By Amy Grant
A relative to mint, basil (Ocimum basilicum) has become one of the most popular, easy-to-grow and versatile of garden herbs. All basil is heat and sun loving, regardless of variety. Originating from India, basil plant leaves may be found in a plethora of cuisines from Italian to Thai and can be used to flavor foods, vinegars, oils, teas, and even to scent soap. But sometimes you may be appalled to find holes in basil leaves or other basil leaf damage.
What’s Eating My Basil Leaves?
Generally speaking, basil plant leaves are not susceptible to many issues as long as you rotate plantings and maintain hygiene surrounding the plant. That said, you may on occasion notice that someone, or rather something, is taking a nibble or two from your soon to be pesto. So what basil pests are capable of this relentless infraction? Let’s learn more about the pests associated with most basil leaf damage.
Holes in Basil Leaves and Basil Pests
When gaps or holes in basil leaves have been discovered, the time for action is now! The most frequent assaulters of your precious basil plant leaves are Japanese beetles, slugs and aphids.
Japanese beetles are usually found for around a month during the summer. They ravage the tender leaf but do not eat the larger veins of the basil plant, leaving a lacy looking skeleton on your plant. Japanese beetles can be plucked from the basil plant with your fingers and squished or dropped into soapy water to dispose. You may also choose to cover plants with garden fabric to reduce the number of mature insects that feed on them, which can also include the grasshopper.
Slugs or Snails
Slugs, ugh, slugs! Slugs find the basil plant leaves almost as delicious as you do. They create ragged holes in the basil plant leaves after climbing up the plant. While basil plants like mulch to help retain the moisture they enjoy, it is also a conduit for the slugs. To retard those munching slugs, try sprinkling diatomaceous earth over the mulch. The diatomaceous earth scrapes the slug’s skin and causes it to dehydrate and subsequently die.
Products such as Bayer Advanced Dual Action Snail and Slug Killer Bait, Sluggo, Escar-Go, and Schultz Slug and Snail Bait, must be reapplied after rain or watering. While not totally nontoxic, these products contain iron phosphate, which is significantly less harmful to pets, birds and beneficial insects than the more antiquated metaldehyde containing products.
Aphids and Soft Bodied Insects
Soft bodied insects, such as aphids, spider mites and whiteflies, can be eradicated with insecticidal soaps like Bonide Multi Purpose Insect Control Soap, Safer Rose and Flower Insect Killer Concentrate, Safer Insect Killing Soap Concentrate and Concern Insect Killing Soap Concentrate. Most of these pests will be on the underside of the basil leaf and must have direct contact with the soapy spray to effectively eradicate them.
If you are interested in using a more environmentally friendly product, you may investigate Azadiractin, which is an extraction naturally produced by the Neem tree, and is also known to gardeners as neem oil. Products which contain Azadiractin include: Align, Azatin, Neemex and Omazin. These products provide the gardener with another option for controlling basil plant marauders.
Finally, remove any basil plant leaves with holes in them to avoid contaminating the rest of your plant. Chances are good that those damaged basil plant leaves harbor some type of pest vying for your next batch of Pesto Genovese.