Colloquially known as the gerber daisy, the gerbera daisy (Gerbera jamesonil)--which is its correct name--is a perennial in warmer zones and annual in cooler zones. It is native to South Africa. This plant is susceptible to many common plant diseases, including mildew and black spots on the foliage, and the most common pests are aphids, thrips and white flies.
These tiny insects, which range in color from clear yellow to black, are also called plant lice. A common pest, aphids feast on the sugary sap of flowers. Female aphids give birth to 50-100 babies during their lifetime and these new insects mature with 10 days, according to Gerbera.org. Aphids damage gerbera daisies at the point at which they draw the sap from the plant, causing lesions. Aphids may be controlled with organic sprays and plants should be treated as soon as an infestation is noted.
Tiny insects that have yellow wings with black stripes, thrips have developed into a more well-known pest in temperate climates in the last two decades. First noted in Europe in the 1980s, thrips lay their eggs in the parenchymal cells of flowers and leaves. When the eggs open, the larvae begin to feed on the cells and the flower pollen. These insects live up to 40 days and the females lay up to 2 eggs per day and about 50 during a lifetime. Thrips lay their eggs on the underside of the foliage, near the main vein and each egg may look like black-spot disease, as the insect covers it with a drop of excrement. Thrips may be controlled with an organic spray or an insecticidal soap.
Insects of less an 1 millimeter in size, the white fly is believed to have originated in Central America and has a whitish-yellow appearance and resembles a moth. White flies reproduce only in warm climates--85 degrees Fahrenheit is optimal. These insects lay their eggs, which resemble small white spots that later turn red and purple, on the underside of foliage. In youth, insects themselves then live on the underside of the leaf, which will begin to wilt and turn yellow. White flies live for about 60 days and females may produce as many as 500 eggs during this time. Set out white-fly traps--which are sticky yellow glue traps--to prevent an infestation. If white flies have already set in, BugSpray.com suggests spraying with insecticidal soap or multi-purpose insect killer.