Five isolates of Uromyces betae Tul Kick. were isolated from five governorates (Domyat, Kafr El-sheikh, Dakahliy, Gharbiya and Beheira). Vitality of urediospores, stored at 2-5ºC, was decreased gradually by increasing storage until approximately loss completely after 210 days. The loss in vitality was clearly varied between the five tested rust isolates. Younger sugar beet plants of Raspoly cultivar (30 and 60 days old) were resistant and susceptibility increased to rust infection at 90 and 120 days old than at 180-days old.
Concerning disease control, rust infection completely suppressed on plants sprayed with optimum concentration of fungicide Sumi-eight whether 24 hours before or after inoculation. Sumi-8 followed by 0.3% garlic extracts and 300 ppm of IAA weather 48 hours before or after inoculation and came to the second and third ranks, respectively after Sumi-8. Sugar beet cultivars tested showed different susceptible reactions against artificial inoculation and could be categorized as less susceptible (LS), moderate susceptible (MS) and high susceptible (HS).
Rusted leaves of all tested sugar beet cultivars contained lower photosynthetic pigments, sugars and total amino acids and higher phenols as well as higher activities of oxidative enzymes in comparison with their healthy leaves. The infected leaves of Lola and Raspoly (HS cvs.) showed the highest increase in activities of oxidative enzymes in comparison with Farida and Golria (LS cvs.) while the opposite trend was detected concerning photosynthetic pigment, reducing sugars and phenols contents.
Keywords: Rust, Uromyces betae, Vitality, Sugar beet, Cultivars, fungicides, plant extracts, growth substances, oxidative enzymes, pigments, sugars, phenols, amino acids.
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