Posts Tagged: IPM
Outsized wildfires, rising sea levels and disappearing glaciers are dramatic signs of climate change, but not the only ones. New UC Agriculture and Natural Resources research provides forewarning of a change that will be economically and environmentally costly to California – a fifth generation of navel orangeworm, the most destructive pest of almonds, walnuts and pistachios.
Navel orangeworm (NOW) will be more problematic in the future because of warming temperatures, UC Cooperative Extension scientists report in Science of the Total Environment.
Like most insects,NOW's development rate, physiology, behavior and reproduction are highly dependent on the ambient temperature. When the weather warms in the spring, NOW moths emerge from the nuts left in the tree or on the ground during the winter. After mating, females then recycle those last year's nuts to lay eggs and complete one generation. Adults emerged from that first and subsequent generations then lay eggs on in-season hull-splitalmondnuts, where larvae feeding damages the crop. Typically the pests fly three to four times per year – with more flights in areas with warmer weather.
“Warmer temperatures can result in early activity of the pests in the spring and increased activity during the season,” said Tapan Pathak, the UC Cooperative Extension climate change specialist and the study's principle investigator.
The scientists looked at 10 climate models to determine what nut farmers can expect to face over the next 80 years and applied NOW developmental models to the changing climate. Daily maximum and minimum temperature data were obtained for 1950 to 2005, and future projections stretched to 2100.
“The fifth generation can happen in the next few decades,” said Jhalendra Rijal, UC integrated pest management advisor and co-author of the research. “The climate models suggest that spring will begin earlier. That causes insect activity to start earlier. With increased temperatures through the season, the number of days to complete a generation is less. At the end of 2050 or so, we'll see an extra generation.”
The study focused on 23 counties in the Central Valley, from Shasta County in the north to Kern County in the south, where 1.78 million bearing acres of nut crops are planted. About two-thirds of that acreage is planted to almonds, 20% in walnuts and 16% in pistachios. The tree nut crops were valued at more than $8 billion combined in 2018, according to the California Department of Food and Agriculture.
The completion of the NOW life cycle is faster in pistachio compared to almonds and walnuts, so the potential risk of crop damage and economic loss is higher in pistachio, according to the research report. There are only a few years historically in which the models detected the fifth generation of NOW in Kern County pistachios. The occurrence of the fifth generation in almonds and walnuts was historically nonexistent, but it starts appearing in three southern counties by 2040 and eleven counties by 2100.
“In order to alleviate some of the risks related to navel orangeworm damage to nut crops, it is important to implement integrated pest management practices,” Pathak said.
IPM preventative and control measures include sanitizing the orchard during the winter by removing all the nuts on the ground and in the trees, applying synthetic reproductive hormones to limit the pests' ability to find mates, encouraging natural enemies, judicious of least-toxic pesticides if necessary and harvesting the crop early to avoid a new generation of the pest.
“A better understanding of future navel orangeworm pressure on California's major nut crops can help facilitate and strategize integrated pest management practices in order to minimize production risks,” Pathak said.
The results of the research can also inform growers and pest control advisers about the potential increased threat from other pests as the climate changes.
Annual Ag Innovations Conference and Trade Show will be held March 18 in Santa Maria, Ca. This year the focus will be on comprehensive crop care.
With the underlying principle of integrated pest management, the conference will cover topics ranging from identifying a pest to forecasting crop health, according to conference organizer Surendra Dara, University of California Cooperative Extension entomology and biologicals advisor.
Each year the Ag Innovations Conference series introduces new technologies for growers.
“This conference provides the latest updates from university, federal agency, and industry researchers and growers on crop production and protection technologies,” Dara said. “Attendees can also visit the trade show and see what various companies offer for their crop needs.”
Speakers will discuss
- Regulatory update on pesticides
- Biology and management of the spotted lanternfly, a potential threat to California grapes
- Living with leafroll virus
- Sustainable pest and disease management in strawberry
- Regulatory, commercial, and social elements in the new integrated pest management model
- Automated weeding in lettuce and tomato using a crop-marking system
- Identification and characterization of a new virus associated with lettuce dieback disease
- Abiotic stress defense, a new way to grow crops
- Transit: Solutions for sustainable agriculture
- Climate smart farming: Improving soil health for improved crop productivity
- Microalgae in agriculture for optimal plant growth
- The future of microbial augmentation in agriculture
- Biocontrol solutions for major crops on the Central Coast
- How the BASF product portfolio supports IPM in small fruits and vegetables
- Mating disruption for managing diamondback moth
- Managing diseases and insects in strawberry with biopesticides
- Disease management in organic crops
- Artificial intelligence in agriculture for forecasting and decision-making
Early registration until March 8 is $50 per individual. View the full agenda and register at https://ucanr.edu/AIC2020. Onsite registration is $100 on March 18. Registration includes lunch and refreshments; 6.0 CCA and 4.0 DPR CEUs have been approved. The conference will be at the Veterans' Memorial Center at 313 W. Tunnell Street in Santa Maria.
For more information about registration or exhibiting in the trade show, please contact Hiromi Peck at (805) 781-5940.
The University of California Statewide Integrated Pest Management Program (UC IPM) is celebrating its 40th anniversary. Established July 1, 1979, with funding from the California Legislature, UC IPM built upon a growing movement to reduce dependence on pesticides. Drawing on expertise across the University of California system, UC IPM develops and distributes UC's best information on managing pests using safe and effective practices that protect people and the environment.
Over the years, UC IPM expanded its efforts beyond agriculture to include residential audiences such as schools, landscape and structural professionals, and public health agencies; public agencies; and natural resource managers. UC IPM works through Cooperative Extension to deliver information to clientele in every California county.
Since its inception, UC IPM delivered science-based integrated pest management (IPM) information. There's no plan to change this, but it's exciting to think about the next 40 years. Improvements in technology have changed how people learn and who they get information from. UC IPM's website and online tools need to grow and change as our users change the way they like to get information. And some of these changes will be mandatory as our funding sources have changed as well.
Some things haven't changed like the IPM advisors and affiliated advisors solving problems and providing local, practical, trusted pest management information. Over the last 40 years, pest management successes happened in both agriculture and communities.
- UC IPM and Cooperative Extension advisors joined a multi-government and grape industry team to develop and extend a low-impact pest management program for European grapevine moth and conduct research to inform regulatory policy. In 2016, European grapevine moth was declared eradicated.
- UC IPM and the UC Master Gardener Program are key partners in assisting the general public with pest issues around the home and garden. UC IPM trains more than 600 UC Master Gardener volunteers each year on topics ranging from pest identification to understanding home-use pesticides.
- UC IPM partnered with stormwater agencies and state regulators to train IPM Advocates. IPM Advocates work as consultants to help retail stores provide information about less toxic products and the safe use of pesticides. Surveys after the IPM Advocates program indicated that 76% of participating stores used the UC IPM website for identifying pests or solving problems, more than 70% increased shelf space for green or less-toxic pest management products, and more than 76% increased sales of green products.
- UCIPMandCooperativeExtensionadvisors worked together with commodity boards and the United States Department of Agriculture (USDA) to develop a successful mating disruption program to prevent codling moth damage in pears without pesticides. In 2009, 95% of California pear acreage used pheromone mating disruption, eliminating the need for codling moth pesticide sprays.
UC IPM has dedicated program staff at the UC Agriculture and Natural Resources (ANR) headquarters in Davis. The staff provides IPM leadership, training, content development, and is the magical information technology (IT) presence behind UC IPM's website and online tools. UC IPM is also the home of the Pesticide Safety and Education Program (PSEP) in California, which trains pesticide safety trainers to teach pesticide applicators, pesticide handlers, and fieldworkers safe practices.
UC IPM will continue conducting research to solve important pest problems, extending IPM programs to practitioners, providing training, and developing outreach material. Over UC IPM's next 40 years, be on the lookout for changes for the better. Changes that engage users by using new technology, adapt UC IPM's existing knowledge into easy to use decision-making tools, and facilitate the development of new products—products that Californians seeking pest solutions can use to safely and effectively solve their pest problems.
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.