Posts Tagged: Rachael Long
UC Cooperative Extension advisors are on the front line and get the most interesting questions from our community. Someone brought some wasps into our office, and was worried they were invading her home, and wondered how to get rid of them. They were identified by the UC Davis Entomology Museum as black and yellow solitary mud dauber wasps, which are natural predators of spiders, and hence beneficial! Before you reach for that can of insecticide or heaven forbid, a blow torch to control spiders, talk to a UCCE advisor or Master Gardener in your county and read this blog for more information on managing them.
Here's all you need to know about mud daubers and spider control
That mud you track into your house is nothing compared to what mud daubers can do — and what they do to spiders. Female mud daubers, or wasps, build mud nests for their young — and provision them with spiders.
Where are the nests and what do they look like?
Female mud daubers, the architects, build those characteristic rectangular mud nests in protected areas of our homes, shops and garages, such as along eaves, walls or ceilings. Mud daubers are black and yellow solitary wasps (Sceliphron caementarium) that hunt spiders for their young. Another wasp, the blue mud wasp, reuses the black and yellow mud dauber wasp nests and primarily preys on black widow spiders.
Do mud daubers sting or bite?
Mud daubers do not aggressively protect their nests. Unlike hornets and other social wasps, they are generally docile and rarely sting.
Are mud daubers dangerous?
No, mud daubers are harmless and actually beneficial. They prey on spiders, including black widows, a favorite prey. They pack each cell with up to 25 to 30 spiders for their young. With about 15 to 20 cells per nest, that's over 500 spiders eaten. This is good news, especially for those of us who fear black widow spiders. True, mud daubers can be a nuisance, as their mud nests look messy, but they are generally peaceful.
How do they make their nests?
Females construct their nests by gathering globs of mud in their mandibles (jaws) from a nearby source of wet dirt. They carry the mud to a protected nest site, where they construct a cell. Then they begin hunting for spiders to provision the cell for their young, and lay a single egg inside. When they capture a spider, they sting it, permanently paralyzing it. This preserves the spider until their larvae are ready to eat it. When the cell is full of spiders, the female mud dauber caps it with more mud and builds another cell next to it. After the egg hatches and the food gone, she pupates. When an adult emerges, it opens the cap, leaving holes behind in the nest for the next cycle.
Mud daubers have a low reproductive rate, with about 15 to 20 eggs per female. Adults are active during the day during spring and summer with multiple generations per year. Queens overwinter in the cells in the larval stage. Adults sip nectar from flowers, where the male mud daubers are often found. Mud dauber wasps have good vision and use landmarks to locate nests and hunt spiders. They prefer protected areas where there are plenty of spiders. Sometimes you might see them going in and out of your house vents, hunting for spiders in your basement or attic.
How do mud daubers avoid being eaten by spiders?
Some are able to land on webs without getting entangled, and pluck the web to simulate an insect in distress. When the spider rushes to capture its prey, it becomes a victim of the wasp's paralyzing sting. The wasp then carries it back to her mud nest.
How do you get rid of mud dauber nests?
Although mud daubers are considered beneficial, you can remove the nests by scraping them off with a paint scraper or a knife into a dust pan, and then tossing them or moving them somewhere else where you don't mind their activity. The best time to remove the nests is in the late evenings when wasps are not active, or during the wintertime when they are dormant.
Do I have to worry about getting stung by a wasp or bit by a spider during nest removal?
No, the spiders are paralyzed and the wasps are not aggressive. Mud daubers can sting, but only if directly handled or if they accidentally snag in your clothing.
What's the best way to get rid of spiders?
Overall, spiders are beneficial because they're predators and feed on pests like flies. Most spiders cannot harm people. Those that might injure people — for example, black widows — generally spend most of their time hidden under furniture or boxes, or in woodpiles, corners or crevices. The spiders that we commonly see out in the open during the day are not aggressive toward people. The brown recluse spider has occasionally been brought into California in household furnishings, and other items, but it does not reside here. Spiders enter houses and other structures through cracks and are also carried inside on plants, firewood and boxes.
According to the UC IPM Spider Management Guidelines, the best approach for controlling spiders in and around your home is to remove hiding spots for secretive spiders such as black widows, and regularly brush or vacuum webs from windows, corners of rooms, storage areas, basements and other seldom used areas. This is effective because their soft bodies generally cannot survive this process. If you see a dust-covered web indoors, it's no doubt an old web that a spider is no longer using.
Why should one protect mud dauber nests?
Because mud daubers eat spiders, especially the cryptic black widows. In the process of cleaning spiders and webs, be sure to try protect those mud nests, because mud daubers naturally help control spiders in and around your home.
Sweeping acres of striking golden flowers may soon grace California's desert southwest. UC Cooperative Extension irrigation specialist Khaled Bali believes sunflowers may be an ideal crop for the state's most punishing agricultural region.
California produces more than 90 percent of the country's hybrid sunflower planting seed, which is shipped around the nation and world. The seed is used to grow sunflower seeds for a healthy snack or salad topper, and for seeds that are expressed into sunflower oil, valued for its clean taste and polyunsaturated fat.
Most California seed is produced on about 50,000 acres in the Sacramento Valley. But the plant's low water use and early maturity hold promise for production in Southern California's low desert.
Bali's research began two years ago with 1,800 plots of sunflowers, nearly 300 different genotypes, at the UC Desert Research and Extension Center in Holtville. All plants were well-watered for four weeks before drought treatment started. In 2016, the trial plots were irrigated at 60 percent of the area's ETo (the full amount of water used by well-irrigated, mowed grass in that environment), and at 100 percent.
“Sunflower is a California native species grown as a hybrid seed crop,” Bali said. “With limited water, we wanted to look at varieties that tolerate drought and stress.”
That year, Bali found significant variation in yield across the varieties, but no difference between plots that received 60 percent of ETo and 100 percent
“I've been doing deficit irrigation for a long time,” Bali said. “I never expected that.”
For the 2017 season, the 60 percent ETo plots were dropped to 10 percent to better understand the implications of severe drought on the sunflower cultivars.
“The emphasis in 2017 was to intensify our drought treatment, giving less water earlier and to quantify the genotypes' drought avoidance strategy by digging up roots and using computer image analysis to determine root traits,” Bali said.
Bali attributes the sunflower crop's low water needs to its deep tap root and crop production timing. Sunflower in the low desert may be planted from January to February, and harvested in May and June.
“Sunflower water needs are relatively low since they are harvested before the hottest part of the summer,” Bali said.
His research is continuing in 2018.
A new UC publication, Sunflower Hybrid Seed Production in California, is now under review and is expected to be available to producers in fall 2018. Written by UC Cooperative Extension advisor Rachael Long and colleagues, including Bali, the publication outlines crop production standards, land preparation, fertilization, pest management, harvesting and more.
Long said sunflowers are favored for crop rotations because they help in long-term management of weeds and diseases, the plants add biomass to the soil after harvest, and they are a profitable specialty field crop.
Read more about California sunflowers in a Green Blog post by Rachael Long, Sunflower seeds are boosting California's ag economy.
Hedgerows enhance wildlife abundance and diversity around farmland without contributing to food safety problems in field crops, according to a new study published by a team of University of California researchers. The UC Agriculture and Natural Resources and UC Davis study documented that field edge plantings around farms are generally too narrow relative to the surrounding landscape to be a source of rodents and foodborne pathogens.
“This study is particularly pertinent right now when FDA's Food Safety Modernization Act (FSMA) is calling for farmers to co-manage wildlife and agriculture, instead of clear cutting wild habitat around their crops,” said co-author Rachael Long, UC Cooperative Extension farm advisor in the Sacramento Valley. “Our paper provides support for this ruling, showing that the presence of hedgerows does increase wildlife diversity, but does not increase wildlife intrusion into the fields and, more importantly, does not increase the prevalence of animals carrying foodborne pathogens.”
This is good news for hedgerows, rows of shrubs, trees, grasses and flowers that are planted on field edges. The plants bordering crop fields provide habitat and floral resources for beneficial insects, such as bees and natural enemies, that help with pollination and biocontrol of pests in adjacent crops. Hedgerows also help enhance biodiversity – especially for insect-eating birds – help reduce wind and soil erosion, and protect water quality.
The two-year study in Sacramento Valley walnut orchards and processing tomato fields was led by Long and Roger Baldwin, UC Cooperative Extension vertebrate pest control specialist at UC Davis, former graduate student Laurel Sellers, the Western Center for Food Safety at UC Davis's Michele Jay-Russell, Xunde Lib and Edward R. Atwill, and Richard M. Engeman of USDA National Wildlife Research Center.
The study, titled “Impact of field-edge habitat on mammalian wildlife abundance, distribution, and vectored foodborne pathogens in adjacent crops,” was published in the February 2018 Crop Protection (Sellers et al. 2018).
Elsevier is providing 50 days of free access to this article. Anyone clicking on the following link before March 31, 2018, will be taken directly to the article on ScienceDirect. No signup or registration or fees are required. Simply click and read at https://authors.elsevier.com/c/1WXU~xPFYej~4.
This journal article supports a growing body of literature suggesting that plantings along the edge of fields do not substantially attract wildlife species that intrude on fields and transfer foodborne pathogens. For example, in a 2015 study, UC Davis researchers found more food pathogens when wildlife habitat was reduced on farms. This may be attributed to the vegetation filtering pathogens, a better breakdown of pathogens in diverse environments, and that removing vegetation may not deter wildlife from entering farm fields.
Relative to the larger crop acreage, hedgerows and similar field-edge habitats are generally too linear and small to serve as a significant source of rodents to damage nearby crops. However, cottontail rabbits favor hedgerows, and can sometimes cause damage to adjacent seedling crops.
“Overall, we found risk of crop loss or contamination of foodborne pathogens in crops bordered by hedgerows wasn't significant in our study in the Sacramento Valley, although potential damage could vary by the stage and type of crop and wildlife species present,” Long said. She will be presenting this work at the 28th Vertebrate Pest Control Conference, which will be held in Rohnert Park Feb. 26 to March 1.
In its Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption, the U.S. Food and Drug Administration says, "We continue to encourage the co-management of food safety, conservation, and environmental protection.”
Hedgerow benefits align with food production and sustainability goals. http://calag.ucanr.edu/archive/?article=ca.2017a0020
Comanaging fresh produce for nature conservation and food safety. http://www.pnas.org/content/112/35/11126
California is in the middle of the Pacific Flyway, a major north-south flyway for migratory birds, and also bats, that extends from Alaska to South America.
“Every autumn, migratory bats, such as the Mexican free-tailed bats, travel to their overwintering grounds in Southern California and Mexico, where there's plenty of bugs to eat; they come back each spring to raise their families,” said Rachael Long, a UC Cooperative Extension advisor who studies bats.
Bats are beneficial because they feed on insects, including mosquitoes and pests such as codling moths that damage fruit and nut crops. The economic value of bats for pest control on farms has been estimated by some studies to exceed $23 billion per year. Long, who serves Sacramento, Solano and Yolo counties, is studying the value of bats for pest control in walnut orchards.
In the city of Davis, officials recently warned people to stay away from bats after bats found on the UC Davis campus tested positive for rabies. Long agrees with the warning, but worries that it might also result in healthy bats being killed.
“This is most unfortunate for people and bats, but not a surprise at this time of year. Right now, thousands of bats are flying through our great Central Valley, migrating south for the winter, just like ducks and geese, so there's a higher chance of contact,” she said “We just don't see bats as much because they are flying at night, using the stars, earth's magnetic field, and landscapes to navigate.”
Their journey south is lengthy, from as far north as Washington state to Mexico, and exhausting, so bats need to rest along the way.
“Sometimes you'll see one or more tucked up in the corner of your house, such as under an eave,” Long said. “If so, use this as an opportunity to share with others the amazing life of a bat that can fly over a thousand miles to their overwintering grounds and back again in the spring. Leave them alone, let them rest, and they will fly away after they've rested and recovered.”
If you have to move a bat, she notes you should wear gloves and not handle a bat with bare hands because they will bite in self-defense.
“If you find a bat on the ground, place a box over the bat and using a piece of card, slip it under, then gently and carefully slide the bat into the box,” Long said. “Place the box at 4 to 5 feet off the ground and open it (bats usually can't take off from the ground). The bat can then crawl out of the box in its own time and fly away.”
“If the bat does not fly away within 30 minutes, it is probably sick or injured. In this case, contact a wildlife rescue unit in your area.”
Long noted that animal control officers have to euthanize bats to test for rabies.
“The bat may be perfectly healthy, just tired,” she said. “If no people or pets have obviously touched the bat, you can call a wildlife rescue organization. If in doubt, call animal control.”
If a bat does have rabies, Long said, “Rabies dies within five to 10 minutes after the bat dies.”
For more information on the benefits of bats, see Long's post in UC ANR's Green Blog, “Bats in the Belfry? No, Bats in Walnut Orchards” at //ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=17395.
River of No Return, 11-year-old Jack learned essential skills that would serve him well as the third and final book of the Black Rock Desert Trilogy children's series unfolds. The novel opens with a touch of danger and distress, but ends with fast moving high adventure as it reaches its exciting conclusion.
River of No Return, written by UC Cooperative Extension advisor Rachael Freeman Long, chronicles the third summer at the family cabin for Jack, where he meets up with his animal pals from the previous books: Pinta the bat and Sonny the coyote. The trio were introduced in Gold Fever, and reunited in Valley of Fire. In River of No Return, Jack, Pinta and Sonny team up with other animal friends and foes – including Lux and Lacy the wolves and Midas the raven – to defeat and bring to justice the last of a band of poachers tormenting wildlife in the Black Rock Desert.
The loss of Sonny's loving parents, Lux's near fatal injuries, and the dark rage of Sarge, a greedy Air Force veteran who is willing to poach endangered species to become “the richest man in the world,” sets a somber stage. But Jack's commitment to his animal friends, his courage and ingenuity take the sting out of the story, even as he braves pitch dark tunnels, a raging underground river, and dreadful villains. Riveted as the novel unfolds, children may not realize that they are learning about wildlife and natural history.
All three books in the Black Rock Desert Trilogy are peppered with facts about animals, but Long gives bats, a focus of her agricultural research for UC Cooperative Extension, the spotlight. For example, readers learn that Pinta the pallid bat has big, pink ears that twitch constantly as they echolocate, when using sound waves to see in the dark. Later, Pinta tells Jack, “Remember, we migrate to the desert southwest during wintertime where it's warmer and there's plenty to eat.” Readers also learn that bats pollinate flowers, when Pinta turns yellow with pollen.
“The characters have been in my head for 20 years,” Long said. “It's sad to let them go.”
She may be hanging up the tale of Jack, Pinta and Sonny, but Long plans to keep writing children's books. Her new series, called Animal Adventures, will begin with A is for Alligator, in which two 8-year-old boys visit a city zoo.
“They wonder what it's like in the animals' natural habitat, and a portal takes them to the Everglades, where they learn everything they need to know about alligators,” Long said.
The series will continue, next is B is for Bear, for 26 volumes, one for each letter of the alphabet.
“I'm hoping to do something fun and teach kids about our natural world,” Long said. “There are a lot of books that are negative about school and authority. My series will focus on courage, resilience and goodness.”
All of Long's books are available on Amazon.com.