Cilantro, or Coriandrum sativum, is a popular annual herb prized for its leaves and its seeds, known as coriander. While it adds a distinct, bright flavor to many cuisines, its appealing qualities also attract a variety of garden pests. Protecting a cilantro harvest requires understanding which creatures cause damage and implementing specific strategies to deter them.
Common Pests That Target Cilantro
Pests that feed on cilantro are broadly separated into larger mammals and smaller invertebrates. Common mammalian threats include rabbits, deer, and groundhogs, which are attracted to the plant’s tender, leafy foliage. These herbivores can consume an entire patch of young cilantro overnight, posing a significant concern for gardeners, even though the plant’s strong scent repels some pests.
Insects also target the herb for its sap and tissues. Aphids are tiny, soft-bodied insects that cluster on the undersides of leaves and stems to suck out sap. This feeding weakens the plant and can cause leaves to curl or yellow. Spider mites are also common sap-suckers that leave fine, silvery webbing on the foliage.
Chewing insects present another challenge by physically consuming the leaf material. Larvae like army worms and cutworms feed on the foliage, often hiding in the soil during the day and emerging at night. The black swallowtail caterpillar feeds heavily on plants in the carrot family, including cilantro, dill, and parsley. Additionally, slugs and snails are drawn to moist environments and chew holes in the leaves, typically feeding at night or on rainy days.
Recognizing Specific Damage Patterns
Identifying the specific culprit is possible by observing the type of damage left behind. Larger mammals like rabbits or deer leave clean, sharp cuts on the stems, making the plant look neatly chopped off near the base. Rodents and squirrels, though less common, may leave similar evidence of substantial consumption of the above-ground portion.
Damage from sap-sucking insects presents as visual changes to the leaf structure. Aphid infestations often result in sticky residue, known as honeydew, and cause leaves to become distorted or yellow. Spider mites produce a distinct, silvery stippling on the leaves, which is caused by the removal of chlorophyll, and their signature silky webbing may be visible between the stems and leaves.
Chewing pests create a less uniform appearance of damage. Caterpillars and army worms leave irregular holes in the leaves or can sever young stems, sometimes causing entire seedlings to topple over. If the damage involves irregularly chewed leaves coupled with silvery trails on the soil or foliage, the presence of slugs or snails is highly probable.
Implementing Effective Plant Protection
Protecting cilantro from larger animals involves the strategic placement of physical barriers. Installing a low fence or chicken wire barrier around the patch effectively deters rabbits and groundhogs. For smaller-scale plantings, using floating row covers or fine mesh netting can shield the plants from both mammals and flying insects like egg-laying moths.
When dealing with insect pests, cultural controls and organic applications provide targeted solutions. Proper plant spacing improves air circulation, which helps reduce the humidity that attracts soft-bodied pests like spider mites and aphids. Companion planting can also offer protection; interplanting cilantro with basil or marigolds can help deter some harmful insects.
For active infestations, organic deterrents can be applied directly to the plants. Insecticidal soaps work by breaking down the protective outer layer of soft-bodied insects like aphids. Horticultural oils, such as neem oil, smother pests and interfere with their feeding and growth cycles. These sprays should be applied to the undersides of leaves where many insects hide, and dilution instructions must be followed to prevent leaf burn.
Introducing beneficial insects is a longer-term, biological control strategy. Ladybugs and lacewing larvae are natural predators that consume large numbers of aphids and spider mites, providing ongoing pest management. Gardeners can save black swallowtail caterpillars by carefully transferring the larvae to a different host plant in the same family, such as fennel or Queen Anne’s lace.