Weeds – More Than Just a Garden Eyesore

by | May 27, 2019 | Best Management Practices, Container Gardening, Food Systems, Garden Design, General Gardening, Integrated Pest Management, Invasive Species, Vegetable Gardening, Weeds

Nobody likes weeds in their garden.  Weeds are not only ugly, they can host insects and diseases that later spread to your garden.  This situation commonly occurs when weeds belong to the same plant family as the desired landscape or vegetable species, but some insects and diseases have diverse palettes.  For example, I recently witnessed a looper caterpillar on a pokeweed plant.

Looper Damage on a Pokeweed

Looper damage on a pokeweed plant. Photo Credit: Matt Lollar, University of Florida/IFAS Extension at Santa Rosa County

Loopers are common pests of vegetable gardens and in the landscape.  Probably the most common loopers found in North Florida gardens are cabbage loopers (Trichoplusia ni) and soybean loopers (Chrysodeixis includens).  Cabbage loopers can be found feeding on cabbage, of course, as well as leafy greens, cucumbers, tomatoes, chrysanthemums, and snapdragons.  Weeds that attract this looper are lambsquarters, dandelions, and curly dock.  Soybean loopers like to feed on sweet potatoes, tomatoes, watermelons, geraniums, and sunflowers.  They can also be found feeding on oxalis, kutzu, and lantana.

Looper insect

Looper found on pokeweed plant. Photo Credit: Matt Lollar, University of Florida/IFAS Extension at Santa Rosa County

Although weeds can be hosts for pests, they may be used advantageously.  Trap crops can be planted at a garden’s perimeter or windward portion to attract pests away from the desired crop.  A trap crop draws the pest crop away from the main crop.  The trap crop is then destroyed or sprayed with insecticide when the pest insect is found feeding on it.  This allows for a reduction or elimination of insecticidal use on the desired crop.  However, it is important that both the trap crop and the desired food crop or ornamental crop are regularly scouted to keep track of pest populations.

For more information on trap crops and other insect and disease diversion methods you can read the EDIS Publication: Intercropping, Crop Diversity and Pest Management.

Matt Lollar
Latest posts by Matt Lollar (see all)