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Profitable heirloom tomato production is a major challenge in the southeast as a result of weathered soil structure, abiotic stress, and diseases caused by foliar and soilborne plant pathogens. Diseases caused by pathogens such as Fusarium

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Mustard (Brassica spp.) cover crop residue has been reported to have significant `biofumigant' action when incorporated into soil, potentially providing disease suppression and yield improvement for the succeeding crop. The effects of growing over-winter mustard cover crops preceding processing tomato (Lycopersicon escultentum Mill.) production were investigated in six field trials in the Sacramento Valley of California from 2002–04. A selection of mustard cover crops were compared to a legume cover crop mix, a fallow-bed treatment (the current grower practice in the region), and in two of the six trials, fumigation treatments using metam sodium. Mustard cover crops removed 115 to 350 kg·ha–1 N from the soil profile, reducing NO3-N leaching potential. Soil populations of Verticillium dahliae Kleb. and Fusarium spp. were unaffected by the cover crops, and there was no evidence of soilborne disease suppression on subsequent tomato crops. Mustard cover crops increased tomato yield in one field, and reduced yield in two fields. In one of two fields, metam sodium fumigation significantly increased tomato yield. We conclude that, while environmental benefits may be achieved, mustard cover cropping offers no immediate agronomic benefit for processing tomato production.

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, designated RH14-1156, RH14-1157, and RH14-1158, are the first to combine resistance to the soilborne diseases corky root and verticillium wilt race 1. The populations are genetically fixed for disease resistance, and all progeny descending from these

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Growers in the Salinas Valley are not able to rotate away from lettuce to other crops such as broccoli, as often as would be desirable due to economic pressures such as high land rents and lower economic returns for rotational crops. This aggravates problems with key soilborne diseases such as Sclerotinia minor, Lettuce Drop. Mustard cover crops (Brassica juncea and Sinapis alba) are short-season alternative rotational crops that are being examined in the Salinas Valley for the potential that they have to reduce soilborne disease and weeds. Mustard cover crops have been have been shown to suppress various soilborne diseases and there are also indications that they can provide limited control of some weed species. However, no studies have shown the impact of mustard cover crops under field conditions on S. minor. In 2003 we conducted preliminary studies on the incidence of S. minor and weeds following mustard cover crops in comparison with a bare control or an area cover cropped to Merced Rye (Secale cereale). There was a slight, but significant reduction of S. minor infection in one of three trials following mustard cover crops. Mustard cover crops also reduced emergence of Shepherd's Purse (Capsella bursa-pastoris) and Common Purslane (Portulaca oleracea) these studies. Mustard cover crops have distinct nitrogen cycling characteristics. They were shown to reach a peak of release of nitrogen in 30 to 50 days following incorporation into the soil. The levels of nitrogen that are released by mustard cover crops were substantial and could be useful in nitrogen fertilizer programs for subsequent vegetable crops.

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not consider effects on other plant health drivers, such as soil-borne diseases. The overarching goal of this study was to assess how shifts in soilless substrate use influence plant health directly and under both water-use reduction and pathogen

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Pathogen populations, disease development and onion yield were compared in solarized, fumigated and non-treated plots during 1992 and 1993. Soil solarization was accomplished by covering plots with clear plastic for six weeks beginning in mid-August, prior to the year of onion production. Solarization was also combined with metham sodium, a plied prior to covering with plastic. Soil temperatures reached a maximum of 48°C at the 10 cm depth in solarized plots, and were consistently 10 to 15°C higher than in non-solarized plots. Disease resistant (Bravo) and susceptible (Valdez) onion cultivars were planted the following spring. Only the solarization + metham sodium treatment significantly controlled pink root and plate rot in 1992. In 1993, all solarization and fumigation treatments controlled pink root. Solarization and fumigation did not significantly increase yield in comparison to the check, except for the solarization + metham sodium treatment in 1992. Bravo exhibited lower disease incidence than Valdez in both years of the study. Bravo produced 32.7 t/ha and 6.2 t/ha higher yield than Valdez in 1992 and 1993, respectively.

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Pink root (Phomaterrestris) is among the major limiting factors for the production of sweet onions on Maui, Hawaii. Few management options exist for the control of pink root in onions. Two split-plot experiments were conducted in the area of Kula, Maui, over 2 years to evaluate several alternative management practices. In Expt. 1, the main plots were a rotation with cabbage, solarization with a clear plastic mulch, and a fallow period. Subplots were plus or minus Vapam fumigation. Sub-subplots were biomass application of Sudex or rape, inoculation with an EM biostimulant, and control. Each treatment had four replications for a total of 96 plots. In the follow-up experiment, the main plots were Vapam fumigation, rotation with either a Sudex or rape cover crop, and controls. The subplots were plus or minus EM biostimulant application. In Expt. 1, three separate treatments: solarization, cabbage rotation, and Sudex incorporation had a synergistic effect with Vapam fumigation. Fumigation and solarization also decreased pink root incidence. Rape contributed to a decreased disease incidence while EM contributed to increased bulb size. In Expt. 2, EM and rape contributed to increased yields. Rape and sorghum rotations contributed to decreased pink root incidence. EM inoculation had differential effects on several diseases, contributing to reduced bacterial bulb rot levels. The data indicate that growers may have several alternative management tools at their disposal, in addition to proper varietal selection, to improve yields and reduce disease incidence in sweet onions.

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strategy to control many soilborne diseases, but because most of these pathogens can survive for a long period of time, the effectiveness of crop rotation is limited once a disease outbreak occurs. Because of the long survival rate of pathogens in the soil

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( Cucurbita moschata Duch.) to overcome yield loss caused by fusarium wilt ( Sato and Takamatsu, 1930 ). Since then, grafting has been widely used in Asia and European countries as an effective tool for managing several soilborne diseases and root

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's survival in cultivation is Daphne Sudden Death Syndrome (DSDS), a disease incited by the fungal root pathogen Thielaviopsis basicola (Berk. & Br.) Ferraris (syn. Chalara elegans Nag Raj et Kendrick) ( Noshad et al., 2006 ). This disease kills plants

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