Early detection is the key to pea aphid management.
Fields should be sampled weekly. Counts should be at least 50 metres apart and observations should be made well into the centre.
Look for symptoms that include leaf discolouration. Severe infestations may appear as large bronze or brown patches in the field.
In younger plants, aphids may cluster near the base, on the upper sides of the leaves. In older plants, check inside leaf whorls.
Sampling should be done when 50-75 percent of the pea plants are in flower. The threshold in Century peas is two to three aphids per 20 centimetres of plant tip at flowering. Trapper peas can tolerate more. Plants infested before flowers open recover without yield loss.
