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The growth of red beet was described by reference to changes in the number of leaves and vascular rings with time. In the glasshouse, decortication (splitting of the hypocotyl) began about 35 days from sowing, when plants had about five leaves and two to three vascular rings. Inoculation at different times and observations of the number of vascular rings disrupted by scab indicated that the plants became susceptible to infection by Streptomyces spp. at about this time. The exposed hypocotyl tissues suberized within 2–3 wk, by which time plants had eight leaves and four vascular rings; this may have prevented further infection. [ABSTRACT FROM AUTHOR]

Ten 'globe' and two 'long' red beet cultivars were tested for susceptibility to Streptomyces scab in a field trial on a scab-infested Black Fen peat soil. The long beet cultivars Red Perfection and Cheltenham Green Top had little scab and about 75 per cent of roots had none or only one small lesion ('scab free'). Of the 'globe' beets, Avon Early and Elsoms No. 257 were most resistant with only 2 per cent of the surface area scabbed and 75 per cent of roots 'scab free'. Little Ball and New Globe were most susceptible with 8 to 9 per cent of the surface affected and only 33 per cent of roots 'scab free'. The widely grown Boltardy and Crimson Globe had about 7 per cent of the surface area scabbed and 45 per cent of roots 'scab free'. [ABSTRACT FROM AUTHOR]

The susceptibility of tubers of different potato cultivars to soft rot by Erwinia carotovora subspp. atroseptica and carotovora was assessed in 3 years by two methods. In one method, whole tubers inoculated at wounds with either bacterium were incubated under anaerobic conditions for 5 or a days at 15°C. In the other method, wounds made in tuber slices were allowed to heal or not, before inoculation with different concentrations of each bacterium and were then incubated under aerobic conditions for 3 days at 15 ° C. Most cultivars gave consistent reactions in repeated experiments using the same method, but there was some seasonal variation. A few cultivars were consistently susceptible (Klondyke and Manna) or resistant (Drayton) in both methods but others gave completely contrasting results (Record). In both methods and with all cultivars more rotting was caused by subsp. atroseptica than by subsp. carotovora because of the temperature of incubation. [ABSTRACT FROM AUTHOR]

Tuber slices of 15 cultivars were inoculated with Erwinia carotovora subsp. atroseptica on two occasions at four test centres and the results compared. Correlations in mean lesion diameter between inoculum concentrations, between the same test on different occasions, between centres and between cultivars in different tests were mostly significant in spite of small differences in procedure at each centre. Satisfactory agreement was reached between centres, particularly concerning the most resistant (Cara, Pentland Hawk) and most susceptible (Record, Wilja, Pentland Crown, King Edward) of the cultivars tested. The implications of the findings are discussed in relation to results published elsewhere and to other methods of inoculation. [ABSTRACT FROM AUTHOR]

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In 1971, irrigation at Gleadthorpe E.H.F. had little or no effect on yields but, when applied early in the season, greatly decreased common scab on the susceptible cultivars King Edward, Majestic and Désirée. Record, and especially Pentland Crown, had little scab with or without irrigation. Most-scab infection occurred during dry weather in late June and early July. Irrigation for 6 wk from 4 June, at 0 6 in. (15 mm) soil moisture deficit (S.M.D.) controlled scab most effectively, but 6 wk was only marginally better than 4 wk. With other regimes, the severity of scab increased as the S.M.D. allowed before irrigation was increased. King Edward tubers from unirrigated plots were blemished more in 1971 than in the two previous dry seasons, partly because rain caused tubers to swell more than previously and enlarged scab lesions so much that healthy tissue between scabs was ruptured. More tubers per plant were formed from King Edward when seed tubers were treated with benomyl and oxycarboxin before planting than when untreated, but irrigation even from 75 per cent emergence had no effect on tuber numbers. [ABSTRACT FROM AUTHOR]

This article cites a study that examined the relative importance of weather, soil- and seed-borne inoculum in determining the incidence of common scab in potato crops in England. Potato seed tubers, without or variously affected by common scab, were planted between 1964 and 1967, in two fields at Rothamsted, one known to produce only slightly scabbed and the other severely scabbed potato crops. The amount of scab at lifting depended most on whether June or early July was wet or dry. If wet, there was little infection on progeny tubers irrespective of the amount of inoculum in soil or on seed tubers.

This article examines irrigation as a practical means to control potato common scab. It notes that irrigation in 1970 at Gleadthorpe E.H.F. increased potato yields and, when given from the time of tuber initiation, controlled common scab on the susceptible cultivars King Edward, Majestic and Record. Pentland Crown had little scab with or without irrigation. It was the driest May and June since 1934 and there was already a soil moisture deficit (SMD) of 1.8 inches at tuber initiation by King Edward and when water was first given. Subsequently irrigation at 0.6 inches or 0.8 inches SMD in controlling scab, and more effective at 0.6 inches SMD when maintained for 4 weeks than for 2 weeks. Irrigation at 0.6 inches SMD for 4 weeks increased the weight of premium potatoes by respectively, 16, 12, 13 and 12 tons/acre for King Edward, Majestic, Record and Pentland Crown. Tubers developed slowly in unirrigated plots both in volume and in the rate that eyes separated. King Edward produced more tubers per plant than Majestic; irrigation did not increase tuber numbers.

Copyright of European Potato Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents several observations on the timing of irrigation of potato tubers and the incidence of potato common scab. Common scab on Majestic potato tubers was checked by irrigation maintaining the soil at saturation throughout the growing season more than it was by irrigating only before the first tubers had grown. It was found out that the stage of the tubers when irrigation was started or stopped affected the distribution of scab lesions on their surfaces and infections were rare on tissue formed when soil was saturated.

This article discusses the effect of nitrogen on the formation of potato tubers and the incidence of common scab (Streptomyces scabies) in Great Britain. The incidence of common scab on tubers from a fertilizer experiment in 1964 increased with increasing amount of nitrogen fertilizer. Nitrogen may have affected tuber susceptibility but the increase was more likely due to nitrogen delaying the time when tubers were initiated and developed. Plants given little or no nitrogen formed tubers during early June when the soil was wet (conditions unfavorable for infection), whereas plants given abundant nitrogen initiated their tubers during the dry weather of late June (conditions favorable for infection).

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)