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Extra care for drought stressed beans


Winter bean crops have suffered intense drought stress over recent weeks, with many crops flowering profusely weeks ahead of normal, and when plants are only 15cm high or less. The unprecedented situation will have implications for the crops agronomy over the rest of the season.

PGRO agronomist, Becky Ward, reports that whilst crops are flowering and typically more vulnerable to effects of disease, for the most part infection levels are low and growers should hold off their fungicide applications. However, they should be ready when rain does arrive and, with the localised sporadic nature of current heavy rain showers, remain vigilant for the first signs of Chocolate Spot.

Given the exceptional early start to flowering, we could end up with a prolonged period of flowers and increased susceptibility to disease, she warns. Theres a chance that growers will need all their armoury of fungicides if a long season ensues, so dont want to start too early now.

PGRO trials have shown good responses to Amistar and Alto Elite fungicide treatments if Chocolate Spot occurs when there are damp conditions during early flowering, with the need for a second treatment after three to four weeks if wet conditions persist. Amistar and Alto Elite will also give protection against Rust in dry conditions following flowering and pod set.

The early flowering may also have an impact on Bruchid Beetle activity, which is likely to start earlier than normal this season. If the early flowers convert to first pod set, crops will be more susceptible to damage from insect activity as temperatures rise. The conditions for Bruchid activity and the optimum spray timings to minimise egg laying are now well established, advises Ms Ward. Growers should be looking to treat with Hallmark Zeon when temperatures exceed 20C for two consecutive days through the susceptible period.

Bean growers can register to receive free local warnings of conditions conducive to Bruchid Beetle activity this season, in order to better time Hallmark Zeon applications. To register for BruchidCast farmers and agronomists should send their contact details and email address to

Settled warm weather has also been conducive to aphid activity, so growers should remain alert for early infestations. PGRO highlight that it is the early attacks that are most likely to result in damaging virus transmission.

Ms Ward points out that a further result of a protracted flowering period could more variable pod and seed maturity at harvest. This will be compounded by the current flowering low down on short drought stunted plants; any rain now may still initiate further top growth, but the first low-down pods will be difficult to pick up and slow to combine.

Whilst the consequence of the drought stress for yields is impossible to assess yet, she believes that it is too early to give up on crops and that, with appropriate care and agronomy, winter bean crops should still perform well. The experience of PGRO advisors is that spring sown bean and pea crops are still looking well, despite the drought conditions.

For detailed local five-day weather forecasts – including the probability for welcome rain – and other on-line tools to help with crop agronomy decisions, log-on to the free Syngenta website,


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