Hot-water treatment of gladiolus cormels for control of corm-borne fungal diseases

S. Bistrichanov1, T. Vatchev2, Z. Avramov1*

1University of Forestry, 10 Kliment Ohridski, 1797 Sofia, Bulgaria
2Institute of Soil Science, Agrotechnologies and Plant Protection, 35 Panayot Volov, 2230 Kostinbrod, Bulgaria

(Manuscript received 18 May 2016; accepted for publication 23 January 2017)

Abstract. A hot-water treatment was used successfully to obtain pathogen-free planting stock from various plants to control some diseases including gladiolus. The objective of this study was to evaluate the effect of hot-water treatments in terms of damaging gladiolus, concerning sprouting and leading to crop loses. Cormels of two gladiolus cultivars, Oscar and Amsterdam, were used for each treatment (temperature x time period) and were immersed in water baths with hot water at 20 ̊C (as control), 45 ̊C, 50 ̊C, 55 ̊C and 60 ̊C for different treatment periods 10, 20 and 30 min and were planted in pots (d10cm) filled with sterile nutrient substrate (peat:soil:perlite in ratio 3:1:0.5). Three replicate pots each containing 10 cormels were used per treatment. The results showed that the increase of the temperature and the extension of exposition duration reduced significantly the percentage of the sprouting plants from both cultivars – more than 80% at 55 ̊C/20min, and Oscar was more resistant to this treatment regime. For phytosanitary purposes two treatment options were considered as non- damaging – 45 ̊C for 30min or 50 ̊C for 20min, wherein the resulting plants showed approximately 90% sprouting. It was concluded that for successful disease control specific hot-water treatment regimes should be established for every particular gladiolus cultivar.