- Author: Christian Jordan
The Forestry Institute for Teachers (FIT) will be hosting two "FIT-Focus" sessions this Fall, including one in Plumas County. Please see the below message and attached flier for additional details:
- Author: Kathy Keatley Garvey
What we've been waiting for all season...
A migratory monarch butterfly fluttered into our Vacaville garden at noon today (Tuesday, Sept. 17) and nectared on a Mexican sunflower, Tithonia rotundifola.
Then she treated us to a butterfly ballet.
The Danaus plexippus touched down, nectared, shot up, dropped down, and did it all over again, while male territorial longhorned bees tried to make her stay short.
But she hung around for and hour.
Wings up...and she was gone.
And then another flashed by...
It's migratory monarch season.
- Author: Ben A Faber
There has been a recent expansion of Avocado Lace Bug into parts of the Carpinteria area. It was more or less located in the San Diego coastal area. It spreads mainly with people.......
Read about it at the UC-IPM website and the observations of Mark Hoddle, IPM Specialist at UC Riverside.
https://ipm.ucanr.edu/agriculture/avocado/avocado-lace-bug/#gsc.tab=0
- ALB does better in the slightly cooler more humid orchards in Oceanside when compared to the hotter inland Bonsall orchards.
- In the lab, under a fluctuating 24 hr temperate cycle similar to an avocado orchard in Escondido, optimal temps for development are a daily average of around 31-32oC (88-90oF)
- ALB life stage densities tend to be greater on leaves over June-Oct
- % leaf infestation measures (i.e., the proportion of sampled leaves with ALB lifestages) tend to be peak over fall-winter (Sept-Feb), but ALB densities on leaves are not as high as what are seen over June-Oct, there are basically more leaves with ALB and those per leaf densities are lower that numbers counted over June-Oct.
- Its hard to predict what the next season's ALB will be as lots of ALB are shed when leaves drop, but like persea mite, some manage to get back onto the new leaves to start the next round of infestations. Adults don't seem to be very flighty, well, at least they don't seem to exhibit mass flight activity that would suggest searching for new hosts as leaves deteriorate.
Keep your eyes open for a future edition of the CA Avocado Commission's magazine - From The Grove - for a more thorough discussion of the pest.
https://www.californiaavocadogrowers.com/publications/from-the-grove
images:
Adult
Adults, young, and fecal pellets
Leaf damage
- Author: Elizabeth J Fichtner
- Author: Carol Lovatt
The alternate bearing (AB) nature of olive is one of the top physiologically-driven challenges faced by olive growers. AB refers to the tree's habit of producing a heavy crop in one year followed by a light crop the next year. The heavy crop is referred to as the “ON crop,” which is characterized by large yields with small size fruit that may mature late and have reduced commercial value due to size. Conversely, the “OFF crop” has characteristically low yields with large sized fruit that may not be cost effective to harvest. AB adversely affects the consistency of the fruit supply, thus having a negative economic impact on every step within the production chain from farm to consumer. Because mitigation of AB can best be achieved by management of crop load, UC researchers have conducted recent studies evaluating the efficacy of a new chemical flower thinning strategy using naphthaleneactic acid (NAA) (Figure 1) applied at full bloom to only on side of the tree annually or biennially to reduce the severity of AB and maintain higher annual yields of commercially valuable size fruit.
There are currently four known mechanisms by which the ON crop reduces flowering and fruit number to contribute to AB of ‘Manzanillo' table olive orchards. The first mechanism of AB is the suppression of summer vegetative shoot growth by the current crop (Figure 1). Flowers and fruit on olive are borne on one year-old shoots; consequently, the vegetative growth in the current year provides the nodes at which inflorescences form in the subsequent spring. Research studies conducted in Tulare County California have demonstrated that the fruit's suppression of vegetative growth is irreversible after pit hardening. As a result, crop management strategies designed to reduce the current season's crop must be implemented by June to promote summer vegetative growth and increase return bloom the following year. The second mechanism of AB is inhibition of floral development (typically initiated in July) by the current season's crop. The third mechanism of AB is the inhibition of spring bud break. As a result of bud break inhibition, even floral buds that have formed may not open at bloom. Last, the current season's crop causes the abscission of floral buds. Since the OFF crop has an effect opposite to that of the ON crop, once AB is initiated in an olive tree, cycles of ON and OFF floral intensity and cropping are perpetuated by the opposing effects of high and low crop loads on these mechanisms.
Historically, olive growers have used NAA, a plant growth regulator, as a fruit thinning agent to reduce the current season's fruit load. Upon application, NAA is absorbed by leaves and developing fruit and is translocated to the peduncle where it incites an abscission layer at the point of attachment to the stem. As an olive fruit thinning agent, NAA is typically applied 12-18 days after full bloom, i.e., during fruit set. Treatments are made with an NAA ammonium salt product, such as Liqui-Stik Concentrate (Loveland Products) applied as a dilute spray (300-500 gallons per acre). Chemical thinning with NAA can be risky; too early an application may result in overthinning, whereas too late an application may not thin sufficiently. Additionally, hot temperatures (> 100°F) within one week of application may enhance the efficacy of NAA resulting in excess thinning. Due to the greater risk of spring heat waves in the south, chemical thinning has been more commonly utilized by table olive growers in the Sacramento Valley than in the southern San Joaquin Valley.
With support from the California Olive Committee, researchers have been evaluating the use of NAA at full bloom (rather than 12-18 days after bloom) as a crop management tool to reduce the severity of AB, which is measured as alternate bearing index (ABI) on a scale from 0 (no AB) to 1 (total AB, crop one year, no crop the other year). These studies tested a full bloom NAA application to one side of the tree with the goal of eliminating crop on one side of the canopy (Figure 2) while maintaining crop on the opposite side. Annual and biennial applications of NAA to just one side of the tree were compared. To implement the annual NAA application strategy in a commercial orchard, growers would apply NAA to one side of the tree at full bloom in year 1, then on the other side of the tree in year 2. In the biennial strategy for NAA application, there would be a year of rest (no treatment) between the application to one side of the tree in year 1 and the other side in year 3.
After 4 years of research, NAA application either annually or biennially at full bloom did not affect cumulative total yield. However, full bloom NAA applications to one side of the tree significantly reduced the severity of AB from near total AB (ABI = 0.94) for the untreated ON/OFF control trees by 20% when applied annually and 38% when applied biennially. The results indicate that annual total yields were more uniform from year to year, especially for trees treated biennially, which improves the economics of all steps in the production chain from farm to consumer.
In addition, both annual and biennial applications of NAA to one side of the tree at full bloom had positive effects on the yield of commercially valuable size (CVS) fruit (medium plus large) compared to the untreated ON/OFF control trees. Biennial NAA application at full bloom reduced the ABI for CVS fruit 43% compared to the untreated control trees, whereas annual NAA application at full bloom only reduced the ABI for CVS by 12.5%. Importantly, application of NAA at full bloom to one side of the tree biennially resulted in 40% greater cumulative yields of medium plus large fruit than untreated control trees, with annual treatment increasing yield of medium plus large fruit only 20%. The increased and more uniform yields of CVS fruit resulting from biennial NAA application at full bloom to one side of the provide growers with greater, more reliable annual income. Moreover, biennial application of NAA (once every three years) is half the cost of annual NAA application. Since NAA is applied to only one side of the tree at full bloom, for which total removal of the crop is desired, the risk of over thinning with NAA is eliminated in this strategy compared to the standard practice of applying NAA to the whole tree during fruit set. Whereas a grower must decide to treat once every three years based on floral intensity and without knowledge of the year's fruit set, the fact that only one side of the tree is treated lessens the effect of a subsequent poor set. The NAA standard practice provides the grower a window of 12-18 days after full bloom to evaluate fruit set when deciding to treat. If the grower sprays NAA according to the standard practice and set is subsequently negatively impacted (potentially by even NAA itself interacting with high temperatures), the whole tree will be affected.
The results of this research demonstrate the potential value of NAA applied at full bloom to shift the crop load to one side of the tree and then the other side biennially. This technique essentially creates a bearing and non-bearing side to each tree, allowing for unsuppressed vegetative growth on the treated side and documents the need for a rest period with no NAA application until year 3 to allow the tree to fully recover. Biennial application of NAA at full bloom to one side of ‘Manzanillo' olive trees successfully reduced the severity of AB and increased yields of commercially valuable size olive fruit better than annual application of NAA or the untreated ON/OFF control trees. The use of NAA at bloom to mitigate AB warrants further investigation. Researchers are also actively investigating the use of pruning 28 days after full bloom to only on side of the tree annually or biennially as a means of mitigating AB to achieve consistent yields of commercially valuable size fruit.
- Author: Haven Bourque, haven@havenbmedia.com, (415) 505-3473
Small and midsize farms, women and BIPOC farmers especially benefit
A new report reveals that California farmers participating in the state's Farm to School Incubator Grant Program are increasing sales of fresh, local and organic produce, meat and dairy products to schools, according to researchers evaluating program impacts. The report found that 57% of the program's farmers made sales to schools between April and September 2023, representing an average of 33% of their total farm revenues. All food producers funded by the Farm to School Grant Program state that they use or plan to use climate-smart agricultural practices in their operations during the grant period.
While existing research shows that kids who engage with farm-to-school programs eat more fruits and vegetables, are more willing to try healthy foods, and even perform better in class, the California farm-to-school evaluation project examines a gap that most farm-to-school research hasn't addressed: how local purchases from schools affect the agricultural sector and the environment.
The report found that the investments are flowing primarily to the farmers the state seeks to support through this program: Of the 50 producer grantees evaluated in this report, 42% are owned by people who identify as Black, Indigenous and People of Color, and 62% are owned by women. Nearly all (94%) are small to midsize operations.
Three producer grantees revealed that the Farm to School Incubator Grant Program funding likely prevented them from going out of business. “This grant … has and will enable us to do things on the farm that would probably take us a decade to do but we'll be able to do that in one or two seasons. So [it] really moves us forward a lot,” noted one farmer.
Beth Katz, a lead researcher and executive director of Food Insight Group, said, “Farmers are expanding their relationships with local school districts, increasing their sales to schools, investing in infrastructure and staff, and forming new relationships with food hubs that can help them with the often complex purchasing requirements unique to school food. While we're still at a very early stage of understanding the impacts of these investments, we're beginning to see patterns emerge.”
A Humboldt County farmer noted that food hubs, which are also supported by the grant program, are critical to their success in accessing the school food market: “[The food hub] is really a huge game changer to be able to make that one drop in town, even though it's an hour away, rather than going to [several school sites] and just making all these little drops. That's been one of the ways that it's very . . .appealing to us as a farm to participate.”
The report also examines the potential for environmental impacts through direct investments in farmers who use climate-friendly farming practices.
“I'm inspired by the potential for the farm-to-school program to support farmers using environmentally beneficial practices like reducing pesticides, planting cover crops and growing organic — and to help farmers expand or adopt these practices. It's essential these farmers have a market for what they grow to see durable environmental benefits,” said Tim Bowles, who is leading the environmental impacts assessment for the evaluation team and is an assistant professor in the Department of Environmental Science, Policy & Management at UC Berkeley and lead faculty director of the Berkeley Food Institute.
“We're also seeing farms actually expand their acreage in order to sell to schools, suggesting this is a desirable market. We're investigating the environmental impacts from these investments, especially for climate,” Bowles said.
As with many new programs aimed at building out long-delayed infrastructure, school food systems improvement demands a deep-rooted approach.
“The challenges around changing a complex school food system are substantial,” Gail Feenstra, a pioneer in farm-to-school research and co-lead on the project from UC ANR stated. “Decades of research shows the value to children from fresh, locally sourced food. However, what is becoming more clear from this research is that long-term investments in the full farm to school system are crucial. Without regional-level infrastructure, staffing, aggregation and distribution in place to support getting that locally grown food from farms to the schools and kids, we'll have challenges moving the needle.
"Fortunately, the state's strategic and innovative investments in the entire farm to school supply chain – meaning funding for school districts, farmers and also their regional partners, combined with support from CDFA's regional staff – are beginning to address those long-standing challenges.”
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