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  • Author or Editor: Inga A. Zasada x
  • HortScience x
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The root lesion nematode, Pratylenchus penetrans, is a production-limiting pest in red raspberry, Rubus idaeus. Genetic resistance, as a tool to manage P. penetrans in raspberries, would reduce the impact of this nematode on raspberry productivity as well as reduce the need for pre- and/or post-plant chemical treatments to keep populations in control. The host status of 11 Rubus species (R. coreanus, R. crataegifolius, R. innominatus, R. leucodermis, R. niveus, R. parviflorus, R. parvifolius, R. pungens, R. spectabilis, R. sumatranus, and R. odoratus) for P. penetrans was evaluated in greenhouse studies. Additionally, hybrids of R. cockburnianus, R. lasiostylus, R. niveus, R. phoenicolasis, and R. sumatranus with R. idaeus ‘Meeker’ or ‘Tulameen’ were evaluated. The industry standard R. idaeus ‘Meeker’ was included in all trials as the control. Across trials, R. niveus and R. leucodermis were identified as poor hosts for P. penetrans. In addition, when another selection of R. niveus was evaluated in the final year of this study, it was also a poor host for P. penetrans. Among the remaining Rubus species materials tested, there were no consistent differences in host status for P. penetrans. It appears that R. niveus and R. leucodermis might be sources of resistance for P. penetrans. However, a hybrid between R. niveus and R. idaeus ‘Tulameen’ did not consistently support fewer P. penetrans than the ‘Meeker’ control. These results indicate that more research is needed to learn about the inheritance of the putative resistance.

Free access

The cut flower and bulb industry in California is an important part of the state's agricultural economy and it has relied heavily upon the use of methyl bromide as a treatment to control soil-borne pests. With the phase out of methyl bromide, it is important to develop alternatives that will maintain crop productivity. This report describes research testing the efficacy of propargyl bromide against selected nematode, fungal, and weed species. Three sites were selected in California to represent different soil types and environments. Propargyl bromide was applied to soil in large, buried containers at rates ranging from 28 to 168 kg·ha−1 and compared with standard soil fumigants. The citrus nematode (Tylenchulus semipenetrans Cobb) and an isolate of Fusarium oxysporum Schlechtend:Fr were both controlled at the lowest rate of propargyl bromide tested: 28 kg·ha−1. Weed species varied greatly in their sensitivity to propargyl bromide. A 100% reduction in common purslane (Portulaca oleracea L.) and pigweed (Amaranthus retroflexus L.) germination occurred at 112 kg·ha−1 propargyl bromide, regardless of geographical location. Results for annual bluegrass (Poa annua L.) control were more variable across locations and years, but more than 90% control was consistently achieved with 168 kg·ha−1 propargyl bromide. Cheeseweed (Malva parviflora L.) and field bindweed (Convolvulus arvensis L.) were never consistently controlled by propargyl bromide. When compared with the soil fumigants methyl bromide, iodomethane, and metam sodium, propargyl bromide provided comparable control of all soil-borne pests, but at much lower rates. Although higher rates of propargyl bromide, more than 112 kg·ha−1, were needed to control weeds, these rates still were almost half that required of the other standard fumigants.

Free access

Cover crops can lessen soil erosion and compaction, improve water infiltration, enhance nutrient availability, suppress weeds, and assist with pest management. However, cover crops are not commonly used in alleyways of established red raspberry (Rubus idaeus) fields in the Pacific Northwest of the United States. Rather, the space between red raspberry beds is repeatedly cultivated and the soil is kept bare, which has detrimental effects on soil quality. Adoption of alleyway cover crops is limited because red raspberry growers are concerned about resource competition between a cover crop and red raspberry crop. A 2-year study was conducted in an established ‘Meeker’ red raspberry field in northwest Washington to evaluate the effects of eight annually seeded alleyway cover crops (cultivars of wheat, cereal rye, triticale, oat, and ryegrass), one perennial ryegrass alleyway cover crop, mowed weed vegetation, and the industry standard of cultivated bare soil (Till) on the physical, chemical, and biological properties of soil quality in alleyways and raised beds. This included evaluating soil bulk density (D b ), compaction, organic matter, pH, cation exchange capacity (CEC), macro- and micronutrients, and bacterial and fungal community structure; red raspberry yield and fruit quality were also evaluated. Although there were statistically significant differences among treatments across sampling dates for CEC, there were no consistent trends. Alleyways planted with the perennial ryegrass mix had the lowest mean D b 6 and 24 months after seeding. Tilled alleyways had the lowest D b 12 and 18 months into the study. Red raspberry grown adjacent to Till did not result in a significantly higher estimated yield or fruit total soluble solids than raspberry grown adjacent to cover crops in either year of the experiment. Differences in microbial community structure were observed among seasons rather than treatments. These results do not demonstrate significant effects of alleyway cover crops on red raspberry productivity when applied to established fields. The potential benefits of alleyway cover cropping on soil quality may outweigh any concerns regarding resource competition. Changes in soil quality are often difficult to quantify and require long-term study.

Open Access