Research and Education Project, Region: North Central. The management of watermelon vine decline through sustainable management practices
One year of data and observations have been gathered on a field study to determine a sustainable method for watermelon production that avoids the disease mature watermelon vine decline. Canola produced a very poor stand. The canola treatments did not prevent vine collapse better than any other treatment, however, canola was associated with higher concentrations of P, Zn, S and Cu than the bare ground control. None of the biological treatments increased early vine growth, however, one of the bacterial treatments, BioYield, increased some aspects of total yield. However, additional yield results suggest that not all the biological treatments are compatible with each other.
Information Growers can use to avoid mature watermelon vine decline-The data gathered to date is tentative for two reasons:
1) only one year’s data has been collected and
2) the winter survival of the canola was poor.
From a practical standpoint, the investigators learned that canola must be planted earlier than October 9 in Indiana to insure an adequate stand. This information will be of interest to watermelon growers, many of who are interested in using cover crops for disease management. The season for winter meetings has just started here, so none of this information has been mentioned in any talks. Likewise, newsletters where this information could be shared have not been published yet.
Although the information gathered needs to be confirmed with year two and three field experiments, the data is discussed here. Vine collapse was assessed on 12 July and 14 August. The treatments where rye had been the cover crop had significantly more vine decline than the canola treatments. There were no significant differences in the August evaluations.
Significant differences were noted in some of the elemental analyses that were conducted. This is surprising since the survival of the canola was so poor. Watermelon vines that were grown in areas that had been in canola had significantly more P, Zn, S and Cu than the bare ground treatment. Note also that the order of the elemental analysis from most to last was always canola, rye and bare ground, respectively This work will have to be repeated in years two and three to confirm these results.
Biological treatments were also part of the experimental design. Two biologicals were included: BioYield and T22. An additional treatment combined these two treatments. Vine growth on May 30 was generally better for treatments that did not have any biological treatment added. Yields were not improved with the use of the biologicals compared to the control, however, the use of BioYield in combination with T22 decreased yield in comparison with BioYield alone. This would indicate that BioYield and T22 should not be used in combination.
Changes in watermelon culture by growers – This project outcome will have to wait until more information can be gathered.
More sustainable culture of watermelon – It is too early in the project to expect this outcome to be achieved.
Impacts and Contributions/Outcomes
Perhaps the largest impact of the work to date has been the discovery of a new virus in Indiana that may be related to the decline of watermelon. The first discovery of this virus was in a commercial field. However, recent work has indicated that the virus was present in the SARE plots of summer 2007. The extent to which this virus contributed to the vine decline observed has yet to be determined. The publication that resulted from this discovery is listed below. This information was shared with growers in March 07 at the Southwest Melon and Vegetable Growers Meeting.
Egel, D.S. and S. Adkins. 2007. Squash Vein Yellowing Virus Identified in Watermelon in Indiana. Plant Disease 91(8) 1056 DOI: 10.1094/PDIS-91-8-1056B.
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