Utilizing the Arthropod Pesticide Resistance Database
Growers face the daunting challenge of managing several pests that exhibit pesticide resistance. In this battle, selecting appropriate pesticides play a crucial role. We know that pesticide resistance is a phenomenon in which certain pest populations develop the ability to withstand the effects of pesticides that were once effective against them. This resistance can occur due to the natural genetic variability within pest populations and is exacerbated by the overuse or misuse of specific pesticides. To prevent or mitigate pesticide resistance, growers can alternate pesticides with different modes of action. This approach involves periodically switching between pesticides that target pests using different biological mechanisms, making it more challenging for pests to develop resistance to all of them. By diversifying the pesticides they use, growers reduce the selective pressure on a single mode of action, slowing down the development of resistance To make informed decisions, agricultural experts can utilize resources such as UC ANR's pest and pesticide recommendations. Another useful tool I just learned about is the Arthropod Pesticide Resistance Database, available at https://www.pesticideresistance.org/. This resource serves as a comprehensive repository of information related to arthropod pesticide resistance.
The Arthropod Pesticide Resistance Database offers a wealth of data on resistance in various arthropod species, such as insects, mites, and ticks. Users can access information about the resistance mechanisms, geographical distribution, and the latest research findings on pesticide resistance in these pests. To use the database effectively, users can search for specific pests or pesticide. Users can utilize the database to identify regions where resistant pest populations are more prevalent, allowing them to tailor their pest management strategies accordingly. What strikes me as fascinating is the availability of data from around the globe. By understanding which pesticides are still effective and which ones may need to be used sparingly or replaced with alternative methods, farmers can make more sustainable and cost-effective choices to protect their crops. Have you used this resource before to make decisions or learn about a pest and it's control? I'd love to hear from you at hcohen@ucanr.edu
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- Author: Bradley Hanson
- Author: Trina Kleist
(excerpted from an obituary prepared by Trina Kleist from the UC Davis Department of Plant Sciences)
Albert Fischer, a professor emeritus of weed ecophysiology in the UC Davis Department of Plant Sciences, was recently named recipient of the Outstanding International Achievement Award by the International Weed Science Society.
Shortly after the award was announced, Fischer passed away on Nov. 22 in Davis, Calif. He was 72. Former student Whitney Brim-DeForest accepted the award on Fischer's behalf at the society's quadrennial meeting Dec. 8 in Bangkok.
Born in Montevideo, Fischer earned his bachelor's degree in crop science and animal husbandry from the University of the Republic of Uruguay; and his master of science and Ph.D. from Oregon State University in crop science. He had a lifelong passion for ending hunger in developing countries and collaborated extensively with colleagues around the world.
He started his career in weed research and extension at the Plant Protection Center, Uruguay, in 1975. He was a professor at the Autonomous University of Chapingo, Mexico, from 1979 to 1981. He was a rice and weed physiologist at the International Center for Tropical Agriculture (CIAT) in Cali, Colombia, from 1989 to 1996. During that time, he also was a visiting weed biologist at North Dakota State University, Fargo.
Fischer joined the faculty at UC Davis in 1997 and spent his time there specializing in weed ecology, competition of weeds in rice and integrated weed management until his retirement in 2016. During that period, he mentored more than 15 graduate students and six postdoctoral researchers, and he hosted short-and long-term visiting scholars from many countries. Fischer and his colleagues published more than 80 papers in peer-reviewed journals and more than 300 non-refereed scientific documents, reports, and presentations at scientific meetings. His writings were mostly in the areas of weed physiology and management.
His research and scientific service were highly regarded, both in California and internationally. He held the Melvin D. Androus Professorship for weed research in rice for most of his career. In 2017, the Cooperative Rice Research Foundation awarded him the Marlin Brandon California Rice Industry Award for his impact on weed management. His peers elected him vice-president of the IWSS, which he served as president in 2014. His students and colleagues remember him as a good scientist and collaborator, an outstanding mentor, and a man of sharp wit and humor.
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The UC Weed Science group is saddened by the loss of our friend and colleague. He was a respected weed scientist and a good man. Our thoughts are with his family and friends.
-Brad
- Author: Saoimanu Sope
Earlier this year, officials in Southern California declared a water shortage emergency resulting in restrictions such as limiting outdoor water use to one day of the week. While mandatory restrictions vary across the region, Amir Haghverdi, UC Cooperative Extension specialist and associate professor of agricultural and urban water management at UC Riverside, is using research to pinpoint irrigation strategies that will help communities reduce their demand for water and increase supply.
Haghverdi and his team are responding to a hotter and drier California by working to identify changes that can make a substantial difference in water savings.
While behavioral changes such as preventing leaks and turning the faucet off while brushing teeth can help, Haghverdi's research focuses on methodical changes like stressing green spaces, planting drought-tolerant plant species, using non-traditional water sources, and investing in technology to better control water use.
Testing a lawn's limits
For six years, Haghverdi and his team have performed stress tests on turfgrass to identify the lowest percent of evapotranspiration rate (ETo) that it can withstand and still survive. To do this, Haghverdi's team applies different percentages of ETo, obtained from weather stations, and monitors the performance of each landscape species over time.
While both cool-season and warm-season species can be stressed and still maintain their aesthetic value for a few weeks to several months, Haghverdi's results showed that warm-season turfgrass species require less water and can withstand water stress better.
The actual duration that people can apply less water depends on the type of turfgrass, the weather conditions and the stress level. For example, results showed that hybrid bermudagrass (a warm-season turfgrass) during summer in inland Southern California could keep its aesthetic value above the minimum threshold for 30 to 50 days, depending on the weather conditions, with irrigation application as low as 40% ETo.
In contrast, tall fescue, a cool-season turfgrass, even with 20% more water, showed signs of stress after only a few weeks and could not maintain its minimum acceptable quality.
Plant drought-tolerant species
Haghverdi's work demonstrates that when water conservation is the goal, alternative groundcover species are clearly superior to all turfgrass species and cultivars that they have tested so far. In fact, his team has identified drought-tolerant species that can maintain their aesthetic values with a third to a quarter less water than cool-season turfgrass (as low as 20% ETo) and can even withstand no-irrigation periods.
Furthermore, extensive field trials showed that new plant species from different regions could be as resilient as native species in withstanding drought and heat stress while maintaining their aesthetic beauty and cool canopy. Occasionally, they have outperformed native species, underscoring the advantages of drought- and heat-tolerant species that are non-native.
Based on Haghverdi's preliminary results for minimum irrigation requirement in inland Southern California, creeping Australian saltbush, a non-native species originally from Australia, and coyote bush, native to California, were top performers. Considering cooling benefits, drought tolerance and sensitivity to over-irrigation, creeping Australian saltbush performed the best.
Counties are already using recycled water
Although he recommends renewing your landscape with drought-tolerant or low-water use greenery and identifying how long your green spaces can live without water, Haghverdi acknowledges that, while contradictory, the cooling benefits of landscape irrigation are essential in Southern California.
“This is one of the tradeoffs of water conservation,” said Haghverdi. “If the only goal is to conserve water, maybe people will conclude that we don't have enough water to irrigate landscape.”
Water conservation efforts could influence counties to stop or reduce landscape irrigation. The consequences, however, would result in hotter environments due to the heat island effect. The loss of landscapes means that the sun's energy will be absorbed into the ground, instead of prompting transpiration in plants, which helps keep environments cool.
Thus, stressing green spaces and investing in drought-tolerant plant species help reduce the demand for water, but increasing water supply is just as vital. Haghverdi urges Southern California counties to prioritize a supplemental water supply such as recycled water – an approach already implemented in Ventura, Orange and San Diego counties.
The Metropolitan Water District of Southern California's Pure Water Southern California Program, formerly known as the Regional Recycled Water Program, aims to do just that. In partnership with the Los Angeles County Sanitation Districts, the program will further purify wastewater to produce a sustainable source of high-quality water for the region.
According to the program's website, this would “produce up to 150 million gallons of water daily when completed and provide purified water for up to 15 million people, making it one of the largest water reuse programs in the world.”
Smart controllers save time, money and water
Making the best use of the water you already have relies on efficiency. Sprinklers that are poorly placed, for example, are not as effective as they could be.
“What I see often while walking my dog in the neighborhood is that there's a lot of runoff, bad irrigation and bad timing like when it's windy,” Haghverdi observed. “People usually set their irrigation timer and then forget it, but they don't adjust it based on the season or weather parameters. That's not going to help us conserve water, a precious resource, in California.”
Thankfully, Haghverdi and his team have done extensive research on smart irrigation controllers, which, simply put, are irrigation timers with a sensor built in. Generally, there are two types of smart irrigation controllers: weather- and soil-based controllers.
Weather-based controllers use evapotranspiration data to automatically adjust their watering schedule according to local weather conditions. Soil-based controllers measure moisture at the root zone and start irrigating whenever the reading falls below a programmed threshold.
Smart controllers that have flowmeters can detect leaks and be activated automatically, whereas rain sensors can stop irrigation during rainfall. Although both additions are ideal for large irrigation landscapes such as parks and publicly maintained green spaces, rain sensors are easy to install and effective for residential areas too.
When asked about cost being a hindrance, Haghverdi responded, “Not a lot of people know that there are grants for smart controllers – some that will pay either all or a majority of the cost.”
To check if grants are available in your area, interested individuals are encouraged to contact their local water provider.
“We need to move towards autonomous and smart irrigation [strategies], and water management in urban areas. That's the future. If we can build autonomous cars, why can't we build smart water management systems that apply the right amount of water to each plant species, can detect leaks and prevent water waste?” said Haghverdi.
To learn more about or stay updated on Haghverdi's research, visit www.ucrwater.com.
- Author: Bradley Hanson
May 2022 - Weed Science Webinar Series Shifting Focus to Mechanisms
Beginning next week, the Weed Science Webinar Series, which is being hosted by the USDA's Agricultural Research Service (ARS) and the Weed Science Society of America (WSSA), will shift in focus from tactics of weed management to the mechanisms.
The three webinars will address basic research topics associated with how weeds and invasive plants are able to do what they do and why, which is key for developing sustainable management strategies. If we don't know the why and the how, then the way that we manage is often continuous repetition, which can have deleterious effects and unintended consequences. We'll start by hearing about plant physiology and competition, then invasive plant control at the molecular level, and finally a look at herbicide resistance. This fundamental weed science research serves a critical role as the building block upon which applied approaches are developed by researchers and used by practitioners.
Each webinar will occur every Tuesday from 2-3 p.m. Eastern Time (ET) and include an interactive Q&A session. Below are additional details including presentation title and speaker information.
- May 3 - Role of Plant Physiology in Weed-Crop Competition: Dave Horvath, Research Plant Physiologist at the Sunflower and Plant Biology Research Unit in Fargo, ND
- May 10 - Molecular Basis for Controlling Invasive Plants: Matt Tancos, Research Plant Pathologist at the Foreign Disease-Weed Science Research Unit in Fort Detrick, MD
- May 17 - Addressing Herbicide Resistance with Alternative Chemistries: Scott Baerson, Molecular Biologist at the Natural Products Utilization Research Unit in Oxford, MS
The webinar series is free. WSSA membership is not required. To register for the webinar series, visit here.
If you missed any of the previous webinars or want to watch them again, they have all been recorded and can be found here: https://go.usa.gov/xzHja
- Author: Ben Faber
A $1.5 million emergency grant is enabling UC Riverside scientists to find plants impervious to a disease threatening America's citrus fruit supply.
Citrus Greening Disease — also known as Huanglongbing, or HLB — results in fruit that is bitter and worthless. It has crippled Florida's citrus industry and has already been detected in California, which grows 80% of America's fresh citrus. An estimated 267,000 acres of Golden State oranges, lemons, grapefruits, and mandarins are at stake.
For these reasons, the National Institute of Food and Agriculture is supporting scientists at UCR, the University of Florida, and the U.S. Department of Agriculture's Agricultural Research Service in their search for plants with natural tolerance to HLB.
“If you find a disease affecting your crops, a good first step is to look for plants that are able to grow and produce despite infection,” said UCR geneticist Danelle Seymour. “Then you can start to identify the genetic basis of the disease tolerance and make sure the next generation of plants includes these genes.”
Following this recipe, Seymour and UCR plant pathologist Philippe Rolshausen will examine a set of 350 citrus hybrids developed and grown by project collaborators in Florida. All trees in the set are already infected with HLB, yet they live longer, are healthier, and yield more fruit than their infected relatives.
While there are a number of projects searching for different solutions to the threat of HLB, this project is different because the plants being tested were all grown in an environment endemic to the disease. Additionally, the number of plants they're able to test is unusually large.
“The environment in which these plants were grown means we can be confident that these rootstocks will enhance tree health and yield in HLB-affected areas,” Seymour said. “Also, because our data set is so large, we've got the opportunity to identify plants with levels of tolerance that exceed current commercial varieties.”
In addition to searching for parts of the hearty hybrids' genomes responsible for their tolerance to HLB, scientists will also be checking for plants that have resistance to other pathogens that are already in California.
Citrus in the state is also threatened by nematodes that chew up roots, preventing plants from taking up nutrients, and by phytophthora, a type of water mold that causes rotting roots.
By searching not only for a solution to the looming threat of HLB but also to problems that have already taken root in California, scientists are hoping to ensure that citrus won't need to be imported from HLB-free countries and costs stay low for both local growers and consumers.
“This way, we're making sure the next generation of rootstocks will include the right genes and that we're being as efficient as possible in our breeding practices,” Seymour said.
ACP nymph image by Sam Droege, USGS
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