Imidacloprid as a Garden Insecticide


Imidacloprid is an insecticide derived from toxins found in tobacco plants. It is applied to plants as a soil granule, sprayed onto foliage or allowed to be absorbed by plant roots. It is a systemic chemical, meaning its active ingredients are absorbed and flow to all parts of the plant via the vascular system. Thus, plants with saps and tissues full of imidacloprid later develop new leaves, stems or flower tissues and seeds that also contain the chemical.

Alternative Names

Imidacloprid (im-ah-dah-CLOE-prid) is rarely sold by its name simple because it is difficult to pronounce and market. Often manufacturers will use this chemical as the active ingredient in a white powder, concentrated liquid or tan crystal granule form and assign it a marketable, easily recognized product or trademark name. Examples include Merit, Marathon, Imicide, Grub-ex, Admire, Condifor, Gaucho, Premier, Premise and Provado, as well as Bayer Advanced. Examining the product label will reveal the active ingredient and show what percentage or dosage is in the product by volume or weight.

Effect of Imidacloprid on Insects

Imidacloprid works by interfering with the transmission of stimuli in an insect's nervous system. Once a bug ingests, inhales or merely comes in contact with residue of the chemical, it experiences a paralysis of the mouth parts, which leads to starvation.

Implications on Other Garden Wildlife

Since imidacloprid is absorbed by the plant and is distributed to all plant parts, the chemical remains in tissues for several weeks or months, depending on how fast the plant grows. Imidacloprid is highly toxic to all types of bees, which can severely and negatively affect pollination of crops if fruits or seeds are desired. While this chemical is generally not toxic to fish or any other warm-blooded animal, ingestion of plant leaves or stems with the chemical can result in stomach upset. The effect depends on the size of the animal and the concentration of chemical in the amount of plant materials consumed.

Application Considerations

Regardless of the physical form in which imidacloprid insecticide is purchased and subsequently applied in the garden, its effects and absorption on plants is widespread. Any foliage or roots exposed to the chemical will absorb it, making targeting application to plants ideal. In the garden, plant roots extend far from the plant's base, and a complex interwoven matrix of roots from flowers, shrubs and distant trees may all be located in the area treated with imidacloprid. Strive to use the chemical on the plant needing the chemical to minimize any effects on other healthy plants. Ideally, you don't want any human-edible plants absorbing imidacloprid. For example, don't use imidacloprid on a flowering plant that is immediately next to your tomatoes, apple tree, lettuce or sweet corn.


Once applied to a plant, the chemical takes time to be absorbed and then move throughout the tissues of the insect-ridden plant. Thus, no effect on bugs may be seen for days or weeks. Once the chemical reaches flower buds, leaves and new stem tips, numbers of insect pests will markedly decrease and then cease. Depending on the size of a plant, imidacloprid persists for many weeks or months, providing some form of insecticide level in the plant. Read product label for specifics on duration in different soils and plant types, such as woody trees and palms, in comparison to smaller plants like turf grasses or annual flowers and small shrubs.

Keywords: imidacloprid, systemic pesticide, systemic insecticide, Merit, Bayer Advanced chemicals

About this Author

James Burghardt has written for "The Public Garden," "Docent Educator," nonprofit newsletters and for horticultural databases, becoming a full-time writer in 2008. He's gardened and worked professionally at public and private gardens in Colorado, Florida, Minnesota, New York, North Carolina and Pennsylvania. He has written articles for eHow and GardenGuides.