Quassia amara

Quassia amara is a species of wood from Central America. Bitterwood is used as an insecticide and as an additive in the food industry.

  • Biological Pesticide

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Quassia amara is a species of wood in the genus Quassia. Bitterwood is used as an insecticide and as an additive in the food industry.
Quassia amara usually takes the form of a shrub and sometimes a small tree. Quassia amara grows about 3 m tall, has 15-25 cm long, pinnate leaves. The panicle-shaped flowers grow 15-25 cm long, are bright red on the outside and white inside. The drupes grow to about 1.5 cm in size.
Quassia amara is native to Central America: from Costa Rica to Argentina. Quassia amara is widely planted outside its original range.
The wood contains quassin, one of the most bitter substances found in nature. Extracts of Quassia amara or the bark act as a natural insecticide. This extract provides good protection against aphids, Colorado potato beetles and the caterpillars of the apple sawfly, among others. Quassine extract acts as a contact insecticide. Adverse effects on beneficial organisms were not found. However, human health risks are not ruled out: tests on rats (1997) showed a sharp reduction in fertility after exposure to Quassin extract.
Application as spray liquid: mix 200 grams of Quassia wood chips with 2 liters of water. Let stand for 24 hours and then boil for 30 minutes. Strain this brew to remove the wood chips, then dilute with 15 liters of water. Spraying apple trees helps prevent damage from the caterpillars of the apple sawfly.

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Quassia amara, photo: Forestowlet - CC BY-SA 4.0