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Scientists search for an odor Asian citrus psyllids cannot resist

New chemical attractants could make a better Asian citrus psyllid trap.
UC Agriculture and Natural Resources scientists based at UC Riverside are honing in on odors that might lure Asian citrus psyllids into traps, and other odors that will keep them away from citrus trees, reported Mark Muckenfuss in the Riverside Press-Enterprise.

Anandasankar Ray, professor in the Department of Entomology at UCR, along with two other researchers, published results recently that Ray believes are promising enough they may soon be adapted for grower use.

Ray and his team tested three attractant odors in El Monte backyards using yellow sticky traps. More than twice the number of psyllids were found in the scented traps compared to unscented traps, the article said. In time the researchers will also test chemicals that can mask odors that are pleasant to Asian citrus psyllids and some that repel the insects.

Other research projects underway at UC Riverside to combat Asian citrus psyllid and the disease it can spread were also noted in the Press-Enterprise article. They are: biological controls, including a tiny wasp imported from Pakistan that feeds on the psyllids; insecticides; developing resistant strains of citrus trees; finding a way to kill the bacteria spread by psyllids once it is in the tree; and discovering ways to identify diseased trees earlier.

Posted on Thursday, October 30, 2014 at 2:19 PM

Good News for the Bees!

Good news for the honey bees!

And none too soon.

U.S. Department of Agriculture (USDA) Secretary Tom Vilsack announced today (Oct. 29) in a press release that "more than $4 million in technical and financial assistance will be provided to help farmers and ranchers in the Midwest improve the health of honey bees, which play an important role in crop production."

 “The future of America's food supply depends on honey bees, and this effort is one way USDA is helping improve the health of honey bee populations,” Vilsack said in the USDA release. “Significant progress has been made in understanding the factors that are associated with Colony Collapse Disorder and the overall health of honey bees, and this funding will allow us to work with farmers and ranchers to apply that knowledge over a broader area.”

The declining honey bee population is besieged with health issues, exacerbated by pests, parasites, pesticides, diseases, stress and malnutrition  Nationally, however, honey bees pollinate an estimated $15 billion worth of crops, including more than 130 fruits and vegetables. If you enjoy such produce as almonds, apples, cherries, cucumbers, and peaches, thank a bee for its pollination services.

USDA's Natural Resources Conservation Service (NRCS) is focusing the effort on five Midwestern states: Michigan, Minnesota, North Dakota, South Dakota and Wisconsin.

Why the Midwest? "From June to September, the Midwest is home to more than 65 percent of the commercially managed honey bees in the country. It is a critical time when bees require abundant and diverse forage across broad landscapes to build up hive strength for the winter."

The announcement renews and expands what USDA calls "a successful $3 million pilot investment that was announced earlier this year and continues to have high levels of interest."  It's all part of the June 2014 Presidential Memorandum – Creating a Federal Strategy to Promote the Health of Honey Bees and Other Pollinators, which directs USDA to expand the acreage and forage value in its conservation programs.

Funding will be provided to producers through the Environmental Quality Incentives Program (EQIP). Applications are due Friday, Nov. 21.

This means that the farmers and ranchers will receive support and guidance to implement conservation practices that will provide safe and diverse food sources for honey bees. This will include appropriate cover crops or rangeland and pasture management. In addition to providing good forage and habitat for honey bees and other pollinators, the actions taken are expected to reduce erosion, increase soil health and inhibit invasive species.

California also will benefit. "This year, several NRCS state offices are setting aside additional funds for similar efforts, including California – where more than half of all managed honey bees in the U.S. help pollinate almond groves and other agricultural lands – as well as Ohio and Florida," according to the release.

A nice push for the pollinators!

Honey bee foraging on mustard. (Photo by Kathy Keatley Garvey)
Honey bee foraging on mustard. (Photo by Kathy Keatley Garvey)

Honey bee foraging on mustard. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, October 29, 2014 at 9:26 PM

My Favorite Bee: The Carpenter Bee

First, I want to say that I have never had an infestation of carpenter bees. I just enjoy seeing them in my front yard. If my home or any of my fences were suffering from an infestation of carpenter bees, I might have to rescind this post. If you think you might have an infestation of carpenter bees, please check out this link.

I think most, if not all, home gardeners have heard about the plight of the honeybees in the past few years. But did you know that there are most than 25,000 species of bees around the world? The United States is home to about 4,000 species. Both honey bees and bumble bees (family Apidae) are what are called "social" bees - meaning that they create colonies (hives) and work as a team. I was surprised to learn during my training to become a Contra Costa County Master Gardener that most native bees are solitary bees - I did not know that any bees were solitary! Carpenter bees fall into this category - a solitary bee.

 

Just because carpenter bees are solitary and do not belong to a colony does not mean that they are not good pollinators. The carpenter bees that I see most often are buzzing around my front yard - specifically around the Hot Lips Sage that grows in the front corner of my front yard

Now, you might wonder, why are these bees called carpenter bees?They make their nests in old wood - in fence posts and eaves most commonly in developed areas. Digger bees are similar in appearance and size to carpenter bees, and they make their nests in bare soil.

I do not know why, but I have always enjoyed seeing one or two of these big, black beauties buzzing around my yard. In researching for this post I learned that male carpenter bees, which are the solid black ones I see most often, cannot sting. So yes, I enjoy them even more now! So keep you eyes open, and the next time you see one of these beauties thank them for the solitary hard work they do in pollinating our plants!

 

 

Posted on Wednesday, October 29, 2014 at 7:00 AM

Anthony Cornel Knows Mosquitoes

The yellow fever mosquito, Aedes aegypti. (CDC Photo)
Medical entomologist Anthony “Anton” Cornel knows his mosquitoes--and a few snakes, too.

When he was doing research in Brazil in September, he draped a snake around his neck and posed for the camera.

His favorite research subjects, though, are mosquitoes.

Among them:

  • The yellow fever mosquito, Aedes aegypti, found throughout the tropics and subtropics and a  newly invasive species in central California.
  • The West Nile virus mosquito, Culex quinquefasciatus, found throughout much of the world.
  • The malaria mosquito, Anopheles gambiae, which wreaks worldwide havoc.

Cornel's name appeared in the news this week when the UC Davis lab of Walter Leal announced that it had found the odorant receptor that repels DEET in the southern house mosquito, Culex quinquefasciatus mosquito. Cornel provided the mosquitoes that allowed the Leal lab to duplicate his colony. Proceedings of the National Academy of Sciences (PNAS) published the work Oct. 27.

Culex quinquefasciatus transmits West Nile virus and other diseases. (Photo by Kathy Keatley Garvey)
Cornel, based at the UC Kearney Agriculture and Research Center, Parlier, and an associate professor in the UC Davis Department of Entomology and Nematology faculty, has studied mosquitoes for more than two decades. He collects, rears and researches mosquitoes from all over the world, including the United States, Mali, Cameroon, Comoros, Tanzania, South Africa and Brazil. 

Cornel's main research keys in on the population genetics and ecology of West Nile virus vectors in the United States and population genetics and ecology of major malaria vectors in Africa.

“Anton is a great asset to our program, a wonderful colleague, and a nice team player,” said Leal, a professor in the Department of Molecular and Cellular Biology.  “We benefit greatly from his generosity by sharing not only mosquito colonies, but also his encyclopedic knowledge on mosquito biology and ecology. We shared co-authorship in a number of publications, and many more are coming.”

Cornel collaborates with Leal on oviposition attraction in Culex quinquefasciatus and “we are now endeavoring to come up with effective oviposition attractive chemical lures to use in virus surveillance and kill traps.”

The malaria mosquito, Anopheles gambiae. (Photo by Anthony Cornel)
However, the mosquito that's alarming residents of central California is the yellow fever mosquito, Aedes aegypti. Infected mosquitoes can transmit dengue, chikungunya and yellow fever viruses and other diseases. 

“The invasion of Aedes aegypti into central California has been of great concern especially as current control methods do not appear to be working very well,” said Cornel, who works closely with state's mosquito abatement personnel. “We have found that the Aedes aegypti have insecticide resistance genes which likely explains why their ultra-low volume (ULV) and barrier spray applications have not worked as well as expected. Work will be ongoing next year when the Aedes aegypti become active again after a brief slow overwintering period from November to March.”

A native of South Africa, Cornel received his doctorate in entomology, focusing on mosquito systematics, in 1993 from the University of the Witwatersrand, Johannesburg. He completed a post-doctoral fellowship with the Entomology Branch of the Centers for Disease Control and Prevention (CDC), Atlanta, before joining UC Davis in 1997 as an assistant professor and researcher.

How did he get involved in mosquitoes? “My interest in mosquito research started in the mid-1980s when I agreed to conduct a masters study under the guidance of Dr. Peter Jupp at the National Institute of Virology who researched West Nile and Sindbis viruses transmitted by mosquitoes in South Africa,” Cornel recalled. “Thereafter I continued to work on mosquitoes as a scientist employed at the South African Institute for Medical Research before moving to the USA.” 

“Who would have thought that that the expertise that I gained on West Nile virus as a master student in South Africa would be used many years later after West Nile virus invaded and spread throughout the USA?”

For more than two decades, Cornel has teamed with fellow medical entomologist and “blood brother” Professor Gregory Lanzaro of the UC Davis School of Veterinary Medicine to study malaria mosquitoes in the West African country of Mali. Their work is starting to show significant results.

“Because of our commitment to conduct long term longitudinal studies and not static investigations,” Cornel said, “we have now shown that considerable selective processes are taking place causing spatiotemporal dynamics of gene flow and fitness events in major malaria vectors M (now Anopheles coluzzii)  and S (now Anopheles gambiae)  and M/S hybrids in West Africa.” 

“We are currently establishing further evidence of the important role of insecticide resistance traits in spatiotemporal dynamics of Anopheles coluzzii, Anopheles gambiae  and the Bamako form.” Cornel noted that these results have “considerably important implications in future efficacies of insecticide treated bednets to control indoor biting malaria vectors in West Africa.”

Cornel also teams with Lanzaro and Professor Heather Ferguson of the University of Glasgow to examine the ecology and associated genetics of the major malaria vector Anopheles arabiensis in Tanzania. They began working on the project four years ago.

One of his newest projects is the study of population/genetics, insecticide resistance and cytogenetics in the major malaria vector in Brazil. Cornel and Lanzaro launched their study in September when they traveled to Brazil to begin targeting the culprit, Anopheles darlingi, a “widely distributed species that has adapted to survive in multiple ecological zones and we suspect that it may consist of multiple incipient or closely related species,” Cornel said.

“While in Brazil I collected larvae and dissected salivary glands from them to examine their polytene chromosome inversion structure and polymorphisms,” Cornel related. “Inversions are vitally important to consider in genetic analyses and it takes considerable patience to interpret the chromosomes.”

Cornel and Lanzaro collaborate with Professor Paulo Pimenta of the Laboratory of Medical Entomology, René Rachou Research Centre- FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil. The UC Davis medical entomologists hope to produce good preliminary data from their research trip to write grants and establish a long-term project in Brazil.

Cornel also studies avian malaria. That interest sparked four years ago when he began working in Cameroon with scientists from UCLA and San Francisco State University (SFSU), including SFSU's Ravinger Sehgal, who studies avian blood parasites. Cornel's graduate student Jenny Carlson, in her final year of her Ph.D studies at UC Davis, is investigating avian malaria in Fresno County. 

The Cornel-Carlson research implicates that considerable fidelity exists between Culex mosquito species and species of plasmodium they transmit. “This is contrary to the currently held belief that all Culex mosquitoes are equally capable of transmitting avian malaria,” Cornel said. “In our investigations, we described a new species of avian malaria which is very common in songbirds in Fresno County (published in Parasitology Research).”

Cornel plans to continue working with Sehgal investigating the effects of deforestation on transmission of avian parasites in Cameroon. They recently submitted a National Science Foundation grant proposal. “A large swath of primary forest is slated to be deforested in Cameroon and replaced with Palm oil plantations and we will investigate the effects of this hopefully, as it happens.”

Also new on the horizon: Cornel will be starting a new mosquito-borne virus project in February. He received a Carnegie Foundation scholarly three-month fellowship to work in South Africa (February through to April). The primary objective of the project? To examine mosquito-borne viruses cycling in seven national parks in South Africa and two National Parks in Bostwana.

“It's extremely difficult to get permission to conduct field research in national parks in Southern Africa and this provides an unprecedented exciting opportunity for me to work with a friend, Professor Leo Braack from the University of Pretoria, in these parks. One has to be very careful working in some of these parks at night because of the wild predators, elephants, hippos and buffalo.”  

Cornel is active in the 30- member Center for Vectorborne Diseases (CVEC), headquartered in the UC Davis School of Veterinary Medicine and considered the most comprehensive vectorborne disease program in California. Both interdisciplinary and global, CVEC encompasses biological, medical, veterinary and social sciences.

Medical entomologist Anthony Cornel with a snake in Brazil.
Medical entomologist Anthony Cornel with a snake in Brazil.

Medical entomologist Anthony Cornel with a snake in Brazil.

UC Davis medical entomologists Anthony Cornel (foreground) and Gregory Lanzaro make annual trips to Mali to study malaria mosquitoes.
UC Davis medical entomologists Anthony Cornel (foreground) and Gregory Lanzaro make annual trips to Mali to study malaria mosquitoes.

UC Davis medical entomologists Anthony Cornel (foreground) and Gregory Lanzaro make annual trips to Mali to study malaria mosquitoes.

Posted on Tuesday, October 28, 2014 at 5:04 PM

California pest invasion rate increasing

Introduction of new invasive pests into California seems to be increasing, reported Todd Fitchette in Western Farm Press. The story was based on presentations at the recent professional crop advisors convention in Anaheim by UC Cooperative Extension specialists Mark Hoddle and UC Riverside entomology professor Richard Stouthamer.

Before 1989, Hoddle said, California saw about six new pest invasions per year. The number has risen to about 10 per year, and the cost amounts to about $3 billion annually.

Asian citrus psyllid, a relatively recent invader in California, has farmers particularly worried because of the pest's ability to spread the lethal bacterial disease huanglongbing in citrus. In late 2011, Hoddle's lab began releasing a natural enemy of the psyllid he collected in the Punjab, Pakistan, a stingless wasp called Tamarixia radiata.

According to the Western Farm Press article, Hoddle is now studying a second natural enemy of ACP -  Diaphorencyrtus aligarhensis - in quarantine at UC Riverside.

Stouthamer is studying another troublesome invasive pest in California, the polyphagous shot hole borer. The pest attacks many tree species that shade California streets, landscapes and parks; their greatest threat to agricultural production appears to be in avocados.

At the meeting, Hoddle said there is a growing and vocal minority of ecologists who believe invasive species are not such a serious problem, Fitchette wrote.

“They think we should just relax and let them install themselves in the environment and do whatever they like,” Hoddle said. “I think that's a wrong viewpoint to be taking with a lot of these organisms.”

UC Cooperative Extension specialist Mark Hoddle inspects a citrus tree for insects.
Posted on Tuesday, October 28, 2014 at 9:05 AM

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