Posts Tagged: IPM
Across the globe, scientists have shown that birds can be farmer allies. Insectivorous birds feed on damaging insect pests in many crops including coffee, cacao, oil palm, corn, cabbage and apples. Raptors, including hawks and barn owls, feed on rodents, including gophers, voles and mice (see blog, Barn owls help clean up rodents naturally).
Despite this deep historic knowledge that birds are important predators of crop pests, over time the perception of birds as natural enemies of pests has been generally replaced with the idea that birds are often major crop pests themselves. Indeed, some bird species — like some types of insects — can cause trouble for farmers, but many others — especially those that eat insects and rodents — can be beneficial.
Do birds control insect pests on farms in California's Central Valley?
They do! Recent studies by Dr. Sacha Heath, UC Davis, and Rachael Long, field crops and pest management advisor, UC Cooperative Extension, showed that birds help control insect pests in walnut orchards. Dr. Sara Kross (UC Davis postdoctoral alumnus, now with Columbia University) showed that birds help control alfalfa insect pests.
Birds are voracious predators of codling moth pests in walnuts
Codling moth is a major worm-like pest that infests walnuts, apples and pears. The larvae go dormant during winter, living in cocoons in crevices in trees. Adult moths emerge in the spring, lay eggs and infest crops.
We evaluated bird predation of codling moth using “sentinel prey” and exclosure cages. We glued codling moth cocoons to walnut trunks and covered them with cages, allowing insects and spiders to access the cocoons, but not bird predators. This allowed us to count how many larvae were eaten inside and outside of the cages to estimate pest reduction by birds.
What did we find?
Natural enemies, like parasitic wasps and lacewings, alone reduced codling moth larval numbers by 11%; adding birds into the pest control system reduced them by 46%! Nuttall's woodpeckers and white-breasted nuthatches did a lot of the work; these birds travel up and down the trunks of trees, searching for insects.
Above, a white-breasted nuthatch preys on a codling moth larva “sentinel cocoon” on a walnut tree. Video by Sacha Heath.
Alfalfa weevils are no match for insectivorous birds
Alfalfa weevils are key pests of alfalfa, reducing yields and hay quality if left uncontrolled. Dr. Sara Kross looked at bird predation of this pest by excluding birds from alfalfa plants via cages, and counting the number of weevils inside and outside the cages. She found that birds reduced the number of weevils by more than 30%, showing their importance in helping to protect alfalfa from this serious pest.
Does field edge habitat, like hedgerows, help attract beneficial birds?
Yes! Hedgerows are important habitat for beneficial birds, serving as nesting, foraging and roosting sites. In a study in the Sacramento Valley, crop margins with hedgerows, tree lines and riparian buffers harbored up to six times more birds and up to three times more bird species than bare or weedy margins.
Walnut orchards adjacent to hedgerows and riparian areas had higher numbers of beneficial birds along with more species. In alfalfa, there were more beneficial birds in fields when at least two tall trees were present along the field edges. More beneficial birds were associated with better pest control, that is, fewer codling moth cocoons and alfalfa weevils.
Birds have large territories, fly long distances, and are influenced by what happens on the farm as well as by what happens in the landscape around the farm. For example, we found that codling moth predation by birds greatly increased in walnut orchards as the amount of habitat in the landscape around the orchards increased (including hedgerows, tree lines, riparian and oak woodlands, and grasslands).
Will hedgerows increase the numbers of pest birds?
Pest birds are present on farms regardless of field edge habitat (such as weedy vegetation or hedgerows). Cases will be different, depending on the crop, but in the fields and orchards of Yolo County, researcher Hillary White (formerly with UCCE and now with U.S. Fish and Wildlife) found that three of the most common avian crop pests (American crow, red-winged blackbird and Brewer's blackbird), were up to 10 times more abundant in agricultural fields with bare or weedy margins than in fields with hedgerows.
What can I do to attract beneficial birds to my farm?
Our avian research team has been quantifying the conditions under which birds are helpful or harmful to growers. We are looking for ways to help farmers create bird habitat on their farms to harness the beneficial pest control services birds can provide, while also protecting crops from the damaging effects of some bird species. This information is available in the new publication “Supporting Beneficial Birds and Managing Pest Birds,” co-authored by the Wild Farm Alliance and Drs. Kross and Heath, and technically advised by UC Cooperative Extension and several farmers. This is a user-friendly guide for farmers and conservation practitioners, with the goal of co-managing farmlands for biodiversity and farming.
A white-breasted nuthatch preys on a codling moth larva “sentinel cocoon” on a walnut tree. (Video still: Sacha Heath)
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.
Pests have always been a bane of human existence. Modern society has developed effective pest management, “but there is no kind and gentle way to kill things,” said Brian Leahy, the director of the California Department of Pesticide Regulation, in remarks at the April 2018 IPM Summit.
The ever increasing incidence of invasive pests and the concerns about how to manage them will be a continuing challenge. Leahy said society is on a pest treadmill; and the best way to address it is with integrated pest management (IPM).
The concept of integrated pest management emerged 60 years ago when scientists recognized that imposing a harsh chemical on a natural system threw it off kilter, often causing unexpected, usually negative consequences. They realized that combining an array of pest control methods – such as careful supervision of insect levels, promotion of beneficial insects, and using less harsh products – would be more effective, safer for families and farmworkers, and kinder to the environment in the long run.
And yet, pesticides are still widely used in agricultural, horticultural and structural systems.
“We need to make IPM more robust,” said Pete Goodell, UC IPM advisor emeritus who spent 36 years as an IPM researcher, leader and teacher. “We need to make IPM easier to adopt.”
The meeting in Davis brought together nearly 200 people engaged in the science, business and regulation of pest management. They were assembled to address the tensions around pesticides and their alternatives, and usher in a new generation of researchers and practitioners to maintain and expand on six decades of progress in integrated pest management.
The IPM Summit is the final chapter of a collaborative effort titled “The Pests, Pesticides & IPM Project,” which was funded by DPR to enhance dialog about pest management. The project leader is Lori Berger, UC IPM academic coordinator.
“This project addresses the challenges pests pose to society,” Berger said. “We want to increase adoption of IPM practices on farms, and also in schools, homes, museums and golf courses. We're all in this together.”
One example of urban IPM efforts was presented by the IPM Summit keynote speaker Kelly Middleton, director of community affairs for the Greater Los Angeles County Vector Control District. She outlined the substantial public health concerns associated with pest control in California's largest urban area. A primary target is mosquitos.
“In the early 1900s, vector control started with concerns about malaria and mosquito populations,” Middleton said.
Over decades, the vector control district worked behind the scenes to keep mosquito populations in check. But in recent years, new species of mosquitos capable of spreading Zika, West Nile encephalitis, chikungunya and yellow fever have made their way to LA, intensifying concerns.
A key IPM tool in Los Angeles is minimizing standing water where mosquitos can breed. With year-round water flow irrigating vast landscapes and concrete drainages that inhibit infiltration, the vector district is faced with mosquito breeding grounds created by “urban drool,” Middleton said.
Trash rife with nutrients – such as discarded food and plant materials – are perfect nourishment for immature mosquitos, a condition referred to as “urban gruel.”
Higher temperatures predicted because of climate change only threaten to exacerbate the problem.
“A warming world is a sicker world,” Middleton said.
An effective IPM approach to mosquitos is short-circuiting their reproduction opportunities by enlisting residents to maintain swimming pools, drain any receptacles that can capture rainwater or irrigation, and be vigilant about basins containing water in their environments.
These efforts are emblematic of the societal collaboration that can tackle pest problems without pesticides.
In his IPM Summit presentation, Goodell called for public sector investment in basic research, applied research, extension and education to find IPM solutions and encourage implementation. He appealed for IPM outreach to include community organizations, home owners associations and other non-traditional partners. He suggested agriculture take advantage of farmworkers' presence in the field for early pest detection.
“Technical pest management skills are critical, but it's connections with people that are key to bringing about change,” Goodell said.
While students and teachers were enjoying summer break, an amendment to the Healthy Schools Act (HSA) went into effect on July 1. It requires teachers, custodians, administrators, other staff or volunteers, and licensed pest management professionals applying any pesticide (this includes disinfectants and antimicrobials) at a school site to take an annual training course covering school integrated pest management (IPM). The training course must be approved by the California Department of Pesticide Regulation (DPR).
An online course, Providing Integrated Pest Management Services in Schools and Child Care Settings, developed by the UC ANR Statewide IPM Program and the Center for Environmental Research and Children's Health (CERCH), has recently been approved by DPR to satisfy the annual training requirement of the HSA. Although this course was designed for licensed pest management professionals, anyone applying any type of pesticide in schools or child care centers will benefit from the course.
IPM is a strategy that focuses on long-term prevention of pests through a combination of techniques such as monitoring for pest presence, cleaning up food sources, sealing up cracks, and excluding pests with screens. Effective pesticides that pose the least possible hazard and that minimize harm to people, property, and the environment are used only after careful monitoring indicates they are needed.
The HSA encourages the use of IPM in schools and child care centers and gives parents and the public the ability to know when and where certain pesticides are used in these facilities. It was originally signed into California law in September 2000 and is located in four different California codes: education, food and agricultural, business and professions, and health and safety. The law has been amended several times. The most recent revision to the HSA was signed into law in September 2014 by Gov. Brown.
Prior to July 1, schools were already required to do the following:
- Designate an IPM coordinator at the school or district level to make sure the requirements of the HSA are met
- Create an IPM plan
- Provide annual written notification to all parents and staff of pesticide products intended for use at the school site during the year and allow the opportunity for them to be notified before certain applications
- Post warning signs where certain pesticides are applied
- Keep records of pesticide applications
- Send pesticide use reports to DPR annually
Some pesticide products are exempt from the IPM plan, notification, posting, recordkeeping, and reporting* requirements of the HSA at school sites. These are reduced-risk pesticide products, and their use is encouraged at schools if pesticides are deemed necessary. These include:
- Self-contained baits or traps
- Gels or pastes used indoors in cracks and crevices
- Antimicrobials, including sanitizers and disinfectants
- Pesticides exempt from registration, such as food grade oils
However, these products are NOT exempt from the Healthy Schools Act annual training requirement that went into effect July 1. Anyone who uses these products—a licensed professional, school staff or child care staff—is still required to take the HSA annual training course.
To satisfy this annual training requirement, take the free UC IPM online course by visiting the UC IPM online training webpage. For more on school and child care IPM and other courses that satisfy the Healthy Schools Act training requirement, visit the DPR website.
*Licensed pest management professionals hired to apply pesticides at schools or licensed child care centers must continue to submit their regular pesticide reports of ALL registered pesticides to DPR annually and to the county monthly.
The San Joaquin-Sacramento River Delta is considered by local farmers to be the birthplace of integrated pest management, said Cathy Hemly of Green and Hemly farms on Randall Island.
"A group of pear growers, working with ag extension, came up with IPM," Hemly said.
Hemly shared the IPM history during a tour of the delta for the International Food Bloggers Conference (IFBC), held over the weekend in Sacramento.
Hemly said about 50 years ago, pear farmers were faced with growing pest resistance to the pesticide glutathione, which was used routinely to control coddling moth.
"Growers got together with a team of UC scientists. They were the NASA engineers of their day," Hemly said. "We had to figure out a better way to monitor pests. The growers and the university got that started."
An emerging technology, confusing male coddling moth by releasing pheromones into the air, was showing promise. Protocols for using pheromone confusion were developed with the pear industry, Hemly said.
The relationship with the pear industry and UC Cooperative Extension continues to this day. The IFBC tour visited the Randall Island pear farm of Richard Elliott and family. Son Rich Elliott said the family attends UC Cooperative Extension advisor Chuck Ingels' pear research meeting every year. Another son, Ryan Elliott, said fireblight is the biggest disease problem they deal with on the farm.
"Chuck Ingels comes by," Ryan Elliott said. "We learn a lot from him."
IFBC ended yesterday, but the organizers announced the conference will be back in Sacramento, scheduled for Sept. 29 - Oct. 1, 2017.