ATTEMPTS TO CONTROL POTATO LATE BLIGHT WITH CATTLE SLURRY

Two years' experiments concerning treatment of potatoes with diluted c attle slurry were carried out in an attempt to find a possible effect on potato late blight infection and to investigate whether slurry coul d be applied as an alternative to fungicides. The slurry was analysed for content of dry matter, total N and NH4+ N, and prior to each treat ment the slurry was diluted with water in the ratio 1:1 to obtain a co nsistency similar to that of liquid manure. Treatment against potato l ate blight was carried out two and four times at 7-10-day intervals fr om mid-July. The dose was 10 tons diluted slurry per hectare per treat ment. The results showed that diluted cattle slurry had no effect on t he number of leaf lesions (sites of infection by late blight), tuber i nfection, yield or tuber content of total N and NO3- N, and no effect was found on taste and boiling quality of tubers. Diluted cattle slurr y applied at high global radiation caused considerable leaf scorching (necrosis) and a tendency to yield losses. Therefore, diluted cattle s lurry cannot be used as an alternative to fungicides for control of po tato late blight.