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50th TWC, Tob. Work. Conf., 2022, abstr. 25

Effect of fungicide programs and lower leaf removal on wrapper leaf production in Connecticut broadleaf cigar wrapper tobacco

PERKINS C.(1); BAILEY W.A.(1); RODGERS C.(1); KEENEY A.B.(1); WITHCER V.(1); RICHMOND M.D.(2); ELLIS R.(2)
(1) University of Kentucky, Research & Education Center, Princeton, KY, USA; (2) University of Tennessee, Highland Rim Research & Education Center, Springfield, TN, USA

Late-season frogeye leaf spot infection that results in ‘greenspot’ in cured leaf has been the greatest problem in producing Connecticut Broadleaf cigar wrapper tobacco in Kentucky. Field trials were established in Princeton, KY and Springfield, TN to evaluate the effects of fungicide programs and lower leaf removal on frogeye leafspot. At Princeton, eleven fungicide/bacteriacide programs were evaluated and included mancozeb, azoxystrobin, fluopicolide, oxathiapiprolin+mefenoxam, copper octanoate, fluopyram, thiophanate-methyl, flutriafol, and pydiflumetofen+difenoconazole, as well as the biologicals Bacillus amyloliquefaciens strain D747 and Reynoutria sachalinensis. In a separate trial, the effects of lower leaf removal at topping and fungicide application were evaluated. Treatments in the lower leaf removal trial were arranged in a 2 x 2 factorial treatment design with 4 lower leaves removed at topping vs. no leaf removal, and fungicide application (azoxystrobin at topping followed by Bacillus amyloliquefaciens strain D747 three days prior to harvest) vs. no fungicide application. The lower leaf removal trial was topped at 10 leaves just prior to lower leaf removal and fungicide application. An additional treatment included no lower leaf removal or fungicide application, but only the top 6 leaves were harvested. In the fungicide trial, applications began three weeks after planting and lasted until the final week before harvest. Different spray regimens and timings followed product labels. In the fungicide trial, highest total yield per acre was from copper octanoate, thiophanate-methyl, and flutriafol treatments, while highest percent wrapper yield was from flutriafol, fluopyram, and pydiflumetofen+difenoconazole treatments. Highest gross revenue per acre was from flutriafol, pydiflumetofen+difenoconazole, thiophanate-methyl, fluopyram, and copper octanoate treatments. In the lower leaf removal trial, lower leaf removal at topping or only harvesting the top six leaves resulted in significant reductions in total yield. Although lower leaf removal or harvesting only the top 6 leaves resulted in significant increases in percent wrapper leaf production, these increases in percent wrapper did not offset the total yield losses reflected in gross revenue. Differences seen in the lower leaf removal trial data were similar at both Princeton and Springfield locations. (Reprinted with permission)