A comparison of the occurrence of aphids and barley yellow dwarf virus in minimum-till and conventional-till autumn-sown cereals

• Published in: The Journal of agricultural science 2010-08, Vol.148 (4), p.407-419
• Main Authors: KENNEDY, T. F., McDONALD, J. G., CONNERY, J., PURVIS, G.
• Format: Article
• Language: English
• Subjects: Agronomy; Agronomy. Soil science and plant productions; Aphididae; Aphidoidea; Autumn; Barley; barley straw; Barley yellow dwarf virus; Biological and medical sciences; Cereal crops; Cereals; Comparative studies; conventional tillage; Crop yield; Cultivation; disease incidence; economic threshold; Fundamental and applied biological sciences. Psychology; Grain; grain yield; Hordeum vulgare; insect pests; insect vectors; minimum tillage; Pest control; Phytopathology. Animal pests. Plant and forest protection; plant damage; plant density; plant diseases and disorders; plant pests; plant viruses; Planting density; population density; seasonal variation; Seasons; sowing; Straw; Summer; Tillage; tillers; Triticum aestivum; Winter wheat
• ISSN: 0021-8596; 1469-5146
• DOI: 10.1017/S0021859610000304

Winter barley was sown by conventional-tillage (CT) and minimum-tillage (MT) cultivation over three seasons. Each cultivation treatment was split so that straw was incorporated into the soil during cultivation in one split, while the other did not receive straw. Aphid occurrences in autumn and incidence of barley yellow dwarf virus (BYDV) in spring were compared. Similar investigations on winter wheat were made over a further three seasons. The method of cultivation affected the number of aphids on barley and wheat plants in autumn and on wheat heads in summer; MT had fewest aphids. Soil incorporation of straw during cultivation had a similar effect. Method of cultivation affected the incidence of BYDV disease, with MT having least infection. Straw-treated cereal plots had fewer aphids and less BYDV than no-straw plots. Aphids and virus reached damaging levels only in the first barley crop. In this season, MT barley had significantly fewer aphids (48% fewer) and significantly less BYDV (71% less) than CT. Straw-treated plots within the CT system had rather similar aphid infestation and BYDV incidence as no-straw plots. Barley grown in the MT system with straw added had significantly fewer aphids (68%) than in the case when no straw was added. Overall, aphids in autumn were significantly fewer on MT relative to CT cereals in three of the six seasons and significantly fewer on straw relative to no-straw plots in two seasons. Aphids on wheat heads in summer were significantly fewer in MT relative to CT plots in one of the three seasons. Aphids on heads were also significantly fewer on straw-treated plots within each system of cultivation in two seasons, while MT wheat with straw had significantly fewer aphids/head than those without straw in one season. BYDV was lower each season in MT barley and wheat when compared with CT crops. These differences were significant for two of the three seasons in which each crop was grown. There was a lower incidence of virus in straw-treated plots than in no-straw plots. This effect was significant for one of the three seasons in which barley and wheat were grown. Plant and tiller density did not differ significantly between MT and CT barley either with or without straw incorporation. Plant density of wheat in autumn was significantly lower for straw-treated plots relative to no-straw plots in one season. Wheat head density was lower for MT relative to CT in one season, while MT with straw had significantly fewer heads than