The influence of climatic conditions around the time of spraying isoproturon on the subsequent injury to barley

Abstract

Winter barley cv. Igri was grown in pots, either outside under cover, in a glasshouse or under controlled conditions and treated post-emergence with isoproturon. There was a linear relationship between the subsequent weight of plants treated with 2.5 kg a.i./ha and either evaporation from a water surface between 2-7 days post spraying or cumulative temperature between sowing and spraying. The relationship between subsequent weight of plants treated to the foliage only with 5 kg a.i./ha and cumulative temperature between sowing and spraying varied between years 1984-86. The post spraying environment had the major influence on subsequent activity of isoproturon at 2.5 kg a.i./ha applied overall to barley under controlled conditions. There was a greater reduction in CO, exchange in plants grown after treatment under high compared to low relative humidity. When isoproturon at 5 kg a.i./ha was applied to barley plants with wet foliage, plants were slower to recover their initial rate of photosynthesis when kept wet for 24 h as compared with 11 h or when allowed to dry after treatment. Photosynthesis was decreased to a lesser extent under the same post spray conditions by 2.5 than by 5 kg a.i./ha and reduction was greater and recovery of photosynthesis slower in plants grown inside compared to outside.

Molecular Mechanism of Mesosulfuron-Methyl Resistance in Multiply-Resistant American Sloughgrass (Beckmannia syzigachne)

“…However, the efficacy of isoproturon is highly correlated to soil humidity and leaf-stage of weeds (Blair 1985). What's more, isoproturon can injure the wheat when applied at low temperature (Blair and Martin 1990). Further research is required to determine the best application time.…”