Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract Full Text

Control of Peronospora schleidenii Unger of onion in Ukraine.


The efficacy of Ridomil Gold MC (2.5 kg/ha), arachidonic acid (0.002 litre/ha), Mycosan B (10.0 litres/ha), and Ridomil Gold MC (1.5 kg/ha) + arachidonic acid (0.001 litres/ha) + Mycosan B (5.0 litres/ha) against downy mildew (P. schlidenii [P. destructor]) in onion (cv. Skwyrska) was evaluated in Ukraine during 2003-05. Ridomil Gold MC + arachidonic acid + Mycosan B was highly effective against downy mildew (biological efficiency of 89.2% on the first year and 87.8% on the second year). The treatments had no significant effects on plant dry matter and vitamin C [ascorbic acid] contents, but had significant effects on peroxidase activity. N and K metabolism was also affected by the treatments, as evident in the increase in nitrate (by 78-84%) and glutamine (by 7-8%) contents, and reduction in K (by 29-32%), and arginine, tyrosine and leucine (by 3.8-7.2%) contents. The fungicides had no significant effects on the contents of isoleucine, threonine, lysine, phenylalanine, cystine, histidine, asparagine, serine, proline, glycine, alanine, tryptophan and methionine.