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The effects of soil moisture at the time potato tubers are forming on the incidence of common scab ( Streptomyces scabies )
Author(s) -
LAPWOOD D. H.
Publication year - 1966
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.1744-7348.1966.tb04404.x
Subject(s) - common scab , stolon , biology , sowing , tubercle , water content , horticulture , agronomy , moisture , streptomyces , bacteria , genetics , materials science , geotechnical engineering , engineering , composite material , bacilli
SUMMARY Two complementary field experiments at Rothamsted in 1965, with the potato variety Majestic, related the incidence of common scab ( Streptomyces scabies ) to rainfall, soil moisture and time of tuber formation. In plots where the soil was maintained at field capacity (less than 10 cm. Hg moisture tension) by watering, tubers had little or no scab; infection increased in amount on plots allowed to dry to 30 cm., 50 cm. or more Hg moisture tension during late June. The time tubers formed was varied by planting sprouted (chitted) and non‐sprouted seed tubers, and tuber development and scab incidence were observed on sample plants lifted at frequent intervals from unwatered plots. Scab lesions were first seen on 12 July when the distribution of lesions on the surface of tubers was affected by size of tuber both within and between the different seed‐tuber treatments. These differences were correlated with estimates of tuber size on 28 June, the beginning of the first dry period. Tubers 1.0 cm. or more in diameter on 28 June had few or no lesions at the stolon attachment (heel) end of tubers on 12 July, whereas tubers smaller than this on 28 June had many lesions in this region on 12 July. The larger the tuber was on 28 June, the greater was the area free from scab lesions on 12 July.