Fungus Gnats on Poinsettias

December 16, 2012 | Common Garden Pests


There are few things more cheerful this time of year than big, beautiful poinsettias. We all love receiving them as gifts, or giving the festive plants to friends and family.  However, no one wants a house full of fungus gnats courtesy of their new poinsettia, which is an all too common problem.

Fungus gnats (particularly their larvae) are destructive to plants and a nuisance to have flying around the house. Unfortunately greenhouses, and any moist environment with high volumes of organic matter, are a great environment for fungus gnats to survive and even thrive. With so many plants kept so close together in greenhouses, nurseries and retail stores, it is very easy for the fungus gnats to spread from plant to plant increasing the chances of your new poinsettia being infested. The fungus gnat adults are small, but visible to the naked eye. See illustration below.

Fungus Gnat Adult

Fungus gnats have a short lifecycle, usually lasting three to four weeks from egg to adult. Adult females can lay up to 200 eggs in their short life span of only 7-10 days, meaning your small pest problem can escalate rather quickly.

The good news is that there are effective, all natural ways of treating your plants to ensure a pest free home. Because fungus gnats have a short lifecycle you will see results soon after treatment as the nematodes kill existing larvae before they are able to reach adulthood. The beneficial nematodes will effectively hunt down and kill the fungus gnat larvae in the potting soil. Since the beneficial nematodes will stop the lifecycle of existing larvae your pest problem will quickly come to an end as existing adults die off in about a week. Beneficial nematodes, such as those found in Scanmask, are safe for humans, plants and pets. Treating your poinsettias with Scanmask is a quick and safe way to ensure a pest free home- and that is something very merry indeed!

Wishing you and yours a blessed & happy Holiday!