Antti Laine

Effects of sowing time on pink snow mould, leaf rust and winter damage in winter rye varieties in Finland

Disease infection in relation to sowing time of winter rye (Secale cereale) was studied in southern Finland in order to compare overwintering capacity of modern rye varieties and to give recommendations for rye cultivation. This was done by using three sowing times and four rye varieties in field trials conducted at three locations in 1999–2001. The early sown rye (beginning of August) was severely affected by diseases caused by Puccinia recondita and Microdochium nivale, whereas postponing sowing for two weeks after the recommended sowing time resulted in considerably less infection. The infection levels of diseases differed among rye varieties. Finnish rye varieties Anna and Bor 7068 were more resistant to snow mould and more winter hardy than the Polish variety Amilo, or the German hybrid varieties Picasso and Esprit. However, Amilo was the most resistant to leaf rust. In the first year snow mould appeared to be the primary cause of winter damage, but in the second year the winter damage was positively correlated with leaf rust. No significant correlation between frit fly infestation and winter damage or disease incidence of snow mould or leaf rust was established. The late sowing of rye (in the beginning of September) is recommended in Finland, particularly with hybrid varieties, to minimize the need for chemical plant protection in autumn.

Sowing time affects the abundance of pests and weeds in winter rye

Selection of an appropriate sowing time for some winter rye (Secale cereale) cultivars could reduce the need for crop protection measures. In this study the occurrence and status of pests and weeds in relation to sowing time and growth habit of winter rye was studied in southern Finland. This was done using three sowing times and four rye varieties in field trials conducted at three locations in 1999–2001. The early sown rye was severely affected by pests (Oscinella frit, Mayetiola destructor) and weeds, whereas postponing sowing for two weeks after the recommended sowing time in late August resulted in considerably less damage and the optimal establishment of crop stands. The German hybrid varieties Picasso and Esprit produced more tillers m -2 in autumn than the Finnish varieties Anna and Bor 7068. However, the number of pests and weeds did not differ among rye varieties. Late sowing of rye should be considered to minimize the need for plant protection. If rye is sown at the recommended time it may still require insecticide treatments promptly in the autumn whereas herbicide treatment need not be determined until spring, after recording the winter mortality of weeds.