UC Food and Agriculture Blogs

UC seeks toddler volunteers for milk study

UC researchers will study effects of whole milk and low-fat milk on toddlers' health and development.

Researchers to study whether whole or low-fat milk is best for toddlers

San Francisco Bay Area toddlers who drink cow's milk are being sought to participate in a 12-month study by UC Nutrition Policy Institute, a part of University of California Agriculture and Natural Resources. Milk will be provided for free to participants.

Milk provides children with calcium, protein and vitamin D, which are essential for health and brain development. In the U.S., the American Academy of Pediatrics recommends that children switch from whole milk to low-fat or nonfat milk after age 2 to reduce their intake of saturated fat and calories.

“The purpose of this UC study is to see how the type of milk toddlers drink affects their health, growth and development,” said Kassandra Bacon, NPI project policy analyst.

Researchers with the Nutrition Policy Institute are recruiting children ages 23 to 30 months old. The 625 toddlers will be randomly assigned to drink either whole fat or 1% fat milk starting at age 2. The scientists will assess diet, health and developmental outcomes.

“We will follow each participant for one year, collecting baseline and follow-up data,” said Ryan Williams, a NPI project policy analyst and registered dietitian who is involved in the research.

For 12 months, the scientists will measure each child's height, weight, waist and head circumference. At the beginning and end of the study, parents will be required to take their children to a local lab for a blood draw to assess lipids, cholesterol, insulin resistance and vitamin D status, as well collect a sample of their child's stool so the scientists may analyze the gut microbiome. During a home visit, researchers will also interview parents about their child's development.

Benefits to participants

The assigned milk type will be delivered to participants free of charge via a grocery delivery service. Participating parents will receive advice from a registered dietitian to support healthy milk consumption as part of a balanced diet. The Nutrition Policy Institute also will send the parents monthly newsletters with general health tips. Participants also may earn up to $275 in gift cards by completing the study.

Requirements to participate

Participants for the milk study must meet these requirements:

• Child must be 23 to 30 months old and have public or private medical insurance
• Child's parent/legal guardian must be 18 years or older
• Child must live with the participating parent/legal guardian in the San Francisco Bay Area (Alameda, Contra Costa, Marin, Santa Clara, San Francisco or San Mateo counties)
• Child's parent or guardian must speak English

Children are ineligible for the study if they are:

• a WIC participant
• lactose intolerant
• allergic to milk protein

Lorrene Ritchie, NPI director and registered dietitian, and Anisha Patel, pediatrician at Stanford Medicine Children's Health and professor in the Division of General Pediatrics at Stanford University, are the principal investigators for the study.

For more information about the research and to sign up for the study, visit https://npi.ucanr.edu/milk.

Grasshoppers gobble crops, farm profits

UCCE advisors share control, abatement strategies across Northern California

That buzzing noise in Northern California is the sound of grasshoppers chewing a path of destruction through crops and pollinator-friendly plants as they hop across an expanding area.

This is the fifth year in a row that massive numbers of grasshoppers have overrun Modoc County and “probably the worst I've seen yet,” said Laura Snell, a University of California Cooperative Extension livestock and natural resource advisor in Modoc County, located in the northeastern corner of the state. 

In past years, Snell has heard from farmers who have lost up to 70% of their hay crop. This year, she is hearing of grasshopper damage from farmers who grow a wider array of crops, including onions and garlic – crops that the pests eschewed in past years.

“I've had an even broader group of producers contact me about damage,” Snell said. “Our local vegetable producers are being affected, decreasing farmers market and food hub products. Bee producers are not seeing good honey yields due to grasshoppers eating huge amounts of pollinator plants.”

Modoc County isn't alone. Lassen, Sierra, Plumas, Siskiyou, Tehama, Butte, Placer and Nevada counties are being invaded by grasshoppers.

“The county ag commissioners are circulating a survey to get an idea of other counties that may be affected,” Snell said. “Things like droughts and – I suppose, fires as well – would affect grasshopper migrations.” 

While scientists don't know what's causing the explosive growth of grasshopper populations, there are some contributing factors, according to Tom Getts, UC Cooperative Extension weed ecology and cropping systems advisor for Lassen, Modoc, Plumas and Sierra counties.

In the past, grasshopper outbreaks seemed to be more isolated, and the populations tended to crash after a year or two. Getts said, “For whatever reason, the population cycle does not appear to have been broken, and they continue to have high numbers.” 

Grasshoppers can consume 30% to 250% of their body weight per day, according to a fact sheet about grasshoppers, co-authored by Getts. While grasshopper nymphs walk, adults can fly 15 miles or more.

Getts and UC Cooperative Extension farm advisors have been giving presentations throughout the intermountain region on grasshoppers and the various control methods.

“The difficulty to controlling them is the scale and their ability to move,” Getts said. “The insects need to be targeted at a small growth stage for the tactics to be most efficacious. Once they are adults, it doesn't matter what one grower does to control them if their neighbor doesn't do anything.”

UCCE farm advisors in multiple counties are working on abatement options.

They recommend monitoring in April­–May to control grasshoppers while they are still nymphs and susceptible to insecticides. Birds, spiders, rodents and fungi also can help keep the insects in check, but years of drought have reduced the fungi.

“The population of grasshoppers in the region have increased in size, scope and density in recent years,” said Rob Wilson, a UC Cooperative Extension agronomy and pest management advisor and director of the Intermountain Research and Extension Center in Tulelake.

The massive growth and spread of the pests is a problem because 30 pounds of grasshoppers can eat as much forage as a 600-pound cow can eat per day, he explained.

Part of the challenge of controlling grasshoppers is their changing behavior. In the past, grasshoppers would go away after a couple of years, now they persist. They used to thrive in dry fields, but last year, grasshoppers migrated 10 to 20 miles into irrigated fields, Wilson said.

Wilson, who has been monitoring grasshoppers near Tule Lake since early April, said that In some fields, there were 20 to 30 nymphs per square yard. More than eight nymphs per square yard can cause economic damage.

As if the grasshoppers themselves weren't enough of a nuisance, they attract other pests, including blister beetles.

“As the grasshopper population increases, you are bound to see an increase in all of the species that eat them over time,” Getts said. “Blister beetles cause terrible blisters when they get on your skin, hence the name, but they can also be problematic for livestock if they contaminate bales of hay.”

Getts recommends that growers take steps to prevent grasshopper populations from building over successive years. Growers should coordinate with neighboring growers to treat their fields due to the limited longevity and efficacy of treatments on individual fields.

[Editor's note: The sentence comparing the appetite of grasshoppers to that of cows was revised to clarify that grasshoppers aren't eating cows.]

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Could empty lots be growing food, economic opportunity?

UCCE scientists study feasibility of specialty crops for small urban growers

The vacant lots around your neighborhood could be growing fruits and vegetables and making local produce more accessible – while reducing energy needed to transport and distribute the food. Could turning those empty lots into small farms also become opportunities for economic development? 

To answer this question, a team of researchers from University of California Cooperative Extension in San Diego County are investigating the economic feasibility of growing high-value specialty crops in urban settings like vacant lots. The project – led by Eric Middleton, UCCE integrated pest management advisor for San Diego, Orange and Los Angeles counties – is currently in progress at The Flower Fields in Carlsbad, a seasonal attraction for locals and tourists.

Tucked away in the back of the field is the Small-Scale Urban Ag Demonstration Site where Middleton and his team established a small farm on approximately 17,000 square feet, starting fall 2023. Funded by the U.S. Department of Agriculture National Institute of Food and Agriculture, the farm is designed to evaluate containerized production both outdoors and under high tunnels.

Growers don't necessarily need land, just space

High tunnels, also referred to as hoop houses, are semi-permanent structures that act similarly to greenhouses in providing a controlled environment. For the experiment, Middleton will compare cost, effort and durability of two types of high tunnels: one made of steel and the other out of PVC pipes.

“We want to give interested growers information on as many options as we can,” said Middleton, who explained that the project is motivated by the challenges of urban settings, including limited space and lack of arable land.

In the trial, they are growing turmeric, ginger and blueberries. The high-value crops were selected because of their potential to earn a profit. Data evaluating plant variety, soil mix, fertilizer, growth performance, yield and pest and disease pressures will be collected and reported when the project concludes in 2026.

As the crops develop in containers – blueberries in pots and turmeric and ginger in grow bags – Middleton pointed out the mobility aspect of the study, noting that growers don't necessarily need land, just space.

Whether it's a backyard or a rooftop, containerized production means easier transport, especially since vacant land doesn't always remain vacant forever and urban lots may often need soil remediation. Growing in containers solves the anticipated problem of having to relocate.

Where to set up shop in San Diego County

Jan Gonzales, project coordinator and community education supervisor for UCCE San Diego County, is leading the effort to identify available urban land in San Diego County as well as the policies and procedures for growers to access these spaces.

Gonzales is collaborating with community members who are working on similar projects to identify space for prospective growers. 

“This has been done before for different objectives and for specific areas in the region, but the information was either project-specific and not publicly available, or not easy to find,” Gonzales said.

Having spoken with people associated with previous or ongoing agricultural land mapping projects, Gonzales has agreed to coordinate and facilitate an advisory work group to discuss areas of potential collaboration and develop project efficiencies. She anticipates holding the first group meeting before the end of the summer.

A production guide to help community members re-create the project

The ideal audience for a study like this is anyone who wants to grow specialty crops, according to Lindsey Pedroncelli, interim director of UC South Coast Research and Extension Center in Irvine, who worked on the project alongside Middleton when she was a staff research associate with UCCE San Diego.

“If you're a new grower or a grower who wants to diversify your crop production, what we're learning here can be applied to you,” said Pedroncelli.

Pedroncelli has been instrumental in bringing the experiment to life and documenting its step-by-step workflow thus far. The production guide, which is being created as the study unfolds, will include instructions detailing how to replicate the experiment from the ground up. Currently, it contains information on how to design your farm, the materials to buy, building structures, irrigation setup and crop management.

The most intriguing open question, whether the operation is profitable, is the driving force behind the production guide and will certainly be addressed, Pedroncelli said.

Book a tour and visit the farm

When visiting the farm, you'll encounter three varieties of blueberries: Star, Snowchaser and Misty. Snowchaser has been a top producer since it was planted in January, but the variety is known to be an early season producer.

Using only one variety of each, the turmeric and ginger were planted in late March-early April. With some unanticipated cold weather in San Diego County, both crops struggled when transitioning out of dormancy, leading to very slow progress, which the team is still navigating today.

Visually, Middleton and his team have noticed differences between the crops growing under the high tunnels versus those grown outdoors, although the data has not been analyzed to confirm or explain notable differences.

Attempting to demonstrate how to profitably grow high-value crops in urban settings using limited space and resources, Pedroncelli said she hopes this study will also encourage people to grow culturally significant crops for their communities.

To tour the Small-Scale Urban Ag Demonstration Site at The Flower Fields in Carlsbad, email Eric Middleton at egmiddleton@ucanr.edu with "Urban Agriculture Demonstration Site Tour" in the subject line.

To learn more about the project and its progress, visit https://ucanr.edu/sites/socalIPM/Small_Scale_Urban_Agriculture_Project_/.

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