Aphids are small, bulbous, soft-bodied sap sucking insects that damage a wide range of plants, from beans to tomatoes. Aphids can harm plants directly through feeding and indirectly by injecting secretions that deform the plant. They also produce honeydew, fostering black sooty mould growth that renders plants unsaleable. Leaves may become stunted, chlorotic, fall prematurely or wilt. Even a small number of aphids can cause significant damage, while a large number can significantly reduce growth rates.
It is crucial to actively monitor aphids because small numbers can easily go undetected and allow populations to grow, increasing damage.
Cultural practices to reduce aphid populations include:
removing or pruning heavily infested stock
monitoring incoming stock
using protected cropping structures with UV-absorbing materials
opting for resistant varieties, where possible.
Several biological control agents are commercially available, as well as many low-risk pesticides that are gentle on predators.