In the middle of the last century, diseases caused by suspected viral agents extracted their toll from the temperate climate fruit tree industries in North America. Data collected from that time painted a dire picture of large numbers of trees being removed annually in an effort to control diseases, and so reducing yields and increasing costs. Much of the fruit produced would not compare favorably with the standards of today’s global marketplace. This was particularly evident in British Columbia, Canada, where the newly discovered little cherry disease had eliminated commercial cherry production from many areas of the province and threatened others. It was in the orchards of his native British Columbia where Kenneth C. Eastwell first saw the impact of virus diseases on fruit tree production and the communities that those industries supported. He managed the little cherry control program and witnessed the difficulty of reducing the impact of insect-borne viruses on commercial perennial crop production. The two-year biological indexing method available at the time made adequate management of the spreading disease very difficult. He was charged with determining the etiological agent of little cherry disease with the intent of developing more rapid detection methods, a challenge that he successfully accomplished.
Growers also needed access to and were encouraged to utilize virus-free planting stock as they replanted orchards to maintain productivity; Eastwell served on the Board of Governors of the British Columbia Certified Budwood Society that provided virus-tested trees to support certification programs. For a number of years, he was also advisor to fruit tree quarantine programs in Canada and the United States. With this life experience in hand, in 1997, Eastwell joined the Department of Plant Pathology at Washington State University (WSU) to direct NRSP-5, the main program by which commercially important temperate climate fruit trees were tested for virus-like agents and subjected to virus elimination therapy if need. This was also a time of dramatic transition for the fruit tree industry, which had relied on a relatively small number of selections for the consumer market, but there was growing consumer demand for diverse fruit selections. The number of fruit tree varieties in the market place expanded rapidly, as did the number of countries from which the new selections were obtained. In 1987, before NRSP-5 was permitted to receive imported fruit tree clones directly, seven new fruit tree selections were introduced annually. A decade later, there were 78 new introductions and 48 of them came from foreign sources. By 2013, there were 283 selections submitted annually with 96 from foreign sources. The fruit tree industry was moving at a blinding pace trying to keep ahead of global markets.
As demand increased, there was also need to accelerate the process by which trees progressed through quarantine at WSU. Initially, all fruit tree selections from foreign sources were required to undergo thermal therapy preemptively to eliminate phytoplasmas. With cooperators in Europe, the PCR method was validated for phytoplasma detection and the mandatory thermal therapy requirement was eliminated. This was the first molecular assay introduced into the program. The introduction of hydroponic culture during the thermal treatment increased survival rate dramatically. The service work demanded by clean plant programs could not attract large research grants so advancements were gradual.
Eastwell became interim manager of the grape foundation program at WSU in 2000, and he began to explore the possibility of a coalition of fruit tree and grapevine programs to attract federal funding dollars. Early discussions progressed slowly but, in May 2004, Eastwell and Deborah Golino of Foundation Plant Services at the University of California (UC)-Davis met with fruit tree and grapevine industry stakeholders to advance the vision of a national alliance of clean plant centers—the National Clean Plant Network (NCPN). This was championed by many, but two deserve special mention: Murali Bandla of USDA-APHIS and Tom Bewick of USDA-CSREES (now USDA-NIFA). In May 2007, with their pilotage, the National Clean Plant Network was fleshed out in a creative meeting attended by more than 60 stakeholders. With tremendous efforts of everyone concerned, the NCPN was embodied in the 2008 Farm Bill. The funding that accompanied the creation of the NCPN allowed much needed investment in basic facilities to reverse years of financial neglect. Today, the infant network continues to grow and mature. New challenges are defined and met as research, regulatory, and industry work together to solve problems with confidence. In 2010, Eastwell’s hop virus research and associated clean plant program formally joined the NCPN. In 2011, the virus-tested foundation programs for fruit trees, grapevines, and hop plants at WSU were officially merged to create the Clean Plant Center Northwest, with Eastwell as its first director. This umbrella organization also includes the WSU ELISA Virus Testing Laboratory, which provides access to virus-testing services for regional industries. He merged these programs into a coherent unit while maintaining unique requirements of each program and high-quality services to U.S. industries.
In addition to regulatory activity, Eastwell continued research in the etiology of virus-like diseases of specialty crops, including hops, fruit trees, and ornamentals. Cooperatively with other members in his department, Eastwell’s team has identified and characterized Helleborus net necrosis virus, causing black death of hellebores, and developed diagnostics that helped limit the spread of the virus. They identified Hop stunt viroid in hops for the first time in North America and initiated a testing program for growers to reduce the propagation of viroid-infected hop plants. Research identified viruses associated with several diseases of cherry so that specific and reliable laboratory tests may replace many of the biological assays required for virus screening. The Eastwell team is also spearheading the drive to have deep sequencing accepted as a diagnostic tool for plants in clean plant centers. This requires widespread support from diverse sectors of the associated industries to gain acceptance domestically and, ultimately, with international trading partners.
In an almost full circle, Kenneth Eastwell is once again working with little cherry disease. His team recently identified a new vector of the disease and has entered a partnership with industry to develop a user-friendly field assay for Little cherry virus 2 that will help growers battle the recent outbreak of this virus in central Washington State.
