The cause of leaf and stem redness in rapeseed

Abstract

Frequent apparition of leaf and stem redness of rapeseed in Vojvodina (Bačka, Banat) was registered in the second half of February 2007. Redness was particularly frequent at the end of February and in the first decade of March. First symptoms were registered on lower leaves as leaf edge redness. Lower leaves quickly became completely red, and the redness than started to appear on upper leaves and stem. Up to 90% of rapeseed acreage on inspected trials manifested plant redness. Plants that strongly exhibited symptoms lagged in growth and did not produce flower buds. Plants were screened for the presence of insects and plant pathogens at mid March. Analysis of basic soil chemical attributes was performed before sowing in 2006. Besides soil analysis, plants were screened for mineral content of macro- (nitrogen, phosphorus, potassium) and microelements (zinc, copper, iron, manganese, molybdenum). On the basis of entomological, phytopathological and chemical evaluations, it was found that the key difference between plants exhibiting leaf and stem redness and healthy plants was the lack of nitrogen in affected plants. We can conclude that the lack of nitrogen caused leaf and stem redness of rapeseed. .

Intenzivna pojava crvenila lista i stabla uljane repice u Vojvodini (Bačka, Banat) je zapažena u drugoj polovini februara 2007 godine. Simptomi crvenila su bili naročito izraženi krajem februara i u prvoj dekadi marta. Prvi simptomi su zapaženi na donjem lišću u vidu crvenila po obodu lista. Veoma brzo donji listovi su postali crveni, a zatim se crvenilo počelo pojavljivati i na gornjem lišću i stablu. Na mnogim parcelama intenzitet crvenila biljaka je bio i do 90%, vizuelno posmatrano. Jače zahvaćene biljke su zaostajale u porastu i bez obrazovanja cvetnih pupoljaka. Polovinom marta izvršen je pregled biljaka na prisustvo insekata i biljnih patogena. Analiza osnovnih hemijskih svojstava zemljišta je urađena tokom 2006. godine pre setve. Pored analize zemljišta urađena je i hemijska analiza biljaka na sadržaj makroelemenata (azot, fosfor, kalijum) i mikroelemenata (cink, bakar, gvožđe, mangan, molibden). Na osnovu entomoloških, fitopatoloških i hemijskih ispitivanja je ustanovljeno da je crvenilo lista i stabla uljane repice prouzrokovano nedostatkom azota, odnosno značajno manji sadržaj azota je bio kod zaraženih biljaka u odnosu na zdrave biljke. .