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Posts Tagged: environment
Diagnosing herbicide problems takes detective work
Field day offers examples, tips for solving the mystery
A grower applies an herbicide to his tomato plants, or thinks a neighbor's treatment is drifting over her almond trees. A short time later, the leaves start to bleach or shrivel. Was it the herbicide? Or maybe water stress? Soil nutrients? Perhaps an insect?
Figuring out the causes of crop problems takes detective work, and like solving any mystery, it starts with knowing the signs, gathering evidence and asking questions.
The Diagnosing Herbicide Symptoms field day at UC Davis was an opportunity to see, up close, the shriveled cotton, scorched corn and dying sunflowers that can result when herbicides are applied incorrectly. Using the right herbicide – in the right proportion, at the right time and in the right field – can make the difference between a thriving crop and a financial loss.
A top take-away to avoid problems: “Don't do stuff at night!” laughed Becky Wheeler-Dykes, a UC Cooperative Extension farm advisor attending the June 26 event to better serve growers in Glenn, Tehama and Colusa counties. “The packages look the same. People grab the wrong jug.” And then, disaster.
Instructors were Brad Hanson, professor of Cooperative Extension; and Kassim Al-Khatib, the Melvin D. Androus endowed professor for weed science; both in the Department of Plant Sciences. They were joined by John Roncoroni, a Cooperative Extension emeritus farm advisor rooted in the department's weed science program. Attendees were a mixture of people from agriculture, industry, government officials, university researchers and Cooperative Extension advisors. The event was hosted by the Weed Research and Information Center, based in the Department of Plant Sciences.
Out in a field west of campus, visitors could see the progression of damage, from control plots with green and healthy crops to plants that looked sadder as herbicide concentrations increased. Visitors could see the patterns of damage for common foliar chemicals such as glyphosate, paraquat, and 2,4-D, as well as soil-applied herbicides from several chemical classes.
“There's a lot of detective work,” said Stephen Chang, a master's student in Hanson's lab aiming for a career in Cooperative Extension. “For example, the company that makes the herbicide says there shouldn't be a problem, but the grower says, there is a problem. This course helps with developing the skills to figure out what happened.”
It might not be the herbicide at all
Detective work and problem-solving frame the approach, Hanson explained. The cause of crop damage can be simple or complex. Like a good mystery, what appears to be a clue can turn out to be a red herring. Professionals need to draw on their inner Sherlock Holmes to observe and document symptoms, look for patterns in the plants and in the field, ask questions, gather information about the larger environment and collect samples.
An herbicidal Agatha Christie would then suggest: What if it's not herbicide damage at all? Participants learned to consider the possibility of insects, pathogens and viruses, as well as problems with water, nutrients, soil condition and even root damage from cultivation practices.
Hanson recalled puzzling over symptoms he found in an orchard. The culprit? “A leaking natural gas line,” he said.
More resources for herbicide issues
Participants also heard from Molly Mathews, deputy agriculture commissioner from Yolo County, on how a field investigation is conducted. Lawyer Robert Davies, of Donahue Davies LLP in Folsom, outlined the basics of what happens when there are lawsuits related to crop damage from herbicide drift.
The Diagnosing Herbicide Symptoms field day is part of a larger program of education and outreach offered through the Weed RIC, said director Julia Stover-Blackburn. It was the first time the event has been offered since the COVID-19 pandemic, she added.
- For more information about field days and resources, visit the Weed RIC webpage.
- For a thorough discussion of herbicide symptoms, visit this page overseen by Al-Khatib and sponsored by University of California Agriculture and Natural Resources.
- This online course follows an earlier version of the Diagnosing Herbicide Symptoms field program.
This story was originally published on the UC Davis Department of Plant Sciences website.
Cinderella and the White Cabbage Butterfly
If Cinderella were a butterfly, she'd probably be a white cabbage butterfly, Pieris rapae. The butterfly--in its larval stage it's a pest of cucurbits--is stunning as an adult. Just think of a flowing white gown, exquisite pirouettes, and a...
A cabbage white butterfly nectaring on lavender in a Vacaville garden. (Photo by Kathy Keatley Garvey)
Caught in flight--a cabbage white butterfly, Pieris rapae, leaves a lavender blossom. Image taken with a Nikon Z8 and 105mm Nikon lens. Settings: shutter speed, 1/3200 of a second; f-stop, 3: and ISO, 800. (Photo by Kathy Keatley Garvey)
UC food-safety specialist tests biosensors to ensure safe produce
Ahmed El-Moghazy joined UC Agriculture and Natural Resources as a UC Cooperative Extension food safety specialist in February and is based at UC Riverside. Food safety, according to El-Moghazy, are measures that ensure food is free from harmful contaminants, prevent foodborne illnesses and is safe to eat. El-Moghazy is responsible for assisting California farmers and food processing facilities to enhance food safety practices by training appropriate personnel and addressing food-safety issues on their farms.
As the principal investigator for the 2-SAFE Lab at UC Riverside, El-Moghazy is investigating the accuracy and applicability of point-of-use biosensor technology. The small, lightweight and easy-to-use sensor can be used while out in the field or in a packing house to test contamination of liquids such as irrigation and washing water or solids like food samples.
Testing for foodborne pathogens traditionally takes two to three days and the process can be costly. The biosensor technology that El-Moghazy is using is inexpensive and can provide results within one work shift, which allows businesses that grow fresh produce to confirm the safety of their products before sending them to the market.
The alternative, selling contaminated food to consumers, is not only detrimental to human health, but can ruin the reputation of businesses, making way for unanticipated costs associated with recalling contaminated products and regulatory consequences including fines and sanctions.
El-Moghazy is also developing the next generation of antimicrobial surface coatings and materials that can rapidly control the foodborne pathogens and hinder the transfer of harmful bacteria from contaminated food to non-contaminated food.
El-Moghazy is optimistic that his research can safeguard public health, reduce the burden of foodborne illness and protect the integrity of businesses. Although El-Moghazy serves the entire state, he is dedicating a large part of his needs assessment and efforts in Southern California where high-value specialty crops such as avocados and citrus are grown.
"Did you know that one in every six Americans get sick from eating food contaminated with a foodborne pathogen?" asked El-Moghazy. Understanding the fatality of foodborne illnesses, El-Moghazy believes that increasing awareness through education is an essential aspect of his role. "It's true, but not many people realize this, or that 40% of foodborne illnesses stem from fresh produce."
To protect consumers, the U.S. Food and Drug Administration requires farms with a certain level of annual sales (adjusted for inflation) of fruits and vegetables typically consumed raw to have one employee who has completed an FDA-approved Produce Safety Rule Grower Training.
In addition to certified trainings, El-Moghazy offers technical assistance to ensure growers comply before and after inspections, as well as resources for several topics including produce safety, agriculture water, flooding, soil amendments, worker health, hygiene and training and postharvest handling and sanitation. He can also assist in developing food-safety plans and other general farm food-safety protocols. His technical expertise covers all aspects of food production and supply including irrigation water quality, hygiene of harvesting tools and transportation.
Before joining ANR, El-Moghazy completed two years as a visiting scholar in the UC Davis Biological and Agricultural Engineering department before continuing as a postdoctoral fellow in the UC Davis Food Science and Technology department for 5 years. Much of his work was rooted in the development of biosensors and antimicrobial materials for food safety. While in Davis, he collaborated with local farms and food processing companies on food safety research and extension.
El-Moghazy earned a Ph.D. studying developmental biosensors for food safety applications to detect pesticides residues from a joint program offered by University of Perpignan in France and Alexandria University in Egypt. He also earned a master's degree in developmental biobased fungicides and a bachelor's in agriculture science from Alexandria University. Finally, he completed a fellowship at the Institute of Plant Protection, Szent Istvan University in Hungary, where he studied how to extend shelf-life of fresh produce using biomaterials.
El-Moghazy is based at UC Riverside in the Department of Microbiology and Plant Pathology. He can be reached at aelmogha@ucr.edu or (951) 827-0257.
Why It's Called a 'Boys' Night Out'
Ever seen the male longhorned bees, Melissodes agilis, zipping around your garden, trying to bump all critters, large and small, off of "their" blossoms? They own them, ya' know. These male bees are SO territorial. We've seen them target honey...
A horizontal view of male Melissodes bees sleeping on a lavender stem. Image taken just after dawn in a Vacaville pollinator garden. (Photo by Kathy Keatley Garvey)
What's up, sleepy head? A sleepy male Melissodes agilis bee begins to stir at dawn. (Photo by Kathy Keatley Garvey)
The Heat. The Butterflies. The Butterfly Guru.
Don't expect to see UC Davis distinguished professor emeritus Art Shapiro monitoring butterflies on the 4th of July. There's a good reason why. Shapiro has monitored the butterfly populations of central California since 1972 and maintains a research...
A cabbage white butterfly, Pieris rapae, nectaring on lavender in a Vacaville garden on June 24. Next Wednesday, July 4, promises to be a scorcher at 106 degrees. (Photo by Kathy Keatley Garvey)
A cabbage white butterfly, Pieris rapae, flutters its wings, ready to fly. (Photo by Kathy Keatley Garvey)
