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www.SugarProducer.com 19 Liphatech.com/Rozol50 Liphatech.com/Rozol50 Decades of killer hits like... • Rozol Ground Squirrel Bait* • Rozol Prairie Dog Bait* • Rozol Burrow Builder* Our fanbase uses Rozol for rodent challenges because we've been listening and collaborating with them for 50 years. We help clean up farms and ranches with the most knowledgeable agricultural rodent control team in the industry and a catalogue of products that are as forward-thinking today as when they fi rst hit the scene. Rozol Rockin' Rebate *These products are Restricted Use Pesticides • Rozol Pocket Gopher Bait • Rozol Vole Bait* • Rozol Pellets Hard-hitting classics endure when you get it right the fi rst time. and California's Central Valley, which parasitized and destroyed soybean cyst and root-knot nematodes, respectively. The feature that all these nematode species have in common is that the femaile remains stationary for her whole life in a host root. While the head is embedded next to root cells that serve as her feeding sites, the body's back end enlarges during maturation and breaks through the root surface. After mating with motile H. schachtii males, the females produce several hundred eggs, mostly contained within her body. This life stage is visible as a diagnostic symptom when roots are dug up and carefully examined. The females are detectable as tiny, lemon-shaped white bodies on host roots. This is the most vulnerable phase for an attack by Hyalorbilia species, which utilize the nematode and young eggs as a food source. The destruction of the female and her undifferentiated eggs by the fungus prevents the development of hundreds of infective juveniles, leading to a dramatic nematode population suppression. In recent studies, researchers at UCR determined that Hyalorbilia fungi were often associated with H. schachtii females in Imperial Valley sugarbeet fields. They were found in representative samples from 21 of 25 fields. More importantly, the presence of young H. schachtii females parasitizing their plant hosts led to an approximately 10,000- fold increase in the population densities of these cyst nematode-destroying fungi during one nematode generation. As H. schachtii goes through up to five generations per cropping season in the Imperial Valley, this suggests that the populations of these natural antagonistic fungi may continue to expand with each nematode life cycle throughout the sugarbeet-growing period. The practical consequence of this discovery could be a considerable increase in the frequency of sugarbeet plantings. When the population densities of both the cyst nematode and the Hyalorbilia fungi are above their threshold values, confirmed by laboratory analysis, the research suggests that cropping sugarbeets would lead to the development of an H. schachtii-suppressive soil by the time the sugarbeets are harvested. To avoid an early-damaging impact of H. schachtii on sugarbeets, it is suggested that this first planting use a cultivar that can endure parasitism by the nematode with reasonably little impact on beet growth. As the reproduction of H. schachtii on such tolerant cultivars is still abundant, it would provide a sufficient number of young females and eggs to enable a substantial Hyalorbilia population expansion, thereby creating a nematode- suppressive soil. Growers should be able to maintain this nematode suppressiveness by following the study's cropping guidelines. This will give growers considerable cropping flexibility and be based on prior research showing the relationships between the type of crop planted and the stability of the nematode suppressiveness. J. Ole Becker is a nematologist and professor of cooperative extension in the Department of Nemtatology at University of California, Riverside (UCR). He can be contacted at ole.becker@ucr.edu. James Borneman is a professor and plant pathologist in UCR's Department of Microbiology and Plant Pathology. He can be reached at james.borneman@ucr.edu. n