Phlox plants are susceptible to red pests that primarily attack perennial species, causing unsightly cosmetic damage. Injury ranges from aesthetic damage to severe infestation that is prevented through proper care. Familiarize yourself with what to look for as well as what to do should a problem arise to keep your home garden looking beautiful.
Vigorous plants are less likely to succumb to, and have a problem recovering from, pest infestations when compared with weakened or stressed plants. Grow phlox in locations that provide full sun exposure. Phlox thrives in moist, well-drained soil and prefers enough space for good air circulation, according to the University of Illinois Extension.
The phlox plant bug (Lopidea davisi) lays eggs during autumn that overwinter on plant stems and hatch in May, according to the University of Guelph Plant Diagnostic Clinic. The nymphs display vivid red bodies and black legs while phlox pests in the adult stage have bodies with red and black coloring that sometimes appears in other variations including orange and black or gray and white. If you see entirely red pests on your phlox, the bugs are still in an immature stage.
Red pests on phlox feed on leaf surfaces as well as buds, according to the University of Guelph Plant Diagnostic Clinic. Nymphs usually consume new growth, causing the development of light spots that change to yellow. Phlox plant bugs are "sucking" bugs, meaning they remove sap or fluid from plant tissue. Though damage is usually a cosmetic problem, extreme cases result in malformed flowers, stunted growth and plant death.
For natural control of red pests on phlox, remove and destroy any dead or injured plant parts to help reduce the population of overwintering eggs. Additionally, you can monitor plants for bugs and crush them by hand; consider placing material or a catch beneath the plant as phlox plant bugs drop from their host when disturbed, according to the Ohio State University Extension.
For chemical control of red pests on phlox, apply a pyrethroid insecticide to your plant as soon as nymphs or symptoms are visible. For a gentler insecticide that is less toxic to humans and to proximate desired plants, apply horticultural oil or insecticidal soap; repeat applications may be necessary as these insecticides kill bugs on contact but do not provide residual control, according to the Ohio State University Extension.