Posts Tagged: Jhalendra Rijal
Outsized wildfires, rising sea levels and disappearing glaciers are dramatic signs of climate change, but not the only ones. New UC Agriculture and Natural Resources research provides forewarning of a change that will be economically and environmentally costly to California – a fifth generation of navel orangeworm, the most destructive pest of almonds, walnuts and pistachios.
Navel orangeworm (NOW) will be more problematic in the future because of warming temperatures, UC Cooperative Extension scientists report in Science of the Total Environment.
Like most insects,NOW's development rate, physiology, behavior and reproduction are highly dependent on the ambient temperature. When the weather warms in the spring, NOW moths emerge from the nuts left in the tree or on the ground during the winter. After mating, females then recycle those last year's nuts to lay eggs and complete one generation. Adults emerged from that first and subsequent generations then lay eggs on in-season hull-splitalmondnuts, where larvae feeding damages the crop. Typically the pests fly three to four times per year – with more flights in areas with warmer weather.
“Warmer temperatures can result in early activity of the pests in the spring and increased activity during the season,” said Tapan Pathak, the UC Cooperative Extension climate change specialist and the study's principle investigator.
The scientists looked at 10 climate models to determine what nut farmers can expect to face over the next 80 years and applied NOW developmental models to the changing climate. Daily maximum and minimum temperature data were obtained for 1950 to 2005, and future projections stretched to 2100.
“The fifth generation can happen in the next few decades,” said Jhalendra Rijal, UC integrated pest management advisor and co-author of the research. “The climate models suggest that spring will begin earlier. That causes insect activity to start earlier. With increased temperatures through the season, the number of days to complete a generation is less. At the end of 2050 or so, we'll see an extra generation.”
The study focused on 23 counties in the Central Valley, from Shasta County in the north to Kern County in the south, where 1.78 million bearing acres of nut crops are planted. About two-thirds of that acreage is planted to almonds, 20% in walnuts and 16% in pistachios. The tree nut crops were valued at more than $8 billion combined in 2018, according to the California Department of Food and Agriculture.
The completion of the NOW life cycle is faster in pistachio compared to almonds and walnuts, so the potential risk of crop damage and economic loss is higher in pistachio, according to the research report. There are only a few years historically in which the models detected the fifth generation of NOW in Kern County pistachios. The occurrence of the fifth generation in almonds and walnuts was historically nonexistent, but it starts appearing in three southern counties by 2040 and eleven counties by 2100.
“In order to alleviate some of the risks related to navel orangeworm damage to nut crops, it is important to implement integrated pest management practices,” Pathak said.
IPM preventative and control measures include sanitizing the orchard during the winter by removing all the nuts on the ground and in the trees, applying synthetic reproductive hormones to limit the pests' ability to find mates, encouraging natural enemies, judicious of least-toxic pesticides if necessary and harvesting the crop early to avoid a new generation of the pest.
“A better understanding of future navel orangeworm pressure on California's major nut crops can help facilitate and strategize integrated pest management practices in order to minimize production risks,” Pathak said.
The results of the research can also inform growers and pest control advisers about the potential increased threat from other pests as the climate changes.
The Community Alliance with Family Farmers and UC Cooperative Extension are working with farmers to establish six demonstration sites in walnut orchards that will examine the effectiveness of mating disruption to control two major pests of the crop – codling moth and navel orangeworm.
The three-year research effort is funded with a $1 million award from the California Department of Agriculture Biologically Integrated Farming Systems program.
“The project sites will be in the Sacramento and northern San Joaquin Valleys, but we expect the demonstration to be of interest to walnut farmers across the state,” said Sara Tiffany, CAFF director of ecological farming and the project lead. “Farmers who grow related crops, like almonds and pistachios, will also be able to benefit from the findings.”
“Farmers need alternatives. In this project, we will be studying the effectiveness of alternatives that already exist,” said Jhalendra Rijal, UC Cooperative Extension integrated pest management advisor for San Joaquin, Stanislaus and Merced counties, the lead scientist on the project. The California Walnut Board is also part of the project team.
Six farmers will be recruited to enroll at least 80 acres each in the demonstrations – three farmers in the Sacramento Valley and three in the northern San Joaquin Valley. The entire acreage will be managed following UC IPM guidelines for walnut production, including cover crops, reduced risk pesticide options and biological control.
Forty acres will be treated with commercially available mating disruption products, while the other 40 acres will not. The treatment works by confusing the pests. Codling moth and navel orangeworm moths naturally release pheromones that help them find mates. The female lays eggs in the immature nuts, and when they hatch, the larvae feed on the nuts, rendering them unmarketable. In the treated area, the orchards will be flooded with a synthetic pheromone that makes it much more difficult for male and female pests to hone in on one another.
Besides codling moth and navel orangeworm, the project will systematically look at the effects of cover crops and predatory mite release on pest mite populations, and improvement in other natural enemy populations in walnut orchards.
The results of the IPM practices will be shared widely with growers, pest control advisors and certified crop consultants in articles, meetings and field days.
“Currently the use of mating disruption in walnuts is significantly lower than in almonds,” said Rijal, who is also the associate director for Agricultural IPM with the UC Statewide IPM Program. “We believe when farmers see the results of using mating disruption, along with other sustainable walnut production practices, we will improve the adoption rate.”
This is one of a series of stories featuring a sampling of UC ANR academics whose work exemplifies the public value UC ANR brings to California.
The coronavirus pandemic has disrupted life for everyone, with information about COVID-19 changing daily. For Californians who aren't fluent in English, obtaining reliable information is particularly difficult. Aparna Gazula, a University of California Cooperative Extension advisor who serves Santa Clara, San Benito and Santa Cruz counties, has been providing COVID-19-related information in Chinese and Spanish for immigrant Bay Area farmers.
In March, when restaurants shut down to curb the spread of the virus, many restaurants and wholesale produce markets cancelled produce orders placed with farmers. Language, cultural differences, low computer literacy and limited access to computers created barriers for small-scale, immigrant farmers in the Bay Area to quickly find new buyers for their perishable produce. Gazula introduced them to food banks, hoping they would accept the produce donations, but the food banks were not set up to pick up donations from small farmers.
Most small-scale farmers lack the financial capital to absorb the revenue shock. To help offset losses from unsold specialty crops, the UCCE advisor and Qi Zhou, the small farm program assistant specialist, have been helping Asian and Latino farmers complete English-language disaster aid applications.
“Since March, we have helped farmers apply for Covid-19-related farmer relief funds,” Gazula said. So far, she said, four of the 17 immigrant farmers who applied to the American Farmland Trust Farmer Relief Fund have received a total of $4,000, and 10 farmers of the 30 who applied to the California Family Farmer Emergency Fund received a total of $42,500.
Recently the U.S. Department of Agriculture expanded the list of specialty crops eligible for its Coronavirus Food Assistance Program to include bok choy, daikon and other vegetables with a deadline of Sept. 11. Communicating by phone and the app We Chat, Gazula and Zhou, who speaks Mandarin, notified local farmers, and advised them how to apply for the disaster funds. Zhou, USDA Natural Resources Conservation Service rangeland management specialist Ling He and another NRCS staff member assisted 64 farmers in completing applications over the past week.
Bob Kuang, president of the Bay Area Chinese Growers Association, shares UCCE information with the association's growers.
“Most of my members don't understand English so they [UC Cooperative Extension] help, like for policy and safety,” Kuang said, providing information the growers can't find elsewhere in Chinese.”
When she was a girl, Gazula saw how hard farmers work to make a living off the land while spending summers and winter breaks at her grandparents' farm in India, where they grew rice, mung beans and chili peppers.
“Farmers are very hardworking people, and small farmers even more so as they manage everything on the farm,” said the small farms and specialty crops advisor. “Their grit, determination to succeed and hardworking spirit truly inspire me.”
“I'd like to help them be successful as much as I can,” she said, “be it research-based information to farm successfully or bilingual support to help them better navigate regulations or apply for grant funds.”
In addition to helping farmers apply for financial relief, Gazula alerted the farmers to shelter in place rules and is delivering COVID-19 safety information about masks, sanitation and social distancing requirements in Chinese and Spanish to them.
“We also helped farmers implement COVID-19-related protocols on their farms,” she said. “We are currently putting together 200 COVID-19 kits that will help farmers comply with worker health and safety-related protocols on their farms. The COVID-19 kits contain reusable masks, hand sanitizer, bilingual Cal OSHA guidelines for employers regarding COVID-19, and a resources sheet listing where to buy the enclosed items.”
When she's not involved in COVID-19 crisis communications, Gazula continues to conduct research on nitrogen uptake in bok choy and bell peppers and irrigation management. She collaborates with Linda Chu, Guo Ping Yuan, Han Qiang Kuang and other Santa Clara County growers who allow the farm advisor to study crops on their farms.
“They do research, like test irrigation systems for right amount of water for the crop and nutrition – fertilizer – for the crop. They do lot of things,” said Bob Kuang, of the Bay Area Chinese Growers Association, who provides land at his farm in Gilroy for UCCE studies.
Gazula also advises farmers on how to implement the Food Safety Modernization Act (FSMA) on their farms and fulfill irrigated land nitrogen reporting. Fines for not complying with regulations can threaten the economic sustainability of small family farms.
Although the majority of growers she works with regularly have limited English and need assistance filing reports to the government, others consult her for production information they can't get elsewhere for the specialty crops they grow. Farmers of Korean, Japanese, Indian and Vietnamese ancestry and others attend meetings to learn the latest research on Asian vegetables such as daikon radish, napa cabbage, bok choy, on choy and various Asian leafy mustard crops including gai choy and pea shoots.
Gazula, who joined UC Cooperative Extension in 2016, currently works with about 180 small-scale growers in San Benito and Santa Clara counties and hopes to expand her outreach to farmers in Santa Cruz County.
To help small farmers adapt to climate change, Gazula and Zhou partnered with UC Agriculture and Natural Resources' Healthy Soils Program staff and Santa Clara County Farm Bureau for technical assistance and held workshops during the winter. Zhou helped the farmers apply for grants from the California Department of Food and Agriculture's State Water Efficiency & Enhancement Program and Healthy Soils Program. The 22 farmers who received CDFA grants brought a total of $424,111 into Santa Clara County.
The outreach work UC Cooperative Extension does wouldn't be possible without the help of bilingual staff such as Zhou, the scientist Gazula hired with grant funds in September, and some translation support from partner organizations and growers as well.
“Relying on partners for translation support isn't practical,” Gazula explained. “Outreach is most effective when it is targeted. It's not just literally translating words, but translating the information the words convey. Because we provide outreach materials to comply with regulations, the language in these materials is very technical and it's important that the information is presented accurately. We also depend on relationships with the farmers to extend the information within their communities. Long-term, it's easier to do outreach with support from our own staff.”
Competition is stiff for money to serve non-English-speaking Californians because the state is home to so many immigrants with different needs. The majority of the grants she uses for outreach are for food safety. The local Open Space Authority, which promotes preserving land for open spaces, has also provided funds for small and beginning farmer outreach and education.
Gazula draws on the expertise of fellow UC Cooperative Extension farm advisors across the state. For example, she said, Richard Smith, who specializes in vegetable production, and Michael Cahn, who specializes in irrigation and water resources, are always willing to help, even though they are not assigned to serve Santa Clara County.
“Farmers already have tremendous challenges when it comes to being successful,” Gazula said. “I feel language barriers and lack of access to the same resources as fluent English-speaking growers shouldn't be the reason they can't farm successfully.”
This is one of a series of stories featuring a sampling of UC ANR academics whose work exemplifies the public value UC ANR brings to California.
Farmers are already seeing the effects of warmer winter nights and hotter summer days on their crops. Climate change is gradual, but increasing overall temperatures affect many aspects of farming, including where and how crops are grown. Tapan Pathak, University of California Cooperative Extension specialist based at UC Merced, is doing applied research that farmers and ranchers can use to adapt to new conditions created by a variable and changing climate.
“You don't have to shift your practice tomorrow, but if you are thinking of making a 30-year investment, it's important to know what risks there are for planting different crops,” said Pathak, who is based in the Sierra Nevada Research Institute at UC Merced.
Pathak co-chairs the UC Cooperative Extension Climate Change Program Team, whose mission is to increase the capacity among UCCE academics to address climate change concerns with science-based information. Pathak also collaborates with extension professionals from across the western U.S. to do extension events related to climate change adaptation. He works closely with state and federal agencies statewide and growers to identify changes occurring as a result of climate change that affect agriculture. Pathak's research will inform growers' decisions, such as crop variety, planting and harvest dates, extreme heat and frost protection and pest management.
“We are seeing impacts of climate change, that's evident. We have some solutions that are available, but we also need to do more locally relevant crop specific research to make agriculture resilient to climate risks,” Pathak said.
The UCCE scientist was the lead author on an important paper that synthesized the impacts of climate change on California agriculture and offers directions for future research and implementation. The authors concluded that almost all of California's crops, collectively valued at more than $50 billion a year, will be endangered to some degree by rising temperatures and variable weather patterns. The study “Climate Change Trends and Impacts on California Agriculture” was published in Agronomy in 2018.
“I think there's a lot of solutions available and there is also a clear need for adaptation research that include growers' perspectives,” said Pathak, who received a Climate Leadership Award for research from the California Climate & Agriculture Network.
Pathak is also collaborating very closely with UC Davis-based UCCE specialist Daniele Zaccaria, who is leading an international project on evaluating bioclimatic indices and developing the index that is more relevant to irrigated agriculture, which includes scientists from the U.S., Italy, Brazil and Chile.
“A bioclimatic index specific to irrigated agriculture can provide more accurate and valuable agricultural drought information that could be helpful for water resources planning and management decisions,” Pathak said.
Pathak is developing a web-based decision support system called Cal AgroClimate to help growers make decisions, in partnership with the USDA California Climate Hub director Steven Ostoja. It is being built on the same platform as AgroClimate, which is popular with growers in the Southeast.
Cal AgroClimate translates historical climate data and future projections into a useful decision support system for growers. For example, growers can get extreme heat and frost advisories for the next 10 to 14 days in their region and relevant resources to mitigate risks for their selected crop. It is in the early phase of development and will include a suite of tools based on the needs and priorities identified by UCCE colleagues, growers and the agricultural community in general.
In addition to his work on Cal AgroClimate, Pathak has been conducting research on specific crops.
In a study looking at processing tomato production in the Central Valley, Pathak and UCCE advisor Scott Stoddard found that changing temperatures will likely change the tomato growing season. The scientists looked at processing tomato data starting from 1950 and projections for 2030-2040 to see how the time to maturity is changing.
“In general, the time from emergence to maturity, the timeframe for processing tomatoes in that region is going to shrink by two to three weeks,” said Pathak. “A lot of processors have their timeline for when they need the tomatoes for processing and so when you have this shift in the phenology, that alters the timeframe for when they mature and are ready for the processors. So, there's a whole shift in the management that growers might have to think about in the future.”
To identify the climate information almond growers need to take adaptation action, UC Berkeley postdoctoral researcher Kripa Jagannathan, former UCCE advisor David Doll and Pathak interviewed almond growers in the Central Valley. During their conversations with farmers, the researchers clarified that long-term climate projections are not seasonal forecasts or weather forecasts for the next 20 to 30 years. The projections provide information on trends or potential of shifts from historical conditions for making long-term planning decisions.
Pest control is one area where growers will need to make changes. Research by UCCE advisor Jhalendra Rijal and Pathak shows the almond pest navel orangeworm is already extending its life to a fifth generation during a season.
For strawberries, Pathak, UCCE entomology and biologicals advisor Surendra Dara and postdoctoral researcher Mahesh Maskey have developed a model to forecast weekly crop yields based on weather data. “The model was pretty accurate for the Santa Maria region,” Pathak said. “A crop-specific model can be used for labor management not just crop management.”
Because California produces more than 400 agricultural products, adapting to climate change will be more complex than in other states.
Central Valley residents from Visalia to Sacramento look forward every year to the beginning of strawberry season in early April, when roadside strawberry stands operated by Hmong and Mien farmers open to the public.
These farms grow strawberry varieties such as Chandler and Camarosa that haven't traded flavor for shelf life – they don't ship or store well, but they are far sweeter than varieties usually sold in stores, and they reach their peak ripeness and flavor in the fields next to the strawberry stands.
As strawberry season opens this year, farmers are hoping that customers will still stop by the stands to pick up their fresh, seasonal strawberries, and also that they will observe 6-foot social distancing and other guidelines to reduce the spread of COVID-19. UC Cooperative Extension agricultural assistant Michael Yang and I were interviewed on a local news station to encourage Fresno residents to practice these guidelines while supporting local farmers.
To assist Fresno strawberry farmers, the UCCE small farms team in Fresno County developed, printed, and distributed signs for roadside strawberry stands reminding customers to observe social distancing and other safety practices, as well as guidelines for farm stands to reduce the spread of COVID-19. Versions of the signs were also developed for strawberry stands in Merced and Sacramento, as well as a general sign for local produce at any farm stand.
Signs and safety guidelines were printed with funding from the Western Extension Risk Management Education Center, and Michael Yang distributed large printed versions of the signs to all strawberry stands on the Fresno County Fruit Trail map in Fresno County. These materials have also been shared with UCCE small farms and food systems advisors as well as nonprofit and agency partners and county Agricultural Commissioner's offices, and they are available for printing on the UCCE Fresno strawberry website.