Norfolk Island Pine (Araucaria)
Plant Health Problems
Diseases caused by Physiological/Environmental Factors:
Branch drop, physiological.
Entire branches yellow and drop. This frequently starts at the bottom of the plant and progresses upward. This condition has been associated with low light and overwatering.
Branch drop can be minimized by careful attention to light and watering practices. It is best to allow the potting mix to dry between waterings.
Mealybugs, Pseudococcus aurilanatus, P. ryani and Planococcus citri.
Pseudococcus aurilanatus, P. ryani, and citrus mealybug may attack this plant. Among the compounds registered for control of this pest in Connecticut are insecticidal soap, horticultural oil, malathion and imidacloprid. When needed, spray with insecticidal soap or ultrafine horticultural oil being sure to contact the insects with the spray. If the plant is outside for the summer, malathion can be used. Imidacloprid, applied as a systemic to be taken up by the roots, will provide long-term control. Consult the labels for dosage rates and safety precautions.
Scales, Eriococcus araucariae, Chrysomphalus
These and other scales are known to occur on this plant. Among the compounds registered for control of this pest in Connecticut are insecticidal soap or ultrafine horticultural oil applied as needed. Malathion can be used if the plant is outside. Scales producing honeydew can be controlled with imidacloprid. Consult the labels for dosage rates and safety precautions.
Twospotted spider mite, Tetranychus urticae.
This is the most serious pest of Norfolk Island pine. It infests the leaves, which turn orange, giving the plant a generally unhealthy appearance. Sometimes the mites form webs, which more or less enclose the foliage. Among the compounds registered for control of this pest in Connecticut are insecticidal soap and ultrafine horticultural oil. Spraying with either product will give sufficient control if applied at least twice at 7-10 day intervals. Special care should be taken with soap or oil to obtain thorough spray coverage, because they only work on contact. Commercial growers can use hexythiazox or abamectin in greenhouses. Consult the labels for dosage rates and safety precautions.