- Author: Anne Schellman
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
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.
- Author: Denise Godbout-Avant
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.
- Author: Ed Perry
- Editor: Anne Schellman
To have your soil analyzed, contact a commercial testing laboratory. For a list of soil laboratories located in Stanislaus, Merced, Fresno, and Merced Counties, visit https://cemerced.ucanr.edu/ClimateSmartAg/HSP/SoilTest/Soil_Testing_Laboratories_in_Fresno_Madera_Merced_and_Stanislaus_Counties/
Vegetable Gardens
For vegetable gardens, the application of a fertilizer containing nitrogen and phosphorus is usually all your soil will need to get your vegetables off to a strong start. Other nutrients like zinc or iron are sometimes deficient or unavailable in certain soils, but they are usually not applied unless plant deficiency symptoms appear.
Diagnosing a Plant Problem
Besides moisture, oxygen is also required in the soil for good root growth. Poorly drained soils often have little oxygen in them because excess water fills all the spaces between the soil particles. My advice to gardeners is to correct drainage problems first, then worry about fertilizers. Often problems with sick and dying plants are caused by overwatering or a lack of good soil drainage than by nutrient deficiencies.
If you have an unhealthy plant, gently dig near the root system and check soil moisture and drainage. Since plant roots need oxygen, roots may suffocate if excess water does not drain quickly. Unfavorable climatic conditions, including temperature extremes and drying winds can also affect plant growth, as well as insect pests and diseases. For small plants, pull up a plant or two and check to see if the roots are healthy.
The best way to keep soil healthy, especially in vegetable gardens is to add compost annually to improve soil health. For perennial crops like fruit trees, annual applications of fruit tree fertilizer in spring can be beneficial.
The UCCE Stanislaus County Master Gardeners Can Help!
If you need help diagnosing a plant problem, take a plant sample to the UCCE office located at 3800 Cornucopia Way Ste A in Modesto. Master Gardeners are available on Wednesdays from 9:00 a.m. to noon in person or by phone (209) 525-6802. You can drop off a sample anytime during business hours or fill out an online survey and attach photos using this link http://ucanr.edu/ask/ucmgstanislaus A Master Gardener will get back to you within 5 days of your request.
If you live in another county in California, you can find your local Master Gardener program by using this link https://mg.ucanr.edu/FindUs/
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County where he worked for over 30 years.
- Author: Anne Schellman
We will keep you updated on our progress through this blog as well as on social media via Facebook, Instagram, and/or our twitter page @UCMGStanislaus.
Many subscribers to this newsletter gave to this campaign, thank you! If you missed your chance to donate, you can still send a check to support the demonstration garden campaign. Please make checks payable to
UC Regents and send them to:
UCCE Stanislaus County Master Gardener Program
3800 Cornucopia Way, Ste A
Modesto, CA 95358
Thank you!
- Author: Anne Schellman
How You Can Help
We appreciate any amount you can give. Credit card donations will be matched if we meet the qualifications below:
- $500 to the twenty groups with the most first time donors
- $500 to the first 10 funds that secure a $500 + donation
- $500 to the ten groups that raise the most funds
Only gifts made by online/credit card donations on the day of the event qualify for the prizes.
Please donate today! 
Now is a great time to make a tax-deductible donation to our organization! Visit https://ucanr.edu/sites/GivingTuesday/ and choose Stanislaus County Master Gardener Program.
If you prefer to donate a check, please make it out to UC Regents and send to:
UCCE Stanislaus County Master Gardeners
3800 Cornucopia Way Ste A
Modesto, CA 95358
When will you begin creating the gardens?
We plan to begin working on one of the gardens in spring, and will keep you posted on our progress through this blog as well as our Facebook, Instagram and twitter accounts (@UCMGStanislaus). Our Sensory and Pollinator Gardens will be open to everyone to visit, and used during classes and workshops on drip irrigation, low water use plants, pollinator plants, and more!
