Pathogenic Species of Verticillium in Horticultural Crops and Weeds in Southwestern Ontario

Abstract

Verticillium wilt is an important disease of many horticultural crops in Essex County of southwestern Ontario. Verticillium dahliae is the predominant pathogenic species, being isolated from all susceptible crops and also from a few common weeds. V. albo-atrum, a virulent pathogen, and V. nigrescens, a weak pathogen, are isolated almost exclusively from potato (Solanum tuberosum L.). V. albo-atrum is virtually dependent on the potato crop for its existence in Essex County. The importance of weeds in the perpetuation of V. dahliae in cropped areas is emphasized.

Verticillium wilt of potato in southwestern Ontario and survival ofVerticillium albo-atrumandV. dahliaein field soil

“…As reported previously (McKeen & Thorpe 1973), we found that V. albo-atrum affects the crop earlier than V. dahliae. and causes more severe wilt symptoms.…”

“…During the last 30 years serious wilt occurrences have been reported in the northern tier of states of the USA; for example, in Maine (Akeley et al 1955), Connecticut (Waggoner 1956, Edgington 1962, RhodeTsland (Beckman 1973), Wisconsin (Robinson et al 1957), Hunter et al 1968), Minne sota (Slatterty 1971), Idaho (Watson & Huber 1971), Oregon (Powelson & Carter 1973), and Washington (Easton et al 1972). Similar wilt occurrences have been reported for eastern Canada in the Atlantic provinces (Robinson & Ayers 1961 ), and in Ontario (Busch 1966, McKeen & Thorpe 1973, Busch et al 1972, 1978. In the USA earlier estimates of losses in tuber yields have ranged as high as 30 to 50% (McLean 1955).…”

Differential sensitivity of Verticillium dahliae, V. albo-atrum, and V. nigrescens to benomyl

“…The present data suggest this is true at the population level but not necessarily at the isolate level. It is perhaps worth noting that other environmental stresses to which V. albo-atrum also shows greater sensitivity than V. dahliae include those provided by elevated temperatures (Schnathorst 1973), UV irradiation (Puhalla 1973), and overwintering in soil (McKeen and Thorpe 1973).…”

Μελετη Των Βερτισιλλιωσεων Των Φυτων Στη Νησο Κρητη

“…Άλλοι ερευνητές (Thanassoulopoulos et al, 1979;Tjamos, 1980;Θανασουλόπουλος, 1992;Παναγόπουλος, 1995) ανέφεραν ότι ο V. dahliae είναι ο αποκλειστικός υπεύθυνος της προσβολής των δενδρωδών καλλιεργειών (ελιά, βερικοκιά, αμυγδαλιά, ροδακινιά και δαμασκηνιά) και ότι είναι το κυριότερο παθογόνο των ετήσιων καλλιεργειών της Χώρας μας (Thanassoulopoulos & Kitsos, 1972;Tjamos, 1980;Θανασουλόπουλος, 1992;Παναγόπουλος, 1995 (Engelhard, 1957;Woolliams, 1966;Isaac, 1967;Evans, 1971;Schnathorst, 1981). Ο μύκητας V. dahliae είναι ένα από τα σπουδαιότερα παθογόνα εδάφους, του αγγειακού συστήματος των ανωτέρων φυτών (Rudolph & Harrison, 1944;Wilhelm, 1950a;1950b;Cox, 1956;Sackston et al, 1957;Purss, 1961;Woolliams et al, 1962;Hoes, 1966;Cimili, 1967;Skadow, 1969a;Hawksworth & Talboys, 1970a;Jordan, 1971;Ashworth et al, 1972a;McKeen & Thorpe, 1973;Pegg, 1974;Ashworth & Zimmerman, 1976;Nothmann & Ben-Yephet, 1979;Puhalla, 1979;Nachmias et al, 1982b;Pullman & DeVay, 1982;κ.ά. ).…”