Some biological charactristics of Saxaoul powdery mildew (Leveillula s(Noouli) in Khorassan Province

Document Type : Research Paper

Authors

Abstract

Powdery mildew has been accounted as the most important disease of Saxaoul plant species (Haloxylon spp.) in Khorassan Province and the other parts of Iran as well. Leveillula saxaouli (Sorok) Golovin has been determined as the causal agent of the disease. In this study, canied out in 1997, variations of conidia population during infection seasons, morphometeric variations of the fungus, infection rate of the disease as well as host range and histopathologic relation of host-pathogen were investigated. The results did not show any morphological differences between the fungus isolates collected from various areas. The highest number of conidia of L. saxaouli trapped on the microscopic slide placed near infected leaves of Saxaoul during 1998-1999 were 125.79 and 51.5 in square centimeter of the slide in early July for Gonabad and Sabzavar areas, respectively. Meanwhile, the lowest rate for these localities were 0.54 and 0.74 in late November. Rate of infection were 22.37%o and l4Yo in Sabzevar and Gonabad, respectivly.
 
 

Keywords


-        ارشاد، ج.، 1374. قارچهای ایران. انتشارات سازمان تحقیقات و آموزش وزارت کشاورزی.740 صفحه.
-        بی نام، 1375. آمارنامه ادارة‌ تثبیت‌ شن‌ و کویرزدایی اداره کل منابع طبیعی‌ استان‌ خراسان.47 صفحه
-        Blumer, S., 1967. Echte Mehltaupilze (Erysiphaceae). Gustav. Ber. Verlag, Jena. Germany, 483p.
-        Boesewinkel, H. J., 1980. Morphology of the imperfect states of powdery mildews. Botanical Review, 46: 167-224.
-        Braun, U., 1987. A monograph of the Erysiphales. Beih. Nova Hedwigia, 89: 1–700.
-        Hirata, K., 1986. Host range and geographical distribution of the powdery mildew fungi, 2nd. Japan Science Society, Tokyo. 386 p.
-        Horsfall, J. B. and Barratt, R W., 1945. An improved grading system for measuring plant diseases (Abstr). Phytopathology, 35: 655.
-        Horsfall, J. B. and Cowling, E. B., 1978. Pathometry: The measurment of plant diseases. 119-136, In: Plant diseases, an advanced treatise. Vol. II. How diseases develops in populations. Horsfall, J. G. and Cowling, E. B., (eds.) Academic Press, NewYork, 646 pp.
-        Khairi, S. M. and Preece, T. F., 1978. Hawthorn powdery mildew: Diurnal and seasonal distribution of conidia in air near infected plants. Trans. Br. Mycol. Soc., 71 (3): 393–397.
-        Pearson, R. C. and Gadoury, D. M., 1987. Cleistothecia, the source of primary inoculum for grape powdery mildew in New York. Phytopathology, 77 (11): 1509–1514.
-        Shipton, W. A. and Brown, J. E., 1962. A whole leaf clearing and staining technique to demonstrate host–pathogen relationship of wheat stem rust. Phytopathology, 52: p. 1313.
-        Sorokin, R., 1956. Tr. Bot. Inst. Im. Komarova. Akad. Nauk. SSSR, Ser. 11. 10. p. 216.