Premium
Verticillium wilt of the hop: field studies on wilt in a resistant cultivar in relation to nitrogen fertilizer applications
Author(s) -
SEWELL G. W. F.,
WILSON J. F.
Publication year - 1967
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.1744-7348.1967.tb04435.x
Subject(s) - biology , bacterial wilt , verticillium wilt , agronomy , acre , fertilizer , cultivar , zoology , horticulture
SUMMARY In two large‐scale observation trials on commercial farms inorganic nitrogen fertilizer was applied at 70 lb. N/acre (N1), 1401b. N/acre (N2) and at a normal commercial rate of 210 lb. N/acre (N3). Mean wilt incidence was 60 and 25% less with Ni and N2 respectively than with N3 during 5 years at one site and 3 years at the other. During these periods wilt declined progressively and this was tentatively attributed to the reduced intensity of host colonization, and to progressive declines in soil infectivity resulting from effects on the quantity, quality and longevity of annually produced inoculum. Marked annual fluctuations of wilt incidence and yields occurred at one site and these were associated with weather in the spring and early summer: wilt incidence was inversely related to soil temperature, and yield was directly related to rainfall. Yields were not diminished by the low‐N treatments, but clear correlations between yields and wilt incidence were probably obscured by the differential effects of weather conditions at the three levels of N application. The results emphasized the importance of reducing traditionally high N applications and, on farms where fluctuating wilt is severe, of applying the minimum levels of N commensurate with the maintenance of satisfactory yields.