what's eating my roses and African violets, our window shades

Asked February 13, 2017, 12:09 PM EST

I have four miniature rose bushes bought on Valentine's Day a few years ago from a reputable florist in my area. They have grown to hip height, and bloom indoors once I take them in for the winter and the blooms are fragrant and beautiful. The leaves are starting to curl under. I have found a few aphids on two of them, and am currently using insecticidal soap on the under-side of the leaves along with using the soap on the roses and the soil. The leaves of the African violets, both of which were presents, are also starting to curl under. We just discovered we have a family of insects nearby which are the size of a thrip or a flea beetle and appears to be nesting on the fabric of our shades on the windows near the roses and violets. It's black, has lacey wings, 1/16" or less, jumps, but does not bite. It appears to leave this area to buzz around us when we read the newspaper in the next room before work. I did also find a slightly larger bug (only one), dead and slight bluish tinge to its back. Friend of mine, daughter of an agronomist, thinks it is a fly. Right now, the only warm place to spray the roses without us inhaling or possibly getting sprayed would be our front porch, which has only a wood teak chair on it right now and faces south. The house was built in 1910, and has storm windows that can be easily opened if it gets too hot or too full of spray. But it will get cold rapidly, too, so it's hard to figure out when I could spray without freezing them if the temperature suddenly drops. Also have a HEPA portable air filter if we need it. This is the first year I didn't have time to spray the plants and isolate them in the bathroom., and boy, am I paying for that decision to hold off since it seemed to be warm! How can I get rid of the bugs on the roses and on the fabric shades without having to throw either out. If you wish, you may share my question, but please don't share my name.

Ramsey County Minnesota houseplants african violets horticulture minature roses

1 Response

Thank you for the question. You will need to accurately identify the insect on your plants and shades. Only then will you know how to control them. Often insect pests flourish when plants are over-watered, leaving the damp soil and decaying organic matter an ideal breeding ground. Many diseases and pests can be controlled by allowing the soil to thoroughly dry out between waterings. The University of Minnesota has a great publication on common indoor houseplant pests, including thrips, with photos and descriptions along with treatment. Read it here: http://www.extension.umn.edu/garden/insects/find/houseplant-insect-control/ Another possibility is fungus gnats: http://www.extension.umn.edu/garden/insects/find/fungus-gnats/

If you have aphids on your rose bushes, insecticidal soap is one of the listed treatments but you will need to be vigilant and persistent in trying to control them. Quarantining the roses on your porch where the temperatures can easily get below zero will only add to the plant's stress. Other ways of handling the aphids are:
  • Use a soft bristled toothbrush and dilute detergent solution to gently scrub the insects off and then spray the plant forcefully in your laundry tub or shower. Use 2 teaspoons per gallon water.
  • If there are just a few aphids, wipe them off and squish them. Pay particular attention to the undersides of the leaves and new growth.
  • Prune or pinch off any heavily infested parts

In Minnesota, the biggest problems during the winter with African violets is overwatering and getting too cold, perhaps from being too close to a window. Either of these cultural issues can cause leaves to darken and curl under. Be sure to check under the leaves for insect pests because it could be suffering from the same pest as the roses. Read more about caring for African violets here: http://www.ext.colostate.edu/ptlk/1301.html

Good luck and thank you for contacting Extension.