United States Department of Agriculture

August 2014

Timeless Mushroom Treasure

Story on pages 12-14

Agricultural Research Service Solving Problems for the Growing World Breeding Rootstocks To Help Apple Growers

Today’s apple growers face a host understand the significance of the work, scions onto them, and grow the plants of challenges. Some challenges come from and the stakes involved, it helps to know for a few seasons before selling them. nature and some from our own changing more about how apples are produced. Typically, orchard operators buy some new tastes. Walk through any supermarket Apples are a $3.1-billion-a-year indus- trees from nurseries every year, and over produce section or stop by any farmer’s try in the United States. They are grown the course of about 20 to 25 years they market and, depending on the season, you commercially in 29 states, and they rank gradually replace all of their trees. The are likely to see a vast assortment of apple second, behind oranges, as the nation’s grower’s choice of rootstock is as critical varieties. We want apples that not only most consumed fruit, when fresh and pro- as the apple variety produced. Sometimes ship and store well, but taste good when cessed uses are combined. Apple trees in growers are reluctant to switch rootstocks. eaten fresh; baked into pies and pastries; or commercial orchards, like other fruit trees, They know that a rootstock that performs used in jellies, candies, or other products. are bred in two parts: the fruit-bearing scion well in one type of soil may not be as This unprecedented variety is the result at the top and the rootstock that forms the successful in another. They are learning, of decades of efforts by breeders, nurser- foundation and roots. The dual approach however, that they can reduce their risks ies, and growers in response to changing makes the fruit and root systems easier to by using Geneva rootstocks. There are consumer tastes and demands. breed. The scion determines the variety of about 2.4 million new Geneva rootstock But such bounty comes at a price. Some apple. The rootstock determines the tree’s trees available to growers each year, but by of our most popular apple varieties are overall size, when it will first bear fruit, some estimates, growers would use about susceptible to a number of diseases and and its ability to resist many diseases. 10 million if they were available. pathogens, which makes producing them Rootstocks forage the soil for nutrients, Individual rootstock plants, however, a challenge. Gala, Honeycrisp, and Fuji which are critical to the tree’s survival, are grown from mother plants, and it are susceptible to fire blight, a bacterial health, and productivity. takes about 4 to 5 years to deliver quality disease that can kill a tree. Apple replant Along with fire blight and replant rootstocks. While the nation’s nurseries disease is found in orchard soils used to disease, other major threats to apple cannot replace all of their rootstock plants grow the same crop year after year. Many producers include woolly apple aphids overnight, they are moving as quickly as of the nation’s most productive orchards and winter cold; in some apple-producing possible to provide Geneva rootstocks to have produced apples for decades, making areas, winter temperatures can dip to –20˚F. the growers who want them. the disease a serious problem. Many of the But of all these, the most serious threat The development of apple rootstock in apple rootstocks traditionally used were may be fire blight. The disease is bacterial, Geneva is a success story. The demand for bred in England decades ago and are not and once a tree is infected, no pesticide of it serves as testimony to the role played equipped to deal with today’s demands. any kind will help. Fire blight likes hot, by ARS scientists in helping apple grow- Fortunately, a unique apple rootstock- humid conditions, and when it gets into a ers provide the nation with this tasty and breeding program in Geneva, New York, 2- to 4-year-old “juvenile” tree, it can kill nutritious fruit. is helping growers meet these modern-day it quickly. Unfortunately, some of the most challenges. Agricultural Research Service popular varieties of apples, including many researchers at the Plant Genetic Resources from Washington State, which produces Sally M. Schneider Unit in Geneva, along with their partners half of the nation’s apples, are susceptible ARS Deputy Administrator at Cornell University, have bundled resis- to it. The best defense is to use resistant Natural Resources and Sustainable tance to several threats into new rootstock varieties and rootstocks. Agricultural Systems varieties. The accomplishments are de- Nurseries often buy rootstocks when Beltsville, Maryland scribed in this issue on page 4. To better they are about the size of a pencil, graft

2 Agricultural Research l August 2014 August 2014 Vol. 62, No. 7 ISSN 0002-161X Solving Problems for the Growing World

ELIJAH TALAMAS (D3241-1) Agricultural Research is published online 10 times a year by the Agricultural Research Service, U.S. Department of Agriculture (USDA). The Secretary of Agriculture has determined that this periodical is necessary in the transaction of public business required by law. Tom Vilsack, Secretary U.S. Department of Agriculture Catherine E. Woteki, Under Secretary Research, Education, and Economics Chavonda Jacobs-Young, Administrator Agricultural Research Service Sandy Miller Hays, Director Information Staff Editor: Robert Sowers (301) 504-1651 Associate Editor: Sue Kendall (301) 504-1623 Art Director: BA Allen (301) 504-1669 Photo Editor: Tara Weaver-Missick (301) 504-1663 Staff Photographers: Peggy Greb (301) 504-1620 Stephen Ausmus (301) 504-1607 A Trissolcus euschisti wasp (about 1.5 millimeters long) that has emerged Most information in this magazine is public property from a stink bug egg. This wasp species is a promising biocontrol for brown and may be reprinted without permission (except marmorated stink bug. Story begins on page 18. where noted otherwise). Articles and high-resolution digital photos are available at ars.usda.gov/ar. This magazine may report research involving 4 Rooting Out the Best in Apple Rootstocks pesticides. It does not contain recommendations for 7 Mosquitoes Reveal a Taste for Repellents their use, nor does it imply that uses discussed herein have been registered. All uses of pesticides must be 8 Switchgrass for Ethanol: Where It Came From—and Where registered by appropriate state and/or federal agencies before they can be recommended. It’s Going Reference to any commercial product or service is 11 Developing Tools To Fight Marek’s Disease made with the understanding that no discri­mination is intended and no endorsement by USDA is implied. 12 Treasures of the National Agricultural Library: Timeless The USDA prohibits discrimination in all its Works of Fungi programs and activities on the basis of race, color, national origin, age, disability, and where applicable, 15 The Ins and Outs of Beneficial Nematode Movement sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, 16 Moisture Meter Technology for In-Shell Peanuts Licensed political beliefs, reprisal, or because all or part of an individual’s income is derived from any public 18 Up Close and Personal With Tiny, Beneficial Wasps assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 20 New Lure May Help Growers Combat Almonds’ No. 1 Insect alternative means for communication of program Pest: Navel Orangeworm information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 23 Locations Featured in This Magazine Issue 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Cover: A watercolor titled “Agaricus ferratis (Agaric with Serrated Gills),” created by Washington, D.C. 20250-9410, or call (800) 795-3272 James Bolton, a noted naturalist who lived in England in the late 18th century. Bolton was (voice) or (202) 720-6382 (TDD). USDA is an equal the author and illustrator of the first published English-language work devoted to fungi. opportunity provider and employer. His manuscript of that work, including his original watercolors, is part of the Special Collections at the National Agricultural Library, in Beltsville, Maryland. Story begins on page 12. J. BOLTON WATERCOLOR (D3253-1)

Agricultural Research l August 2014 3 Rooting Out the Best in Apple Rootstocks GENNARO FAZIO (D3231-1) GENNARO FAZIO

Honeycrisp apple trees with Geneva rootstocks in a large nursery in Washington State. These trees will be shipped all over the United States for planting in large commercial orchards, small family farms, and backyards. With 600 acres of apple trees in just behind oranges, as the nation’s most Two-Part Trees Walden, New York, Jeff Crist faces a consumed fruit, when fresh and processed Most commercial apple trees are bred number of threats from nature each year. uses are combined. in two parts: the fruit-bearing scion and Fire blight, a bacterial disease that at- Commercial apple growers routinely the rootstock, which forms the foundation tacks blossoms, shoots, and limbs, has been replace trees every 20 to 25 years, and and roots. The two parts are completely known to kill off entire orchards. Replant this year, about 1 in 5 of the new trees different and address different needs, so disease, which reduces growth of new shipped from nurseries to growers—some the dual approach makes breeding easier. trees in soils that support the same type 2.4 million trees—is on Geneva rootstock. The scion determines the variety of apple. of tree year after year, can cause major Rootstocks from Geneva are also being losses. Aphids and cold temperatures can used in some European countries, as well also cut into apple production. as in Brazil, Chile, New Zealand, South “The challenges from a horticultural Africa, and Uruguay. Geneva rootstocks standpoint are always there. You just have are in high demand because they have to try to do everything possible to minimize proved to be effective at overcoming many them,” says Crist, a fourth-generation of the obstacles growers face in producing farmer whose family has grown apples in a bountiful harvest. the region for about 100 years. “The Geneva program has made major Crist and other apple producers are better contributions. It’s given us new tools to equipped to face those threats because of combat fire blight, replant disease, woolly a one-of-a-kind program in Geneva, New apple aphids, and winter cold, among other York, operated by Agricultural Research problems,” says Phillip Baugher, who is Service scientists and Cornell University. chairman of the research committee for The program, overseen by Gennaro Fazio the U.S. Apple Association and president of the ARS Plant Genetic Resources Unit of Adams County [Pennsylvania] Nursery, in collaboration with Cornell scientists, which propagates 600,000 apple trees produces new rootstock varieties that will annually. play a major role in the continued success A typical rootstock. Millions of trees of some of of a $3.1-billion-a-year apple industry in America’s favorite apple varieties are grown on the United States. Apples rank second, Geneva rootstocks. SARAH BAUER (D3229-1)

4 Agricultural Research l August 2014 SARAH BAUER (D3228-1) Each tagged set of these Gala apples was grown on a different type of Geneva rootstock. The variation among the sets illustrates how the rootstock can affect fruit color and size and, ultimately, eating qualities.

The rootstock determines the tree’s size, when it will begin to bear fruit, and how well it resists soil diseases. Rootstocks also transport nutrients from the soil to the scion, which is critical to the tree’s survival, health, and productivity. “Certain scions may do better with certain rootstocks. Figuring out the right pairings is part of the challenge for growers. They have to mix and match,” Fazio says. Breeding apple rootstocks is a time- consuming process. Each rootstock is field tested for about 10 years in different environments to evaluate its strengths and weaknesses in the climates and soils of the 29 states where commercial apple trees are grown. Along the way, many rootstocks fall prey to soil diseases or perform poorly when exposed to different climates. One example shows the time sometimes required: Three rootstocks released by ARS and Cornell scientists in 2010 were based on crosses of trees done in 1976. The work, however, pays off. Since the 1970s, the Geneva breeding program has produced trees that are 10 to 20 percent more productive and are better at taking up certain nutrients from the soil. Focus on Fire Blight, Early Bearing, and Dwarfing Efforts start with a rigorous screening process at an ARS site based on the Cor- nell University campus in Geneva that includes apple rootstocks and trees from throughout the world. Seeds made from the hybridization of plants with promis- ing characteristics are germinated in a greenhouse and inoculated with a series of pathogens. The pathogens usually kill 70 to 80 percent of the seedlings. Surviving rootstocks are then screened with DNA markers associated with aphid resistance and productivity. The remaining seedlings are then field screened in Geneva and sent

Commercial apple trees are usually produced by grafting a scion onto a rootstock. The scion determines the apple variety, and the rootstock determines tree size, disease resistance, and more. Far left: A section of the rootstock’s trunk is chipped out where the scion will be attached to it. Near left: A completed graft. PEGGY GREB (K10813-1) PEGGY GREB (K10810-1)

Agricultural Research l August 2014 5 PEGGY GREB (K10803-1) PEGGY GREB (K10805-2) In one study, Fazio and his colleagues measured nutrients in the leaves of Gala and Golden Delicious apple trees grafted to different sets of rootstocks. They analyzed the DNA of the rootstocks to search for genes associated with enhanced uptake of specific nutrients, such as calcium and phosphorus. Calcium deficiencies cause postharvest disorders, and phosphorus is a commonly applied fertilizer. “If two rootstocks are transporting Left: ARS geneticist Gennaro Fazio examines a limb of a Gala apple tree heavily damaged by fire different concentrations of the same blight. Above: Close-up of the leaf damage. nutrients, one may have more efficient nutrient uptake or transport genes than duce fruit. Early bearing is determined by the other, and identifying those genes several genes, which makes breeding for will help with selection of more efficient, it extremely challenging. The new Geneva improved rootstocks in the future,” Fazio rootstocks, however, have reduced the time says. Results, published in 2013 in Aspects it takes for a traditional large tree to start of Applied Biology, showed that certain bearing fruit from 5 years to 2 years, and genes are likely to enhance the uptake of to nurseries and research sites across the they are fire blight resistant as well. specific nutrients, including calcium and country and overseas to be evaluated for Dwarfing produces trees that grow to phosphorus. cold tolerance, response to different soil about 10 feet instead of 20 to 30 feet. The In another study, Fazio and his col- conditions, and disease resistance. smaller trees take up less space, and that leagues analyzed genetic markers in two One major achievement in the rootstock- increases yield per acre. Commercial apple populations of rootstocks to see whether breeding program has been advancing growers began to adopt dwarf trees in the genes associated with certain markers play resistance to fire blight. Significant fire 1930s, and since then, yield per acre has a role in dwarfing, early bearing, and fruit blight outbreaks in New York, Michigan, quadrupled. Dwarfing can also improve productivity. The rootstocks they analyzed and Washington State have caused millions fruit quality, cut back on insecticide use, had been studied and characterized at Ge- of dollars in annual losses over the years. and reduce harvest-related injuries. neva for up to 7 years. They discovered the It’s also a concern in Europe and New Zea- Like their full-size counterparts, dwarf location of a new genetic marker (Dw2) land. A fire blight epidemic in New York trees are susceptible to a number of pests and described its relationship to a previ- and Michigan in 2001 and 2002 wiped out and diseases, so growers still face tough ously discovered marker (Dw1), shedding entire orchards. In the Northwest, many decisions about the types of rootstocks light on how genes associated with both growers refused to plant new orchards and scions to use in their orchards. With markers and their locations affect those key until their apples could be grafted onto more trees per acre, the stakes are higher. characteristics. The results were published resistant rootstock. A grower who may have once spent about in 2014 in the Journal of the American All rootstocks released from Geneva $3,000 per acre for about 200 trees now Society for Horticultural Science. in recent years are tolerant or immune to buys 5 to 10 times as many trees and spends Researchers at Geneva are aware that fire blight. In the wake of the fire blight 5 times as much per acre. the stakes are high for growers and others outbreaks, rootstocks from Geneva are “The density of the plantings has in- interested in quality apples.“Our goal is to proving instrumental in allowing apple creased, so the amount of investment for give growers more choices, so that they producers to plant new varieties that are every planting is that much greater, and have healthier trees, increased productiv- very fire blight susceptible, Fazio says. every decision you make about planting ity, more nutritious fruit, and hopefully a “Growers were leaving land fallow, wait- becomes that much more important,” future with reduced use of fertilizer and ing for our rootstocks to become available, Crist says. the nutrient runoff that goes with that,” and when the nurseries began propagating Examining Rootstocks’ Role in Fazio says.—By Dennis O’Brien, ARS. our releases, some fruit companies ordered Nutrient Uptake This research is part of Plant Genetic tens of thousands of trees with our root- Researchers in Geneva have also focused Resources, Genomics, and Genetic Im- stocks,” he says. on finding ways to improve the rootstock’s provement, an ARS national program Researchers in Geneva have also been ability to take up soil nutrients, which is (#301) described at www.nps.ars.usda.gov. instrumental in developing trees with a key to tree health and productivity. Im- Gennaro Fazio is in the USDA-ARS improved dwarfing and early-bearing proved nutrient uptake could also increase Plant Genetic Resources Unit, Cornell characteristics, which are both critical traits the nutrient content of the fruit and reduce University, 620 W. North St., Geneva, NY to apple producers. Early bearing reduces the need for fertilizer, which would reduce 14456; (315) 787-2480, gennaro.fazio@ nutrient runoff. the time required for a young tree to pro- ars.usda.gov.* 6 Agricultural Research l August 2014 PEGGY GREB (D3239-1) Mosquitoes Reveal a Taste for Repellents

The more scientists learn about mosqui- Entomologist Joseph toes’ sense of smell and taste, the better Dickens (left) and they’re able to develop ways to protect us postdoctoral associate Jackson Sparks use a against mosquito bites, which can some- gel to separate genes times transmit dangerous pathogens that in the mouthparts of the cause diseases such as malaria, yellow yellowfever mosquito fever, and West Nile virus. that are involved in detection of DEET. Previous research has shown that DEET, the most common active ingredient in insect repellents, interacts with the mosqui- to’s sense-of-smell (olfactory) receptors, “We found that at located on its antennae and mouthparts. least three sensory These receptors pick up carbon dioxide cells were activated and other odors emitted by humans and in the hair,” Dick- animals, leading the mosquito to a host. ens says. “One was Recently, Agricultural Research Ser- sensitive to increas- vice scientists in Beltsville, Maryland, ing concentrations of showed that insect repellents also affect salt—sodium chlo- the mosquito’s sense-of-taste (gustatory) ride. Another one was receptors. Entomologist Joseph Dickens sensitive to increas- and his colleagues in the Invasive Insect ing concentrations Biocontrol and Behavior Laboratory dis- of sugar, and another covered that a taste receptor located on a cell was responsive to JOSEPH DICKENS AND GARY BAUCHAN (D3238-1) mosquito mouthpart is sensitive to DEET. DEET and quinine.” “We know that DEET deters blood Dickens and postdoctoral research as- feeding by interactions with olfactory sociate Jackson Sparks are working to receptor cells,” Dickens says. “Mosqui- distinguish other receptors located on toes become confused and fly away. The the mouthparts and legs of mosquitoes fact that DEET is also interacting with a and determine their molecular genetic specific taste receptor might indicate that functions. “We’re getting an idea of the there is a sensory pathway for taste that specific receptors at a gene level involved helps inhibit feeding.” in the response to DEET,” Dickens says, “and we have candidate genes that we’re After discovering that certain nerve cells Sensory hairs at the tip of the proboscis, or going to examine.” respond to DEET and other repellents, beak, of the yellowfever mosquito have cells that scientists looked for the receptors respons­ The research, which was published in respond to a feeding deterrent and the mosquito repellent DEET. Magnified about 500x. ible for this reaction. Experiments involved Naturwissenschaften in February 2013, recording responses of yellowfever has given scientists a better understanding that less chemical has to be applied to the mosquitoes to different insect repellents— of how mosquito repellents work, and it skin.”—By Sandra Avant, ARS. DEET, IR3535, picaridin, and citronellal— could help provide methods to uncover and a feeding deterrent, quinine. novel and improved chemicals to better This research is part of Veterinary, manage insects and other arthropods. At the tip of the mosquito’s “beak”— Medical, and Urban Entomology, an ARS or proboscis—is a pair of flaps called “DEET works, but it’s only effective national program (#104) described at “labella” that make the first contact with at high concentrations,” Dickens says. www.nps.ars.usda.gov. a person’s skin. These flaps have tiny hairs “Products to keep mosquitoes from biting Joseph Dickens is with the USDA-ARS that serve as chemical-sensing organs. generally have 20 percent DEET. Some Invasive Insect Biocontrol and Behavior Electrodes were placed over a single hair even contain 50 percent or more. We’re Laboratory, 10300 Baltimore Ave., Belts- to record electrical impulses from nerve trying to discover alternatives that are ville, MD 20705-2350; (301) 504-8957, cells within the hair. many times more active than DEET so [email protected].*

Agricultural Research l August 2014 7 WOLFGANG HOFFMANN (D764-1)

Switchgrass was originally valued as a forage crop, but its more recent claim to fame has been as a potential feedstock for bioenergy production. Now, after decades of combined research, Agricultural Re- Where It Came From—and search Service scientists have announced the release of Liberty, a variety of switch- Where It’s Going grass specifically developed for bioenergy generation. PEGGY GREB (D745-1) Says ARS geneticist Ken Vogel, who re- cently retired from the ARS Grain, Forage, and Bioenergy Research Unit in Lincoln, Nebraska, “With Liberty, we were able to combine the high yields of the southern lowland varieties with the winter hardiness of the northern upland types. Right now, Liberty can yield 8 tons of biomass per acre, and with further breeding,we have the potential to get to 10 tons per acre—maybe as soon as 5 years from now.” The release of Liberty is a significant milestone for ARS. It’s also a key ac- complishment for CenUSA Bioenergy, a project funded by the U.S. Department of Agriculture’s National Institute for Food and Agriculture that is tasked with developing perennial bioenergy produc-

Top: Geneticist Michael Casler harvests switchgrass seed in a program to develop high-yielding new cultivars that are well suited to bioenergy production in different environments. Bottom: Molecular biologist Gautam Sarath analyzes switchgrass cell-wall samples for their lignin content. The data will be used to identify elite switchgrass plants for improvement through breeding.

8 Agricultural Research l August 2014 PEGGY GREB (D748-1) tion systems in the Midwest. Other ARS In Nebraska, technician Marty Schmer harvests researchers who contributed to Liberty’s switchgrass to evaluate yield. The results will help guide breeding and management efforts to development include agronomist Rob increase switchgrass yields. Mitchell, molecular biologist Gautam Sarath, and geneticist Michael Casler. to produce from 700 to 1,500 more liters Mitchell and Sarath both work at the ARS of ethanol. laboratory in Lincoln, and Casler works at Teamwork and Time the U.S. Dairy Forage Research Center in It took a multi-location effort to get to Madison, Wisconsin. Casler, Mitchell, and this point. For years, Casler and others have Vogel have all played significant leadership been studying the evolutionary history of roles in CenUSA Bioenergy. switchgrass, which now flourishes in a Another Name for Success range of North American environments. Liberty made a previous appearance Lowland ecotypes are found on flood as “KxSNETO2,” one of the switchgrass plains, wetlands, and other low-lying areas, types used in a 16-year breeding study by while upland ecotypes are found in flood- Vogel and others to increase long-term free areas subject to frequent droughts. yields. In the study, breeding for increased Since switchgrass has successfully the primary center of origin for modern biomass yield in upland switchgrass re- adapted to these different environments, its switchgrass was along the eastern Gulf sulted in average gains of 4 percent every genome contains a diverse array of traits, Coast between 1 and 1.5 million years year, while biomass yields in lowland types many of which could be useful in breeding ago. A less significant center of origin and increased an average of 1 percent every efforts. But switchgrass types can have as diversity was located along the western year. However, the lowland-upland hybrid many as eight sets of chromosomes in each Gulf Coast. Meanwhile, a western moun- KxSNETO2 increased biomass production cell, so natural crossbreeding over thou- tain ecotype became the source of upland as much as 43 percent. sands of years has produced some varieties ecotypes that migrated to the arid and Their results convinced the researchers that contain an unwieldy genetic mix. semiarid Great Plains, which then became that switchgrass biomass yield is a mod- To identify evolutionary patterns in a secondary—not the primary—center of erately heritable trait that can be readily the complex genome, Casler and his col- switchgrass diversity. improved using conventional breeding leagues examined the genetic makeup of The scientists surmise that after these methods. However, they did not observe 480 individual plants from 67 lines and types were established, repeated rounds any genetic links between biomass yield cultivars, including upland, lowland, and of North American glaciations affected and quality. This suggested that breeders hybrid types. Using advanced genetic tech- switchgrass dispersal and development by might be able to combine different traits niques, the team identified several distinct forcing diverse types into relatively close to mitigate production challenges posed by switchgrass “clades” (groups of organisms proximity. By increasing the opportunity climate change, weather, and pests. descended from a common ancestor) in for different types of switchgrass to mate, Another plus with the new cultivar is North America. The researchers located the glacial intervals created favorable con- that gains in yield were achieved without two lowland clades in the eastern Gulf ditions for much of the gene flow between an increase in nitrogen fertilizer use, which Coast and southern Great Plains and three upland and lowland ecotypes. helped lower expected farm-gate produc- upland clades in the central Great Plains, northern Great Plains, and eastern savanna. tion costs by around $20 to $30 per ton. These “crossing cages” are used to make up to And with the increased yields, each hectare The team determined that despite 100 switchgrass hybrid crosses per year in the of switchgrass could potentially be used switchgrass’s renown as a prairie dweller, breeding program at Madison, Wisconsin.

MICHAEL CASLER (D3242-1)

Agricultural Research l August 2014 9 PEGGY GREB (D2614-1) Geneticist Ken Vogel (left) and molecular continue the switchgrass studies at Lincoln biologist Gautam Sarath compare switchgrass and the collaborations with Casler and plants produced by mating plants from upland and lowland ecotypes with parent plants. other ARS scientists. Meanwhile, Vogel is pleased that with the release of Liberty, yield traits. The study also showed the plant he began studying so long ago is that forage digestibility is affected by finally living up to its promise. “It’s nice to many traits that could be improved with retire on a high note,” he says.—By Ann breeding. Perry, ARS. For instance, breeding solely for This research is part of Biorefining, an increased IVDMD initially lowered for- ARS national program (#213) described age and biomass yields, but yield levels at www.nps.ars.usda.gov. stayed the same after the scientists began To contact the scientists mentioned in improving the plant’s winter-survival this story, contact Ann Perry, USDA-ARS characteristics. And while the first sever- Information Staff, 5601 Sunnyside Ave., al rounds of breeding increased biomass Beltsville MD 20705-5128; (301) 504- digestibility and ethanol yields, both 1628, [email protected]. Conversely, as the plants migrated characteristics declined in the improved * northward, the opportunities for genetic varieties when breeding selection began mixing declined, and upland types adapted for winter survival. to frost and longer days and started flower- Starting With the Seeds ing earlier. Meanwhile, lowland varieties Researchers often focus on modifying For a plant that can survive the remained relatively intolerant of cold and tough cell-wall lignin characteristics to challenges of a prairie environment, continued to flower much later in the sum- improve the conversion of plant biomass switchgrass seeds can be surpris- mer. Many “hot spots” of genetic diversity to liquid fuel. However, as a result of their ingly delicate. Fewer than 50 percent still thrive in the southeastern United States study, the ARS scientists determined that of switchgrass seeds planted in and along the Atlantic Seaboard. many other cell-wall and cell constituents drilled plots germinate and emerge influence this process. After sorting through their results, the as seedlings, and more than 90 scientists identified eight regional gene In addition, the scientists demon- percent of those seedlings will die pools with traits that might be beneficial strated that breeding to improve IVDMD within a year. But the competitive in breeding switchgrass varieties for dif- significantly changed the concentration environment of the prairie provides ferent production environments. Results of almost all the cell-wall components. a real-world laboratory that fosters from these studies have been published These changes altered the way carbon was development of genetic traits that in Genetica and Crop Science. distributed between lignin and carbohy- favor survivorship, such as high drates throughout the biomass, but did not rates of root growth or shoot growth. Room for Improvement notably alter total overall biomass carbon ARS geneticist Michael Casler Vogel and Casler also evaluated how concentrations. previous switchgrass breeding for in vitro analyzed 5-year survivorship rates The researchers were surprised to find of switchgrass varieties planted at dry matter digestibility (IVDMD) altered that breeding for winter survival in later biomass composition, forage quality, and four locations in Illinois and Wis- generations led to decreased IVDMD, consin. Although he concluded that potential ethanol yield. IVDMD is a labora- which indicated a clear association between tory test that mimics the rumen processes most survivorship is random, he the two traits. They believe that selecting determined that survivors at the of cattle to measure forage digestibility. It for IVDMD might result in plant vascu- is a good indicator of ethanol yield from northernmost location were hardier, lar structural changes that reduce winter with better value for breeding, and switchgrass via a process known as “si- survival. multaneous saccharification and fermenta- their progeny displayed better sur- The team concluded that breeding to tion,” which researchers hope will become vivorship and better yields. improve IVDMD also affects plant char- a cost-effective method for extracting and “From an agronomic and breeding acteristics that are important for ethanol fermenting plant sugars into ethanol. point of view, we want to know if production. The results confirmed that survivorship has a positive genetic The researchers used six breeding traits affecting biomass composition can correlation with any important ag- generations of switchgrass in their study. also affect plant hardiness—information ronomic traits,” Casler says. “From The first four generations had only been that plant breeders can use to guide their a practical standpoint, we can use bred to improve IVDMD, while the last work in developing switchgrass varieties the survivors to support our breeding two generations had been bred to improve for forage or for bioenergy. Results from programs.” winter survival as well. these studies were published in Crop Sci- The analysis showed that the six types ence in 2013. Results from these studies were had notable differences in a range of vari- Mitchell and Sarath, who have been published in Crop Science in 2013. ables linked to forage quality and ethanol working with Vogel for over a decade, will

10 Agricultural Research l August 2014 KEITH WELLER (K3627-16) Developing Tools To Fight Marek’s Disease

New tests and vaccines are making it easier to detect viruses in chickens and protect them from the cancer-like diseases some of them cause. One of the latest tools developed by scientists at the Agricul- tural Research Service’s Avian Disease and Oncology Laboratory (ADOL) in East Lansing, Michigan, is a modified polymerase chain reaction (PCR) test to detect unique genetic sequences of both Marek’s disease and avian reticuloendotheliosis viruses in various tissues from chickens. Marek’s disease is caused by a highly contagious herpesvirus that primarily affects young adult chickens. It causes severe production losses and usually death and is spread from bird to bird by contaminated dust and dander in chicken houses. Avian reticuloendotheliosis, a retrovirus, infects a broader host range—chickens, turkeys, ducks, geese, and quail. It can also cause tumors, production losses, and death in affected birds. Diagnosis of these diseases includes taking tissue from the bird’s organs, preserving it in formalin, and examining it under a microscope. “If a definitive diagnosis cannot be reached by gross and microscopic examinations, additional tissue must be obtained from affected chickens and sent to the laboratory for PCR or other tests,” says Aly Fadly, ADOL research leader. “These tests, ARS scientists are developing new tests and vaccines that are making it easier to detect viruses in chickens and protect them from the cancer-like called ‘immunohistochemistry’ and ‘virus isolation,’ require use diseases some of them cause. of fresh or frozen tissue.” Most, if not all, laboratories are equipped to preserve tissues in “promoter.” A promoter is a region of DNA that initiates gene formalin and to process them further for microscopic examina- transcription—the process by which genetic information is copied tions, Fadly adds. Now, the modified PCR allows any laboratory from DNA to RNA. The RNA sequences are then translated into to extract virus DNA from preserved tissues to detect Marek’s amino acids to form specific proteins, and these proteins stimulate disease and reticuloendotheliosis. the immune system of the vaccinated host. “This simple test offers poultry breeders, growers, and diagnos- In laboratory and field trials, the new vaccine was as effective ticians an effective alternative to current cumbersome biological as or superior to the commercial vaccine in protecting chickens and molecular tests that require use of frozen or fresh tissues,” against highly virulent Marek’s disease viruses. he adds. “It also lowers costs.” ARS recently approved a license agreement with a private To help prevent the spread of Marek’s and other avian diseases, company to develop a commercial Marek’s disease vaccine commercial flocks are routinely vaccinated. “However, we are from CVRM2. seeing the emergence of more virulent viral strains of Marek’s Results of both the vaccine and modified PCR studies were disease virus,” Fadly says. “Therefore, there is a critical need published in Avian Diseases in 2013. —By Sandra Avant, ARS. for improved vaccines to protect birds against highly virulent This research is part of Animal Health, an ARS national pro- virus strains.” gram (#103) described at www.nps.ars.usda.gov. While working at ADOL, former ARS scientist Sanjay Reddy Aly Fadly is with the USDA-ARS Avian Disease and Oncology developed a novel Marek’s vaccine called “CVRM2.” He used Laboratory, 4279 East Mt. Hope Rd., Lansing, MI 48823-5338; state-of-the art molecular technology to generate CVRM2 (517) 337-6829, [email protected]. from the best available commercial vaccine—CVI988—and a *

Agricultural Research l August 2014 11 Treasures of the National Agricultural Library

PHOTO USED WITH PERMISSION FROM DAN MOLTER (CREATIVE COMMONS 3.0 LICENSED) Mushroom hunters—and their more scientific colleagues, the mycolo- gists—are accustomed to seeking their prizes in unusual places. But finding mushroom treasures inside the National Agricultural Library (NAL) is a unique encounter even for them. For preserved in NAL’s Special Col- lections is a truly irreplaceable specimen: Icones Fungorum circa Halifax Sponte Nascentium, James Bolton’s original, hand-drawn manuscript of his highly regarded published work, An History of Fungusses, Growing about Halifax. The manuscript is 6 volumes with 242 exquisite watercolors of fungi, mostly life- size, with extravagant detail about where Bolton collected the specimen and what he discovered of its biology. A self-taught naturalist and James Bolton, who had no formal training in artist, Bolton came from a family taxonomy or art, drew so accurately that, for of weavers in Yorkshire, England. the first time, mycologists in different countries His original patron, Margaret Cav- could be sure they were talking about the endish Bentinck, Dowager Duchess same mushroom, making his book an essential reference until cameras became of Portland, had the largest natural practical, about 100 years later. history collection in Great Britain. Left: Bolton’s watercolor of Agaric violaceus, After her death in 1785, Henry Noel, drawn about 1784. Above: The same Earl of Gainsborough, to whom the mushroom species, photographed in 2008. manuscript is dedicated, supported Bolton’s work. vitellinus as two separate species and Bolton is credited with describing recognized all five different species hundreds of fungi, many new species of Armillaria (honey fungus), when or new British records, although the these had been put together by the rest of number was later reduced by taxonomic J. BOLTON WATERCOLOR (D3254-1) the early mycologists. The ultimate tribute reclassifications. to his outstanding talents is that his ideas When published, in 1788, An History of mycology (retired) Roy Watling. The late have been confirmed by modern mycol- Fungusses established Bolton’s place in 1700s and early 1800s were dynamic times ogy,” Watling says. mycological history. Because of the exact- for mycology, with experts contending in The published version of Bolton’s ness of his depictions, it became a standard identifying new species and expanding manuscript­ fills just 4 volumes, each resource for mushroom identification. It is and resolving taxonomic order. nearly the same dimensions as the manu- as regularly quoted today as it was by Elias Bolton “was criticized as being both script, with 182 plates, 40 of them grouped Magnus Fries, the founding father of mush- a ‘lumper’ and a ‘splitter,’ but we now with more than 1 illustration to a plate. But room taxonomy, in the 1800s, according to think of him as being mainly the latter. what NAL Special Collections has that is Royal Botanic Garden Edinburgh head of He designated Bolbitius titubans and B. unique is Bolton’s original manuscript.

12 Agricultural Research l August 2014 J. BOLTON WATERCOLOR (D3255-1) J. BOLTON WATERCOLOR (D3256-1) According to a 1932 Transactions of the British Mycological Society article written by famed U.S. Department of Agriculture plant pathologist and mycologist Cornelius Lott Shear, NAL purchased the manuscript for 1,000 Swiss francs from “an old bookseller in Zurich, Switzerland.” The published edition contains all of the illustra- tions that are in the manu- script, plus a few additional. In the manuscript, the wa- tercolors are arranged in the order in which the fungi were collected and drawn. But when the watercolors were transferred to copper plates for printing, they were Blue agaric (Agaricus caeruleus). Cherry colored agaric (Agaricus aurentius). rearranged and renumbered, according to Shear. Bolton wrote, in the manuscript notes, that he made some of “Stevenson was a renowned collector the drawings directly on the copper who amassed a wonderful library about J. BOLTON WATERCOLOR (D3257-1) plates from fresh specimens for the published illustrations. Since Shear wrote of it in the third person, he probably was not NAL has not the manuscript’s purchaser. But NAL has not yet located the records yet located of how it obtained the manuscript or what brought it to the library’s the records attention in 1932. of how it Some think it could have been John Stevenson who discovered obtained the the Bolton manuscript or advocat- ed for its purchase. Stevenson was manuscript in charge of the USDA National or what Fungus Collections from 1927 to 1960 at the Agricultural Research brought it to Service’s Beltsville [Maryland] Agricultural Research Center. the library’s Amy Rossman, who recently retired as research leader of the attention in ARS Systematic Mycology and 1932. Microbiology Laboratory in Belts- Tough boletus (Boletus tenax). ville, which now administers the fungus collections, concurs with the Stevenson possibility.

Agricultural Research l August 2014 13 all things mycology,” Rossman says. “He the manuscript to the museum for the show, apparently even spent a lot of his own possibly the first time it had been publicly money for what he considered important.” “As“As wewe orgaorga-- displayed since 1932. Just before Rossman retired, a large Edmondson also raised the question of cache of historical papers from her lab, nizenize thethe matemate-- whether this is truly the “original” manu- including many from Shear and Stevenson, rials, we will script, as Shear claims. Edmondson holds was turned over to NAL for proper stor- rials, we will that its watercolors are copies prepared age and to provide access to researchers, bebe keepingkeeping aa from earlier drawings, and the published says Susan Fugate, head of NAL Special plates were based on those earlier drawings. Collections. specialspecial eyeeye outout According to Shear, the last mention “As we organize the materials, we will for any that of the originals before 1932 was in The be keeping a special eye out for any that for any that Halifax Naturalist in 1902 that said, “it mention the Bolton manuscript and how mentionmention thethe is doubtful whether the originals for the NAL came to acquire it,” Fugate says. History of Fungusses are still in existence. Only in the Manuscript BB o o lto lto n n They were probably destroyed by fire when the old hall at Exeton [the Earl of The manuscript has significance far manuscript Gainsborough’s family seat] was burned beyond its prized historical value. One manuscript in 1810.” unquestionable extra is that its pages andand howhow NALNAL preserve three actual specimens of fungi. Shear said an appeal to the Zurich Except for a specimen preserved at Kew camecame toto bookseller for information about the Royal Botanic Gardens, and a few recently manuscript’s missing background brought discovered in a brown paper packet at the acquireacquire it.”it.” only that it had been bought at a sale. But Sunderland Museum, these are the only —Susan Fugate, those who possessed it during the 141 years fungi collected by Bolton known to have —Susan Fugate, between the final volume’s publication and survived. NAL its 1932 purchase must have cared for the NAL manuscript well, as it is in excellent condi- The description opposite each drawing tion.—By J. Kim Kaplan, ARS. in the Bolton manuscript “often makes fascinating reading, and frequently a memoir that accompanied an exhibition Susan H. Fugate is head of Special provides more detailed information than he organized on Bolton’s work at the Collections, USDA-ARS National Agri- the rather brief comments found in the Liverpool Museum in 1995. NAL loaned cultural Library, 10301 Baltimore Ave., printed book,” wrote John Edmondson in Beltsville, MD 20705; (301) 504-5876, [email protected].*

J. BOLTON WATERCOLOR (D3260-1) J. BOLTON WATERCOLOR (D3258-1) J. BOLTON WATERCOLOR (D3259-1)

Scaly boletus (Boletus squamosus). Bundled agaric (Agaricus fascicularis). Lacerating agaric (Agaricus lacerates).

14 Agricultural Research l August 2014 JUAN MORALES-RAMOS (D3232-1) Beneficial nematodes are small roundworms that can be used as envi- ronmentally friendly biopesticides. Ag- ricultural Research Service scientists are The Ins interested in finding out how these tiny worms navigate through soil over vast distances to find insect pests to attack. and Outs of Nematodes are known to respond direc- tionally to various cues, including electrical stimuli. In prior research, ARS entomolo- Beneficial gist David Shapiro-Ilan, plant pathologist Clive Bock, and collaborators found that the nematode Steinernema carpocapsae was attracted to an electrical current they Nematode applied to an agar dish. From this study, the researchers concluded that the worms rely on electricity, or electrical fields, to Movement help them navigate in the soil. They then hypothesized that the nematodes may also use magnetic fields for the same purpose. To test their hypothesis, Shapiro-Ilan and Bock, both with the ARS Fruit and Tree Nut Research Laboratory in Byron, Georgia, placed magnets on opposing sides of a petri dish containing agar and S. carpocapsae nematodes. One magnet ARS scientists are studying how small roundworms, such as this Heterorhabditis indica nematode, was oriented toward the North Pole and navigate through soil to find insect pests to attack. the other magnet was oriented to the South Pole, creating a magnetic field of 0.1752 todes and found that their movement was (Wake Forest University), Teva Ilan (a Tesla. (For perspective, a medical MRI not random. Instead, the worms moved student who worked in Bock’s laboratory), uses a magnetic field of 1.5 to 3 Tesla.) The together as a group. “One might liken Ed Lewis (University of California-Davis), scientists wanted to see whether the nema- their movement to group behavior in other and Paul Schliekelman (University of todes would move directionally—either animals, such as a school of fish or a pack Georgia). north or south—within the magnetic field. of wolves,” says Shapiro-Ilan. The findings of these studies have “We did note a directional response of In the laboratory, tests were set up to implications for understanding nematode the nematodes, with more of them moving observe nematode group movement in a foraging behavior and improving natural toward the South Pole than the North,” wet soil environment. “In 20 of 24 analy- pest-control tactics. Knowledge of how says Shapiro-Ilan. “Magnetoreception can ses, nematodes demonstrated nonrandom, and why beneficial nematodes find their be important in facilitating or enhancing or coordinated, movement,” says Shapiro prey is essential to optimizing their use in foraging ability in various organisms.” Ilan. “Based on our findings, we contend the future.—By Sharon Durham, ARS. The finding that the nematode responds that aggregated movement behavior may This research is part of Crop Protection not only to electrical fields but also to further contribute to a patchy distribu- and Quarantine, an ARS national program magnetic fields was published in the tion, or clumping, of natural or applied (#304) described at www.nps.ars.usda.gov. entomopathogenic nematode populations International Journal for Parasitology David Shapiro-Ilan is with the USDA- that is seen in crop fields.” in August 2013. The researchers believe ARS Fruit and Tree Nut Research Labora- this study was the first report of nematode These findings were published in the tory, 21 Dunbar Rd., Byron, GA 31008; directional movement in response to a International Journal for Parasitology in (478) 956-6444, david.shapiro@ars. magnetic field. October 2013. usda.gov. Next, Shapiro-Ilan and colleagues Shapiro-Ilan and Bock acknowledge the * looked at the movement of six different contributions of James Campbell (ARS in entomopathogenic (insect-killing) nema- Manhattan, Kansas), Daniel Kim-Shapiro

Agricultural Research l August 2014 15 JERRY HEITSCHMIDT (D3210-1) Moisture Meter Technology for In-Shell Peanuts Licensed

ARS engineers Samir Trabelsi (left) and Stuart O. Nelson (retired) test a sample of peanuts for moisture content using the new moisture-sensing meter they invented in Athens, Georgia.

A new meter developed by Agri- microwave signal received by the other plants, where further grading takes place. cultural Research Service scientists to antenna, after the signal has passed through During peanut grading, inspectors deter- measure the moisture of peanuts inside the sample material. mine quality factors such as peanut size, the shell, or pod, has been licensed by a “The microwave circuit measures the shell size, peanut damage, foreign-material manufacturer of agricultural-use instru- loss of energy and the change in the speed, content, and kernel-moisture content. ments. The moisture-sensing meter was or velocity, of the microwaves as they pass Representative samples of harvested invented by engineers Samir Trabelsi through the pods,” says Trabelsi. peanuts are taken from the farmers’ and Stuart O. Nelson (retired) in the ARS When a sample material is exposed to transport vehicles, and the peanuts must Quality and Safety Assessment Research microwaves, part of the wave is transmit- be removed from their shells before mois- Unit, in Athens, Georgia. ted and part is reflected, or not transmit- ture content is determined. If the kernel “It is important that peanuts are dried ted, providing the individual “electrical moisture content is too high, the sample is to a kernel moisture content of less than signature” of the sample material being marked “no sale,” and the corresponding 10.5 percent for storage purposes, because tested. “Our patented calibration method lot of peanuts has to be taken to the drying higher levels can lead to fungal growth,” uses this information to produce a moisture shed for further drying. says Trabelsi. calibration equation that is programmed “We have been exhibiting prototypes of The meter is based on patented low- into the meter,” says Trabelsi. this technology to farmers and inspectors power microwave sensing technology and The Road to Market in various states for a few years,” says an algorithm that produces a crop-specific Drying is an essential task that takes Trabelsi. “This new meter is groundbreak- moisture calibration equation—also place at farms and at local peanut “buying ing in terms of changing the way moisture developed by Trabelsi. The equation is points” right before the grading process. has always been measured in peanuts and used to customize an individual meter for U.S. peanuts are required by the U.S. De- in terms of simplifying the process and use with a specific crop type. partment of Agriculture to be inspected at reducing costs and labor.” The components of the microwave these buying points, and farmers take their During 2012, Trabelsi worked under an meter include a peanut-sample holder, a peanuts there to be weighed, cleaned, in- agreement with Dickey-John Corporation, power source, a “mixer,” and two antennas spected, graded, and ultimately purchased. based in Auburn, Illinois, a wholly owned facing one another. The mixer compares Local buying points are under contract to subsidiary of TSI Incorporated, based in the microwave signal transmitted by the peanut product manufacturers and shelling Shoreview, Minnesota, to build a work- first antenna into the peanut pods with the

16 Agricultural Research l August 2014 JERRY HEITSCHMIDT (D3211-1)

Above: Peanuts are normally dried to a moisture content of less than 10.5 percent for JERRY HEITSCHMIDT (D3225-1) storage. Higher levels of moisture can lead to fungal growth (left) compared to properly dried, fungus-free peanuts (right). Below right: Postdoctoral engineer Micah Lewis visually inspects peanuts for quality factors before checking the peanut moisture content using the meter behind him. ing prototype of the latest version of the peanut moisture in cleaned peanut patented in-shell peanut moisture sensor. pods,” says Trabelsi. But the re- “The prototype, together with our mar- searchers have also been working for keting research, allowed us to evaluate the several years on developing a sensor accuracy and effectiveness of the sensor system that rapidly and accurately and get a better sense of what we needed measures moisture content and to do to bring the meter to commercial density of cereal grains, oilseeds, markets,” says Beau Farmer, chief technol- and tree nuts for use on production ogy officer with TSI. lines and in processing applications. The technology allows government Trabelsi’s microwave moisture- inspectors to skip the labor-intensive step sensing technology can be used to of shelling peanut samples from lots prior measure moisture in harvested grain, to measuring moisture content. “A version although the calibration equation based on the same technology could also will be different for cereal grains be developed for farmers who want to test than for peanuts. The method can their peanut pods before sending them off perform better than existing technologies fort required to roll out these meters and for grading,” says Farmer. and has the potential to benefit both the satisfy market demand.”—By Rosalie Marion Bliss, ARS. In addition to moisture content, the peanut and grain industries, according to instru­ment can also reveal bulk density of Trabelsi and Farmer. This research is part of Quality and the peanut pods. This is important because “The microwave moisture-sensing Utilization of Agricultural Products, an that measurement reveals the size and qual- technology is a revolutionary application ARS national program (#306) described ity attributes of the peanuts inside the shell. for in-shell peanut testing,” says Farmer. at www.nps.ars.usda.gov. “A higher density may indicate a higher “We wanted to develop a portable system Samir Trabelsi is in the USDA-ARS peanut meat content,” says Trabelsi. for moisture measurements of unshelled Quality and Safety Assessment Research or shelled peanuts that can be used at Other Potential Uses Unit, Richard B. Russell Agricultural Re- peanut-grading stations and possibly in search Center, 950 College Station Rd., “The first generation of meters available the farmer’s field. We are working hard Athens, GA 30605; (706) 546-3157, samir. commercially will be used to measure on the underlying commercialization ef- [email protected].* Agricultural Research l August 2014 17 Up Close and Personal With Tiny, Beneficial Wasps

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Highly detailed image of the wasp Trissolcus japonicus, a primary candidate for biological control of brown marmorated stink bug. Here, the wasp appears to be huge, but it is actually only 1-2 millimeters long. The actual size is apparent from the dime on the left, which has several of the insects sitting on it.

Using specialized digital photog- “One of the challenges of taxonomy for It Starts With a Slice raphy methods, Agricultural Research such small creatures is that taxonomists The process begins with positioning a Service scientists and their collaborators have had to rely on written descriptions holotype specimen under a specialized are producing high-resolution images of and illustrations to understand what they camera with a single-column lens attached members of the wasp superfamily Platy- have not seen firsthand,” explains Elijah to a vertical joist and taking stacks of gastroidea. Their goal is to improve the Talamas, an entomologist with the ARS photographs throughout the depth of the identification and taxonomic description of Systematic Entomology Laboratory (SEL) specimen. Each photograph contains a these tiny insects—including species with in Washington, D.C. “In some cases this small part of the insect in focus, due to the potential to biologically control important has worked very well, and high-quality il- small depth of field at high magnification. crop pests. lustrations are extremely useful. However, These “slices” are then combined into Of particular interest are 1- to 2-milli- illustrators simply cannot capture all of the a single, highly detailed, digital image meter-long Trissolcus wasps that parasitize detail that a photograph can.” magnified up to 100 times the specimen’s stink bug eggs. The larvae of such wasps Toward that end, Talamas, together original size. The image is then uploaded hatch inside and devour the interior of with ARS entomologist Matthew Buff- to online databases, operated by Ohio State the bug’s eggs, killing them in the pro- ington, has begun a project to photograph University (OSU) collaborator Norman cess. Some species attack the eggs of the the collection of Platygastroidea wasp Johnson, and linked to a description of the brown marmorated stink bug (BMSB), “holotypes” managed by colleagues at holotype and other information about it. Halyomorpha halys, an invasive species the Smithsonian Institution’s National “Making the images freely available from Asia that’s become established in Museum of Natural History (NMNH) in online makes it possible for anyone with 39 U.S. states and, in 2010, inflicted $37 Washington, D.C. Holotypes are the refer- an Internet connection to assess the mor- million in damage to corn, soybean, grape, ence specimens on which species names phology of the holotype specimens,” says and other crops. and descriptions are based. Talamas. “Each specimen has a unique

18 Agricultural Research l August 2014 KIM HOELMER (D3223-1) team headed by Kim Hoelmer at the ARS Beneficial Insects Introduction Research Unit in Newark, Delaware. There, under quarantine conditions, Hoelmer’s group is examining the host specificity and safety of several Asian Trissolcus species with potential use in biocontrol-release programs against BMSB. (See “ARS Works Toward Control of Brown Marmorated Stink Bug,” Agricultural Research, January 2013, pp. 18-20). Being able to tell the Asian species apart from one another and from native Trissolcus wasps will be critical on sev- eral fronts, including monitor- ing the purity of numerous research cultures, tracking the wasps’ spread from introduc- Above: In Newark, Delaware, ELIJAH TALAMAS (D3227-1) ARS research specialist Ashley tion sites, monitoring their Colavecchio uses the stacking behavior patterns in new environments, system to produce high- and gauging their effectiveness as bio- resolution images of wasps to control agents. improve the identification and taxonomic descriptions of the In a side project, using the NMNH col- insects. Left: An image of a lection, Talamas has begun photographing Calotelea wasp in amber that is Platygastroidea wasp specimens entombed about 20 million years old. in amber dated 20-30 million years of were made long ago. Talamas age. There are many questions about the and colleagues published diversity and origins of the wasp superfam- one such correction for T. ily, as well as its co-evolution with host halyomorphae, a promising insects, that are relevant to modern-day biocontrol agent for BMSB, biocontrol pursuits. in the Journal of Hymenop- “Right now, we don’t have enough speci- tera Research. This species mens in amber to show the co-evolution of was described as new in Platygastroidea with stink bug hosts,” says 2009, but it was actually de- Talamas. “But we can begin to learn what scribed more than 100 years groups were prone to extinction, which ago by U.S. Department of were more diversified, and conversely, Agriculture entomologist which are present today but are not in the William Ashmead, and it fossil record.”—By Jan Suszkiw, ARS. is now called by its proper This research is part of Crop Protection name, T. japonicus. and Quarantine, an ARS national program As an OSU graduate (#304) described at www.nps.ars.usda.gov. co­l­­l­ecting unit identifier (CUID)—which student under Johnson’s Elijah Talamas is with the USDA-ARS allows a user to determine the specimen’s mentorship, Talamas produced over 3,000 Systematic Entomology Laboratory, Na- origin on a species-distribution map. Tax- digitized images of Platygastroidea wasps, tional Museum of Natural History, 10th St. onomists can refer to a particular speci- and he has produced hundreds more since & Constitution Ave., N.W., Washington, DC men via its CUID without ambiguity.” joining SEL in March 2013. 20560; (202) 633-0998, elijah.talamas@ Such capabilities are especially Searching for Biocontrols ars.usda.gov. important in validating or correcting The documentation of Trissolcus species * holotype names or descriptions that provides invaluable taxonomic support to a

Agricultural Research l August 2014 19 New Lure May Help Growers Combat Almonds’ No. 1 Insect Pest

Navel Orangeworm PEGGY GREB (D1719-1)

It’s no wonder that almonds are Left: An adult navel orangeworm moth. Females lay eggs on almonds, and one of America’s favorite nuts. They larvae that hatch from the eggs feed on taste great and are heart-healthy, too. the nutmeat. Most of the almonds grown in the United States today come from vast Typically, these “monitoring traps” orchards in California. For the past are baited with a lure that attracts the 50 years, however, the Golden State’s female moths. That lure is usually almond harvests have been threatened almond meal (almonds ground to by what is today the number-one a cornmeal-like texture) to which insect pest of almonds—the navel almond oil may have been added. orangeworm. Now, a team of Agricultural Re- The troubles begin when the female search Service and almond industry navel orangeworm moth lays her investigators, led by ARS chemist eggs on the exterior of the almond John Beck in Albany, California, has hull, also called its “husk.” The husk developed a promising new lure. Ac- protects the layers beneath it, notably cording to Beck, the lure proved to be the light-tan almond shell and the “at least seven times more powerful” nutmeat that develops within it. than the almond-meal-based formu- Female moths are attracted to lation in preliminary tests. almonds with husks that have split The new lure’s effectiveness is due, open—which happens naturally as in part, to its ability to attract both the nut matures. Other sorts of damage JOHN BECK (D3234-1) male and female moths. In so doing, also have appeal, such as entry holes it should provide a more accurate left by other insects, or injury caused and useful picture of moth numbers when a husk is slammed against a within an orchard, Beck says. nearby branch on a windy day. The lure is a unique, carefully Each kind of injury may make researched blend of five natural it easier for the navel orangeworm chemicals. Known to scientists as larvae that hatch from the eggs to “aromatic volatiles,” these com- find their way to food (the nutmeat) pounds are emitted into the orchard and the shelter of the husk’s interior. air from damaged almond husks. But the harm that the larvae cause Beck’s team used leading-edge tech- doesn’t stop there. They wreak further niques to collect, isolate, identify, havoc when they inadvertently bring and measure the compounds, and spores of mold-forming Aspergillus used electroantennograph assays to flavus or A. parasiticus fungi along select and compare finalists. with them as they make their way to Almond husks, or hulls, naturally split open as the nut The electroantennograph tests the almond kernel. The fungi are of matures on the tree. This opening makes it easier for navel enabled the researchers to evaluate, concern because they can produce orangeworm larvae to find their way to the nutmeat inside. in the laboratory, the extent to which cancer-causing compounds known navel orangeworm moth antennae as “aflatoxins.” Almond processors A Better Lure responded to a “whiff” of a candidate spend millions of dollars every year Some almond growers hang small traps on tree chemical. inspecting harvested almonds to en- branches to help detect incoming navel orangeworm Three of the chemicals selected sure that any nuts that contain unsafe moths and track their numbers. This way, the growers, for the experimental blend—aceto- levels of these toxins don’t end up in and their pest control advisors, can determine the best phenone, ethyl benzoate, and methyl your shopping cart. times to apply insecticides.

20 Agricultural Research l August 2014 PEGGY GREB (D1720-1) A navel orangeworm larva. This combined for use as an effective navel or- pest is the number-one insect angeworm lure. ARS is currently seeking enemy of almonds. a patent for the formulation. More Discoveries Ahead salicylate—are produced by Much remains to be learned about the the almond tree itself. The blend, its use, and some of its components. other two, conophthorin An example: Beck and colleagues want to and 1-octen-3-ol, are emit- guarantee that the lure is compatible with ted by spores of fungi that “mating disruption,” an environmentally may dwell on almond trees, friendly pest-control strategy used in many almond orchards. This well- COREY M. GRIFFITH (D3233-1) established tactic relies on dispersing a synthetic version of the sex pheromone emitted by female navel orangeworm moths. Normally, male moths home in on the pheromone to find mates. But the oversupply of the pheromone can confuse them and disrupt mating. “Our lure should be compatible with mating disruption,” Beck says, “but we want to be certain of that.” In addition, the researchers want to make the lure more effective in pistachio orchards, which also are vulnerable to attack by the navel orangeworm. Their experiments have shown that the current blend works in pistachio orchards, but not as well as it does with almonds. The team also plans to tailor the lure to work effectively in walnut orchards, where the insect is sometimes a major pest of that crop.

Above: In Albany, California, chemist John Beck There’s more. The scientists are tackling (left) and technician Wai Gee count eggs laid by including A. flavus and A. parasiticus. the problem of how to keep the ratio of a female navel orangeworm moth on an egg trap. The blend resulted from about 7 years blend components stable. Maintaining the Beck and Gee use egg and moth monitoring traps of laboratory and orchard research. correct ratio is essential to the lure’s suc- in laboratory and orchard tests to evaluate lures. Outdoor tests included a 3-year ex- cess, but it is complicated by the fact that periment that pitted the blend against the compounds evaporate at different rates. the standard almond-meal lure. The Other work may yield a fast, easy way scientists used more than 100 traps, to dispense the lure. “It’s a liquid, and distributed throughout 2 commercial right now we’re using small plastic vials almond orchards, for the research. filled with about a half-teaspoon of it in Each of the individual compounds in the monitoring traps,” Beck says. “We’d the blend was already known to exist in rather use something like a small pouch nature, and all were previously known that’s impregnated with the lure. All you’d to have some role in insect ecology. At have to do to start releasing the lure would least one—conophthorin—has been be to peel the cover off the pouch.” suggested for use in insect control, Perhaps the most intriguing study on specifically, control of bark beetles their “to-do” list involves probing into that attack forest trees. But the five what may turn out to be a mutually benefi- compounds had not—until now—been cial relationship that might have evolved between the moths and the molds. “We New lures that ARS scientists are formulating think that these Aspergillus molds, and may help growers keep pistachios (shown), almonds, and walnuts safe from navel some other mold species that can occur orangeworms. in almond orchards, may help the female SCOTT BAUER (K7504-1)

Agricultural Research l August 2014 21 BRADLEY S. HIGBEE (D3236-1)

The small vial suspended in this monitoring trap dispenses an insect lure. ARS researchers have developed a new lure that attracts both male and female navel orangeworm moths to monitoring traps placed on almond tree branches. The traps help growers detect incoming moths and determine the best time to spray insecticides. navel orangeworm moth by giving off Beck, who is based at the ARS Western of Food and Agriculture, the Almond aromatic volatiles that attract her to a dam- Regional Research Center in Albany, col- Research Board, the California Pistachio aged husk,” Beck explains. “The moth is laborated in the lure studies with ARS col- Research Board, a cooperative research and looking for a good place to lay her eggs. leagues Doug Light, Noreen Mahoney, and development agreement with Paramount If the moth lays her eggs on a damaged Wai Gee—all at Albany; Dan Cook, with Farming and with the assistance of other husk, her larval young should benefit ARS in Parlier, California; Brad Higbee of collaborators, including D&D Farms, S&J because they won’t have to crawl far to Paramount Farming Co., LLC; and others. Ranch, Strain Ranches, and Nickels Soil find food and shelter. The mold benefits Peer-reviewed scientific articles -pub Laboratory.—By Marcia Wood, ARS. because its spores get a free ride on the lished in the Journal of Agricultural and This research is part of Food Safety, an larvae into the interior of the husk. That’s Food Chemistry, Journal of the Science of ARS national program (#108) described a more hospitable environment than the Food and Agriculture, Phytochemistry Let- at www.nps.ars.usda.gov. exterior for spore development.” ters, and elsewhere, as well as a chapter in John J. Beck is with the USDA-ARS If such mutualism does indeed exist, the the book “Pest Management with Natural Western Regional Research Center, 800 researchers might be able to exploit it in a Products,” document their studies. Buchanan St., Albany, CA 94710; (510) strategy that harms moth and mold alike. The research was conducted with fund- 559-6154, [email protected]. ing from ARS, the California Department *

22 Agricultural Research l August 2014 The Agricultural Research Service has about 100 labs all over the country.

Locations Featured in This Magazine Issue

Locations listed west to east. Map courtesy of Tom Patterson, U.S. National Park Service

Albany, California Athens, Georgia 8 research units ■ 202 employees 9 research units ■ 167 employees Center for Grain and Animal Health Research, Byron, Georgia Manhattan, Kansas 1 research unit ■ 27 employees 6 research units ■ 105 employees Geneva, New York Lincoln, Nebraska 2 research units ■ 47 employees 2 research units ■ 69 employees Henry A. Wallace Beltsville Agricultural Madison, Wisconsin Research Center, Beltsville, Maryland 3 research units ■ 102 employees 27 research units ■ 806 employees East Lansing, Michigan Newark, Delaware 2 research units ■ 31 employees 1 research unit ■ 19 employees

Agricultural Research l August 2014 23