Diseases
Colletotrichum lagenarium (Pass.) Ell. et Halst. - Anthracnose of Cucumber
Systematic position.
Division Ascomycota, order Phyllachorales, family Phyllachoraceae, genus Colletotrichum.Synonym.
Colletotrichum orbiculare (Berk. et Mont.) Arx.Biological group.
Facultative parasite.Morphology and biology.
Cucumber, water-melon, melon, less often pumpkin are affected by the Anthracnose. The disease appears on all overground organs of young and adult plants, being especially severe on fruits. Pale-green, rounded at first, localized between veins, later merging spots are formed on leaves, covering significant part of a leaf. The affected leaves grow brown, become fragile, and dry up. On fruits the spots are pale-green, impressed, looking like ulcers; the fruits become bitter, darken and rot. On stems and leaf petioles the spots are lengthened, impressed, brown-yellow, weeping. In these the stems crack at places of spots, and plants perish. Under damp weather conditions the spots become covered with pink bloom of fungal sporification, and later black dots of sclerotia are formed there. Sporangia flat, lenticular, 40 mkm to 1 mm, with setae being 90-120 mkm in length. Conidia ellipsoid, cylindrical, crescent, unicellular, granular, 10-40 x 3-8 mkm.Distribution.
Anthracnose of gourd cultures was found for the first time in Russia by A.A. Yachevskii in 1901 on cucumbers in the Novgorod Region. Now the disease is distributed everywhere in zone of the cultures cultivation in protected and open ground. In hothouses it is the most nocuous disease in the Northwest (Leningrad, Vologda, Novgorod, Pskov Regions), Central area (Vladimir, Ivanovo, Moscow, Kaluga, Smolensk Regions), Volga-Vyatka area (Nizhnii Novgorod Region, Chuvashia and Mari El Republics), Western and Eastern Siberia (Chelyabinsk, Sverdlovsk, Omsk, Novosibirsk, Kemerovo, Chita Regions, Krasnoyarsk Territory), in the Far East (Amur and Sakhalin Regions). In open ground the Anthracnose is more nocuous disease in the Northern Caucasus (Chechnya, Ingushetia, Kabardino-Balkaria, Krasnodar and Stavropol Territories), in Rostov and Volgograd Regions, in mainly southern and central areas of Ukraine, and in Moldova. In these regions to 30-100% of plants are affected, the disease development reaches to 50%, and yield reduction reaches to 48%.Ecology.
Mycelium and sclerotia are sources of the infection, keeping on the affected vegetation residues and seeds. Optimum temperature for the fungus development is 22-27.C, relative air humidity is 88-92% (the disease does not develop at 54% air humidity); the incubation period is 3-6 days.Economic significance.
Anthracnose results in decrease of quality and quantity of yield; it can also cause premature destruction of plants; the photosynthesizing surface of plants is reduced by 29-42%, yield losses vary from 6 to 48%, the content of ascorbic acid is reduced by 34%. Control measures are removal and destruction of vegetation residues; deep autumn plowing; maintenance of crop rotation (replanting of gourd cultures on the same field in 6 years); disinfection of hotbeds and hothouses; seed dressing before sowing; preventive spraying of plants by fungicides during vegetation; introduction of resistant varieties.Related references:
Chumakov A.E., & Zakharova T.I. 1990. Harmfulness of cultural plants diseases. Moscow: Agropromizdat. 127 p. (in Russian).Hawksworth D.L., Kirk P.M., Sutton B.C., Pegler D.M. 1995. Ainsworth & Bisby.s Dictionary of the fungi. Kew: CAB International. 616 p.
Kuporitskaya K.I., Stanko A.I. 1968. Diseases of gourd plants. In: Verderevskii D.D., ed. Handbook of agronomist on plant protection. Kishinev: Kartya Moldovenyaske, p. 343-352 (in Russian).
Lopukhina G.P., Antonov Yu.P., Blinova Z.P., Kosacheva R.Z., Yaremko T.N. 1977. Diseases of vegetable cultures. In: Polyakov I.Ya., Semenov A.Ya., Zakharova T.I., eds. Pests and diseases distribution on agricultural crops in RSFSR in 1976 and the forecast of their appearance in 1977. Moscow: MSKH RSFSR, GUZR, VIZR, p. 217-232 (in Russian).
Natalenko G.S., Sorokina V.K. 1966. Diseases of cucumbers. In: Sorokin B.L., ed. Pests and diseases distribution on agricultural crops in Rostov Region in 1966 and the forecast of their appearance in 1967. Rostov-na-Donu: Rostov STAZR, Don NIISKH, p. 47-48 (in Russian).
Osnitskaya E.A. 1968. Diseases of vegetables. In: Polyakov I.Ya., Chumakov A.E., eds. Pests and diseases distribution on agricultural crops in RSFSR in 1967 and the forecast of their appearance in 1968. Moscow: Rosselkhozizdat: 120-125 (in Russian).
Osnitskaya E.A. 1969. Diseases of vegetables. In: Polyakov I.Ya., Chumakov A.E., eds. Pests and diseases distribution on agricultural crops in RSFSR in 1968 and the forecast of their appearance in 1969. Moscow: Rosselkhozizdat: 137-144 (in Russian).
Osnitskaya E.A. 1970. Diseases of vegetables. In: Polyakov I.Ya., Minkevich I.I., eds. Pests and diseases distribution on agricultural crops in RSFSR in 1969 and the forecast of their appearance in 1970. Moscow: MSKH RSFSR, VIZR: 252-263 (in Russian).
Osnitskaya E.A. 1971. Diseases of vegetables. In: Polyakov I.Ya., Minkevich I.I., eds. Pests and diseases distribution on agricultural crops in RSFSR in 1970 and the forecast of their appearance in 1971. Moscow: MSKH RSFSR, VIZR: 187-198 (in Russian).
Vasil'evskii N.I., Karakulin B.P. 1950. Parasitic imperfect fungi. Part 2. Melanconiaceae. Moscow & Leningrad: AN SSSR, 680 p. (in Russian).