Arrowhead plant

(Question)

I brought this plant back to life with a new pot and soil about 7 mths. ago. Then I had to do Ed’s soap and water spray for bugs and it worked. Plant is very lush and putting out new growth.
Yesterday I noticed what looked like clear rain or dew drops on the tip and edges of the leaves. I freaked and gave the plant an Ed Lawrence spray again. Today no dew drops but I’d like to know if I should worry about this? Have I stressed the plant? It is in south east window and gets watered every Friday with standing water that I’d put one squirt of Shultz food in ( 1 squirt to 1L) and give about 1/2c at watering time. Thanks for any help. Maybe I should stop calling it Rasputin??

(Answer)

It’s very satisfying to bring a plant back to life!  The lovely Arrowhead, Syngonium podophyllum, is a beautiful specimen. Arrowheads are susceptible to a variety of insect pests, such as aphids, spider mites, mealybugs and scale, all of which feed on the plant and excrete a sticky liquid substance known as honeydew.  This is likely what you are seeing on your leaves, and it is often the first visible sign of an insect problem.  When an infestation of this kind is advanced, a black mold can appear on the surface of the honeydew.

Spraying affected plans with an insecticidal soap is recommended, so your first response is a good one.  You’ll need to repeat these sprayings, being sure that both upper and lower surfaces of leaves and stems are sprayed.  You could start first with clear water (in the shower, if you like, with the plant pot inside a plastic bag to prevent soil being washed away) to dislodge as many insects as possible.  Then follow up with a soap spray.  If you spot any hard brown shell-like spots on stems, these are the adult scale insect and must be scraped off.  White cottony masses indicate mealybugs, and these also need to be gently removed.  An infected plant should also be isolated if you have other houseplants nearby that might be vulnerable.

Your Arrowhead is obviously otherwise very healthy and well-looked-after, so it should have no problem weathering an insect infestation that has been caught early and is being treated.  You might enjoy this blog by a gardener dealing with scale, not on an Arrowhead, but close enough: https://torontogardens.blogspot.ca/2008/12/bad-case-of-scale-on-monstera-and-why.html

Although you are an experienced houseplant enthusiast, this Toronto Master Gardeners guide may have some useful information:

https://www.torontomastergardeners.ca/index.php/factsheet/beginners-guide-to-growing-houseplants-a-toronto-master-gardeners-guide/