EFFECT OF SPRAYING LIME AND SOME FUNGICIDES ON VINE GROWTH AND CONTROL OF DEAD ARM DISEASE AND BUNCH ROT OF RUBY SEEDLESS GRAPEVINES

A field trial was conducted in 2005, 2006 and extended to January 2007 on 12-years-old Ruby Seedless grapevines trained by quadric lateral cordon and spur pruned. Vines were sprayed with lime after two weeks of berry set, CaCl₂ one week later, lime and CaCl₂ with wettable sulfur at short intervals weekly from full bloom   until the fourth week after berry set. Copper oxichloride was sprayed at the fourth week of berry set mixed with the dose of wettable sulfur of this week. One concentration (3 g/L) was used from each compound. All the experimental vines   were sprayed with wettable sulfur at 15 days interval from bud burst as long as  temperature was lower than 28 ^oC.
Vine vigor expressed in terms of weight of pruning wood, dry weight and carbohydrate content of basal canes  were improved in the second and third season of the study; carbohydrate content was improved in the second season compared to control as affected by experimental foliar spraying compounds. The best  improvement occurred with spraying vines with lime (3 g/L), CaCl₂ and wettable   sulfur (3 g/L) at short interval weekly from full bloom until fourth week of berry set. Copper oxichloride       (3 g/L) was applied once  mixed with the dose of wettable sulfur in the fourth week of berry set. However, this treatment significantly reduced disease severity of both dead-arm and bunch rot disease. Also, this treatment reduced the number of both dead spurs of last season seasons compared with        the first and second  of winter pruning of the study.