What are the effects of fire and smoke and ash and heat and all the other potential things that might affect plants and animal products that we eat?????? Can you simply wash off contaminants? What impact on the soil, itself? Does anything special need to be done to start producing food again? Come learn more.
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There is a purpose
Without their keen sense of smell, mosquitoes wouldn't get very far. They rely on this sense to find a host to bite and spots to lay eggs.
And without that sense of smell, mosquitoes could not locate their dominant source of food: nectar from flowers.
"Nectar is an important source of food for all mosquitoes," said Jeffrey Riffell, a professor of biology at the University of Washington. "For male mosquitoes, nectar is their only food source, and female mosquitoes feed on nectar for all but a few days of their lives."
Yet scientists know little about the scents that draw mosquitoes toward certain flowers, or repel them from others. This information could help develop less toxic and better repellents, more effective traps and understand how the mosquito brain responds to sensory information -- including the cues that, on occasion, lead a female mosquito to bite one of us.
Riffell's team, which includes researchers at the UW, Virginia Tech and UC San Diego, has discovered the chemical cues that lead mosquitoes to pollinate a particularly irresistible species of orchid. As they report in a paper published online Dec. 23 in the Proceedings of the National Academy of Sciences, the orchid produces a finely balanced bouquet of chemical compounds that stimulate mosquitoes' sense of smell. On their own, some of these chemicals have either attractive or repressive effects on the mosquito brain. When combined in the same ratio as they're found in the orchid, they draw in mosquitoes as effectively as a real flower. Riffell's team also showed that one of the scent chemicals that repels mosquitoes lights up the same region of the mosquito brain as DEET, a common and controversial mosquito repellant.
Their findings show how environmental cues from flowers can stimulate the mosquito brain as much as a warm-blooded host -- and can draw the mosquito toward a target or send it flying the other direction, said Riffell, who is the senior author of the study.
The blunt-leaf orchid, or Platanthera obtusata, grows in cool, high-latitude climates across the Northern Hemisphere. From field stations in the Okanogan-Wenatchee National Forest in Washington state, Riffell's team verified past research showing that local mosquitoes pollinate this species, but not its close relatives that grow in the same habitat. When researchers covered the flowers with bags -- depriving the mosquitoes of a visual cue for the flower -- the mosquitoes would still land on the bagged flowers and attempt to feed through the canvas. Orchid scent obviously attracted the mosquitoes. To find out why, Riffell's team turned to the individual chemicals that make up the blunt-leaf orchid's scent.
"We often describe 'scent' as if it's one thing -- like the scent of a flower, or the scent of a person," said Riffell. "Scent is actually a complex combination of chemicals -- the scent of a rose consists of more than 300 -- and mosquitoes can detect the individual types of chemicals that make up a scent."
Riffell describes the blunt-leaf orchid's scent as a grassy or musky odor, while its close relatives have a sweeter fragrance. The team used gas chromatography and mass spectroscopy to identify dozens of chemicals in the scents of the Platanthera species. Compared to its relatives, the blunt-leaf orchid's scent contained high amounts of a compound called nonanal, and smaller amounts of another chemical, lilac aldehyde.
Riffell's team also recorded the electrical activity in mosquito antennae, which detect scents. Both nonanal and lilac aldehyde stimulated antennae of mosquitoes that are native to the blunt-leaf orchid's habitat. But these compounds also stimulated the antennae of mosquitoes from other regions, including Anopheles stephensi, which spreads malaria, and Aedes aegypti, which spreads dengue, yellow fever, Zika and other diseases.
Experiments of mosquito behavior showed that both native and non-native mosquitoes preferred a solution of nonanal and lilac aldehyde mixed in the same ratio as found in blunt-leaf flowers. If the researchers omitted lilac aldehyde from the recipe, mosquitoes lost interest. If they added more lilac aldehyde -- at levels found in the blunt-leaf orchid's close relatives -- mosquitoes were indifferent or repelled by the scent.
Using techniques developed in Riffell's lab, they also peered directly into the brains of Aedes increpitus mosquitoes, which overlap with blunt-leaf orchids, and a genetically modified strain of Aedes aegypti previously developed by Riffell and co-author Omar Akbari, an associate professor at UC San Diego. They imaged calcium ions -- signatures of actively firing neurons -- in the antenna lobe, the region of the mosquito brain that processes signals from the antennae.
These brain imaging experiments revealed that nonanal and lilac aldehyde stimulate different parts of the antenna lobe -- and even compete with one another when stimulated: The region that responds to nonanal can suppress activity in the region that responds to lilac aldehyde, and vice versa. Whether this "cross talk" makes a flower attractive or repelling to the mosquito likely depends on the amounts of nonanal and lilac aldehyde in the original scent. Blunt-leaf orchids have a ratio that attracts mosquitoes, while closely related species do not, according to Riffell.
"Mosquitoes are processing the ratio of chemicals, not just the presence or absence of them," said Riffell. "This isn't just important for flower discrimination -- it's also important for how mosquitoes discern between you and I. Human scent is very complex, and what is probably important for attracting or repelling mosquitoes is the ratio of particular chemicals. We know that some people get bit more than others, and maybe a difference in ratio explains why."
The team also discovered that lilac aldehyde stimulates the same region of the antenna lobe as DEET. That region may process "repressive" scents, though further research would need to verify this, said Riffell. It's too soon to tell if lilac aldehyde may someday be an effective mosquito repellant. But if it is, there is an added bonus.
"It smells wonderful," said Riffell.
Mosquitoes are Drawn to Flowers as Much as People
Caption: An Aedes mosquito with pollen sacs on its eyes feeding from Platanthera flowers.
Credit: Kiley Riffell
The following is compiled from the January newsletter of the Ventura County ACP-HLB Task Force
Results of November scouting trip are available for the Canine Detection Team
A team of six dogs and three handlers from F1K9 scouted 20 citrus ranches in Ventura County between Nov. 18 and Nov. 22, 2019. The visit included returns to several ranches scouted during F1K9's July deployment, as well as numerous ranches in new areas. A total of 4,650 trees were inspected, and dogs alerted on 353 (8%). Alerts occurred at every location. The percentage of scouted trees that triggered alerts at each ranch or block ranged from 3% to 22%. Download the full report here.
The canine detection team is returning next week to scout more orchards. However, their time is fully allocated. Planning is under way for their more permanent return by February or March 2020. If you wish to have your grove(s) scouted in the future, please send an email indicating your interest to Farm Bureau CEO John Krist at firstname.lastname@example.org.
A total of 1,760 residential citrus trees have been confirmed PCR-positive for HLB in San Bernardino, Riverside, Los Angeles, and Orange counties. Information about the expanded HLB quarantine, and a tally of the HLB confirmations (updated weekly) can be found at CitrusInsider.org. Regulatory actions required by the state in response to an HLB detection are detailed in CDFA's Action Plan (https://www.cdfa.ca.gov/citruscommittee/docs/ActionPlan.pdf). To see the proximity of your citrus to the nearest confirmed HLB, you can enter an address in this Google maps-style website: www.ucanr.edu/hlbgrowerapp. The site also provides a direct link to the HLB Voluntary Best Practices most relevant to your location.
The winter ACP area-wide management treatments have begun, and treatment reminders have been distributed. If you did not receive a reminder, please contact grower liaison Sandra Zwaal (email@example.com) or Cressida Silvers (firstname.lastname@example.org) to be added to the distribution list.
Twenty-four of Ventura County's 50 psyllid management areas (PMAs) qualified for the winter buffer treatments, in which the California Department of Food and Agriculture will apply pesticides to residential citrus within 400 meters of commercial groves. The requirements to qualify for residential buffer treatments are expected to change slightly in the future. Stay tuned for the UC recommendations and a vote from the Citrus Pest and Disease Prevention Committee (CPDPC) on the new requirements.
Report neglected and abandoned citrus
Help prevent neglected and abandoned citrus from serving as a breeding ground for ACP and the spread of HLB by reporting its location to the County Agricultural Commissioner's office at (805) 388-4222. If your citrus is not worth the resources required to protect it from ACP and HLB, it may be a good time to consider removing the trees.
The next CPDPC meeting will be on Jan. 15. Click here to download the agenda.The CPDPC makes decisions on behalf of the citrus industry, and attendance by all citrus growers and affiliates is encouraged. The Coastal Region committee representative is Kevin Ball; contact him at email@example.com. Meetings are free and open to the public, and can be attended in person, via webinar, or by phone. The agenda and prior meeting minutes can also be found at https://www.cdfa.ca.gov/citruscommittee/.
The 9th Annual UC Riverside Citrus Field Day for citrus growers and citrus industry representatives is Jan. 29. Click here to download the agenda and registration information.
The University of California has developed a series of one-hour webinars, designed for growers and pest control advisors, that will highlight various pest management and horticultural topics for citrus and avocados. During each session, a UC expert on the subject will make a presentation and entertain write-in questions via chat during and/or after the presentation. To learn more, go to https://ucanr.edu/sites/ucexpertstalk/.
Contact your grower liaisons if you have additional questions:
Craft breweries aren't just a fun place to meet up with friends. They may be fueling an unprecedented geographic expansion of hop production across the U.S., according to researchers at Penn State and The University of Toledo. Their findings suggest that as more craft breweries emerge around the country, so may new opportunities for farmers.
Hops are a key ingredient in beer production, providing aroma and bittering characteristics. Before 2007, hop production in the U.S. was limited to only three Pacific Northwest states--Oregon, Washington, and Idaho--according to Claudia Schmidt, assistant professor of agricultural economics in Penn State's College of Agricultural Sciences. Citing a report released this year by the Hop Growers of America, she said that 29 states are now engaging in hop production.
"Our study is the first to systematically show that the number of hop farms in a state is related to the number of craft breweries," said Schmidt. "It suggests that in areas where hop production is possible and not cost-prohibitive, breweries are expanding markets for farmers and providing an opportunity to diversify farm income."
Using data from the U.S. Census of Agriculture and ReferenceUSA, the researchers found that from 2007 to 2017, the number of breweries in the U.S. more than quadrupled from 992 to more than 4,000, and that the number of breweries in a state is associated with more hop farms and hop acres five years later. The number of hop farms grew from 68 to 817, and hop acreage expanded from 31,145 to 59,429 acres.
"This growth has not only led to interesting changes in the locations of hop farms across the U.S., but it has positioned the U.S. as the largest producer of hops globally, both in terms of acreage and production," said Elizabeth Dobis, a postdoctoral scholar at the Penn State-based Northeast Regional Center for Rural Development, and lead author of the study.
Working with farm, brewery, and climate data, the researchers developed a statistical model to determine whether new craft breweries in a state between 2007 and 2017 resulted in a larger number of hop producers and hop acres planted, by both new and existing growers in that state. They built a time-lag into their model to identify the effect of new breweries over time. They also controlled for other variables that may influence farmers to start growing hops, such as average farm size, average net farm income, and climate.
Their findings, which were published recently in the Journal of Wine Economics, are correlational and do not point to a clear cause-and-effect. However, the time-lag built into the model indicates that the growth in breweries preceded the growth in hop farms, said Dobis.
One possible explanation for the trend is that the growing consumer demand for locally sourced food and beverages encourages craft brewers to seek out locally grown ingredients, said Schmidt.
"While most craft breweries serve a local market, they haven't always sourced local ingredients for their beers," Schmidt said. "But if you're a brewer looking to differentiate yourself in an increasingly crowded market, sourcing ingredients locally is an approach that some brewers have found to be effective."
For example, in a project unrelated to this study, Penn State Extension's Kristy Borrelli and Maria Graziani conducted focus groups with Pennsylvania craft brewers, who reported that sourcing ingredients locally helps them connect with their customers' sense of place and preference for a flavor profile that is unique to the region.
If more brewers are looking for hops grown nearby, then more farmers may be willing to try growing them, even if only on a small scale. For instance, in Pennsylvania only 17 farms reported hop production in 2017, and their combined acreage is small--only 21 acres in all, according to the U.S. Census of Agriculture.
Looking forward, the researchers said that they will collaborate with Penn State Extension to identify the specific attributes and price points that Pennsylvania craft brewers are looking for in order to help inform farmers' production decisions.
The Role of Craft Breweries in Expanding (Local) Hop Production
- Author: A. James Downer
Jim Downer is an Advisor who has worked extensively on tree - avocado especially - pathology. His title econpases Pathology of landscape ornamentals , Phytophthora Root Rot, Mulches, Potting soils, Palm horticulture, "climate ready" trees, arboriculture, Master Gardener Advisor.
The word sabbatical comes from the word Sabbath which most of us take to be a day of rest. So naturally most people not affiliated with Universities would assume that sabbaticals are a kind of paid vacation. After a certain number of years professors can leave for a year-long vacation somewhere. The reality of sabbaticals is quite different. As UC academics farm advisors have a sabbatical privilege, although many of my colleagues never take the opportunity. A well-known pomologist in Northern California has never taken one in her entire career. Her choice is not uncommon, because it takes a lot of change to make Change happen. You have to uproot yourself and create a life elsewhere and that takes much planning. A sabbatical is a kind of rest, because we are not doing our normal job functions, but also a time of renewal, study, or exploration that should have outputs of interest to those with whom we work (our clientele).
It is an academic privilege to take sabbaticals, but UC has requirements before we can go. Before we can leave we have to accrue credit toward the sabbatical. It takes about nine years of full time work before we are able to go away for a year. Shorter versions are also possible. While gone, we can't use any of our office or County based resources. In order to go, we need to write a plan that details what will be done, how we fund our activities, what will be learned, and how it will help our clientele. When we return, a detailed report must be filed that describes what was accomplished. Sabbaticals often involve foreign travel, but that is dependent on the nature of the sabbatical. They may be focused on research or on professional development (going back to school). In my last sabbatical over 25 years ago, I did the coursework for my Ph.D. in plant pathology.
On this sabbatical, my emphasis was writing. I have so many projects that were not written up either for journal articles or popular clientele-based publications. I had never written a UC publication before, so that was also a goal ( https://anrcatalog.ucanr.edu/) I was also interested in looking at the origin of some of the “Climate Ready Trees” that grow in the desert Southwest, and finally I did some travel to Thailand and Texas to look at shade trees in very different places.
I took up residence in the small town of Portal, AZ last October (2018). Located there is the South Western Research Station (SWRS). SWRS is a nexus for biologists studying bio diversity in the Chiricahua Mountains of Arizona. I held two meetings - one at the beginning of my sabbatical and one just at the end - on the ecology of trees in the Chiricahua Mountains. Clientele from California and all over the country and world attended. The meetings were in Collaboration with the University of Arizona. My trip to Thailand focused on horticulture in Chiang Mai and it was fascinating to see trees struggling with urban life in a tropical country. In Texas, I spoke at Texas A and M about palms and drought and learned about local drought tolerant species. My travels and findings about “climate ready” trees were summarized briefly in a sabbatical report on our website at http://ceventura.ucanr.edu/Environmental_Horticulture/Landscape/. There are links there to other publications that I was able to produce while on leave. Several of the publications are open access journals and can be easily viewed on the web. I am in the process of developing my final sabbatical report and another Landscape Notes article on trees that I recommend for Southern California landscapes.
While sabbaticals are a time of renewal and rest from current duties they also result in new knowledge and ways we can better help our clientele. I am back now and look forward to working with everyone in Ventura County on tree and plant pathology issue.