Continuous Testing for Scab Infection Weather Using Apple Rootstocks

Preece, T.F.

doi:10.1111/j.1365-3059.1964.tb00249.x

Cited by 12 publications

(3 citation statements)

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“…Mills & LaPlante (1954) anticipated or than current interpretations of instrument charts would suggest. Reasonably accurate disease forecasts seem feasible in Britain as in the U.S.A. ('Mills periods') when general wetness conditions amply satisfy accepted infection criteria (Preece, 1964), but discontinuous wetting is more difficult to interpret confidently. I n spring 1963, for example, the occurrence of widespread infection at one observation site was preceded, at an expected interval, by two marginal subinfection wet periods separated by a dry interval of 10.5 hr.…”

Section: Scab Infection Might Thus Results From Discontinuous Wetting mentioning

confidence: 99%

“…Wet periods longer than the minima cited above would usually be necessary to establish infection in apple plantations, where conditions rarely remain at optimum levels (Keitt & Jones, 1926;Mills & LaPlante, 1954;Preece, 1964). Moreover, a variable period must be added for spore-dispersal, ascospores requiring longer from first leaf-wetting than conidia, most of which are merely transported locally on the same tree.…”

Section: Discussionmentioning

confidence: 99%

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Glasshouse experiments on apple scab I. Foliage infection in relation to wet and dry periods

Moore

1964

Annals of Applied Biology

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A technique of investigating apple scab infection periods using M M 109 rootstocks in the glasshouse is fully described. Inoculation by ascospores in aqueous suspension was less reliable than that by sedimenting the spores direct from source leaves on to the host plants, but fresh conidia in aqueous suspension consistently gave high levels of infection under optimum conditions.Ascospores required a shorter period of continuous wetness (6 hr.) than conidia (7-9 hr.) for infection at near-optimum temperatures. Maximum infection from both sources was reached after about 18 hr. continuous wetness; much longer periods were sometimes inimical. With discontinuous wetness, most ascospores tolerated a dry interval of 24 hr. on the host leaves, although infection was somewhat reduced if the dry period began when the spores were starting to germinate. Conidia were more inhibited than ascospores by 24 hr. drying during minimal infection periods, but many survived and produced lesions.Some ascospores survived dry periods of at least 96 hr., but mature leaves had acquired resistance during the interval and thus infection was reduced. The reduction was partly offset by greater infection of the youngest leaves, which meantime had expanded and were thus easier to wet. No infection resulted, however, when the dry interval was extended to 10 days.T h e implications of the results are discussed in relation to the interpretation of infection periods in the field.

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Section: Scab Infection Might Thus Results From Discontinuous Wetting mentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Glasshouse experiments on apple scab I. Foliage infection in relation to wet and dry periods

Moore

1964

Annals of Applied Biology

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“…Nach adit bis zehn Tagen hei 20 ^' C erfolgte durch SchCitteln der Kulturen fine gleidimafiige Inokulierung der gesamten Filterpapieroberfladie mit Hilfe der inzwisdien gebildeten Konidicn. Innerhalb (KEITT und JONES 1926, ROOSJE 1955, PREECE 1964, SYS und SOENEN 1970, IHSANULLAH 1973 4, 6, 8, 10, 12, 14, 16, 18, 20,22, 24, 26, 28 "C; D 1 in vivo: 4, 8, 10, 12, 16, 20, 24, 28 (HOLZ 1937, BROOK 1969a, 1969b (ADBRHOLD 1900, KEITT und JONES 1926, RUDLOFF 1935, WINKELMANN und HOLZ 1936, ROOSJE 1955, PREECE 1964, MOORE 1964, SYS und SOENEN 1970 Conidia are formed in the temperature range between 4 and 28 "^C. Maximum sporulation was reached at 16*^C with a fungus strain from Western Germany, and at 20 ^' C with a strain from Lebanon.…”

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