When you think of potatoes, your thoughts probably turn to baked potatoes, French fries, the "one-potato-two-potato" game, or "couch potatoes" (especially during the sheltering-in mandates). 

You're not thinking of root-knot nematodes, major pests of potatoes.

But potato growers and nematologists are.

So are the editors of the scientific journal, Nature Plants. Their current edition showcases research on root-knot nematodes by Washington State University (WSU) scientists Lei Zhang and Cynthia Gleason, and a commentary by UC Davis nematologist Shahid Siddique and colleague Clarissa Hiltl of the University of Bonn, Germany.

“Plant-parasitic nematodes are among the world's most destructive plant pathogens, causing estimated annual losses of $8 billion to U.S. growers and of nearly $78 billion worldwide," according to Siddique, an assistant professor in the UC Davis Department of Entomology and Nematology.

 “Most current control methods rely on chemical nematicides, but their use is increasingly limited due to environmental concerns," Siddique and Hiltl wrote in their News and Views column, New Allies to Fight Worms.

They commented that the WSU scientists' proposed alternative pest management strategy--naturally occurring molecules  or plant elicitor peptides (Peps)—shows promise: “Engineering a naturally occurring rhizobacterium to deliver Peps to the plant root system offers a new opportunity in integrated pest management.” 

It's better to build up the host plant's immune system rather than directly target the pathogen with chemical nematicides which “are highly toxic and have negative effects on the ecosystem," Siddique told us. 

The root-knot nematode Meloidogyne chitwoodi is a noted pest of potato production in the Pacific Northwest. Idaho leads the nation in commercial potato production, followed by Washington. Oregon ranks fourth.  California, which ranks eighth, grows potatoes year around due to its unique geography and climate.

The WSU scientists demonstrated the effective use of Peps to combat root-knot nematodes in potato (Solanum tuberosum). They engineered a bacteria, Bacillus subtillis, to secrete the plant-defense elicitor peptide StPep1.  They wrote that pre-treatment of potato roots “substantially reduced root galling, indicating that a bacterial secretion of a plant elicitor is an effective strategy for plant protection."  (See article.) 

“Besides chemical nematicides, methods of nematode management include the use of crop rotation, microbial biocontrol agents, cover crops, trap crops, soil solarization, fumigation and resistant plant varieties,” wrote Siddique and Hiltl. “However, several of these strategies are not effective or available for all crops. Nematicides are highly toxic, and their use is strictly limited due to environmental concerns. Resistant plants are often ineffective or unavailable. Microbial biocontrol agents have produced inconsistent results. In this context, the current work provides a new opportunity to manage plant-parasitic nematodes by combining two progressive strategies: the use of plant elicitors to enhance crop resistance to pathogens and the use of B. subtilis to deliver.”  

According to the UC Statewide Integrated Pest Management Program (UC IPM), root-knot nematodes "usually cause distinctive swellings, called galls, on the roots of affected plants. Infestations of these nematodes are fairly easy to recognize; dig up a few plants with symptoms, wash or gently tap the soil from the roots, and examine the roots for galls. The nematodes feed and develop within the galls, which can grow as large as 1 inch in diameter on some plants but usually are much smaller."

"Nematodes are too small to see without a microscope," UC IPM points out. "Often you become aware of a nematode problem by finding galled roots on a previous crop. However, you also can use a simple bioassay to detect root knot nematodes in garden soil. Melons seeded in pots in moist soil collected from the garden will develop visible galls on the roots in about 3 weeks when pots are kept at about 80ºF if root knot nematodes are present. As a comparison, melons planted in heat-sterilized soil won't develop galls."

Stay tuned.

The sensationalism. fear-mongering and general panic surrounding those Asian giant hornets, aka "murder hornets," detected last year in British Columbia and Washington state, are enough to curdle both the blood and the brain.

First there were the Africanized honey bees, which sensationalists called "the killer bees."

Don't even mention "assassin flies" or "bullet ants" or "deathwatch beetles."

Now there are the Asian giant hornets (AGH), Vespa mandarinia, which sensationalists have dubbed "murder hornets." 

"It's ridiculous to call them murder hornets,” says noted UC Davis wasp expert and researcher Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology, UC Davis Department of Entomology and Nematology.

“It's no more likely to sting and kill a human than a honey bee,” said Kimsey, a two-term past president of the International Society of Hymenopterists, an organization that studies bees, wasps, ants, and sawflies.

“Actually it's less likely, as honey bee venom packs quite a punch and it is exclusively designed to defend against vertebrates,” she said.

“The colony everyone is hyperventilating over was actually found on Vancouver Island, British Columbia, last September when it was destroyed and then a single, dead hornet was found in December in Blaine, Wash.,” Kimsey said. “There is no evidence that there are any more hornets in the vicinity of Vancouver or anywhere else on the West Coast.”

A colony of the Asian giant hornets was found and destroyed Sept. 18, 2019 in Nanaimo, Vancouver Island, and the single dead hornet was found Dec. 8, 2019 in Blaine.

These were the first detections of this species in North America, but there may be more, according to the Washington State Department of Agriculture (WSDA). Beekeepers have reported “observations” (which may or may not be the same species) dating back to October 2019, according to officials in Washington State University's  Department of Entomology and Cooperative Extension. They and the beekeeping organizations want to know what's out there and they want folks to keep a lookout for them. 

Said Kimsey: “A decade or more ago there was a colony of another species, Vespa asiatica, reported near the Port of Long Beach but nothing ever came of that either. A European species, Vespa crabro, was introduced into the East Coast perhaps a century ago and it is now fully established in the southeastern U.S.”

Kimsey points out that insects often come in cargo boxes from Asia to U.S. ports, establish colonies, and expand their range.

A soon-to-be-published article in the Entomological Society of America's journal, Insect Systematics and Diversity, promises to shed more light on the genus and the history of introductions in the United States.Kimsey and colleagues Allanmith-Pardo of the USDA and James Carpenter of the America Museum of History, New York, co-authored the review article.

In the abstract, the authors define Vespa as social wasps that are “primarily predators of other insects, and some species are know to attack and feed on honey bees, Apis mellifera, which makes them a serious threat to apiculture.”

“Vespa nests can be physically large, with over 1,000 workers, but usually with hundreds of workers,” they wrote. “Nests can be aerial, attached to tree branches or in shrubs, in crevices, under eaves or underground depending on the species. Depending on the latitude, nests can be either annual, started by a new queen every spring, or perennial, where young queens take over from old ones. Colonies in warm tropical climates tend to be perennial.”

Washington State University (WSU) Extension recently published an AGH fact sheet, the work of three scientists: Susan Cobey, bee breeder-geneticist and husband Timothy Lawrence, county director of Island County Extension (both formerly of UC Davis), and Mike Jensen, county director of Pend Oreille. (See https://bit.ly/2SA3TxS)

Yes, hornets are huge. They measure about two inches long, and the queens can fly up to 20 miles per day, said Cobey, who examined specimens in Japan last December and shipped some of them to WSU.

The WSU scientists wrote that AGH “is the world's largest species of hornet, native to temperate and tropical Eastern Asia low mountains and forests. The hornet is well adapted to conditions in the Pacific Northwest.”

“The primary purpose of venom is defense against predators by inflicting pain and damage,” they wrote. ”Vespa mandarinia is one of the two most venomous known insects in the world.. The amount of venom each wasp delivers (4.1 μl/ wasp) has designated V. mandarinia as the most venomous insect. In comparison, the honey bee has about 0.6μl/bee. When foraging for food in spring, the AGH is not highly defensive – unless its nest is disturbed. Late summer and fall, with the high demand for protein, they become very aggressive when attacking or occupying a honey bee colony.”

“It is critical that we identify, trap, and attempt to eliminate this new pest before it becomes established and widespread,” they wrote. “Attempts to contain the spread and eradication of this invasive insect will be most effective in trapping queens during early spring before their nests become established. Finding the nests can be a bit of a challenge. Their nests are typically in the ground though they can also be found under overhangs and within wall voids. The AGH is a strong flier and often will fly up and away and have an extensive flight range. Thus tracking can be difficult.”

They advise residents to “proceed with extreme caution and contact WSDA immediately. Do not try to exterminate the nest yourself.”

Entomologists call them Asian giant hornets or Vespa mandarinia.

Social media?

Murder hornets. 

Could we just go back to calling them Asian giant hornets or AGH or Vespa mandarina?

Please?

 

If you're a beekeeper or scientist and want to know more about bee breeding, you should access the newly produced video, "Selecting Methods for Honey Bee Breeding."

It's the work of Washington State University's Honey Bee Research Program, College of Agricultural, Human and Natural Resource Sciences (WSU CAHNRS), and accessible free online on Vimeo at https://vimeo.com/380776410.

The 28-minute video, two years in the making, is aimed at helping beekeepers improve their stock and overcome some of the obstacles they may face in their breeding efforts.

The UC Davis connection is strong. The video chronicles the work of "the father of honey bee genetics,"  Harry H. Laidlaw Jr., of the University of California, Davis, for whom the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, UC Davis, is named. The husband-wife scientific team, Susan Cobey and Timothy Lawrence, both formerly of UC Davis and now of WSU, are executive producers and are featured in the video, as is noted bee scientist Steve Sheppard, director of the WSU Center for Reproductive Biology and former chair of the WSU Department of Entomology. The trio, also the authors, describe the Page-Laidlaw Population Breeding Program, one of the most successful bee breeding program and named for Laidlaw and Robert E. Page Jr., now a distinguished emeritus professor at UC Davis and emeritus provost, Arizona State University.

The video abstract: "The selection and breeding of honey bees is perhaps the best long term and sustainable solution to the current issues facing beekeepers. Honey bee breeding poses unique challenges in that selection is at the colony and population level. This video presents a review of the complexities and basic selection methods...Beekeepers can implement this program in working toward establishing and maintaining honey bee stocks that are productive, express increased resistance to pests and pathogens, and well adapted to their environment."

The video is "a guideline, that bees respond to selection but they need to be aware of some of the pitfalls that can hamper progress," said Lawrence, county director of WSU Extension for Island County. He's been working with bees since 1963 and landed his first commercial beekeeping job in 1969.

 Sheppard says in the introductory remarks: "Honey bees are fascinating animals to work with and essential to pollination of our food supply. Currently faced with many challenges, one of our most important tools for long-term sustainability and improved honey bee health is a program of selection for stock that is hearty, productive, winters well, and has a reduced susceptibility to pests and pathogens."

Sheppard, Cobey and Lawrence know their bees. Between them, their bee experience encompasses some 150 years. Cobey, a bee breeder-geneticist who began working with bees in 1976, studied with Laidlaw, and later managed the Laidlaw facility. She is recognized as a global expert on instrumental insemination. Sheppard, who specializes in genetics and evolution of honey bees, and insect introductions and mechanisms of genetic differentiation, began working with bees while a graduate student at the University of Georgia.

 In the video, Sheppard points out that "beekeepers recognize the need for more rigorous programs to select, improve and maintain their breeding stocks. The varroa mite and the movement of Africanized honey bees adds to this urgency. The principles discussed here serve as a guide to develop and establish a successful and practical breeding program with a focus on the traits you choose to enhance is your breeding population." 

Sheppard describes the basic prerequisites for a bee breeding program as six-fold:

1. Maintain a diverse population to provide the basis for selection
2. A proficiency in queen and drone rearing
3. Establish a selection index of desired traits 
4. Careful record-keeping
5. Control of pests and diseases, and
6. A method of controlled mating.

"The honey bee colony is a superorganism and this complicates the selection process," says Cobey, who breeds Carniolan bees. "Keeping your breeding program simple is key. Genetic diversity within the colony as well as within the population increases honey bee fitness. Several mechanisms contribute to this diversity:

1. The high mating frequency of the queen.
2. Semen storage--after mating only about 10 percent of the semen collected migrates to the spermatheca, although this represents each drone she has mated with."
3. The high rate of recombination. a queen can mate with up to 60 drones, though typically mates with 15 to 20 drones. This mating behavior seems risky and inefficient, though is very successful in creating a genetically diverse superorganism, the colony."

"The many subfamilies of worker bees represented by the different drones mated, subfamilies specialize in different traits," Cobey says, "which together contribute to colony fitness."

She relates that "beekeepers and bee researchers have been selecting the honey bee for many years--some of the earliest attempts included attempting to mate bees in a confined enclosure or by hand .discoveries in the queens anatomy and physiology led to the first break through in controlled mating of honey bees with instrumental insemination.we owe a lot to some of the early pioneers in bee breeding like Laidlaw, (Lloyd) Watson, (Otto) Mackensen, (William) Roberts and many others."

Page-Laidlaw Closed Population Breeding Program
Noting that the Page-Laidlaw Closed Population Breeding Program "is one of the most successful practical breeding systems used, Cobey explains "the system basically is how most beekeepers approach selection--choose the best and propagate from these. The key component is an annual selection program supported with controlled mating and record keeping. Beekeepers rely on natural selection pressure to increase desirable traits in the population. The goal of the closed population breeding program is to increase the selection pressure and the frequency of desirable traits in the breeding population. Given the behavioral complexity of honey bees, this can be a challenging process. To be successful and give the program, longevity, it must be simple and repeatable."

The video drew nearly 1,000 views the first week. The first comment: "Great video! ....where can i buy that bee hat that Susan is wearing? Thanks so much!"

Cobey does have some nice hats!