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Cucurbit Genetics Cooperative Report 11:87-90 (article 37) 1988

Pathogenicity of Erysiphe cichoracearum to cucurbits

Yigal Cohen and Helena Eyal

Department of Life Sciences, Bar Ilan University, Ramat-Gan, Israel 52100

Powdery mildew is a devastating disease of cucurbits throughout the world. The two page reported causal agents are Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll. and Erysiphe cichoraceatum DC ex Merat (5,8). The distribution of different Erysiphaceae (including Leveillula taurica (Lev.) Arn.) on cucurbits in the world was reviewed by Khan (5). He stated that S. fuliginea (=Sf) and E. cichoraceatum (=Ec) may singly or together attack Cucumis, Cucurbita and Citrullus. Other workers (see below) reported on cross-susceptibility of cucurbits and species of other families to powdery mildews. Molot and Lecoq (9) reported that both Sf and Ec are economically important on cucurbits in France. Ec from tobacco, Aster sp. and Senecio vulgaris, but not from Lactuca serriola, was pathogenic to cucurbita pepo (Diamant). Cucumis sativus (Marketer) became infected with Ec from Aster sp. or L. serriola but not from tobacco, whereas C. melo (Verndrais) was resistant to all Ec's. Molot et al. (10) further showed that Ec from other cucurbits or tobacco was pathogenic to squash and cucumber. In Hungary Ec and Sf were found in the field on cucumber, squash, melon and watermelon (12). Ec was able to overwinter on Aster dumosus (11). In Germany all 12 greenhouse cucumber cultivars were highly susceptible to both Ec and Sf (19). Lebeda, in cultivars were highly susceptible to both Ec and Sf (19). Lebeda, in Yugoslavia, failed to transfer Ec from L. serriola to cucumber (7). Stone (20) suggested that Sonchus aspen (Compositae) is a very probable source of reinfection for cucurbits with Ec in the UK. In New Zealand Sf and Ec can each attack Cucurbitaceae, Compositae and Solanaceae (1). In Israel Sf was recognized as the causal agent of powdery mildew in cucurbits (2,3,13,16,18) although earlier reports claimed for Ec as a causal agent (14,17). Eshed and Whal (3) found that powdery mildew from Hibiscus esculentum, Xanthium stratmanium and Verbena hybrida was infective to melons. Khan (5)observed observed both Ec and Sf on cucurbits in India. While Sf attacked most of the cucurbits, Ec was confined to Benincasa hispida and Coccinia cordifolia in the field but produced perithecia on muskmelon in the greenhouse. In the USA since 1900 up to 1963 powdery mildew in cucurbits was assigned to Ec (5). In 1979Sf was found on C. pepo (6). Kontaxis (6) suggested that the causal agent of powdery mildew in California and possibly in all USA is Sf in spite of the fact that perithecia of Sf were reported on various cucurbits in North Carolina in 1986 (4). McCreight et al. (8) observed Sf only on muskmelons in both the USA and France but in 1964-67 and 1981-86. In Canada, Ec was reported on cucurbits (5), but cleistothecia of Sf were found in 1983 in Ontario on glasshouse-grown cucumbers (4a).

The present study was aimed at elucidating the pathogenicity of Sf from muskmelon and Ec from tobacco to various cucurbits. Plants were grown in the greenhouse to the 2-3 true leaf stage and inoculated with powdery mildew in growth chambers at 23 C. Results are given in Table 1. They show that Ec was highly infective to cucurbita pepo, Cucurbita maxima and Lageneria vulgaris, moderately infective to Citrullus lanatus and Citrullus colocynthis, but not infective to Cucumis sativus or Cucumis melo var. reticulatus. C. melo var. makuwa and C. melo var. acidulus were highly susceptible. Ec from Cichorium pumillum and L. serriola was infective on tobacco and C. pepo (yellow zucchini cv. Goldy) but Ec from Senecio vernalis, S. vulgaris, Erigeron crispus and Crepis sp. was not infective to C. pepo (Goldy) or tobacco. Susceptibility to Sf varied according to plant species, cultivar and fungal race (Table 1). All cultivars of C. lanatus were resistant to Sf race 1 (although became slightly infected on hypocotyls and stems) and susceptible to race 2. All cultivars of C. pepo and C. maxima were susceptible to both races of 1 and 2. In Cucumis species reaction to Sf ranged from resistance to susceptibility to either race.

We concluded that Nicotiana tabacum, C. pumillum and L. serriola are potential sources for infection of cucurbits with Ec.

Table 1. Infectivity of Erysiphe cichoracearum from tobacco (cv. KY-16) to cucurbits.

Disease severity
Species
cultivar
origin
Sf race 1
Sf race 2
Ec
Citrullus lanatus Adom Israel
-
++
+
  Karmit Israel
-
++
+
Talmor Israel
-
++
+
Hazera - 2 Israel
-
+++
+
Dafna Israel
-
++
-
Malali Israel
-
+
+
Charleston Gray USA
-
++
-
Shin-Yamoto Japan
-
Citrullus colocynthys   Israel
-
-
+
Cucurbita pepo Goldy Israel
+++
+++
+++
  Lavan Israel
+++
+++
++
Maayan Israel
+++
+
+
Bereketh Israel
+++
+++
++
Beiruti Israel
+++
+++
+
Cucumis sativus Dalila Israel
+++
++
-
  Poinsett-76 USA
+
+
-
Marketer USA
-
Aonagao Japan
++
-
Sagami-hanjiro Japan
++
-
Howay GOGIO Japan
+
-
Jomaki Japan
+
-
Lagenaria vulgaris
-
Israel
+++
++
-
Lageneria sp. Williams USA
+++
Lagenaria sicereria Oomatu-yungao Japan
-
Benincasa hispida Naga-tougan Japan
+++
Cucurbita maxima   Israel
+++
+++
+++
Luffa cylindrica   Israel
+
-
Luffa acutangula   USA
-
-
-
Cucumis melo

var. makuwa

Kinpyo Japan
+++

var. conomon

Honen-ao Japan
+++
-

var. acidulas

Kinpyo Japan
+++

var. reticulatus

Sunrise Japan
-
  Ananas  
-
Yokneam Israel
+++
+++
-
Ein-dor Israel
-
++
-
Galia Israel
+
++
-
Charantais-T France
+++
++
-
PMR-45 USA
-
++
-
PMR-5 USA
-
-
-
PMR-6 USA
-
-
-
PI124111 USA
-
-
-
PI124112 USA
-
-
-
Seminole USA
-
+
-
- no disease; + to +++ increasing amount of disease.

Literature Cited

  1. Boesewinkel, H.J. 1979, Observations on the host range of powdery mildews. Phytopath, T. 94:241-248.
  2. Cohen, Y. and H. Eyal. 1983. Occurrence of sexual fruiting bodies of Sphaerotheca fuliginea on powdery mildew-infected muskmelons. Phytoparasitica 11:3-4.
  3. Eshed, N. and I. Wahl. 1963. Morphological characters of conidial germination tubes as a means of identification of powdery mildew fungi in Israel. 2nd Isr. Cong. Plant Patholog., Page 35.
  4. Grand, L.F. 1987. Perithecia of Sphaerotheca fuliginea on cucurbits in North Carolina. Plant Dis. 71:761.
    4a. Jarvis, W.R. and K. Sligsby. 1984. Cleistothecia of Sphaerotheca fuliginea on cucumber in Ontario. Plant Dis. 68:536.
  5. Khan, M.W. 1983. The identity of powdery mildew of cucurbits - A critical appraisal. Acta Botanica Indica 11:97-126.
  6. Kontaxis, D.S. 1979. Cleistothecia of cucurbit powdery mildew in California - a new record. Pl. Dis. Reptr. 63:278.
  7. Lebeda, A. 1985. Auftreten der naturlichen Infektion durch den Echten Miehltau (Erysiphe cichoraceorum) lei der Gattung Lactuce in der Tschechoslowakei. Acta Phytopthol. Acad. Sci. Hungaricae. 20:149-162.
  8. McCreight, J.D., M. Pitrat, C.E. Thomas, A.N. Kishaba, and G.R. Bohn. 1987. Powdery mildew resistance genes in muskmelon. J. Amer. Soc. Hort. Sci. 112:156-160.
  9. Molot, P.M. and L. Lecoq. 1986. Powdery mildews of cucurbits. I. Bibliographical review and preliminary experimental results. Agronomie 6:355-362.
  10. Molot, P.M., J.P. Leroux,and H. Ferriere. 1987. Powdery mildews of cucurbits. II. A Method for preserving isolates in axenic culture. Agronomie. 7:339-343.
  11. Nagy, G. Sz. 1972. Studies on powdery mildews of cucurbits. I. Host range and maintenance of Sphaerotheca fuliginea and Erysiphe sp. under laboratory and glasshouse conditions. Acta Phytopathol. Acad. Hungaricae. Sci. 7:415-420.
  12. Nagy, G. Sz. 1976. Studies on powdery mildews of cucurbits. II. LIfe cycle and epidemiology of Erysiphe cichoracearum and Sphaerotheca fuliginea. Acta. Phytopathol. Acad. Sci. Hungaricae. 11:205-210.
  13. Palti, J. 1962. Prediction of powdery mildew outbreaks on cucurbits on the basis of seasonal factor. Bull. Res. Counc. Israel Section D10:236-249.
  14. Peleg, Y. 1953. Outbreaks and new records. Israel FAO Plant Prot. Bull. 14:60-61.
  15. Randall, T.E. and J.D. Menzies. 1956. The perithecial stage of the cucurbit powdery mildew. Pl. Dis. Reptr. 40:255.
  16. Rayss, T. 1947. Nouvelle contribution a l'etude de'lamycoflor de Palestine (q'uatrieme partie). Palestine J. Bot. 4:59-76.
  17. Reichert, I., J. Palti, and B. Iapuler. 1973. Trials for the control of diseases of vegetable marrows. Bulkl. Rehovoth Agr. Ext. Stn. No. 33.
  18. Rudich, J., F. Karchi, and N. Eshed. 1969. Evidence for two races of the pathogen causing powdery mildew of muskmelon in Israel. Israel H. Agric. Res. 19:41-46.
  19. Schlosser, E. 1973. susceptibility of cucumber cultivars against the two species of cucurbit powdery mildew pathogens, Erysiphe cichorecearum D.C. ex Merat and Spaerotheca fuliginea Schl. ex Fr. Gorten bouwissenschaft 44:217-219.
  20. Stone, O.M. 1962. Alternate hosts of cucumber powdery mildew. Ann. Appl. Biol. 50:203-210.
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Page citation: Wehner, T.C., Cucurbit Genetics Cooperative;
Created by T.C. Wehner and T. Ng, 1 June 2005; design by C.T. Glenn;
send questions to T.C. Wehner; last revised on 9 April, 2010