“Weather patterns associated with climate change may adversely affect the performance of some of the most important insecticides, systemic insecticides, against coleopteran and lepidopteran pests,” Nansen says.
“These insecticides depend on efficient water and nutrient uptake through the root system and on vascular flow – both mechanisms may be partially compromised under drought conditions,” Nansen points out. “This leads to lower uptake and non-uniform distribution of systemic insecticide in plant tissues – and therefore, higher risk of pests NOT acquiring a lethal dosage.”
In an opinion-based article published in the current edition of the Journal of Economic Entomology, Nansen and three lab researchers take it one step further, and argue that non-uniform distribution of systemic insecticide in plant tissues may also select for behavioral resistance in target pest populations.
The research, “Does Drought Increase the Risk of Insects Developing Behavioral Resistance to Systemic Insecticides?” is the work of Nansen, doctoral students Trevor Fowles and Emily Bick and researcher Haleh Khodaverdi. The researchers cite some 60 references.
“Increases in severity and frequency of drought periods, average global temperatures, and more erratic fluctuations in rainfall patterns due to climate change are predicted to have a dramatic impact on agricultural production systems,” they wrote in the abstract. “Insect pest populations in agricultural and horticultural systems are also expected to be impacted, both in terms of their spatial and temporal distributions and in their status as pest species.”
The UC Davis researchers discussed how indirect effects of drought may adversely affect the performance of systemic insecticides and also lead to increased risk of insect pests developing behavioral insecticide resistance. “We hypothesize that more pronounced drought will decrease uptake and increase the magnitude of nonuniform translocation of systemic insecticides within treated crop plants, and that may have two concurrent consequences: 1) reduced pesticide performance, and 2) increased likelihood of insect pests evolving behavioral insecticide resistance,” they wrote in the abstract.
“Under this scenario, pests that can sense and avoid acquisition of lethal dosages of systemic insecticides within crop plants will have a selective advantage. This may lead to selection for insect behavioral avoidance, so that insects predominantly feed and oviposit on portions of crop plants with low concentration of systemic insecticide.”
Nansen noted that limited research has been published on the effect of environmental variables, including drought, on pesticide performance. It's important to study the many ways environmental factors can affect, directly and indirectly, both the performance of insecticides and the risk of target insect pests developing resistance, Nansen says.
Potato beetles and diamondback moths are two of the pests mentioned in the research article. Potato beetle larvae attack potato crop foliage, while the larvae of the diamondback moths are major pests of cabbage.
Godfrey, who has addressed Rice Field Day for 25 years, will discuss how the California rice industry's use of insecticides is threatened by two major factors: the development of insecticide resistance and regulatory actions.
Materials registered for California rice, Godfrey said, include pyrethroids (Mustang®, Warrior®),neonicotinoid (Belay®), insect growth regulator (Dimilin®), and carbamate (Sevin®). One additional product is in the registration pipeline, a ryanodine receptor modulators (Coragen®).
“However, as shown in the 2015 season when armyworms reached unprecedented levels--the highest of the last 25 years-- the insecticide choices were limited and all options had some deficiencies in terms of efficacy on armyworms,” Godfrey said. “Fortunately, the California Rice Commission was able to get an emergency exemption (Section 18) for Intrepid® to help with this situation. All these registered insecticides need to be managed carefully so they are available and effective in future years and for future generations.”
Joanna Bloese, a student in the Godfrey lab, will present a poster, "Evaluating the Effects of Chemical and Cultural Management Practices on the Population Dynamics of Tadpole Shrimp (Triops longicaudatus) in California Rice." (Research by J. B. Bloese, L. Espino, K. Goding, L. D. Godfrey). Ongoing research is focused on developing pest management methods in rice to reduce the need for insecticide use while still producing a profitable crop. Kevin Goding, staff research associate, also will be participating in Rice Field Day.
The purpose of the Rice Field Day, sponsored by the California Cooperative Rice Research Foundation (CCRRF) and the University of California, is to give rice growers and others an opportunity to observe and discuss research in progress at the Rice Experiment Station (RES).
The program will begin at 8:30 a.m. with a general session that serves as the annual membership meeting. Posters and demonstrations will be displayed during registration until after lunch. Field tours of research will emphasize progress on rice variety improvement, and disease, insect pest, and weed control. The program will conclude at noon with a lunch that includes rice.
More information is available on the CRRF website at http://www.crrf.org/
It chronicles how Hammock's basic research on caterpillars--how caterpillars become butterflies--led to key discoveries about chronic pain, including diabetic pain.
It includes information on Hammock's collaborator, John Imig, professor of pharmacology and toxicology at the Medical College of Wisconsin, who recently received a $2.3 million grant from the National Institute of Diabetes and Digestive and Kidney Diseases "to investigate the development of a drug to treat type 2 diabetes and metabolic syndrome."
"But what we didn't tell you is that this translational grant is all thanks to some caterpillars in California and decades of research," wrote communication specialist Karri Stock. "It's a tale of pure curiosity with a great lesson for budding scientists and the public alike: You can't always predict where basic science discoveries will lead."
She related how, more than 40 years ago, a young entomologist in California named Bruce Hammock found a key enzyme (epoxide hydrolase or EH) in the metamorphosis of caterpillars into butterflies. "The enzyme degrades a caterpillar's juvenile hormone, allowing it to move from the larval stage into an adult insect. Early in his career, Dr. Hammock found that if he exploited this EH and prevented larvae from becoming adults, he had on his hands an effective genetically engineered insecticide."
Then came the basic science and fundamental questions that Hammock asked. "Does the enzyme occur in plants? Does it occur in mammals?"
"And it turns out that it does, particularly as soluble epoxide hydrolase (sEH) in mammals, including mice and humans, and its distribution suggested it was involved in regulatory biology," Stock wrote. She went on to detail the collaboration of Hammock and Imig. Read the entire MCW story here.
Hammock's work has drawn national and international attention. Groundbreaking neuropathic pain research emanating from the Hammock lab made Discover magazine's Top 100 Science Stories of 2015 ranking among the Top 15 in the medicine/genetics category.
The UC Davis research was singled out for its “Endoplasmic Reticulum Stress in the Peripheral Nervous System is a Significant Driver of Neuropathic Pain,” published in July 2015 in the Proceedings of the National Academy of Sciences. (See UC Davis news story).
Highly honored by his peers, Hammock is a fellow of the National Academy of Inventors, which honors academic invention and encourages translations of inventions to benefit society. He is a member of the U.S. National Academy of Sciences, a fellow of the Entomological Society of America, and the recipient of the Bernard B. Brodie Award in Drug Metabolism, sponsored by the America Society for Pharmacology and Experimental Therapeutics. He directs the campuswide Superfund Research Program, National Institutes of Health Biotechnology Training Program, and the National Institute of Environmental Health Sciences (NIEHS) Combined Analytical Laboratory.
The event, free and open to the public, begins at 10 a.m. on the Wyatt Deck. It is billed as an event to “explore the amazing diversity of butterflies and moths both near and far.” All ages are invited.
Butterflies they spot may include monarchs, gulf fritillaries, and pipevine swallowtails, as well as skippers and cabbage whites. Hernandez will also display his own collections of butterflies.
Hernandez, who received a bachelor of science degree in entomology from UC Davis in 2014, currently works for the Steve Seybold lab as a research/field assistant. He hopes to attend graduate school and receive his doctorate in entomology.
Hernandez worked for the Sharon Lawler lab for four years, both as a student and as a post-graduation junior specialist. A volunteer at the Bohart Museum of Entomology and the UC Davis Arboretum, he recently participated on a Bohart Museum insect collecting trip with entomologist/Bohart associate Fran Keller. “It was an amazing experience,” he said.
Hernandez has collected and curated insects for 19 years. “I have a passion for Lepitoptera and would like to use it as a target group for research in graduate school,” he said. “The species of butterfly that interests me the most is the blue morpho. The family of moths that interests me the most and the one I would like to study is Sphingidae.”
"I've been interested in insects ever since I was small," Hernandez said. "It was their unique life histories and morphologies that really propelled my passion for insects and entomology. What draws me to butterflies is the plethora of different colors and patterns that they display on their wings, as well as their life cycle.”
Hernandez presented a well-attended talk and tour on butterflies and moths at the Arboretum last September. Elaine Fingerett, the Arboretum's academic coordinator, chronicled the event in photos.
For more information, contact the Arboretum at (530) 752-4880 or by email, firstname.lastname@example.org.
Saturday, Aug. 20, is National Honey Bee Day. Observed on the third Saturday every August, this day educates people about the importance of honey bees and promotes the work of beekeepers.
Various insects, birds, and other animals pollinate plants. Bees, especially honey bees, are the most vital for pollinating food crops. Many California crops rely on bees to pollinate their flowers and ensure a good yield of seeds, fruit, and nuts. Pesticides, especially insecticides, can harm bees if they are applied or allowed to drift to plants that are flowering.
Our mission at the University of California Agricultural and Natural Resources (UC ANR), Statewide Integrated Pest Management Program (UC IPM) is to protect the environment by reducing risks caused by pest management practices. UC IPM developed Bee Precaution Pesticide Ratings to help pest managers make an informed decision about how to protect bees when choosing or applying pesticides.
The bee precaution ratings are based on the reported effects of a pesticide's active ingredient on adult honey bees or their brood. You can find and compare ratings for active ingredients including acaricides (miticides), bactericides, fungicides, herbicides, and insecticides.
Ratings fall into three categories. Red, or rated I, pesticides should not be applied or allowed to drift to plants that are flowering. Plants include the crop AND nearby weeds. Yellow, or rated II, pesticides should not be applied or allowed to drift to plants that are flowering, except when the application is made between sunset and midnight if allowed by the pesticide label and regulations. Finally, green, or rated III, pesticides have no bee precautions, except when required by the pesticide label or regulations.
It is important to note that the bee precaution pesticide ratings are not the pollinator protection statements on the pesticide label.
Each crop in the UC Pest Management Guidelines has links to the bee precaution ratings and provides guidance on how to reduce bee poisoning from pesticides. For more information on protecting bees from pesticides, see UC IPM's Protecting Natural Enemies and Pollinators, and use the Bee Precaution Pesticide Ratings.