Two Veteran Nut Researchers Retire
July 11, 2012 
Two highly regarded members of the University of California’s (UC) research community, who long helped growers in their battles with destructive pests, have recently stepped down. Both entomologist Walt Bentley and nematologist Mike McKenry, who were based at the UC- Kearney Agricultural Research and Extension Center in Parlier, retired June 30.
Bentley, an esteemed member of UC’s regional integrated pest management (IPM) team, transferred to Kearney in 1994 after 17 years as a UC Cooperative Extension advisor in Kern County, specializing in entomology. The IPM team — with advisors representing the core pest management disciplines, entomology, nematology, weed science, and plant pathology — was formed in response to concern about the effect of pesticides on food safety, the environment, and farmworker safety.
McKenry focused on nematodes, destructive pests recognized as one of the greatest threats to prolonged agricultural production worldwide, during a distinguished 40-year career for UC Cooperative Extension. McKenry is a nematologist in the Department of Nematology at UC-Riverside and based at the UC-Kearney Agricultural Research and Extension Center.
The IPM Champion
Bentley collaborated with IPM and commodity-specific UC Cooperative Extension advisors, specialists, and farmers to develop IPM approaches and alternative control strategies that have reduced the use of carbamates and organophosphates in California by 80% to 90% in almonds, grapes, and tree fruit, since 1995.
Bentley’s career success is demonstrated by the numerous awards he received in the past year. A group of world IPM leaders presented Bentley with a Lifetime Achievement Award March 27 at the 7th International IPM Symposium in Memphis, TN. He also received a Lifetime Achievement Award from the California Association of Applied IPM Ecologists in February. In October 2011, Bentley received the UC Agriculture and Natural Resources Distinguished Service Award for Outstanding Extension.
Bentley grew up on his family’s cherry, walnut, and peach farm in Linden, CA. He began laboring in the orchards as a young boy, but the hard work didn’t deter him from pursuing a career in agriculture. “Growing up on a farm is probably the best life a youngster can have,” Bentley said. “But I can’t say that it was easy for my parents. It was a struggle for them to raise a family and depend solely on income from the farm.”
Bentley earned a bachelor’s degree in horticulture and biology in 1969 at Fresno State, and then spent two years in the U.S. Army working on tracing mosquito movement in the 4th Army area of Texas and Oklahoma and later in Utah. He earned a master’s degree in entomology in 1974 at Colorado State University. Bentley worked in biological pest control for the Colorado Department of Agriculture before returning to his native California for the UC Cooperative Extension position in Bakersfield.
As the Kern County farm advisor, Bentley worked with his colleagues to develop an IPM program for almonds, addressing primarily problems with spider mites, navel orangeworms, and ants. Perhaps his greatest accomplishment, however, was the relationship he cultivated with growers and pest control advisors in Kern County.
At Kearney, Bentley continued his work on almonds. During his 36-year career, Bentley authored 65 chapters or sections in pest management manuals and 75 peer-reviewed articles. “Mr. Bentley’s career represents the best UCCE’s faculty has to offer,“ said his IPM colleague, Pete Goodell, UC Cooperative Extension advisor based at Kearney. “Unselfish service, loyalty to his peers and clientele, intellectual honesty, dedication to the mission of UCCE, and a genuine love for his work.”
Bentley credits the success of his program to the UC Cooperative Extension research and education continuum, which is designed to foster communication and collaboration from campus laboratories to farm fields and back again.
The Nematode Crusader
A native of Selma, CA, Mike McKenry was raised on a farm, where his family produced fruits and vegetables for sale at Highway 99 fruit stands. McKenry earned his degree in soil science with a biochemistry minor at California Polytechnic State University, San Luis Obispo, in 1966, where his senior project targeted the soilborne worms that would shape his career.
“Very few farmers knew much about nematodes at the time,” McKenry said. However, the pest was causing serious yield loss, especially when crops were replanted into previously farmed land.
After serving as a vocational agriculture teacher in Yucaipa, a town east of San Bernardino, and conducting field trials with his students, McKenry was offered the opportunity to study nematodes at UC-Riverside. He obtained his Ph.D. in 1972 and was soon appointed by UC-Riverside to his nematology research position at Kearney.
McKenry said his research focus changed with the times. The first two decades, he studied the movement of fumigants and other pesticides in soil, and the timing and placement for nematode congregation under trees and vines. Equally important were his activities to develop newer methods to assure that California’s nursery stocks would remain nematode-free.
Increasingly stringent regulations and bans on the use of certain fumigants began to turn nematologists’ attention to reduced rates using timing and placement as well as botanically derived alternatives to synthetic products. McKenry noted an unreported biological control process under way at Kearney where certain naturally occurring fungi and bacteria were lethal to nematodes.
“We’ve been working on that for 40 years,” McKenry said. “We’re still missing pieces, but the potential and limitations are better understood.” During this period, McKenry also developed a portable drenching system that reduced off-gassing of soil fumigants and led the way for pre-plant delivery of degradable nematicides deep into soil.
The next 20 years was the period of rootstock exploration. Grape rootstocks that had been released in the 1960s were losing their resistance to nematodes in the 1980s. McKenry and his staff evaluated as many as 1,000 potential grape rootstocks from around the world. This was followed by evaluation of 100 peach and almond rootstocks and then thousands of potential walnut rootstocks.
McKenry’s nematological expertise provided industry awareness of three fruit and nut rootstocks including Krymsk 1, useful for dwarf plum trees; HBOK-1 and Hansen 536, for peach and almond orchards; plus a new walnut rootstock named VX211. In addition to durable nematode resistance with these rootstocks, some may be planted without soil fumigation. If some fumigation was necessary, he demonstrated how a portable boiler could provide relief.
More recently, McKenry identified the first effective nematode treatment that in very low doses could be sprayed onto leaves of trees and vines. McKenry and his research team at UC reported that if farmers followed a few guidelines, their yields could be boosted 10% to 20%.
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