Pyrethrum

• Pyrethrum is a broad-spectrum insecticide made from the dried flower heads of the pyrethrum daisy. The term 'broad spectrum" means it is approved to reduce the populations of many different insect species, such as caterpillars, beetles, aphids, flies, mites, whiteflies, thrips and leafhoppers. Pyrethrum is often marketed as an outdoor insecticide for use on garden plants. It can be used indoors if the product labeling indicates that it is safe for indoor use.
  
  

Indoor Use for Aphids

• If a product is not approved for indoor use, never use it indoors. However, pyrethrum pesticides approved for indoor aphid control are very effective. Along with neem, pyrethrum is the active pesticide ingredient frequently recommended for efficient aphid control. A Cornell University fact sheet on pyrethrum found that it reduces the apple aphid population by 40 to 60 percent.
  
  

Possible Hazards

• So long as only products approved for safe indoor use are used indoors and application instructions are followed, pyrethrum pesticides are relatively safe for indoor use. A Cornell University fact sheet on pyrethrum concludes that "[c]ompared to many other insecticides, pyrethrum is relatively non-toxic to humans." Citing numerous scholarly studies, Cornell University researchers claim that pyrethrum has low acute and chronic toxicity in humans and pyrethrum compounds are mostly broken down by internal organs or excreted. Pyrethrum is highly toxic to some species of fish and birds, so exercise caution.
  
  

Other Control Methods

• Whether used in lieu of chemical pesticides or combined with a pesticide program, natural control methods only boost your chances of controlling an indoor aphid infestation. Remove small population by hand. If aphids are infesting indoor plants, take them outside during summer months and wash off the plants to remove lingering aphids. If the infestation remains, prune the most heavily infested parts of the plants before moving the plants back indoors.