Tending an Australian Ficus henneana tree

Today's task was to tend to a sickly ficus (fig) tree located in the tropical rainforest room of the University of Minnesota's Conservatory. Ficus henneana is in the strangler fig family. The plant is native to Australia and nearby islands in the south pacific. It produces small fruits which are edible, but not very tasty to humans. The specimen in the Conservatory's collection has for months suffered an infestation of hard scale insects, and possibly mealybugs as well. The tree sits in a large pot measuring 24 inches diameter. The tree has grown to be about 4 meters high.

The leaves of this ficus are supposed to be dark green, but every leaf on the tree has been infested by several scale insects sucking out the sap and depositing sticky honeydew sap. Sooty black mold has thrived on the honeydew, turning the leaves black and blocking light from reaching the leaves.

Also, under the stress of the infestation the leaves have all acquired yellow spots, distributed in a uniform pattern across each and every leaf on the tree. I'm not sure what is causing the yellow spots, Coordinator A... thought perhaps the plant has been overwatered, adding to the stress the plant has been experiencing.

I found a tall ladder which allowed me to reach all the way to the top of the plant. With a bucket of soapy water attached to the top of the ladder I was able to scrub the sooty mold and insects off of each leaf. I'm sure I missed a few leaves and insects, but the burden of insects has been significantly reduces, and the sooty mold has been largely removed. The plant will now have a better chance to fight off future infestations.

I noted that there were several beneficial predator Cryptolaemus larvae on the plant, so they may also continue to keep down the population of scale insects.

Ficus henneana leaves

Ficus henneana

Nearby the ficus tree, I spotted a jewel orchid (Ludisia discolor) in full bloom. This orchid is popular among orchid growers. I see it is available locally at some plant shops. The plant has showy dark leaves with attractive pinstripe. The flowers are small and not particularly colorful, but the spikes are tall and attractive.

Ludisia discolor (jewel orchid)

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