Crops are susceptible to attacks by pests which can cause severe yield reductions. Pest problems can sometimes be predicted and prevention measures taken. But often, pest attack is erratic and you may need to act on the first signs of damage.
Crows, rooks, pigeons and pheasants can pull up the seed and emerging plants and can destroy a crop if left undisturbed.
When sowing the crop, avoid shallow drilling, and consolidate the seedbed by rolling, if possible. Shooting and the use of scaring devices may have to be used to prevent a flock settling on a field.
The black bean aphid can occasionally be a problem, especially during hot, dry weather conditions. If more than 5% of plants are infected, spray with an appropriate insecticide.
The bean weevil: Adults feeding on the leaves leave "U-shaped notches" on leaf margins. The real damage is done by developing larvae which feed on the nitrogen fixing nodules. Bad attacks can result in stunted, pale crops and yield losses
Pea & Bean Weevil
Pea and bean weevil is a grey/brown weevil with characteristic snout. It feeds on leaves, producing u shaped notches but it is its larvae that produce most of the yield reductions in beans. Eggs are laid on the soil and the larvae hatch, burying into the soil to feed on the roots. Pea and bean weevil can dramatically reduce root nodule formation and thus nitrogen fixation. Leaf notching should be across the field before you spray an insecticide as notching is common near headlands most years.
Apply a suitable insecticide at start of leaf notching.
Options include: Cypersect 250 ml/ha, Decis 300 ml/ha, Karate Zeon 75 ml/ha, etc
Black bean aphid – Aphis fabae
Black bean aphids overwinter on the spindle tree, migrating to bean and sugar beet crops in the summer. Damage mainly caused by aphid populations which colonise plants prior to flowering.
You should only spray if aphids are seen evenly (>5% of plants) across the field as the aphid normally colonises a few plants in an area which is of little consequence. Aphid populations initiated after flowering cause little damage.
Products that are cleared for use on peas and beans are available at: