A surge in temperatures is set to coincide with first pod set in many winter bean crops, creating ideal conditions for bruchid beetle activity.
Localised warnings have been issued by Syngenta’s Bruchidcast alert system, which identifies when conditions are conducive to bruchid breeding activity, enabling growers to intervene before egg laying occurs.
Bruchid larvae feeding on developing pods can result in yield loss and low value damaged beans.
Becky Howard of PGRO says growers have made significant advances in recent years to reduce the incidence of bruchid damage, with BruchidCast integral to helping with timing of Hallmark Zeon (lambda-cyhalothrin) application.
“Last year, however, there was an increase in recorded levels of bean damage, up to levels last seen in 2012. That was possibly down to growers’ perceived low risk in the dull conditions, when temperatures were actually plenty warm enough for the beetles.
“It really reinforced the value of the forecasting service and the need for growers to take heed of the warnings,” she adds.
Syngenta’s Max Newbert says adult beetles should be targeted when there has been two consecutive days with temperatures above 20degC – as is likely to occur across much of England this week.
“Weather conditions indicate that the pest is more likely to be active in the south, but damaging outbreaks have been recorded as far north as Yorkshire and Humberside,” he warns. “Whilst the average levels of infection have typically been reducing, most seasons we see instances of catastrophic failure where growers have not treated – with lower yields of beans acceptable for premium export," he says.