Spider mites, fruit moth and twig borer larvae, aphids, and bark cankers are just a few pests that can wreak havoc on stone fruit trees.   With spring well underway and trees in full bloom and beginning to develop fruit, it's time to monitor and take action before these pests get out of hand.

UC IPM teamed up with UC farm advisors to develop a series of how-to videos that can help growers and pest control advisers monitor for pests and damage and determine if and when treatment is needed.

In one video, Sacramento Area IPM Advisor Emily Symmes gives a brief overview of how to monitor for webspinning spider mites.  Spider mites build up in stone fruit trees as the weather warms up.  Late spring through summer is the ideal time to monitor for mites and their damage, which includes leaf stippling and webbing.  If mites build up too much, leaves can drop, fruit may not fully develop, and branches and fruit can be exposed to sunburn.

Shoot strikes, or dead drooping leaf tips, are often seen on young peach and nectarine trees.  In a second video, UC Sutter and Yuba County Farm Advisor Janine Hasey explains how to monitor for shoot strikes and how to distinguish the culprits, oriental fruit moth and peach twig borer.  Although Oriental fruit moth and peach twig borer can bore into both foliage and fruit, they cause the most devastating damage by feeding on fruit.  Early season monitoring and treatment can prevent future fruit loss.

In plum and prune orchards, leaf curl aphids and mealy plum aphids cause leaves to curl and become distorted.  Aphids produce honeydew, which can lead to the development of sooty mold, causing fruit to crack and blacken.  Aphids are often present when leaves start to grow.  In his video, Rick Buchner, UC farm advisor for Tehama County, discusses how to monitor for aphids and explains how to decide when treatment is warranted.

In a final video, UC Sacramento County Farm Advisor Chuck Ingels teaches how to distinguish Phytophthora root and crown rot from bacterial canker.  The two diseases are often confused because they both cause bark cankers.   Phytophthora root and crown rot is confined to the lower trunk, but when a bacterial canker infection occurs in the tree trunk, the diseases can often be confused.  Bacterial canker can be confirmed by cutting away the outer bark and looking for characteristic red flecks on the inner bark.  Correct identification of these diseases will help in choosing a management strategy.

You can find all of these how-to videos on the UC IPM video library page.  For specific information about managing pests in stone fruits or other crops, see the Pest Management Guidelines. Photos (below) by Jack Kelly Clark.

Web-spinning spider mites.

Shoot strike indicates presence of larvae.

Leaf distortion caused by aphid feeding.

Bark canker.

When you hear the words ‘Harvard-educated', what comes to mind? Washington executive? Nobel Laureate? How about UC Cooperative Extension Farm Advisor.

Katherine Pope, UCCE Orchard Systems Advisor, Sacramento-Solano-Yolo Counties.

She continued her education at UC Davis, working with Pomologists Ted DeJong, Patrick Brown and others, following her interest in plant biology, particularly tree nutrition and phenology modeling for deciduous trees. Along the way, she earned a Ph.D. in Horticulture & Agronomy and an M.S. in International Agricultural Development. She could have followed a pathway to a Faculty position. But Katherine wanted to be a UCCE Farm Advisor…

Katherine was hired last year to the position of Orchard Systems Advisor, working in a broad region which covers Yolo, Solano and Sacramento counties. She is delighted to stay in the area, as she had spent her youth in Sacramento, including a few years of houseboat living with her parents on the Sacramento River.

Katherine's principal crop duties now include almonds, walnuts and prunes. She is involved in several projects, including rootstock and irrigation trials, and of course, is taking farm calls. Despite the demands of her new job, Katherine volunteered to chair the annual Pomology Extension Continuing Conference (PECC), which was held earlier this month. When asked about mentors among her colleagues in Cooperative Extension, Katherine begins to list a few: Ted DeJong, Rick Buchner, Franz Neiderholzer, Joe Connell, Allan Fulton, Janine Hasey…then summarizes: ‘I have the support of the whole network' of UCCE Farm Advisors and Specialists. So welcome Katherine Pope — intelligent, cordial, diligent—a great addition to UC Cooperative Extension.

We thank the above IPM Program staff for this article about a new IPM resource:

The thumbnail image accompanying text 'pops-up' for a detailed view. IPM photo©UC Regents.

Herbicides applied to manage weeds may move from the site where it was applied in the air or by attaching to soil particles and traveling as herbicide-contaminated soil. When an herbicide contacts a nontarget plant, a plant it was not intended to contact, it can cause slight to serious injury. Herbicide injury also occurs when the sprayer is not properly cleaned after a previous herbicide application. Herbicide residue can be found in the spray tank, spray lines, pumps, filters and nozzles so a sprayer must be thoroughly cleaned after an application. Dry herbicide particles can be redissolved months later and cause herbicide damage to plants. Economic damage includes reduced yield, poor fruit quality, distorted ornamental or nursery plants, and occasionally plant death.

Accurately diagnosing plants that may have herbicide injuries is difficult. In many cases, herbicide symptoms look very similar to symptoms caused by diseases, nutrient deficiencies, environmental stress and soil compaction. Plant disease symptoms such as mottled foliage, brown spots or stem death and plant pests such as insects or nematodes cause foliage to yellow and reduce plant growth similar to herbicide injury.

Dr. Kassim Al-Khatib, weed science professor at UC Davis and director of the UC Statewide Integrated Pest Management Program (UC IPM), has gathered nearly a thousand photos of herbicide-damaged plants, drawn from his own and others' research. The images are cataloged to show damage that can occur from 81 herbicides in more than 14 specific herbicide modes of action, applied in the field to demonstrate the symptoms or when known herbicide spray has drifted onto the plant.

Each image is characterized with the name of the plant, mode of action of the herbicide, and notes the specific symptoms of damage. Together these photos provide a comprehensive archive of damage to over 120 different crops and ornamental plants by known herbicides, which users can easily compare with what they see in the field.

Also included in the repository is information about the modes of action of various herbicides and an index of example herbicide trade names and active ingredients. Users can learn how unintended injury from herbicide occurs from misapplication and carryover from previous crops in addition to drift and herbicide-contaminated tanks.

The repository can be found at http://herbicidesymptoms.ipm.ucanr.edu. Increased knowledge about what causes herbicide damage and how it occurs can lead to fewer cases of herbicide injury occurring through drift or herbicide-contaminated tanks. Using the repository can increase the skill to correctly identify plant damage. Correctly identifying damage as herbicide injury and not from a plant pest or nutrient deficiency can prevent unnecessary applications of pesticides or fertilizers. Fewer applications can lessen the risk of harm of pesticides and fertilizers to people and the environment.

http://fruitsandnuts.ucdavis.edu

It has been an honor serving our California clientele as the Director of the Fruit & Nut Research and Information Center (FNRIC) for one more active year.  I am blessed to have great support from Ms. Janet Zalom, Ms. Penny Stockdale, Ms. Antoinette Machado, the Department of Plant Sciences, and peers, without them nothing would have been possible.  In cooperation with our UCDAVIS-UCANR peers, we were able to expand and maintain our website, and produced and delivered ‘state of the art courses.'  Blogs, models, animations, and smart phone applications were incorporated to our website as an approach to maintain and reaching new clienteles.

We ended this 2014 year very strong with several outreach courses.  The international conference, Understanding and Preparing for the Threat of Plum Pox Virus Spreading to California and the Western States was led by Ted De Jong and supported by Brooke Jacobs (FNRIC).  This conference held on the UC Davis campus (September 29-30, 2014) provided useful information concerning the threat posed by Plum Pox Virus to California stone fruit growers and prepares them for any potential problems.
Our third course in two years, the ‘Principles of Fruit and Nut Tree Growth, Cropping and Management' was completed in November.  An exciting component of the class is the four-day field trip throughout fruit and nut growing regions of California that helped to increase the participants' network and develop friendships.  We are still in communication with our first rooster of students (2013 course) as we expect their feedback on ways to improve our California outreach mission.  Ted and I enjoyed interacting with a group of students of different ages and levels of experience in orchard management.  We had many young students and beginner farmers interested in Pomology.  FNRIC is committed to developing and providing support through our courses and website as part of the UC land grant mission.

Almost at the same time, the Pistachio workgroup UCANR, with the support of the FNRIC and ANR, delivered the three day extension course, Advances in Pistachio Production (November 18–20, 2014).  Dr. Louise Ferguson (Plant Sciences) from FNRIC coordinated the delivery of this course.  This course encompassed a wide array of farm advisors, specialists and faculty instructors representing decades of experience in California pistachio production.

In the last few weeks, we organized our future activities calendar that includes three important short courses:
• Advances in Walnut Production Short Course    Nov. 16 to 20, 2015
• Principles of Fruit and Nut Tree Growth, Cropping & Management Feb., 2016
• Advances in Almond Production Short Course    Nov., 2016

During the coming year, I will keep pursuing ideas on how to improve the coordination and dissemination of University of California research-based information, accomplishments, and statewide research and extension activities related to fruit & nut crops.  I will keep listening to our supporters, increasing our network, improving our relationship with our clientele to fulfill our FNRIC mission.

Thank you for all you do to make our FNRIC useful.  I wish everyone a Happy Holiday season with your family and friends, and a fruitful New Year.

I keep listening to the rain and I say to myself let it rain, rain, rain ….

Sincerely,

Carlos
http://fruitsandnuts.ucdavis.edu