Question
Please HELP!  I have three ficus trees living in my living room (9th flr) facing south.  They receive more than enough sunlight (maybe too much) throughout the day and were thought to be pretty happy within there new environment (from Florida to Chicago) until I discovered an infestation of hundreds of tiny thin black worms (or bugs) settling in, cocooning themselves within the leaves of all three ficuses.  The leaves continue to grow, however they remain closed sheltering the bugs inside.  I can抰 seem to identify the insects, which limits my ability to do further research.  I used ORTHO, but it doesn抰 seem to have done the trick. They are such lovely large  trees.  I have a  8ft(green and white leaves), 7ft, and  4ft hybrid tree.  I don't want to get rid of them, but what else can I do?  I continually cut the infected leaves off and spray, but they continue to multiply.

The insect is about 3-4cm long (including the tail), it appears to be smooth and black, with about 4 legs on each side. However,  I抳e just spotted all white ones as well!!   Please excuse the ambiguity, but the cocoon is the actual leaf itself (whether the leaf is newly grown or aged, these tiny complex creatures simply take over the entire leaf!)  The bugs enclose themselves within the leaf, which holds  about 15-20 insects ea.  BTW, the ORTHO is discarded.  I hope this description helps.


Answer
Hi Fateen,

Thanks for the detailed description of the critters infesting your Ficus trees. I did some additional research and learned that these trees, most of which are grown in Florida, are experiencing a major infestation of thrips. Thrips have been around for a long time, but this recent infestation of Ficus trees is unusual.

I suggest you start your treatment by removing as many of the infested leaves and stems as possible. Because most of the thrips are in new growth and new growth is always at the ends of stems, simply trimming off the last several inches of all stems will probably remove most of the critters.

If you don't mind using pesticides, Malathion is effective in treating thrips. Alternatively, you can use a fine horticultural oil spray. With both products, it is important to spray in a well ventilated area and to get complete coverage of all leaf and stem surfaces.

Good luck!

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC