Effects of alternative spray programs and various combinations of green pruning on powdery mildew [Uncinula necator (Schw.) Burr.] in Karasakız (Kuntra) grape cultivar


Abstract: The effects of alternative spray programs, NaHCO_3/K_2SiO_3 + sulphur, KH_2PO_4/di - 1 - p - menthone, and a conventional spray program, penconazole/sulphur, as well as various levels of shoot toppings (to the 1st, 3rd, and 5th buds) on powdery mildew disease [Uncinula necator (Schw.) Burr.] and grape quality were investigated in this study. The study was carried out on grape variety Karasakız (Vitis vinifera L.) during 2003 and 2004 growing seasons. The effectiveness of NaHCO_3/K_2SiO_3 + sulphur, KH_2PO_4/di - 1 - p - menthene alternate spray programs against powdery mildew was found as 74.8% and 70.7% on leaf and 65.7% and 62.1% on bunch in the 2003 vegetation period, which were close to the results (80.3% on leaf, 72.3% on bunch) obtained with the conventional control program (penconazole/sulphur). In 2004, NaHCO_3/K_2SiO_3 + sulphur (44.7%) was more effective for the control of leaf powdery mildew than penconazole/sulphur (29.0%). In addition, it also exhibited a similar effect on bunches. NaHCO_3/K_2SiO_3 + sulphur and penconazole/sulphur treatments showed positive effects on the yield and quality of grapes. All spray programs demonstrated a better performance in the vineyards where pruning was practiced from the 1st and 3rd buds after the last bunch of the grapes rather than from the 5th bud. According to the results of the study, NaHCO_3/K_2SiO_3 + sulphur spray program could be used in combination with the green pruning from the 3rd bud to control the disease in organic and integrated wine grapes, while KH_2PO_4/di - 1 - p - menthene spray program is more effective with the same pruning practice in the areas where climatic conditions are less favourable for U. necator, and pathogen-resistant grape varieties are grown.

Keywords: Alternative spray program, shoot topping, Uncinula necator, Vitis vinifera.

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