E. Tuomola et al., OCCURRENCE OF COMMON SCAB IN POTATO-TUBERS ALTER FOLIAR TREATMENT WITH GLYCINEBETAINE UNDER GLASSHOUSE CONDITIONS, Agricultural and food science in Finland, 5(6), 1996, pp. 601-608
A single foliar spray with 2.5 mM glycinebetaine (GB) was applied on p
otato (Solanum tuberosum L.) cvs. Matilda, Sabina and Saturna grown in
a sand bed infested with Streptomyces scabies (Thaxter) Waksman & Hen
rici at tuber initiation. A period of drought was maintained after GB
treatment to enhance scab infection. Legit models were used to compare
scab incidence in all harvested tubers (n = 622) and the type of scab
in the symptomatic tubers (n = 382), whereas the tuber surface areas
covered with scab lesions were compared using ANOVA. A 10 g increase i
n tuber weight increased the odds of scab incidence by 11.3%. Scab inc
idence was lowest in Sabina and highest in Matilda. Raised scab and su
perficial scab were common in all cultivars, but pitted scab developed
only in a few tubers of Sabina and Matilda. Among the scabby tubers,
the incidence of raised scab was highest in Sabina and lowest in Satur
na. The mean surface area covered with scab was 32.8% in Matilda, 11.7
% in Saturna and 7.5% in Sabina. Treatment with GB slightly reduced th
e severity of scab symptoms, as shown by the reduction in the proporti
on of tubers with raised scab among the scabby tubers (odds 0.60). No
effect on the incidence of scab or the tuber area covered with scab le
sions was detected following GB treatment.