Systemic Insecticides
How They Work: Systemic insecticides are absorbed by the plant and travel internally, killing pests that feed on the plant, including both chewing and sucking insects. This makes them effective for pests that are harder to reach, such as those found in the top branches of large trees or dense foliage like cordylines.
- Duration: These insecticides can protect the plant for 2-3 weeks.
- Application: Once sprayed, the insecticide is absorbed into the plant, making it effective against pests that encounter the plant’s tissues.
- Bee Safety: Systemic insecticides are unsafe for bees when the foliage is wet or the plant is in flower, so they should be applied when bees are not active, such as early in the morning or late in the evening and only to plants with no flowers.
Contact Insecticides
How They Work: Unlike systemic insecticides, contact insecticides must directly contact the pest to be effective. They are often used on pests like whiteflies, aphids, or other insects on the plant’s surface.
- Application: These sprays generally require more than one application to be fully effective, as they kill adult insects but not necessarily their eggs or larvae.
- Bee Safety: While many contact insecticides are unsafe for bees when wet, some bee-friendly options are available.
- Organic Options: Many organic insecticides are contact-based, making them an option for those looking for environmentally friendly pest control. Remember, though, just because it's organic doesn’t mean it's safe for bees.
Additional Considerations
Withholding Periods: This refers to waiting before harvesting and eating plants sprayed with insecticide. Withholding periods vary depending on the crop and the insecticide used and can range from a day to several weeks. Always read the label for specific recommendations.
Drying Time
After applying an insecticide, the plant should dry completely, with 6 hours being the general guideline. Applying insecticides in the early morning or late afternoon is best to prevent the sun from burning the leaves. Watering the plant before spraying helps, as it provides extra moisture to prevent burning and aids in the effectiveness of the spray.
Pest-Specific Solutions
The type of pest you’re dealing with will determine which insecticide to use. For quick and accurate advice, bring a sample of the affected plant in a snap lock bag, and we can help recommend the best product for your needs.
By understanding the differences between systemic and contact insecticides and other key factors like withholding periods and drying time, you can make a more informed decision about controlling pests in your garden and protecting bees.
