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EXPERIMENTS ON BLACK LEG DISEASE OF SUGAR‐BEET SEEDLINGS
Author(s) -
GATES L. F.,
HULL R.
Publication year - 1954
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.1744-7348.1954.tb01152.x
Subject(s) - thiram , biology , sugar beet , seedling , rhizoctonia solani , pythium , seed treatment , horticulture , agronomy , fungicide , phoma , sugar , damping off , soil water , germination , ecology , biochemistry
Phoma betae was usually the predominant pathogen attacking sugar‐beet seedlings in the field in eastern England, but Pythium spp. sometimes predominated when the seedlings were very young. Fusarium spp. were associated with acid soil conditions. Rhizoctonia solani only occasionally caused severe losses. Black leg, caused chiefly by Phoma betae , was most prevalent at low soil temperatures when, in stands from untreated seed, up to 45 % of the seedlings were attacked. Disease decreased by 0·8 to 2·4 diseased seedlings per 100 in stands from untreated seed per 1° F. rise in soil temperature. Seed treated with Panogen, * thiram and ethyl mercury phosphate regularly gave better stands in small‐scale trials than seed treated with Ceresan or Agrosan. In large‐scale experiments average increase in seedling emergence following treatment with Panogen, thiram and Agrosan varied in different years between + 6·4 and + 19·2 %. Average response to BHC soil dressing was + 4·2 and + 8·6 %. Response to seed dressings increased as the time taken for emergence increased and as percentage emergence decreased; when emergence was 50 % of the possible, dressing gave on average 20 % more seedlings. Response to dressing increased as soil became more acid or alkaline than the optimum for beet, and was lower on heavy soils and on soils dressed with farmyard manure. Maximum emergence varied from year to year between 2100 and 2700 seedlings per oz. seed; minimum between 690 and 1050. Emergence of both treated and untreated seed varied greatly and was related to time taken for emergence, suggesting that effects of soil moisture, temperature or texture are important. Emergence WM not correlated with pH, but when the pH was below 6·5 or above 8·7 it was not more than 75 % of that at pH 7·0–7·4. In 2 out of 3 years emergence was increased by 32 and 84 seedlings/oz. seed by each extra cwt. per acre of inorganic fertilizer (N, P, K). Seed rate, cultural operations and drill type had no consistent effect. A 1 % increase in seedling stand increased the final plant population on average by 0·2%.