Spray For Basil

Basil Pests

• When the weather warms up, the aphids (Aphis spp.) march in, sucking the juices from basil plants. You may also find whiteflies -- tiny winged bugs from several genera in the Aleyrodidae family -- sucking the juices from the undersides of basil leaves. Another sucking pest that feeds on basil is the leafhopper, a catch-all name for any member of the Cicadellidae family. Gardeners in the eastern U.S. may be troubled by the metallic-looking Japanese beetle (Popillia japonica) that chews holes in the basil plant’s leaves.

Basil Diseases

• Basil is affected by several diseases, both bacterial and fungal. Unfortunately, there is no cure for a bacterial (Pseudomonas cichorii) leaf spot that the plant is prone to. Downy mildew (Peronospora belbahrii), a common fungal infection, is treatable with a spray product.

Sprays for Sucking Insects

• Before using an insecticide -- synthetic or organic -- try spraying the pests off the basil with a strong blast of water from the hose. This typically works well with aphid and whitefly infestations. Aphids, whiteflies and leafhoppers can be controlled by a variety of sprays and pyrethrin sprays will kill all three. Read the instructions on the product label for dilution and application rates. A rule of thumb in to dilute 3 tablespoons on pyrethrin in 1 gallon of water and spray all surfaces of the basil plant with the solution. The spray can be used up to the day of harvest.

Sprays for Chewing Insects

• Japanese beetles are challenging pests to manage. In the grub stage they chew on the plant’s roots. Adults produce a pheromone that summons other beetles for miles around. They can devour an entire basil garden in one day. Milky Spore powder is recommended to kill grubs and pyrethrin spray will manage the adults. Follow the mixing instructions on the label, or use 3 tablespoons of the product in 1 gallon of water and spray the plants completely, until the insecticide drips.

Fungicide Spray

• Downy mildew infections, which typically occur when humidity levels are high and temperatures are cool, require the use of a broad spectrum bactericide/fungicide. Read label instructions carefully before applying the product to basil. As a general rule, use 1.25 ounces of the product per gallon of water and spray the plants until they drip.