What Do I Use to Cure Brown Scale?

A pest that commonly infests plants both indoors and outdoors, brown scale does damage when it sucks the sap from tender plant tissues. Although brown scale doesn't usually kill the host plant, it causes wilting and stunted growth. Additionally, brown scale leaves sweet honeydew on the leaves, which makes plants susceptible to powdery mildew.

In the garden, a number of natural predators effectively keep brown scale in check, including lady beetles and several types of small, parasitic wasps. The best way to maintain a healthy population of natural predators is to avoid use of pesticides, which kill both pests and beneficial insects but are generally an ineffective treatment for brown scale. Without natural predators, brown scale is difficult to control.

Hand-picking is a safe, effective means of controlling brown scale, especially for light infestations or for houseplants. To remove brown scale, dip a cotton swab in rubbing alcohol and remove the pest from the plant. Work carefully to avoid leaving excessive amounts of alcohol on the leaves. You can also remove brown scale with a toothpick, tweezers or a toothbrush.

Horticultural oils smother brown scale by cutting off their oxygen supply. Because the oils have no residual effect and kill only on contact, the damage to beneficial insects is minimal. To treat brown scale on houseplants, mix horticultural oil at a rate of 2.5 to 5 tablespoons per gallon of water. The mixture for outdoors plants is generally the same, although fruit trees and berry plants may require a stronger mixture. Always read the label, because garden supply centers sell a variety of horticultural oils, all with specific applications.

When used properly, insecticidal soap spray is considered safe for people and pets, although the soap may irritate the skin or eyes. While the spray is an effective treatment for brown scale, it also kills beneficial insects on contact. Use insecticidal soap only if other means of control are ineffective and don't spray if you notice beneficial insects on the plant. You can make your own insecticidal soap by mixing 3 to 5 tablespoons of liquid dish detergent in a gallon of water with a few drops of vegetable oil. You can also use a premixed commercial product or a concentrated product mixed at a rate of 5 tablespoons of concentrate in 1 gallon of water.