Azalea Whitefly Diagnostic Guide
Azalea whitefly, Pealius azalea, is a common pest of azalea in the landscape. It is very similar to other whiteflies in that it lives and feeds primarily on the undersides of leaves. Whiteflies suck out the plant juices causing yellowing of leaves. They also cause a sticky sap like substance, called honeydew, to coat leaves. This honeydew can attract other insects as well as allow black sooty mold to grow on coated surfaces.
Shrubs at Risk
Azaleas are known to be infested by azalea whitefly.
Signs of Damage
- Eggs, nymphs, adults, and skin casts can be seen on the underside of leaves.
- Leaves become yellow from whiteflies sucking the sap from them.
- Sooty mold will often grow on excreted honeydew.
- Heavy infestations may cause leaf cupping.
- Small, white, two-winged flies emerge as a cloud when host plant is disturbed.
- Pupae are yellow and lack fringes common to other whitefly species, and look similar to scale insects.
Monitoring and catching populations early will help greatly with control efforts. Systemic insecticides are the easiest products to use to control this insect since whiteflies feed primarily on the undersides of leaves, making foliar sprays a difficult option. Begin Xytect™ applications in the fall for next season control. Early spring applications can work but you must get the product applied before nymphs emerge in May. Transtect™ applications can provide current season control, and should begin in May with the hatch of eggs.
Soil Application using Xytect 2F
Dosage: 3-6 ml/inch DBH or foot of shrub height Timing: Preferable in fall, but anytime during the growing season Re-Treatment: AnnuallyXytect 2F$69.60
Soil Application using Transtect
Dosage: 1 packet/5 inches DBH Timing: Spring Re-Treatment: AnnuallyTranstect$326.00
Soil Application using Xytect 75WSP 22 packets
Dosage: 1 packet for 24-48 feet of shrub height Timing: Apply late summer to early fall Re-Treatment: AnnuallyXytect 75WSP 22 packets$148.00
Foliar Spray using Xytect 75WSP 22 packets
Dosage: 1 packet/300 gallons of water Timing: Apply when insects are visible Re-Treatment: AnnuallyXytect 75WSP 22 packets$148.00
Systemic insecticides are very effective for controlling this insect.
A Diagnostic Guide is designed to help you identify a pest issue and management solutions. Always refer to product label for all rates and approved uses. Some images courtesy forestryimages.org. Use of the images does not imply endorsement of treatments by forestryimages.org