- Author: Michael I Jones
by Michael I. Jones, PhD, UCCE Forest Advisor, Mendocino, Lake, & Sonoma County
As someone who has studied forest health for a while, I have developed the rather unfortunate habit of noticing only the red and brown canopies that appear in a sea of green (my wife says it makes visiting the forest with me rather depressing). Unfortunately, the tell-tale sign that a tree just died has become a common sight in the coastal forests over the past few years. While there is a suite of forest health issues (invasive species, fire suppression, and climate change to name a few) that are likely driving this decline and dieback, there is one that I am currently most concerned about: Drought.
I noticed the first signs that drought stress was becoming an issue in early spring, when ponderosa pine began to die in eastern Mendocino County. Upon investigation, I found extensive western bark beetle and red turpentine beetle activity. I suspect the insects had established in fire stressed trees and their populations had built up over the past few years, to the point where they were spreading to trees that had no or little fire damage and into areas where there had not yet been wildfire. My colleagues and I have now observed ponderosa pine morality from northern Mendocino to northern Napa. It would seem we are at the initial stages of a western pine beetle outbreak, and I would suspect we will see a significant increase in pine mortality throughout the summer and into the next year.
Another conifer I have been getting questions about recently is Douglas-fir. Over the past few years there has been noticeable Douglas-fir decline and mortality, especially in young trees that have encroached into oak woodlands and rangeland. While this is an indication of unhealthy forests and stressed trees, I do not necessarily see this as a serious forest health issue since the expansion and growth of Douglas-fir in high densities into other habitats is the result of forest succession in the absence of fire. So, in my opinion the decline of some of these trees is a natural process resulting from the stress of growing on low quality sites and competing for water and nutrients, resulting in insect and disease infestations. Drought further increasing water stress and accelerates the rate of decline and dieback. However, I have yet to see extensive Douglas-fir mortality in high quality sites such as north facing slopes with moist, mild climates.
The next significant sign that drought stress was becoming an issue was the decline and mortality of interior live oak and CA Black oak in southern Mendocino County (Hopland). Upon investigating several clusters of declining trees, I found that the mortality was not associated with sudden oak death, but instead appeared to be caused by outbreaks of western oak bark beetle, a native bark beetle that is attracted to stressed trees. While many of the declining trees have extensive evidence of the bark beetle activity, several trees have only a few galleries, but were covered in cankers which are indicative of foamy bark canker, a disease caused by a pathogen the bark beetle vectors. While I have only observed this decline in the Hopland area, western oak bark beetle is found throughout California and could easily outbreak in other areas where oaks are highly drought stressed. Additionally, other native oak pests such as twig blight, branch canker, pit scale and invasive pests such as sudden oak death and Mediterranean oak borer are becoming more common in drought stressed trees throughout the Coastal Range.
What can we do about forest health and the drought? Many of the pests I mentioned are native and are simply acting as natural disturbances that help cull stressed and dying trees and begin the process of nutrient cycling. While eradicating pests or preventing them from infesting trees is extremely difficult, their populations can be controlled by pruning or removing and destroying heavily infested material. Suppressing insect and disease populations will not prevent all tree mortality but can help mitigate outbreaks that could spread to relatively healthy trees.
Thinning is another way to help the forest gain resiliency to drought. It can improve tree vigor through the reduction of competition and increase access to water and nutrients. But, when thinning is not an option, such as in an oak woodland or savannah and trees are still showing drought stress, then hopefully the drought adaptations these trees have evolved will be enough to help them survive.
For more information check out the UCCE Mendocino – Forest Health webpage at cemendocino.ucanr.edu. Also, feel free to contact me if you have questions, firstname.lastname@example.org or (707) 463-4495.
- Author: Cheryl Reynolds
UC Statewide IPM Program is pleased to announce that a new online course on managing ground squirrels and pocket gophers has been added to UC IPM's growing library of online training courses. This course consists of eight video segments recorded by Dr. Roger Baldwin, a University of California Cooperative Extension Specialist in Human-Wildlife Conflict Resolution. Originally presented in June of 2020 as part of the UC Ag Experts Talk webinar series, the course covers pest identification, types of damage they cause, and the importance of their biology and ecology.
If you are a pest management professional or grower interested in vertebrate pest management, then check out this course! You'll learn about current control strategies such as habitat modification, baiting options, fumigation, and trapping. The course content is free to anyone who wishes to view it. For those requiring a certificate of completion and continuing education units (CEUs), the regular cost is $20, but we are offering a reduced price of $10 through October 31, 2021. To receive the discount, enter the code SquirrelGopher50 in the voucher box when making the payment.Managing Ground Squirrels and Pocket Gophers has been approved by the California Department of Pesticide Regulation (DPR) for 1 CEU in the Other category and also by Certified Crop Advisor (CCA) for 0.5 unit of IPM credit.
If you are a DPR license or certificate holder with a last name beginning with letters M through Z, then this will be your year to renew. Now is a good time to check out the other UC IPMonline training courses offered. All are 50% off the regular price through October 31st. DPR will be sending out renewal packets in August and strongly suggests returning them by October so that your license or certificate can be renewed before it expires.
UC IPM not only offers courses accredited by DPR, but many courses are also approved by the California Structural Pest Control Board (SPCB), Certified Crop Advisor (CCA), the Western Chapter of the International Society of Arboriculture (WCISA), and the Arizona Department of Agriculture.
- Author: Karen Giovannini
¿Está interesado en ganar dinero vendiendo alimentos hechos en su casa?
Venda alimentos hechos en su hogar en tiendas locales, mercados comunitarios y directamente a los clientes como parte del programa Cottage Foods. Aprenda lo que se necesita para convertirse en un negocio de comida cottage en un seminario ofrecido por la Extensión Cooperativa de la Universidad de California.
Participación de expertos del:
- Departamento de Servicios de Salud del Condado de Sonoma
- Departamento de Salud Publica de California
- Centro de Desarrollo de Pequeños Negocios de Napa/Sonoma
Este seminario gratuito de una hora de duración cubrirá los tipos de alimentos permitidos, los requisitos del programa, el proceso de registro y el inicio de un negocio.
Jueves 15 de abril a las 18:00 horas vía Zoom
Para Registrarte visita: ucanr.edu/cfosp
- Author: Michael I Jones
The Mediterranean oak borer (Xyleborus monographus), or MOB, is an invasive ambrosia beetle that was first collected from declining oak trees (Quercus spp.) near Calistoga (Napa County) in 2019 (Fig 1). Subsequently in early 2020, the beetle was detected in the neighboring counties of Lake and Sonoma, and more recently a separate infestation was discovered in suburbs near Sacramento. MOB is native to the Mediterranean regions of Europe, the Middle East, and North Africa and was likely introduced to North America in infested wood material. Within its native range MOB is a pest primarily of dead and dying oaks. In California, MOB has been detected in valley oak (Q. lobata) and blue oak (Q. douglasii). Given the cryptic nature of the insect, the extent of the infestations, and presence of dead trees with evidence of the beetle, the insect has likely been in California for more than five years.
Ambrosia beetles are interesting insects because they carry symbiotic ambrosia fungi which they cultivate along their galleries (boring tunnels) for food. Most ambrosia fungi are weak pathogens (typically only colonizing the tissue near the galleries), but a fungus associated with MOB, Raffaelea montetyi, appears to cause wilt disease in cork oaks in Portugal. This fungus and several others associated with MOB, have been recovered from infested trees in California and research is underway to determine if these ambrosia fungi could cause similar diseases in North American oak species.
MOB appears to initially attack the canopy of host trees where it kills branches, with persistent infestations spreading to the main stem and eventually killing the tree (Fig. 2). The extensive network of MOB galleries can weaken trees and make them more susceptible to failure. Thus far, trees in California with MOB infestations appear to have been stressed by other biotic and abiotic factors prior to MOB colonization, so it is unclear if the insect and its ambrosia fungi can infest and kill healthy trees.
Signs of MOB infested trees are declining canopies, tiny exit holes and boring dust in cracks of the bark, and occasionally sap flux; however, these symptoms could be caused by other boring insects or diseases. The best way to detect MOB infested trees is to observe the pattern of canopy decline. MOB begins by colonizing a large branch in the upper canopy, so newly infested trees will often have one declining branch while the rest of the canopy appears healthy. As the infestation progresses, the entire canopy begins to decline and in some instances, heavily infested branches can produce extensive epicormic sprouting with leaves diminished in size and densely clustered (sometimes referred to as “popcorn foliage”). The most reliable way to confirm MOB is from the architecture of its galleries, which are trellis-like, intersecting, and fan out in a single plane (Fig. 3A). These gallery patterns distinguish it from native Monarthrum spp. of ambrosia beetles, which have galleries branching from a single point and do not intersect neighboring galleries (Fig. 3B). These native beetles will only attack trees that are already dead, dying, or diseased.
Research is currently underway to determine the extent of the two infestations and to find effective management strategies to control MOB. From other similar invasive insects, such as the shot hole borer in southern California, options like chipping (≤1” size), solarization, burning, or burying infested material will likely be crucial in mitigating spread. However, since infestations can be cryptic for several years, there is significant potential for the beetle's range to expand as they can be moved in infested wood and are capable fliers. The best method of control is preventing the movement of the insect and its host material from known infested areas. For more information, please visit: ucanr.edu/sites/mobpc.
If you have a tree that you believe to be infested, please contact the California Department of Food and Agriculture:
- Pest Hotline: 1-800-491-1899
- Report a Pest: cdfa.ca.gov/plant/reportapest/
Michael I. Jones, PhD, UC Cooperative Extension Forest Advisor, Mendocino, Lake, & Sonoma County, email@example.com, (707) 463-4495
- Author: Pamela Kan-Rice
While most Americans choose their Thanksgiving turkeys from the meat department at the local grocery store, Brylee Aubin and Yaxeli Saiz-Tapia can tell you the life histories of their holiday birds. The Sonoma County teenagers raise heritage turkeys together as part of a 4-H youth development project and sell them for Thanksgiving. For the last two years, Yaxeli's older brother Uli has joined the project and, between the three of them, they raised 47 turkeys this year.
The Heritage Turkey Project in Sonoma County has about 15 members of the UC Cooperative Extension's 4-H youth development program and the National FFA Organization growing more than 200 heritage turkeys this year, according to Catherine Thode, who has been leading the project for 15 years.
“Our project leaders are active breeders of heritage turkeys and some of our 4-H and FFA youth are now raising breeding pairs and hatching their own birds,” Thode said. “Each project member raises their small flock of birds on their own property and shoulders the responsibility of providing their feed and care.”
The Heritage Turkey Project promotes the preservation of heritage turkey breeds, sustainable farming and responsible animal husbandry. While raising the animals, the youths learn life skills and earn money for their work.
“The money I raise from raising and selling turkeys goes towards my college fund and to more 4-H projects like market goats or sheep,” said 15-year-old Brylee, who sells her turkeys for $9.50 per pound.
Three years ago, Brylee's neighbor, Yaxeli joined her in the heritage turkey project.
“I have learned how to care for animals, the importance of raising organic and the costs involved,” said Yaxeli, 14. “I have gained a firm understanding of how my birds are raised and processed versus corporate methods. Having the opportunity to participate in this project has strengthened my value for the importance of where my food comes from.”
Consumers benefit by getting turkeys that are farmed organically, fed high-quality grains, and never frozen, said Brylee.
“There are so many benefits to raising these beautiful birds,” said Uli Saiz-Tapia, 17. “First, you learn the cost of running a business, how to reinvest for the next year, the different stages of turkey growth and how to manage issues that arise such as the turkeys fighting, how they react to fluctuating temperatures, how to keep them safe and nourished properly. Learning about the process of getting our turkeys ready to be purchased has really benefitted my understanding of anatomy, the amount of work it takes in preparing them and the importance of not wasting food.”
The group sold out of turkeys in early November.
“Back in March, we really wondered if we should even do the project this year, not knowing what was going to happen with COVID restrictions and the impact on the economy,” Thode said. “We ended up with more project members than we've ever had, and over 200 turkeys to be sold for the Thanksgiving market.”
The 4-H members started the season with more turkeys, but lost some birds to predators. Wildfires seemed to drive more predators to the Sonoma County farms this year, she said.
“Things are fast and furious right now,” Thode said a week before Thanksgiving as the group prepared their turkeys for processing and distribution to people who placed orders. “I'm about to enter the busiest seven days of our year. It will take all weekend to have the birds processed, weighed, labeled. Then, we hunker down to sort and assign turkeys to our customer list.”
While selling turkeys, the group encourages customers to meet the farmers and to visit Livestock Conservancy to look up the history and breed characteristics of the turkey they are purchasing. In past years, some customers have taken photos of themselves with the person who raised their bird.
“We not only have a master list of customers and their desired sizes, but we create a spreadsheet for every project member with a list of the turkeys they've grown that year,” Thode said. “Each turkey is identified in the spring or early summer with a small metal wing band that lists the grower and an individual number for that turkey. When the turkey is sold, the buyer knows which project number grew their turkey, and the variety of turkey that they are purchasing. We think it's important that our customers know this. In fact, when they come to pick up their turkey, they write their check to the actual grower of their turkey.”
Visit Heritage Turkey Project to learn more about the project.