[From the UC IPM blog Pests in the Urban Landscape]

We all encounter pests in our homes, gardens, and landscapes, but which ones are most popular in California? While we can't say for certain, website traffic to UC IPM's Pest Notes gives us a glimpse of popular pests. Here are the top ten most frequently viewed publications in 2021.

1. Aphids

These insects may be small, but they can quickly build up large populations. With many different species in California that feed on vegetables, flowers, fruit trees, and woody ornamentals, aphids are a common sight in landscapes and gardens. Year after year, aphids continue to hold the top spot. Learn more about aphids and their management in Pest Notes: Aphids. 

2. Fungus Gnats

This pest has become more popular in recent years, perhaps a result from growing numbers of houseplant enthusiasts. Fungus gnats are small flies that often infest soil and potting mix. They can be a common houseplant problem with larvae, or immatures, damaging roots and stunting plant growth when present in large numbers. More information on these frustrating flies can be found in our Pest Notes: Fungus Gnats.

3. Thrips

Another tiny insect sometimes found on houseplants, thrips are slender insects about the size and shape of a dash printed in a newspaper. They suck out the cell contents, leaving a discolored speckling on leaves or stunting plant growth. For more about thrips monitoring and management, visit our Pest Notes: Thrips.

4. Mealybugs

If you've found soft, oval insects that are white in color with wax filaments on your indoor or outdoor plants, it is likely you have mealybugs. These wingless insects are often found in clustered colonies. In yards and gardens, handpicking, pruning, or high-pressure water sprays can reduce populations. For small infestations indoors, spot treatments may help reduce populations. For houseplants with severe infestations, consider disposing of the plant. Find additional information in Pest Notes: Mealybugs. 

5. Carpet Beetles

Immature carpet beetles feed on natural fibers such as wool, silk, or furs. The adults may be brought into the home on cut flowers or when they fly in through open doors, windows, or holes in screens. Regular cleaning of rugs, upholstered furniture and can prevent infestations or reduce damage. Check out the Pest Notes: Carpet Beetles for more information.

6. Peach Leaf Curl

Peach leaf curl can affect the blossoms, fruit, leaves, and shoots of peach and nectarine trees. The symptoms of the disease first appear in spring, when distorted red foliage emerges. However, focus management for nonresistant varieties in the late fall and early winter, after leaves drop. Read more about this disease in our Pest Notes: Peach Leaf Curl.

7. Clothes Moths

New to the top ten list this year were clothes moths. These pests tend to hide when disturbed, so you may not realize you have an infestation until after the moths have already damaged fabric, fur, or feathered items. Some clothes moths make webs while others are casemaking moths. Regularly monitoring and cleaning clothing and storage areas can help prevent or reduce infestations. Find more identification and management information from Pest Notes: Clothes Moths.

8. Springtails

Springtails made an unexpected appearance on this year's top ten list. These are small, jumping insects that can be found near kitchen sicks and bathtubs as well as in the soil of indoor houseplants. They often appear in the spring and early summer but can be found year-round in moist environments. They get their name because they jump when disturbed. Learn more about this pest in Pest Notes: Springtails. 

9. Whiteflies

Whiteflies are not actual flies but are tiny insects that are often found on the underside of leaves, feeding on the phloem of many different plants. Certain species can cause significant loss in vegetable gardens; other species found in fruit trees are less damaging. Both adult and immature whiteflies also attack houseplants.  Management information can be found in Pest Notes: Whiteflies.

10. Scales

Scales are small, legless insects that look like tiny scabs on the stems, leaves, or fruit of plants. While some scale species can weaken a plant when abundant, other species do not appear to damage plants at all. Think you have a problem with these insects? Visit our Pest Notes: Scales for identification and management options.

If you have a peach or nectarine tree in your landscape, most of the leaves have probably dropped. This is a great reminder to gardeners that it's time to spray for peach leaf curl.

Why spray for peach leaf curl disease?

Right now, the fungus that causes leaf curl is present on your trees. Once spring arrives, its spores “move” via water droplets splashed onto developing leaves. When the environment is right, these spores invade newly developing leaves, growing in between leaf cells and causing distortion of cells.   

Symptoms of peach leaf curl disease include puckering leaves that curl and turn a reddish color. Often the entire first set of leaves may drop off. When new leaves begin to grow, these leaves are also infested. Twigs and shoots distort and often die. Fruit is rarely affected. However, left untreated, nectarine and peach trees begin to decline and fruit production is substantially reduced.

Often when gardeners see symptoms of leaf curl disease on their tree, they are tempted to pull off the affected leaves, thinking this will help. Unfortunately, there is little to do at this point to control the disease.

Prevention

The only way to prevent peach leaf curl disease is to protect your tree with a preventive spray. This is done once during the dormant season using a copper-based fungicide. However, during wet winters you may want to spray a second time late in the season before green leaf tips begin to show.

Using Pesticides

Insects, diseases, and weeds are pests, and products used to kill them are called pesticides. Whether a product is organic or not, it can still have an impact on you and/or the environment, so be sure to follow the directions on the product label regarding personal protection, correct mixing, and application. When spraying, make sure to coat the tree until the product is dripping off. Come spring, your peach and nectarine tree trees should leaf out and grow vigorously, followed by a healthy crop of fruit.

Learn more about peach leaf curl by visiting the UC IPM website and reading their Quick Tips on it at http://ipm.ucanr.edu/QT/peachleafcurlcard.html  For more detailed information about this disease, read the Pest Notes at http://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html

Coming Soon

Bare root fruit trees are arriving in nurseries and garden centers. If you are thinking about planting fruit trees but aren't sure what to plant, how to plant, and how to care for them, you'll want to attend our online Bare Root Fruit Tree Planting and Pruning Class on January 25, 2022. More details coming next week.

If you have fruit trees that produce a lot of small fruit, you may be missing an important step in growing fruit trees called "thinning." Next month we'll publish an article on how and when to thin fruit from Ed Perry, retired UCCE Stanislaus County Emeritus Horticulture Advisor.

Anne Schellman is the UCCE Stanislaus County Master Gardener Program Coordinator.

 

 

 

January has always been my least favorite month of the year. The often dreary, short, gray days seem especially dull after all the December festivities. Going outside to work in my garden is a chore when I'd rather be snuggled under a blanket with a good book in front of a fire with a hot drink. However, there are many important gardening chores that should be done during the cold winter days.

Seasonal Landscape IPM Checklist for Home Gardeners

UC's Integrated Pest Management (IPM) Home, Garden, Turf and Landscape Pests Quick Link has a Seasonal Landscape IPM Checklist which is a wonderful resource with monthly checklists within your selected county/region to help guide you how to keep your landscapes healthy. 

https://www2.ipm.ucanr.edu/landscapechecklist/

Topics include common pest problems to look out for, preventative measures, and links to more information. You can also subscribe to receive an automated monthly list by email. 

December and January Lists

I reviewed the December and January checklists for Stanislaus County. The following are some topics listed and additional appropriate links:

• Frost – Temperatures sometimes drop to freezing during the winter months. Cold temperature can kill bark, buds, flowers, and shoots, so protect sensitive plants from frost.  To increase a soil's ability to absorb heat rake away mulch to expose the ground around the base of the plant. If frost is expected irrigate the soil (if there hasn't been any rain recently) at least three days prior. You can also cover sensitive plants overnight with cloth or similar material other than plastic but leave covers open at the bottom so heat from soil can help warm plants and remove covers during the daytime. http://ipm.ucanr.edu/PMG/GARDEN/ENVIRON/frostdamage.html
• Irrigation – Always adjust your watering schedule according to the weather. We have had a very wet December, which followed an atmospheric river storm in October. So, gardens have needed little to no irrigation lately, depending on your soil type. Overirrigation can lead to root rot. Resume irrigation if storms diminish during the remainder of the winter (let's hope it remains wet!). If there is an extended dry spell during upcoming winter months, irrigate infrequently and deeply. http://ipm.ucanr.edu/homegarden/irrigating/
• Clean up – Remove old fruit and nuts in and under trees to avoid harboring pests. Also rake up fallen leaves beneath deciduous fruit trees and roses (but leave the leaves elsewhere in your yard for beneficial overwintering insects including butterflies and bees). http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/CULTURAL/sanitation.html
• Prune – Trees and shrubs that need pruning including apple, crepe myrtle, pear, rose, spirea, and stone fruits (exception are apricot and cherry trees which can harbor certain pests, i.e. shothole borer, which should be pruned in the summer). Remove dead and diseased wood. http://ipm.ucanr.edu/homegarden/pruning/ 
• Mistletoe – Mistletoes are parasitic plants that absorb nutrients and water from a host tree. Healthy trees can tolerate a few branches infected with mistletoe, but a heavy infestation could ultimately kill a tree, particularly if the tree is stressed or unhealthy.  With leaves having dropped during fall months from deciduous trees, mistletoe is visible on the now-bare trees, and thus can be removed easily. Remove branches at least a foot below the mistletoe attachment before it produces seeds that will infest other limbs and trees. Since mistletoe often infects many trees on the same street, a neighborhood effort to remove all mistletoe from any trees on the block will help reduce continued spread in the area. http://ipm.ucanr.edu/QT/mistletoecard.html
• Peach leaf curl –If leaf curl has been an issue on your peach or nectarine plants apply preventive spray once or more times until bud break. http://ipm.ucanr.edu/QT/peachleafcurlcard.html
• Bare root plants – Now is the time to plant bare root deciduous trees, shrubs, and vines, including roses, fruit, nuts and grapes. Select species and cultivars that are appropriate for the site it is being planted. http://ipm.ucanr.edu/homegarden/planting/

This compilation is a partial overview of the lists I reviewed. Check out the January seasonal landscape checklist for your area to see which tasks you need to do. Then bundle up, get your garden tools, and go outside (preferably on a sunny day!) to do the necessary winter maintenance chores in your garden. You and your landscape will be rewarded for your cold weather efforts come spring.

 Denise Godbout-Avant has been a UCCE Stanislaus County Master Gardener since July 2020.

 

Peach leaf curl is a disease that affects peach and nectarine trees. Although you may not see symptoms right now in the dormant season in California, it's time to think about treatment, especially if your tree had the disease last year.

Symptoms of this fungal disease include distortion, thickening, and reddening of foliage as trees leaf out in the spring. As weather warms, damaged leaves that die and fall off trees are replaced with new, usually healthy leaves. However, after several years without treatment, peach leaf curl will cause tree decline and reduced fruit production.

Avoid peach leaf curl by growing varieties resistant to the disease. For nonresistant peach and nectarine trees, consider spraying with preventive fungicides in the dormant season just before or as buds swell.

See the UC IPM publication Pest Notes: Peach Leaf Curl for more information about the disease and management options. Always read and carefully follow all precautions and safety recommendations given on the pesticide label.

[Courtesy of UC IPM Pests in the Landscape blog]