Through the Macro Lens
As the first month of 2016 nears its end it would appear that we are finally getting some true winter weather in the form of arctic cold and snow that will keep even the most ardent green thumb inside. Is it any wonder that January is a popular time for perusing seed catalogs and forcing paperwhite and amaryllis bulbs to bloom indoor? It also presents a great time to pay a bit more attention to our houseplants: cleaning the foliage, repotting specimens that have outgrown their current containers, and doing a visual inspection for insects. This year, however, checking for unwanted visitors took on a whole new meaning.
I received a great present from my husband this Christmas in the form of a macro lens that clips over the camera lens of a smartphone (he knows how much I enjoy getting close-up images of insects and flowers). This tiny tool increases the magnification power of the ordinary camera lens by 10X allowing for some really incredible images from a phone camera. The first thing that I did with it was to start snapping pictures of just anything that was around such as the true flowers of a poinsettia that are usually insignificant, the new blooms of a paperwhite, and some fuzzy, cotton-like areas on a dieffenbachia.
What I saw in the lens was amazing. It was not just a cobweb substance on the dieffenbachia but a group of tiny insects that turned out to be the nymphs of the mealybug.
These tiny insects, along with scale and aphids, are a common pest of houseplants. They feed on the sap of the plant by piercing the outer layer of plant tissue with their long, slender beak. As a by-product they secrete a sweet honeydew that provides a base for the black fungus called sooty mold. Plant tissue that has been fed upon will be stunted, yellowed or malformed. A severe infestation can weaken a plant to the point of death. I found that many of the mealybugs were in the crevices of the leaf axils or in the unfurled new leaf growth.
A bit of research showed me that one of the easiest remedies was to wipe the affected areas with an isopropyl alcohol soaked cotton ball. I did this, making sure to get both sides of the leaves as there were many nymphs on the undersides.
There are also many products such as insecticidal soaps and neem that can be used to control nymphs, scale, spider mites and aphids. These should be used with caution and always according to the label directions. A few more non-chemical approaches include spraying the plant with a forceful stream of lukewarm water, placing it near a cold window (only if the plant can tolerate the cold) so that the nymphs migrate to the leaf that is furthest from the cold and will therefore be easy to wipe off, or introducing a natural predator such as a ladybeetle (probably a good idea for greenhouse specimens, not plants in a home environment).
It is important to check for new generations of any insect pest that may not have been controlled with the first application. I have been scouting my houseplants every few days but I have not seen a recurrence. I can see, however, the results of the initial infestation. There are areas of foliage that are devoid of green, have turned brown and thin and almost appear like water spots. These areas are not much bigger than a quarter so I may leave that foliage on the plant and wait to see how it does.
I am really looking forward to getting outside in the upcoming seasons and getting some incredible close-up shots of flowers and insects, many of which will be shared with you in my blog posts. Happy New Year!
All images by Susan Pelton