Valuable residual Nitrogen from this season’s pea and bean crop could be lost because of the current high level of Pea and Bean Weevil activity in establishing spring sown crops. Whilst the weevil have been active during the warm days, the cool nights and dry conditions have slowed the development of crops, making them especially susceptible to damage, warns Syngenta Field Technical Manager, Ian Holmes.
Most crops can outgrow the characteristic leaf notching damage on seedlings caused by adult weevils, however the main impact is the subsequent feeding activity of the weevil larvae on the nitrogen fixing root nodules. This can affect both the vigour and yield of the current crop, and the level of root nodule residual nitrogen - typically worth 50 kg/ha for the following wheat crop.
Mr Holmes advocates growers should treat pea and bean crops with Hallmark Zeon at the first signs of leaf notching. ’With the current level of pest activity and soil conditions putting plants under extra stress, this initial treatment should be a priority,’ he advises. ’A follow-up treatment should be made after 10 ’ 14 days if signs of damage continue.’ The aim is to disrupt the egg laying cycle and minimise risk of future larvae attack.
Mr Holmes adds that where growers are using Hallmark Zeon to control weevil, maintaining rates at the recommended 75 ml/ha will ensure the best possible results where pests are hard to hit.
Thrip threat
Some growers are also reporting damage from thrips in both pea and bean crops. The pest poses a serious problem for sprayer operators, where the adult thrips are embedded in the tightly rolled new leaf shoots that makes targeting with spray especially difficult.
The PGRO reports that: ’Hallmark Zeon has been shown to give better control of thrips in peas than other products.’
