As perennials, poinsettias (Euphorbia pulcherrima) brighten late-season Mediterranean-climate gardens in U.S. Department of Agriculture plant hardiness zones 9 through 11. In colder areas, they’ve become fundamentals of indoor winter decorating schemes. Thus a mysterious white material and streams of ants covering your poinsettia’s flame-red bracts and pine-green leaves are nothing if not alarming. The prisoners accountable are messy, sap-stealing insects. Without quick therapy, they might doom your own plant.
Fulfill the Mealybugs
As tender-stemmed plants, poinsettias are favorite feeding sites for pink hibiscus mealybugs. The pinkish insects conceal themselves under a protective layer of wax. As a result of the wax and their heavenly white egg sacs, the mealybugs resemble bits of cotton fluff scattered over the poinsettia’s leaves and stalks. Adult mealybugs overwinter on poinsettia leaves and stalks or in the soil around the plants. Their newly hatched larvae crawl out of the egg sacs to start feeding. Breeze and ants also carry them to new locations.
Detect the Damage
The mealybugs feed by sucking the sap leaf and stems. In the process, they also inject toxic, leaf-curling saliva. Twisted stems, stunted development and failure to blossom all point to their presence, and a badly infested poinsettia may die. The insects have another annoying habit: They excrete undigested sap as sticky, transparent honeydew, a sugary waste which lures hungry ants to the plant.
Annihilate the Ants
Ants are voracious honeydew feeders, and you’re going to have them on your own poinsettia so long as your plant has mealybugs. To control the ants, place sugar-based, boric-acid-laced ant bets along the ant trails leading to your plant. When they come to collect the honeydew, some of the ants may also transport the lure back to their nests, in which it can slowly poison the entire colony. It may be more than a month before your poinsettia is free of their ants.
Ax Them With Alcohol
While awaiting the ants to evaporate, combine your baiting campaigns using a direct assault to the mealybugs. Chemical insecticides do not penetrate the insects’ wax covering. To do the task, spray on your poinsettia till it drips with a solution of 1 quart of water, 1 cup of rubbing alcohol and one tsp of insecticidal soap concentration. The alcohol dissolves the adult bugs’ waxy coating so they die, and the insecticidal soap suffocates the larva and eggs. Duplicate the application daily or every other day till the mealybugs are eliminated.
Wash Them Away
Pink hibiscus mealybugs are capable of reproducing several times per year. After you’ve eliminated an infestation, then track your poinsettia frequently. At the very first indication of a new infestation, then place your garden hose attachment to fine and also direct the spray to the backs of their leaves and the stems. For optimum effectiveness, spray in the early morning for 2 consecutive days.