Symptoms and damage
Various species of aphids are pests of flowering bulbs.
Aphids are small, soft-bodied, pear-shaped insects. Different aphid species
vary in color from yellow to green to pink to black. Adult aphids may or may
not have wings.
Aphids are typically more of a problem during cool weather
in the spring. They have piercing-sucking mouthparts, and are usually found in
clusters feeding on new growth. They insert their mouthparts and suck plant
sap. Their feeding can cause deformed growth of leaves and flowers. In
addition, as they feed they excrete a sugary material called honeydew, which
covers the leaves making them sticky. Sooty mold fungi can grow on the
honeydew, producing unsightly, dark splotches on the plant surfaces.
Many natural enemies, including ladybird beetles (ladybugs),
lacewings, syrphid flies, damsel bugs and wasps, feed on or are parasites of
aphids, generally keeping them under control. Insecticides are available, but
aphids are difficult to control with chemicals because of their ability to
multiply rapidly. Insecticides also kill the aphids` natural enemies often
making the problem more severe. Aphids can be removed with a strong stream of
water if applied regularly. When population numbers are low, insecticidal soap
can effectively control aphids. Thoroughly spray both leaf surfaces when using
insecticidal soap. For more severe infestation, sprays of bifenthrin,
cyfluthrin, lambda cyhalothrin or permethrin will control aphids.