Effect of some Plant Extracts on Sugar Beet Powdery Mildew

The research was conducted on 11 sugar beet varieties, grown at the Rumokai Experimental Station of the Lithuanian Research Center for Agriculture and Forestry, in 2016 and 2017. The experiments were carried out on two backgrounds: the crops were not sprayed and sprayed with fungicide epoxiconazole 125 g l–1. During the study years, rust (causative agent Uromyces beticola), powdery mildew (causative agent Erysiphe betae Vaňha Weltzien) and leaf spot disease (causative agent Cercospora beticola Sacc.) were the most prevalent in sugar beet. Rust, the intensity of which was 9.66–61.79%, caused most damage to sugar beet. The intensity of powdery mildew was 12.71–55.98% and that of leaf spot disease was 7.47–54.23%. Of the investigated varieties of sugar beet, the most sensitive to leaf spot disease were ‘Merens’, ‘Balear’, ‘Davinci’, ‘Kashmir’ and ‘Pottok’, the most resistant were ‘Berton’, ‘Selma KWS’ and ‘Wellington’. ‘Merens’ and ‘Texel’ were the most sensitive to rust. This disease was least damaging to the ‘Minta’, ‘Berton’ and ‘Strauss’ varieties. Powdery mildew was most harmful to leaves of the ‘Merens’, ‘Balear’ and ‘Minta’ varieties of sugar beet. The most resistant to powdery mildew was ‘Texel’. According to the average two-year data, the most productive was the ‘Pottok’ variety, whose root yield was 90.46– 93.85 t ha–1. The ‘Straus’ variety had the highest sugar content. Epoxiconazole increased the sugar beet yield from 0.44 to 6.53 t ha–1 in 2016 and from 0.07 to 11.63 t ha–1 in 2017.

Download Full-text

Occurrence of the Perfect Stage of Powdery Mildew of Sugar Beets in Southern Montana in 2003

Plant Disease ◽

10.1094/pd-89-1362b ◽

2005 ◽

Vol 89 (12) ◽

pp. 1362-1362

Author(s):

B. Jacobsen ◽

M. R. Johnston ◽

H. C. Weltzien

Keyword(s):

Powdery Mildew ◽

Sugar Beet ◽

Genetic Recombination ◽

Its Region ◽

The United States ◽

Long Distance ◽

Separate Species ◽

Sugar Beets ◽

Perfect Stage ◽

Erysiphe Polygoni

Wide spread powdery mildew infections on sugar beets were observed at the Southern Agricultural Experiment Station in Huntley, MT during September, 2003. Throughout the area, lower leaves were frequently heavily covered by the vegetative stage of the fungus with plants at the edge of the field having clearly visible abundant mature (black) and immature (brown) globose ascocarps on the leaf surfaces and stems. The fruiting structures had mostly branched appendages and were imbedded in the superficial mycelium. Their diameter ranged from 70 to 100 μm. Each ascocarp contained five to eight asci with one to four ascospores (mostly three) per ascus. Elliptical ascospores were hyaline and measured 20 to 25 μm long and 12 to 20 μm wide. On the basis of the descriptions given for isolates from Idaho and Colorado (1) and the usage of Erysiphe polygoni DC for powdery mildew on sugar beet in the United States, this isolate may be classified as E. polygoni DC. However, measurements taken show that ascocarps, asci, and ascospores also fall within the range of E. betae (Vanha) Weltz. as described by Weltzien (2). We strongly suggest that these species be compared by using rDNA analysis of the ITS region to determine whether they are separate species. If survival of the ascocarps and the viability and pathogenicity of the ascospores can be confirmed, epidemics of sugar beet powdery mildew could be understood as local and regional events that are not dependant on long distance dispersal of conidiospores. The occurrence of the perfect stage also could lead to the more frequent appearance of new races through genetic recombination. References: (1) J. J Gallian and L. E. Hanson. Plant Dis. 87:200, 2003. (2) H. C. Weltzien. Phytopathol. Z. 47:123, 1963.

Download Full-text