Palms (Palmaceae)
Plant Health Problems
Diseases caused by Physiological/Environmental Factors:
Leaf spot or Tip burn, physiological.
Tips of leaves or fronds develop brown, necrotic areas. This
problem can be associated with a number of factors including root
damage from overfertilization and low relative humidity.
Symptoms can be minimized by careful attention and review of
cultural practices. The appearance of the plant can be improved
when affected portions are removed with clean, sharp scissors.
Insect Problems:
Mealybugs. Phenacoccus citri,
P. gossypii, P. longispinus
Palms and other plants in greenhouses and homes are commonly
infested with mealybugs. White cottony masses appear on leaf
surfaces, in leaf axils and sheaths. These insects damage plants
by sucking plant sap. Sprays of insecticidal soap, ultra-fine
horticultural oil or resmethrin, which are among the compounds
registered for control of this pest in Connecticut, are most
effective against crawlers. Because of overlapping life stages in
a home environment, multiple applications will be needed to
control this pest. The spray needs to contact the insect so
direct it downward into growing tips and leaf axils. Root
mealybugs specialize as root feeders, and the only aboveground
sign of infestation is loss of vigor in infested plants.
Foliar-feeding and root mealybugs can be controlled with
imidacloprid applied as a systemic to be taken up by the roots.
Read and follow all label directions for any insecticide used.
For egg-laying mealybugs, such as P. citri, releases of
the mealybug destroyer ladybeetle may be useful.
Scale insects.
Many kinds of scale insects infest the different species and
varieties of palms in greenhouses and dwellings. Some of the more
important species are as follows: hemispherical scale, soft
scale, circular scale, Morgan's scale, and thread scale. Among
the compounds registered for control of this pest in Connecticut
are horticultural oil, insecticidal soap and imidacloprid. Except
for coconut palms, palms can be sprayed with ultrafine
horticultural oil to suffocate scales. Otherwise, repeated
application of insecticidal soap may be necessary to control
crawlers. Imidacloprid is only useful as a systemic treatment for
honeydew-producing species of scales. Consult the labels for
dosage rates and safety precautions.