- Author: Kathy Keatley Garvey
You're not thinking of root-knot nematodes, major pests of potatoes.
But potato growers and nematologists are.
So are the editors of the scientific journal, Nature Plants. Their current edition showcases research on root-knot nematodes by Washington State University (WSU) scientists Lei Zhang and Cynthia Gleason, and a commentary by UC Davis nematologist Shahid Siddique and colleague Clarissa Hiltl of the University of Bonn, Germany.
“Plant-parasitic nematodes are among the world's most destructive plant pathogens, causing estimated annual losses of $8 billion to U.S. growers and of nearly $78 billion worldwide," according to Siddique, an assistant professor in the UC Davis Department of Entomology and Nematology.
“Most current control methods rely on chemical nematicides, but their use is increasingly limited due to environmental concerns," Siddique and Hiltl wrote in their News and Views column, New Allies to Fight Worms.
They commented that the WSU scientists' proposed alternative pest management strategy--naturally occurring molecules or plant elicitor peptides (Peps)—shows promise: “Engineering a naturally occurring rhizobacterium to deliver Peps to the plant root system offers a new opportunity in integrated pest management.”
It's better to build up the host plant's immune system rather than directly target the pathogen with chemical nematicides which “are highly toxic and have negative effects on the ecosystem," Siddique told us.
The root-knot nematode Meloidogyne chitwoodi is a noted pest of potato production in the Pacific Northwest. Idaho leads the nation in commercial potato production, followed by Washington. Oregon ranks fourth. California, which ranks eighth, grows potatoes year around due to its unique geography and climate.
The WSU scientists demonstrated the effective use of Peps to combat root-knot nematodes in potato (Solanum tuberosum). They engineered a bacteria, Bacillus subtillis, to secrete the plant-defense elicitor peptide StPep1. They wrote that pre-treatment of potato roots “substantially reduced root galling, indicating that a bacterial secretion of a plant elicitor is an effective strategy for plant protection." (See article.)
“Besides chemical nematicides, methods of nematode management include the use of crop rotation, microbial biocontrol agents, cover crops, trap crops, soil solarization, fumigation and resistant plant varieties,” wrote Siddique and Hiltl. “However, several of these strategies are not effective or available for all crops. Nematicides are highly toxic, and their use is strictly limited due to environmental concerns. Resistant plants are often ineffective or unavailable. Microbial biocontrol agents have produced inconsistent results. In this context, the current work provides a new opportunity to manage plant-parasitic nematodes by combining two progressive strategies: the use of plant elicitors to enhance crop resistance to pathogens and the use of B. subtilis to deliver.”
According to the UC Statewide Integrated Pest Management Program (UC IPM), root-knot nematodes "usually cause distinctive swellings, called galls, on the roots of affected plants. Infestations of these nematodes are fairly easy to recognize; dig up a few plants with symptoms, wash or gently tap the soil from the roots, and examine the roots for galls. The nematodes feed and develop within the galls, which can grow as large as 1 inch in diameter on some plants but usually are much smaller."
"Nematodes are too small to see without a microscope," UC IPM points out. "Often you become aware of a nematode problem by finding galled roots on a previous crop. However, you also can use a simple bioassay to detect root knot nematodes in garden soil. Melons seeded in pots in moist soil collected from the garden will develop visible galls on the roots in about 3 weeks when pots are kept at about 80ºF if root knot nematodes are present. As a comparison, melons planted in heat-sterilized soil won't develop galls."
Stay tuned.
- Author: Kathy Keatley Garvey
Let's hear it for biocontrol.
You've seen lady beetles, aka ladybugs, preying on aphids.
But have you seen an assassin bug attack a spotted cucumber beetle?
No?
How about a crab spider munching on a stink bug?
All biocontrol, part of integrated pest management (IPM).
If you access the University of California Statewide Integrated Pest Management Program (UC IPM) website or more specifically, this page, you'll learn that "Integrated pest management, or IPM, is a process you can use to solve pest problems while minimizing risks to people and the environment. IPM can be used to manage all kinds of pests anywhere–in urban, agricultural, and wildland or natural areas."
Or, UC IPM's more in-depth definition:
"IPM is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and nontarget organisms, and the environment."
Think of biocontrol as beneficial: "Biological control is the beneficial action of predators, parasites, pathogens, and competitors in controlling pests and their damage. Biological control provided by these living organisms (collectively called "natural enemies") is especially important for reducing the numbers of pest insects and mites, but biological control agents can also contribute to the control of weed, pathogen, nematode or vertebrate pests."--UC IPM
Yesterday we witnessed an incredible case of biocontrol in action.
At Bodega Bay's Doran Regional Park, Sonoma County, we spotted a great blue heron stepping stealthily through a thatch of ice plant in the Jetty campground. It was 6:30 in the morning. As campers slept in their recreational vehicles a few feet away, the great blue heron just kept stepping silently through the ice plant. One step. Another step. And another.
And then it happened. Its long sharp beak speared a rodent. Yes, they eat rodents. It crunched the body from head to toe, breaking the bones, and then swallowed it whole.
Not a pretty picture, but a simple case of biocontrol, compliments of a hungry heron.
- Author: Kathy Keatley Garvey
Have you ever heard anyone say that when they see the larva of a lady beetle (aka ladybug, family Coccinellidae)?
Unfortunately, it's quite common among non-gardeners and non-insect enthusiasts.
The larvae of lady beetle are mostly black and look like tiny, spiny alligators, but they're beneficial insects just like the adult lady beetles. In the adult and larval stage, they're both predators that prey mainly on aphids, but they'll also eat thrips, spider mites, scale insects, and other soft-bodied insects.
An adult lady beetle can eat as many as 5000 aphids in its lifetime, scientists say. Who knows how many a larva can eat! Who's counting?
"Young lady beetle larvae usually pierce and suck the contents from their prey," according to the UC Statewide Integrated Pest Management Program's website. "Older larvae and adults chew and consume their entire prey. Larvae are active, elongate, have long legs, and resemble tiny alligators."
You've seen lady beetle jewelry and t-shirts and the like (check out the gift shop at the Bohart Museum of Entomology at UC Davis, located in Room 1124 of the Academic Surge Building on Crocker Lane), but the larvae? They aren't represented.
They're well represented in many gardens, however. In our garden, the adults and larvae are polishing off the oleander aphids on our milkweed plants.
- Author: Kathy Keatley Garvey
However, bed bugs, carpet beetles and pantry pests got into the act and competed mightily for the spotlight.
The occasion: The UC Davis Bohart Museum of Entomology open house, held Sunday afternoon, Nov. 18. The theme: "Urban Entomology."
The three-hour event starred a cockroach--well, a human dressed as a cockroach.
Karey Windbiel-Rojas of the UC Statewide Integrated Pest Management Program (UC IPM)--she's the associate director for Urban and Community IPM who serves as the area urban IPM advisor for Yolo, Sacramento and Solano counties--donned her cockroach costume and joined Bohart scientists in fielding questions about urban pests.
The pests the UC IPM scientist has been dealing with lately include carpet beetles, bed bugs and pantry pests. She handed out two newly published Quick Tips on carpet beetles and pantry pests, as well as information on other pests. What are some of the other pests? Check out UC IPM's Quick Tips library at http://ipm.ucanr.edu/QT/index.html.
UC IPM offers a wealth of information on its website, including
- home, garden, turf and landscape pests
- agricultural pests
- natural environment pests, and
- exotic and invasive pests
But when a cockroach is scurrying about (that was Karey's Halloween costume, by the way), the mind focuses on the "ins" and "outs" of cockroaches. Mostly the "outs."
As in: Stay. Out. Never. Ever. Come. Back. In.
"There are six species of cockroaches in California that can become pests: German cockroach, brownbanded cockroach, oriental cockroach, smokybrown cockroach, American cockroach, and Turkestan cockroach. A seventh species, the field cockroach, is not really a pest. It is usually found outdoors, but sometimes comes indoors when it is hot or dry and is often mistaken for the German cockroach. Of these seven species, the one that has the greatest potential for becoming persistent and troublesome is the German cockroach, which prefers indoor locations. Oriental and American cockroaches occasionally pose problems in moist, humid areas."--Excerpt from UC IPM Pest Note on Cockroaches.
As the UC IPM website indicates, cockroaches "may become pests in homes, schools, restaurants, hospitals, warehouses, offices, and virtually in any structure that has food preparation or storage areas. They contaminate food and eating utensils, destroy fabric and paper products, and impart stains and unpleasant odors to surfaces they contact."
Cockroaches can definitely give you a difficult time.
And speaking of giving, today (Tuesday) is Giving Tuesday, and UC IPM Director Jim Farrar has committed to eating a pest if at least 20 people make a donation of $10 or more to UC IPM.
UC Agriculture and Natural Resources (UC ANR) spokesperson Pamela Kan-Rice, assistant director of News and Information Outreach, informed us: "With your donation and Jim's appetite, there will be one less pest to deal with! Spread the word to colleagues, family and friends to help UC IPM meet this goal. All UC IPM donors will be invited to the special pest eating event which will take place in the afternoon on Wednesday, Nov 28 in the UC ANR building." The dining experience is expected to begin at 4 p.m.
Here's where to donate before midnight tonight: https://donate.ucanr.edu/pages/integrated-pest-management.
We asked Karey if the pest to be consumed could possibly be a cockroach. Or a garden-variety pest, such as a dandelion.
"To my knowledge he will not be eating a cockroach or a dandelion," she commented in an email. "I don't want to give away what he might be eating (so I don't actually know for sure)."
That would be a definite "no" on the roach!
(Update: Director Farrar ate corn smut, grasshoppers and live mealworms.)
- Author: Kathy Keatley Garvey
Think bed bugs, cockroaches, carpet beetles and pantry pests, among others.
Those are some of the critters you'll learn about if you attend the Bohart Museum of Entomology's open house on urban entomology, set from 1 to 4 p.m., Sunday, Nov. 18 in Room 1124 of the Academic Surge Building on Crocker Lane, UC Davis campus. It's free and family friendly.
Karey Windbiel-Rojas of the UC Statewide Integrated Pest Management Program (UC IPM)--she's the associate director for Urban and Community IPM who serves as the area urban IPM advisor for Yolo, Sacramento and Solano counties--will be there to greet visitors and answer questions, as will Bohart Museum scientists and staff.
The pests the UC IPM scientist has been dealing with lately include carpet beetles, bed bugs and pantry pests. She'll hand out two newly published Quick Tips on carpet beetles and pantry pests, as well as information on other pests. What are some of the other pests? UC IPM's Quick Tips library ("some are household insects, some are pests in the garden/landscape, and some are obviously not arthropods") is here: http://ipm.ucanr.edu/QT/index.html.
The open house will focus on both household and garden insects, said Lynn Kimsey, director of the Bohart Museum and professor of entomology at UC Davis. "The focus is urban entomology," she said. "We'll have out examples of all the wonderful household pests/friends and garden pests, along with the kinds of things they inspect restaurants for."
Like cockroaches, which thrive in human habitats and date back 350 millions years ago.
As an aside, Windbiel-Rojas promises to wear--or display--her cockroach costume that she wore on Halloween.
For the family arts and crafts activity, visitors will create mosaics rice in various colors. The youngsters will layer the colors in glass jars with lids. "This can serve as pretty artwork but also remind their parents to store grains in tightly sealed containers to keep pantry pests from infesting," Windbiel-Rojas said.
At a previous open house, youngsters glued dried rice and beans on insect images created by UC Davis entomology student/artist Karissa Merritt. It proved to be a popular activity.
Entomologist Jeff Smith, who curates the butterfly and moth collection at the Bohart, will be among the scientists at the open house. He worked in the pesticide industry for years, training people about entomology, noted Tabatha Yang, the Bohart's education and outreach coordinator.
The open house is free and open to the public. A donation jar will be set up to help Bohart Museum specialist Brennen Dyer; he and his wife lost their home in the wildfire fueled by strong winds that destroyed most of Paradise, Butte County. Profits from the sale of items in the gift shop on Sunday are also earmarked for the Dyers. (See Bug Squad blog.)
The Bohart Museum, home of nearly eight million insect specimens, is the seventh largest insect collection in North America and houses the California Insect Survey, a storehouse of insect biodiversity. In addition, the Bohart features a live "petting zoo," comprised of Madagascar hissing cockroaches, walking sticks, tarantulas and praying mantids; and a year-around gift shop, which is stocked with T-shirts, sweatshirts, books, jewelry, posters, insect-collecting equipment and insect-themed candy.
Other public weekend hours for the academic year 2018-2019 are:
- Saturday, Jan. 12, from 1 to 4 p.m.: "Time's Fun When You're Studying Flies"
- Saturday, Feb. 16, times vary: (campuswide) Biodiversity Museum Day
- Saturday, March 9, 1 to 4 p.m., "Eight-Legged Wonders"
- Saturday, April 14, 10 a.m. to 3 p.m., (campuswide) UC Davis Picnic Day
The Bohart Museum's regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. It is closed to the public on Fridays, Saturdays and Sundays and on major holidays. Admission is free. More information on the Bohart Museum is available on the website at http://bohart.ucdavis.edu or by contacting (530) 752-0493 or emailing bmuseum@ucdavis.edu.
