The plant known as lemongrass, belonging to the genus Cymbopogon, is a tropical perennial grass widely recognized for its vibrant citrus scent and its common use as a culinary herb. This aromatic grass is also commercially cultivated for its essential oil, which is a source of citronella and contains high levels of citral. While many people associate the strong, refreshing aroma of lemongrass with repelling insects, the plant possesses a dual nature that also actively attracts several organisms. The mechanisms of attraction range from chemical mimicry to simple nutrient foraging, drawing in a variety of creatures.
Attracting Honey Bee Swarms
The most distinct and scientifically specific attraction mechanism involves the honey bee, Apis mellifera. Lemongrass essential oil contains two primary chemical components, neral and geranial, which are isomers of citral and are present in high concentrations. These compounds are structurally almost identical to the honey bee’s Nasonov pheromone, a scent released by worker bees to communicate a safe and suitable location to their hive mates.
Beekeepers intentionally exploit this chemical similarity to attract swarms to empty hives or designated swarm traps. Worker bees, known as scout bees, fan their wings and release this pheromone to guide a swarm to a new nesting site. A few drops of lemongrass oil applied near the entrance of a bait box powerfully mimics the natural “home-finding” signal, providing a natural and effective way to capture and relocate wild swarms.
General Pollinators and Nectar Seekers
The lemongrass plant also attracts a range of general pollinators when it flowers. Although it is a grass, Cymbopogon species produce small, pale yellow flowers in clusters, typically in warmer climates or during extended growing seasons. These flowers offer a functional attraction, providing pollen and nectar for general sustenance.
The flowering structure draws in generalist bees and various butterflies, such as the Painted Lady and the Eastern Tiger Swallowtail. These visitors are not drawn by the pheromonal oil in the leaves but by the readily available sugars and proteins within the bloom itself. The plant’s overall presence contributes to the biodiversity of a garden ecosystem by offering a food source.
Pests That Feed on the Plant
While the potent scent of lemongrass is known to repel certain flying pests, the plant also attracts numerous organisms that feed directly on its foliage and roots. These attracted pests view the plant as a readily available food source, particularly when the plant is stressed or grown in monoculture.
Common sap-sucking insects like aphids, spider mites, and scale insects can be drawn to the tender parts of the blades, causing discoloration and stunted growth. Chewing pests, including various caterpillars and grasshoppers, are also attracted to the leaves, creating ragged holes and visible damage to the plant structure. Below the soil, microscopic root-knot nematodes are drawn to the roots, where they feed and create galls that impair the plant’s ability to absorb water and nutrients.
Harnessing Lemongrass for Beneficial Attraction
The attractive qualities of lemongrass can be strategically utilized in gardening and apiculture for beneficial outcomes. This is achieved primarily through two methods: using the essential oil as a swarm lure and integrating the plant into the garden ecosystem.
Swarm Luring
Beekeepers regularly use the plant’s essential oil as a natural swarm lure. Applying one or two drops to a cotton ball placed inside a swarm trap encourages colonization. This practice leverages the oil’s Nasonov pheromone mimicry to naturally increase the apiary population.
Garden Integration
In a garden setting, planting lemongrass can enhance a pollinator garden, especially where the plant is encouraged to flower, providing nectar and pollen for general bees and butterflies. Furthermore, the plant’s attractive qualities can be used in a “trap cropping” strategy. This involves intentionally using the plant to draw certain pests away from more valuable crops.