Remember back awhile ago (last summer, I think) when ’scapers were wringing their hands over the breakout of what appeared to be Cuban Laurel Thrips on Ficus benjamina cultivars produced in Florida? Now it seems that the pest has been specifically identified, according to an article by David Held and David W. Boyd, Jr. in the current issue of GM Pro magazine.

This thrips is an exotic species named Gynaikothrips uzeli (say that three times fast), native to China, Taiwan and India but reported to have been identified in Trinidad, Florida, Georgia, Alabama, Mississippi and Louisiana and possibly other states as well.

The thrips in question is similar in appearance and activity to the Cuban Laurel Thrips that we saw back in the 70’ and 80’s on Florida-grown Ficus. The large adults are nearly black in color and occur almost exclusively in "cigars" or galls made up of rolled-up, immature leaves at the shoot tips of the plant. Fortunately, the larvae and eggs are completely confined to the galls, so they can be pretty easily (if tediously) removed by pruning or picking off the "cigars"...and while the adults obviously venture elsewhere in order to colonize new sites on the plant, they appear to stay on the plants and do not colonize the soil or other non-plant areas around the crop.

The authors report finding some naturally-occurring biological controls (lacewing larvae, pirate bugs, spiders and a gall-forming-thrips-specific parasitic wasp) inside the galls...the wasp having already been exploited by the authors in their research into controlling the thrips in interiorscapes.

Chemical controls are somewhat spotty in their results...Marathon is one of a group of pesticides applied as a foliar spray that gave better than 90% control; unfortunately, soil-applied systemics did about half as well. Talstar sprays gave a very high percentage of control in the first week after treatment, but dropped off drastically in terms of residual control thereafter.

We are still seeing this pest on new shipments of Ficus from Florida nurseries. If you have a lot of specimen-sized Ficus benjamina cultivars in mass plantings in atriums, malls, etc., be very careful about introducing new Ficus plants into these interiorscapes...they can soon colonize your entire grove and require very expensive control and grooming methods to preserve the economic value of the trees.

Clem

Its not cheap, and as far as I know has still not been labeled for interior use, but Safari is an excellent control method for this and many other pests. It is a true systemic, and if you prune affected leaves in conjunction with a drench before install you should very nearly eliminate the possibility of establishment and spread of the thrips. I have definitely seen ficus come in with this thrips, and fortunately it is pretty easy to identify. Sometimes I’ll see plants that have older leaves that have obviously been affected at some point, but the grower did a fairly good job of gaining control. They are very rarely ever 100% eliminated coming from the grower; however, scapers can have very good results once the tree is drenched and installed provided no more thrips are introduced from the outside. Pyrethrin sprays are pretty effective, and I would combine with a merit drench as well once on the jobsite if you didn’t catch it ahead of time. Nasty little creatures.

Yours in benevolence (except toward piercing-sucking insects,) Lynnae Dehoff.