Department for Environment, Food and Rural Affairs
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It has also been clearly demonstrated that the following herbicides could be safely used on lupins were the relative approvals to be put in place; diflufenican, isoxaben, metribuzin, quinmeric, pendimethalin pyridate and triasulfuron. All except pyridate and triasulfuron (post-emergence only) could be applied pre and post crop emergence. 4.0. Disease control in summer. There are two major diseases of white lupin in summer – rust (Uromyces lupinocolous) and anthracnose (Colletotrichum spp.). 4.1. Rust. Rust is endemic in the UK, in most seasons most crops become infected. Left uncontrolled the effect can be crop loss as demonstrated in 1997 at Rothamsted when omitting a sequence of two applications of tebuconazole resulted in only 10% of the treated yield. The disease defoliates the crop during the period of rapid seed growth. Control with fungicides is simple, but requires management effort and incurs a cost. In 1998 an experiment was designed to study fungicide options and timing of application (Etheridge and Bateman 1999). Early applications of all three fungicides failed to control the rust, but later application of tebuconazole significantly increased the seed yield by controlling the foliar symptoms (Table 2). Where all combinations of date of application were tested only those involving tebuconazole on the third date controlled the rust. Table 2. Selected data on the effects of fungicide choice and the timing of application on seed yield (t ha-1 at 15% moisture content) in white lupin cv. Lucille at Rothamsted in 1998. The complete experiment included all combinations of the three dates of application.
S.E.D. for whole experiment = 0.138, 48 D.F. Experience from commercial crops suggested that cyproconazole may be a more effective fungicide for rust control under certain conditions, particularly in the west of England and in Ireland. In 2000-01 at Rothamsted and in 2001-02 at Rothamsted and Taunton (managed by Arable Research Centres) experiments were sown to investigate the theory that this may be due to the presence of different pathotypes in the geographic regions. In 2000-01 rust did not develop to any great extent, the only statistically significant result from the experiment was that any application of either fungicide increased yield (2.97 t ha-1) over the untreated control (2.40 t ha-1). This included applications of tebuconazole as only 0.25 l ha-1 Folicur and cyproconazole as only 0.16 l ha-1 Alto. In 2001-02 rust developed at Rothamsted to a greater extent than recorded previously. It was also present in the crop on the earliest date recorded (mid April). Despite the early presence of disease in the crop the early application of fungicide had only a small (non-significant) effect on seed yield. As in previous years the later application gave the greater benefit. However in this experiment the combination of application at both dates was beneficial in the case of Alto (Table 3.). At Taunton the result was a smaller (non significant) yield advantage to using Alto (3.46 t ha-1) compared to Folicur (3.31 t ha-1). Table 3. The effect of fungicide, rate of application and timing on seed yield (t ha-1 at 15% moisture content) of cv. Lucille at Rothamsted in 2001-02.
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