Journal Article
About harmfulness of Phoma macdonaldii (Boerema) on sunflower [2018]
Araslanova, N.M.; Saukova, S.L.; Antonova, Т.S., The V.S. Pustovoyt All-Russia Research and Development Inst. of Oil–Producing Crops, Krasnodar (Russian Federation);
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The purpose of the present work is to study symptoms of infection and aggressiveness of Phoma fungus on sunflower plants in greenhouses at artificial inoculation of root system. The experiments were conducted in greenhouses of the All-Russian Research Institute of Oil Crops by Pustovoit V.S. (Krasnodar). We created an infectious background using different isolators of Phoma in boxes with a size 250 cm x 60 cm, soil quantity 250 kg. As inoculator we used three monospore isolators of Phoma macdonaldii differed with their aggressiveness. We cultivated the isolators preliminary on sterilized sunflower seeds and oat kernels in a thermostat at temperature of 25 Centigrade degrees during 25 days. The experiment allowed establishing the sunflower plants can be infected by Phoma pathogen at the first stages of plant development through close contact of root with infected plant residues and seeds. The main symptoms of infection were as follows: delay in plants growing and development, black necrosis spot on root collar often spreading on hypocotyl or cotyledonary leaves, surrounding black necrosis spot on main root or hypocotyl. We united the similar symptoms into four groups on an infection level. We determined Phoma harmfulness by fourth infection group (plants death in an emergence phase and unviable seedlings with black necrosis spot on hypocotyl and cotyledonary leaves). Such account of root infection showed Phoma harmfulness for a sunflower line VK 653 was 66%
, for a hybrid Altair – 53%.
