Daisies (Gerbera jamesonii) are perennial or annual plants that feature brightly colored blooms. They are part of the sunflower family and have flowers similar to sunflowers. The showy display attracts a wide range of insect pests who like to munch on the plants; deer and rabbits are also attracted to these plants.
Most insects that eat daisies are sucking insects. Sucking insects have mouthpieces that pierce the leaves, petioles and stems of the daisies, feeding on the plant juices, which includes plant sap and cell contents. This causes wilting, spotting, and in severe cases, yellowing of the foliage. These insects may also feed on new flower buds, causing stunted growth or even preventing the buds from opening at all. Sucking insects that plague daisies include aphids, mites, leafminers -- which are known to even feed on the flower petals -- thrips and whiteflies.
Nematodes are tiny round worms that live in the soil and feed on the roots of daisies and other plants. Several species of nematodes exist, most of which leave distinctive, swollen areas on the roots called galls. The damage to the roots impairs the plant's ability to absorb water and nutrients. If you don't want to dig your daisies up to look for galls on the roots, check the above-ground symptoms of nematode damage, which include stunted growth, wilting, yellowing of the leaves and an overall failure to thrive.
Mammals can be just as damaging to gardens -- if not more so -- than insects. Deer and rabbits are the two that are most troublesome. Both will eat daisies, munching on the plants until nothing is left but stubs. This may even happen overnight. Gerbera daisies are often severely damaged by deer, according to the Rutgers University Extension website.
Prevention and Treatment
Insecticide can be effective against insect pests, provided it is applied correctly and at the right time of the year. Cover the plant thoroughly, and use insecticide formulated for the specific kind of insect that is infesting the daisies. Insecticides are most effective in the spring and require repeated applications. Deer and rabbits are harder to keep from eating your flowers. Deer can easily leap over fences that are high enough (3 feet) to keep rabbits out. Still, fencing is the most effective way of protecting your garden from deer, according to the University of California's Integrated Pest Management website. The fence must be at least 7 feet tall to keep the deer out, however. An easier way is to place netting, chicken wire or another cover over the bed of daisies each night, and remove it in the morning.