Natural Pyrethrum for Whiteflies

Pyrethrum Source

• Pyrethrum pesticides are organic, plant-based chemicals obtained from dried pyrethrum daisies such as Chrysanthemum cinerariaefolium, C. marshalli and C. coccineum. The flowers are natives of southwest Asia. The nonsynthetic chemical is used for the cultural, preventive and mechanical control of numerous pests, including houseflies, mosquitoes and whiteflies.

Mode of Action

• Pyrethrum is a contact poison with a rapid rate of action. The toxin contained in the insecticide paralyzes pests and affects the nervous system leading to nerve discharge. Continual discharge of nerve fluids eventually causes paralysis and death. It is important that you administer pyrethrum in the correct dosage for full effectiveness, otherwise, insects are likely to recover after the initial knockdown effect.

Use Suggestions

• The use of insecticides like pyrethrum for the control of whiteflies is often difficult since the pests tend to develop resistance to it. For this reason, pyrethrums may be effective on whiteflies on certain areas of the landscape only. Repeat applications at an interval of five to seven days are recommended for best control. Cover the foliage undersides specifically with the chemical and start the use of insecticides at the earliest sign of infestation. It is best not to let the pest population get severe prior to starting chemical use.

Tips

• Do not mix pyrethrum with products containing sulfur, lime or other soaps as the insecticide disintegrates in alkaline and acidic solutions. Since the chemical breaks down rapidly in direct sunlight, it is recommended to use pyrethrum-based pesticides during early morning. It is necessary for the contact poison in pyrethrum to directly touch the pests for it to be effective.