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United States Department of Agriculture

Agricultural Research Service

Research Project: EVALUATION AND CHARACTERIZATION OF EXOTIC PLANT PATHOGENS FOR BIOLOGICAL CONTROL OF INTRODUCED, INVASIVE WEEDS Title: First report of anthracnose of Salsola tragus caused by Colletotrichum gloeosporioides in Russia

Authors
item Kolomiets, Tamara - ALL RUSS RES INSTIT PHYT
item Skatenok, Oleg - ALL RUSS RES INSTIT PHYT
item Alexandrova, Alina - MOSCOW STATE UNIVERSITY
item Mukhina, Zhanna - ALL RUSS RICE RES INSTIT
item Matveeva, Tatiana - ST PETERSBURG ST UNIV
item Bogomaz, Denis - ST PETERSBURG ST UNIV
item Berner, Dana
item Cavin, Craig

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 30, 2008
Publication Date: September 1, 2008
Citation: Kolomiets, T., Skatenok, O., Alexandrova, A., Mukhina, Z., Matveeva, T., Bogomaz, D., Berner, D.K., Cavin, C.A. 2008. First report of anthracnose of Salsola tragus caused by Colletotrichum gloeosporioides in Russia. Plant Disease. 92:1366.

Interpretive Summary: Russian thistle or tumbleweed is a problematic invasive weed in the western United States and a target of biological control efforts. In October of 2006, dying tumbleweed plants were found along the Azov Sea at Chushka, Russia. All of the plants in the area were diseased and about 80% of these were dead or dying. Diseased stem pieces were taken to the All Russian Research Institute of Phytopathology, Moscow, Russia. There, a fungus with characters conforming to the description of Colletotrichum gloeosporioides was isolated from the diseased stems. Pure cultures from these isolations were sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit, USDA, ARS, Fort Detrick, MD, for testing. Healthy stems and leaves of 13, 30-day-old plants of tumbleweed were spray-inoculated with a suspension of spores. Thirteen control plants were sprayed with water and surfactant only. Plants were placed in an environmental chamber, and after one day, all plants were transferred to a greenhouse. Lesions developed on stems of all inoculated plants after 7 days. After 14 days, 9 plants were dead, and all inoculated plants were dead after three weeks. No symptoms occurred on control plants.C. gloeosporioides was reisolated from stem pieces of each inoculated plant. This isolate of C. gloeosporioides is a destructive pathogen on tumbleweed and is a potential candidate for biological control of this weed in the U.S. To our knowledge, this is the first report of this disease caused by C. gloeosporioides on tumbleweed in Russia.

Technical Abstract: Salsola tragus L. (Russian thistle, tumbleweed), family Chenopodiaceae, is a problematic invasive weed in the western United States and a target of biological control efforts. In October of 2006, dying Salsola tragus L. plants were found along the Azov Sea at Chushka, Russia. About 40 plants in the area were diseased and about 80% of these were dying. All plants were ca. 1 m tall x 0.5 m diam. Dying plants had irregular necrotic lesions extending the length of the stems. Leaves of these plants were also necrotic. Lesions on stems and leaves were dark brown and usually coalesced. Diseased stem pieces were taken to Russian State collection of phytopathogenic organisms at the All Russian Research Institute of Phytopathology. Diseased plant parts were disinfested and placed into Petri dishes on the surface of potato-glucose agar (PGA). Numerous waxy subepidermal acervuli with black setae were observed in all of the lesions after 2-3 days. Conidiophores were simple, short, and erect. Conidia were one-celled, hyaline, ovoid to oblong, falcate to straight, 12.9-18.0 x 2.8-5.5 um (mode 16.1 x 4.5 um). These characters conformed to the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. Axenic cultures were sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit, USDA, ARS, Fort Detrick, MD, for testing. Conidia were harvested from 14-day-old cultures grown on 20% V-8 Juice agar, and healthy stems and leaves of 13, 30-day-old plants of S. tragus plants were spray-inoculated with an aqueous conidial suspension of conidia. Another 13 control plants were sprayed with water only. Plants were placed in an environmental chamber at 16 h dew in darkness at 25 C. After one day, all plants were transferred to a greenhouse at 20-25 C, 30-50% relative humidity, and natural light, augmented by 12-hour light periods with 500 watt sodium vapor lights. Lesions developed on stems of all inoculated plants after 7 days. After 3 weeks all inoculated plants were dead. No symptoms occurred on control plants. C. gloeosporioides was re-isolated from stem pieces of all inoculated plants. This isolate of C. gloeosporioides is a destructive pathogen on S. tragus and is a potential candidate for biological control of this weed in the U.S. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on S. tragus in Russia.

Last Modified: 10/31/2014
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