First report of Volutella colletotrichoides in Turkey

Alfalfa (Medicago sativa) is the most important forage crop in Erzurum, Turkey. Volutella colletotrichoides is a facultative pathogen on stems and leaves of alfalfa previously recorded by Chilton (1954) in the USA. In 1999 we isolated Volutella colletotrichoides from alfalfa leaf lesions observed on plants in Pasinler district in Erzurum. The lesions were brown, irregular in shape, small and sunken. When grown on potato dextrose agar (PDA), colonies were at first orange, later becoming brownish orange. Mycelial growth rate at 15 to 25 °C on PDA was 1.50 to 1.87 mm per day. Conidia were 6.5-9 x 1.75-2 µm and broadly fusiform. Dark setae were abundant in culture. Morphological characters and growth rate agreed with previous reports on V. colletotrichoides (Chilton, 1954; Domsch et al., 1980).

Our isolate CE-06 (deposited as CBS 109728) was sprayed on leaves and stems of 8-week-old seedlings of the alfalfa cultivar Bilensoy with a suspension of 1.7 x10⁶ conidia per ml of sterile water. Twelve plants were treated with V. colletotrichoides. Control plants were sprayed with sterile water. Inoculated and control plants were placed in a greenhouse at 20 to 25 °C and seedlings were enclosed in plastic bags for three days. Seven to 10 days after spraying, necrotic leaf lesions developed on inoculated plants only. These occurred at the leaf edge and were irregular in shape, sunken, brownish and 1-6 mm across (Fig. 1). V. colletotrichoides was reisolated from lesions on inoculated plants. This is the first report of V. colletotrichoides on alfalfa from Turkey and the first from outside the USA.