Etiology and control of the grey disorder in flue-cured tobacco

• Main Author: Arnold, Neville Patrick.
• Format: Others
• Language: en
• Published: McGill University 1984
• Subjects: Tobacco > Diseases and pests.; Plants > Effect of minerals on.; Plant-soil relationships.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71877

Leaf and associated soil samples from 15 locations in Quebec showed that grey tobacco contained less N, P, K, Ca, B, nicotine, total alkaloids, organic acids, fatty acids, but more Fe and Al than non-grey (normal) tobacco. Soils producing grey tobacco had less N, Ca, organic matter, a lower cation exchange capacity but more Cl. === Fe('55) fed to tobacco plants grown in soil known to produce grey tobacco was translocated to vascular and associated tissue in leaves. The grey disorder symptoms were duplicated in hydroponically grown plants. === In a two-year field study, grey tobacco had 20% less dry weight and 30% less leaf area. Relative growth rate and net assimilation rate decreased less rapidly during growth in grey than in non-grey tobacco. N and K content in leaves was lower in grey tobacco but higher in Fe and Mn. === The grey effect was decreased or eliminated in tobacco plants grown in pots with manure and lime. The leaf contents of Fe, Mn and Mg were associated with grade index ((CENTS)/kg) and dollar value/ha of tobacco. Fertilizer and manure reduced leaf Ca. Fertilizer alone increased the leaf content of N, P and K while manure increased leaf dry weight. The ratio of K/Ca and K/(Ca + Mg) increased with increasing levels of manure relative to each level of lime while the percent grey tobacco decreased dramatically.