I Have White Flies on My Plumerias

The Giant Whitefly

• Though hardly a true giant, the giant whitefly can grow to three-sixteenths of an inch long, much larger than other whitefly species. These pests look like tiny white moths and are commonly found on the undersides of leaves. Whiteflies use needle-like, piercing mouthparts to suck sap from leaves, causing wilting and leaf drop. Large infestations contribute to the general decline of the tree but rarely cause death.

Cultural Control

• Whiteflies tend to congregate and feed in large groups on a single leaf or plant, according to the University of California. Use this behavior to your advantage and remove any heavily infested branches or leaves. Seal them tightly in a plastic bag and throw the bag in the trash. A strong jet of water from the hose applied to the undersides of leaves will kill adults, nymphs and eggs. Spray once a week until populations decline and then reduce to once every two to three weeks.

Chemical Control

• Chemical control is often not necessary since cultural controls are highly effective in ridding the plumeria of whiteflies. If you do need to use insecticides, try safer options like insecticidal soaps and horticultural oils. Make your own insecticidal soap by mixing a few drops of mild, unscented liquid dish soap in a spray bottle of water. Use this spray once a week during the summer on heavily infested leaves.

Tips for Growing Healthy Plumeria

• The best defense against pests is maintaining a healthy tree. Healthy plants can fight off pests and will sustain and outgrow any damage they do incur. Supply supplemental irrigation during dry summer months at a rate of about 1 inch of water each week. Apply a well-balanced fertilizer at a rate of about 1 lb. per inch of tree trunk during summertime.