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Timely Information > Posts > Impact of Seeding Rate and Planting Date on the Severity of Target Spot and Hardlock in Cotton

2017 Cotton Target Spot Timely Information.pdf

Seeding rate and planting date studies were conducted at the Gulf Coast Research and Extension Center and Field Crops Research Unit, respectively.  A factorial arranged as a split-split plot with variety (Phytogen 499 WRF and Deltapine 1555 B2RF) as the whole plot, seeding rate of 2, 3, and 4 seed/ ft of row as the split plot, and fungicide program as the split-split plot for the former study; and a 12 May and 27 May planting date as the whole plot, variety (Phytogen 499 WRF, Phytogen 444 WRF, and Deltapine 1538 B2XF) as the split plot, and fungicide program as the split-split plot for the latter study.  The fungicide program consisted of four applications of Headline SC at 9 fl oz/A or three applications of Priaxor at 6 fl oz/A beginning at first bloom on a 14 day schedule and a non-fungicide treated control. Both studies were irrigated.  Overall, rainfall totals were higher at the former than latter study site.  In the seeding rate study, final defoliation differed by variety and fungicide program but not seeding rate, while yields rose with increasing seeding rates.  Defoliation was greater regardless of fungicide program on Phytogen 499 WRF than Deltapine 1555 B2RF.  Drier weather suppressed target spot at the Field Crops Research Unit.  Significant planting date × cotton variety, planting date × fungicide program, and variety × fungicide program interactions for defoliation were noted.  For the non-fungicide treated control and Priaxor program, defoliation was higher in the 27 May than 12 May-planted cotton.  While no differences in defoliation were noted between varieties planted on 12 May, 27 May-planted Phytogen 499 WRF suffered greater defoliation than Phytogen 444 WFR and Deltapine 1538 B2XF, which had similarly lower defoliation ratings.  Greater yields were reported for the latter than the former variety.  For all varieties, reduced defoliation and higher yields were obtained with the Priaxor program than the non-fungicide treated control.  


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