in Gardens and Landscapes and How to Control Them with the link below! 

Posted on Friday, June 10, 2016 at 12:30 PM
  • Author: Tyler Ash

Comments:

1.
Master Gardener 2009

Posted by Janet Wall on June 13, 2016 at 5:01 AM

2.
I am appreciative of your information. It is uniquely valuable. I have been so busy its hard to go as far as Davis. Thank you for all of the information! Beth

Posted by Beth Blair on June 13, 2016 at 8:15 AM

3.
Thank you for all your information sharing.

Posted by Richard Koch on June 13, 2016 at 10:27 AM

4.
I would love a copy of the top ten pests guide

Posted by Mark Barton on June 13, 2016 at 4:19 PM

5.
I love all of the information you send. I just get so much stuff even when I unsubscribe that most of the time I do not have time enough to read the stuff I get from you that I am really personally interested in because there is so much regarding my business that I need to read and respond to. Wish I made a nickel for each email I get and must deal with. I would be getting rich.  
Thank you for all that you do to keep us informed.  
Proud Master Gardener- Class of 2002

Posted by Kari Walker on June 13, 2016 at 7:08 PM

6.
Yes I would like to continue receiving this information. Thank you

Posted by Ted Elder on June 14, 2016 at 12:17 PM

7.
I use your information periodically in gardening classes I teach for the Pleasant Valley Rec. and Park District.  
 
As a trained Master Gardener, I have a long time knowledge of the great work done by farm advisors and staff. I enjoy reading about new methods used in farming and also ways we can protect our natural environment and save resources.

Posted by Carol Haverty on June 14, 2016 at 5:04 PM

8.
Thanks for the free pest guide. It seems like a more challenging year for farming this year.

Posted by Ty Turrone on June 16, 2016 at 8:41 AM

9.
Rats totally freak me out and I would be so mad if I found any running around my garden. It does seem like a good idea to find a pest control company that can help you get rid of them. I wouldn't want to have to deal with controlling the rats myself.

Posted by emily bennette on November 10, 2016 at 9:31 PM

10.
Rodents might seem little animals to you but consequences of having them in your house are unimaginable sometimes. In the past decade more than 10 million people have died because of the rodent-spread diseases. This shows how badly you need to get rid of mice away. Have you ever tried googling ‘How to catch a mouse’? Well, hundreds of thousands of people search this phrase, indicating how serious this issue is. Even Tom doesn’t know how to catch a mouse–Jerry.

Posted by Bilal Khan on July 27, 2017 at 3:32 AM

11.
I loved when you mentioned how you can manage rats by getting rid of their food and shelter. It is good to know that you can have simple solutions for these types of problems. We have an ant infestation, so I'm glad I found your page.

Posted by Marcus on August 23, 2018 at 4:38 PM

12.
I've started to notice an increase in aphids in my garden and they're greatly affecting the growth I usually have. The information you've provided that purchasing natural predators for aphids like ladybugs or soldier beetles was really interesting. Personally, I would just like to call a landscape pest control service so that I could be more assured that they would not be able to come back.

Posted by Sarah Smith on September 24, 2018 at 4:18 PM

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