Chrysanthemum - Insect identification & control: 

Aphids: Aphids come in many colours, such as are brown, black, green and pink. Aphids feed by piercing plant tissue and sucking plant sap. They prefer new growth in such areas as shoots, the undersides of leaves, buds and flowers. Their feeding can result in distorted growth, stunting and sometimes killing the whole plant. In their wake, they leave a sugary trail called honeydew - which attracts fungus, often seen as a dark growth.  Aphids can also transmit viruses to your mother plant, so control of aphids is rather important.  For control, you may gently spray-wash the leaves (especially the underside) or try to keep natural aphid predators (such as ladybugs) present.  Chemical control is also possible (check with your gardening centers), but should be used as a secondary method of control,  since these chemical controls tend to kill the natural enemies of the aphids in the process.

Two-spotted spider mites: Mites are not insects, but are a bit like spiders. They tend to be more of a problem during hot, dry periods. Mites are so small they are often missed until damage shows up as small yellow dots or perhaps as dust on the leaves.  Best seen with a magnifying glass, you may see small webs on the plant.  If the infestation is advanced, you risk getting distorted and off-colour blooms.  As above, you may gain some control by spraying them off with water, or use an insecticidal soap, using as directed.

Chrysanthemum leafminer:  This pest is actually the larva of a small fly. Eggs are laid on the underside of the leaf, and the larva hatches and burrows into the leaf.  Look for dots of waste or even wilted leaves.  If you find either, simply cut off and destroy affected leaves. 

Send mail to mg.thompson@sympatico.ca with questions or comments
Last modified: 11/15/08