In gardens and managed landscapes, some plants are specifically chosen to attract certain caterpillars, such as swamp milkweed or butterfly weed (for monarchs) and parsley (for black swallowtails), which are equally as attractive as their adult forms that hopefully follow. Dr. Doug Tallamy at the University of Delaware has also highlighted the ecological importance of caterpillars in landscapes for sustaining bird populations, suggesting that "each plant in the landscape should be thought of as a bird feeder." In floriculture and herbaceous perennial production, however, they can be an unpleasant surprise. While among the less common pests encountered, a review of those that keep popping up might be of interest to readers.
Yellowstriped armyworm (Spodoptera ornithogalli) is among the most troublesome species seen in greenhouses, usually entering during the onset of cool fall weather and sometimes remaining into spring. They have been found chewing on cyclamen, zonal geraniums, begonias, and other annuals as well as vegetable transplants. The older stages are mostly dark with two thin bright yellow, sometimes broken, lines along the back and are notorious for resistance or tolerance to some insecticides.
European pepper moth (EPM, Duponchelia fovealis) hasn't quite turned into the widespread serious pest in greenhouses that was expected, but it has been persistent around some operations and caused some losses. Despite a long list of host plants (see [https://edis.ifas.ufl.edu/publication/IN910](https://edis.ifas.ufl.edu/publication/IN910)) and reports of crop damage in California, it is mostly found in chrysanthemums, chewing lower stems and foliage. It pupates in silk cocoons covered with soil or media and frass attached to the plant, the pot, or soil surface. The small (to 30mm/1.25") whitish to light brown caterpillars, with small dark spots, may vary in color according to the host plant. Pheromone traps can be used to monitor moth (male) activity.
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