Ficus or fig trees are one of our most decorative and useful indoor plants. Their dark evergreen leaves provide a welcome reminder of the verdant spring still several months away. Most of the time fig trees are relatively pest free, but a few weeks ago I received a sample of leaves from a fig that were grossly disfigured. Instead of appearing broad and flat, leaves were gnarled and folded. Worse yet, inside the curled leaves were dozens of black, squirming bugs. These strange insects were thrips, tiny insects with feathery wings and rasping mouthparts used to puncture the surface of a leaf and lap up the nutritious contents of the plant's cells.
Inside the folded leaf, thrips rasp the surface and suck nutritious plant fluids.
Within the folded leaves thrips lay batches of cylindrical eggs. These hatch into small larvae that feed and grow for several weeks before forming pupae. The pupae develop into winged adults that repeat the life cycle. Several generations take place every year. The feeding of thrips on the young leaves of the fig tree causes the leaves to develop abnormally and form folded refuges where thrips hide and multiply. Leaves are peppered with orange and brown spots and turn an anemic yellow or brown rather than their characteristic deep green. If many thrips are present, the fig may drop its leaves prematurely.
Adult thrips mill about amidst dozens of empty egg cases.
Cuban laurel thrips is a native of many tropical countries throughout the world where fig trees commonly grow. It was first reported in Florida in the late 1800's and in the United States it is found outdoors in Florida, Texas, California, and Hawaii. Thrips infesting the Benjamin fig in my friend's home probably traveled with the plant from a southern nursery to its present home in Maryland. Many predatory insects feed on Cuban laurel thrips in the wild but these beneficial insects are unlikely to be present in your home. One practical method of controlling Cuban laurel thrips is to remove and destroy the young folded leaves that house them. A thorough and regular policing of the foliage should help bring these rascals under control in the course of a few months. If you decide to tackle thrips by removing leaves, you might want to wear gloves. Cuban laurel thrips have been reported to give humans, as well as ficus leaves, a bit of a nip.
References:
Many thanks to Dick Byrne for sharing his thrips with us. To learn more about this pesky creature, please visit the following web sites.
http://creatures.ifas.ufl.edu/orn/thrips/cuban_laurel_thrips.htm
http://www.entomology.umn.edu/cues/inter/inmine/Thripe.html