While rosemary is well loved as a culinary herb and for aromatherapy, you may not realize that it is also an natural pest and insect repellent that is also effective against garden slugs. That being said a rosemary plant is vulnerable to a few pests that will search it out.
Scale insects are related to aphids and whiteflies. These insects are very small but do tend to vary in size. Not many of them will bug the rosemary plant but when and if they do the solution is very simple. Cut off the tip of the plant that is infected to get rid of the areas where the insects tend to take hold of the plant. You will also want to prevent them and other insects from coming back by applying alcohol with a cotton ball to the whole surface of the plant. You will not want to eat the plant or use it for cooking for 24 hours. Giving the alcohol time to dissipate from the leaves so it will not affect the flavor of the plant.
Spider mites are little tiny bugs that like to drink the sap from different types of leaves. As they drink the sap they also inject the leaf with a poisonous toxin causing discoloration to the leaves. You can get rid of spider mites by forcefully removing them with a high pressure stream of water. Repeat as needed. If the problem persists, you can use an approved pesticide to remove the spider mites.
Whiteflies are tiny little insects about the size of a pinhead. They are insects that love to feed on the sap of rosemary. In small numbers you can get rid of them with a soap water solution. However, you might need to resort to an organic insecticide to eliminate the problem completely. Whiteflies give off honeydew from eating the sap, and the honeydew can cause mold to form on the plant, which can eventually overtake and kill it. So it is best to get rid of the bugs so that you do not need to deal with a dead rosemary plant due to excessive amounts of mold.
Rosemary is so highly pest resistant that many different natural pest cures are made with it. You can find lice shampoos for ridding lice as well as many different insect repellents for humans, animals and gardens. Learning all of the benefits of rosemary as an herb and as a deterrent can at sometimes seem endless, however; taking the time to learn what types of pests thrive on your rosemary is very important. By keeping your rosemary healthy and strong you will have access to an herb that naturally can rid your home and garden of many unwanted pests.