ERZURUM YÖRESİNDE AYÇİÇEK MİLDİYÖSÜ

Özet

ÖZET Erzurum Pasinler Ovasıııda Zirai Araştırma Enstitüsü ayçiçek denemelerinde 1981 yılında dikkati çeken hastalık Plasmopara helianthı' Novot,un oluşturduğu ayçiçek mildiyösü olarak belirlenmiştir. O yıl sadece Trakya dan gelirıi/en ayçiçek tohumlarından oluşan bazı bitki/erde ortaya çıkan hastalığın, 1982 yılında çevredeki çiftçilerin ayçiçek ekim alanlarına da yayıldığı görülmüştür. Yörede ayçiçeklerinde sadece primer sistemik enfeksiyonlara neden olan fungusun sekonder enfeksiyon/arı oluşmamıŞtır. DOWNY MILDEW OF SUNFLOWERS (Plasmapara helianthi Novot.) IN THE PROVINCE OF ERZURUM-TURKEY SUMMARY The disease recorded on sunflowers in 1981 at the Agricultural Research Institute Station in Pasinler Plain of Erzurum, was identified as downy mildew caused by Plasmopara helianıhi Novol. In 1981 downy mildew of sunflowers appeared only on some plnnts developed from the seeds brought from Thrace. But in 1982 it was found to be spreaded to the sunflower fields of the farmers around the research station. So it was believed that the disease was introdueed to this region by the infected seeds brought from Thrace and the residues of these plants were served as an inoculum source for the next year's crop. In 1982 the di· sease was mainly found on the plants sown before the spring r~ins which provide free soil water for the spread of the pathogen in soil from the plant reSİdues. No secondary Jocal infections were observed in the distrlct, although sporüİation \-vas seen after the rainy periods on the leaves of systemicaI1y infected plants.' The failure in the oCcurance of secondery infections was attributed ,to the short dura· tin of windy moisı periods during the time of secondery spread.