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. Aphids can be removed with a strong stream of water if applied regularly. Many natural enemies feed on aphids, generally keeping them under control. Insecticides are available, but aphids are difficult to control with these because of their ability to multiply rapidly.
Insecticides also kill the aphids natural enemies often making the problem more severe.
Bulb mites are not insects but are more closely related to spiders. They are tiny, yellowish-white and slow moving. They feed on the bulb, causing weakened plants, stunted leaves and deformed flowers. Infested bulbs develop soft dying areas and should be removed and discarded. Avoid replanting in infested soil.