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THE EFFICIENCY OF CHEMICAL TREATMENTS OF VEGETABLE SEEDS AGAINST SEED‐BORNE AND SOIL‐BORNE ORGANISMS
Author(s) -
JACKS HARRY
Publication year - 1951
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1951.tb07794.x
Subject(s) - rhizoctonia solani , sowing , fungicide , pythium , biology , seed treatment , agronomy , horticulture , rhizoctonia , damping off , fludioxonil , metalaxyl , germination , seedling
Out of thirty‐four newer fungicides tested in greenhouse and field trials, red cuprous oxide (Cuprocide), tetrachloro para benzoquinone (Spergon), methyl mercury dicyandiamide (Panogen), tetramethylthiuram disulphide (T.M.T.D.), ferric dimethyldithiocarbamate (F.D.D.), zinc trichlorophenate (Dow 7B) and 1‐ p ‐sulphamylphenyl‐3:5‐dimethyl‐4‐nitrosopyrazole (36L) were selected for detailed investigation on lettuce, pea, French bean, turnip, red beet, tomato and celery. Derivatives of dithiocarbamic acid, and 36L and Spergon among non‐metallic compounds compared favourably with cuprous oxide and organomercurial compounds. Addition of hormones, insecticides or nemacides did not improve emergence. Soil tests were more satisfactory than laboratory selection. Rates of application recommended by manufacturers often injured small seeds, and the optimum dosages were determined by extensive tests. Results obtained depended on conditions of test. Under glass, emergence was lower at 5–12° C. than at 16–20° C. Emergence was optimum at 45 % water‐holding capacity, and additional tests are required at higher and lower moisture to assess phytocidal and protectant action. In field trials seed treatments were generally most beneficial in cool and moist soil, and improved emergence in all but driest soil. T.M.T.D., Spergon and 36L were the most effective seed protectants. Mixing of these materials did not improve emergence. Emergence in relatively dry soil (25 % w.h.c .) was improved by watering after sowing, but emergence was decreased in moist soil by watering within 2 days of sowing. A seed‐borne form of Rhizoctonia solani was isolated from most seeds. Pythium, Rhizoctonia and Fusarium were commonly isolated from seedlings. Pythium was commoner at low and Fusarium at higher temperatures. Surface disinfection of seed by Spergon and Panogen compared favourably with acidulated mercuric chloride. Ascochyta on pea seed was not controlled, but all treatments except Cuprocide improved emergence of spotted pea seed. T.M.T.D., 36L and Spergon were the most efficient in controlling pre‐emergence damping off. Seed treatment was more beneficial for pea than other vegetables, but emergence was usually improved by protectants except for turnip and celery seed. Treated seed stored dry for 10 months gave better emergence than untreated seed, and showed no evidence of diminished germination.