Effect of perennial grasses ploughed in as green manure on the occurence of net blotch in spring barley

R. Skuodienė¹ and R. Nekrošienė²

¹Lithuanian Institute of Agriculture, Vėžaičiai Branch, Gargždų 29, LT–96216 Klaipėda distr.,Lithuania; tel: + 370 46 458233; e-mail: rskuod@vezaiciai.lzi.lt
²Botanical Garden of Klaipėda University, Kretingos 92, LT–92327 Klaipėda, Lithuania;e-mail: rita_nekrosiene@mail.ru

Abstract:

Experiments were carried out in the Vėžaičiai Branch of the Lithuanian Institute of Agriculture (West Lithuania) in 2005–2007. The aim of this research was to assess the impact of using perennial legumes (red and white clover, lucerne) and timothy as green manure in crop rotation on the occurence of net blotch disease (causal agent Drechslera teres (Sacc.) Shoem.) in spring barley. Preceding crops of spring barley were winter triticale and winter rye (perennial grasses were preceding crops of these winter cereals). The yearly occurence of net blotch disease was high: incidence was about 70.00–100.00% severity; at the spring barley booting stage (BBCH 37-39) – from 4.45 to 12.25%, at milk maturity stage (BBCH 73-75) – 43.75–70.95%. The variously-managed perennial grasses in the crop rotation had a significant effect on the occurence of net blotch: the spring barley grown after timothy was 1.1–1.5 times less affected in 2005 and 2007, compared to the spring barley grown after red and white clovers, and about 1.2 times less affected grown after lucerne, compared with spring barley grown after other grasses in 2006.

Key words:

disease, Drechslera teres, incidence, net blotch, perennial grasses, severity, spring barley

Resistance of red clover to diseases and pests under different growing conditions

R. Repšienė¹ and R. Nekrošiene²

¹Vezaiciai Branch, Lithuanian Institute of Agriculture, Gargzdu 29, VezaiciaiLT-96216 Klaipeda distict, Lithuania; e-mail: regina@vezaiciai.lzi.lt
²Botanical Garden of Klaipeda University, Kretingos 92, LT-92327 Klaipeda, Lithuania;e-mail: bot.sodas@one.lt

Abstract:

Experiments were carried out in the Vėžaičiai Branch of the Lithuanian Institute of Agriculture (West Lithuania region) in 1998−1999 and 2005. The aim of this research was to estimate the incidence of diseases and pests of red clover in soils with different agrochemical characteristics. The soil acidity varied from 3.9-6.7, available P2O5 from 47–317, available K2Ofrom 100–360 mg kg-1, amount of humus from 1.71–2.36%. Ecological conditions of soils contained differing amounts of lime, mineral and organic fertilizers.Common leaf spot (agent Pseudopeziza trifolii (Biv.-Bern:Fr.) Fuskel) had a 1.3−1.7greater incidence on the red clover growing in the soil with pHKCl 3.9−4.9 in comparison withthose grown in the soil with pHKCl 5.7−6.7, and with intensively damaged red clover whichgrew in soils with fewer nutrients. Increasing the quantity of nutritious materials increased the incidence of powdery mildew (agent Erysiphe polygoni DC.) in 1999 and 2005 but reduced the incidence of clover seed weevil in soils with pHKCl 5.7−6.7 in those years.

Key words: