Description and Biology
The southern purple mint moth, Pyrausta laticlavia, is a native species with a wingspan of 3/4 inch. It is a typical snout moth (the palps stick out in front) with reddish-purple wings marked with brownish-yellow bands. In some specimens the purple areas may be brown. Little has been published on the biology of this insect. Moths must lay eggs from which hatch tiny caterpillars. Older caterpillars are pale to green, are relatively slender and have rows of black spots down the back and sides. The caterpillars spin loose webbing as they feed. The webbing accumulates pellets of frass. Pupae are dark brown, slender, and taper at both ends. They are found in the silk webbing. These moths fly from June to August. We probably have several generations per year in North Carolina.
Caterpillars of the southern purple mint moth have only been reported feeding on rosemary, Rosmarinus officinalis. The mint-loving pyrausta moth, Pyrausta acrionalis, is a similar species that feeds on mints in the genus Mentha. It has deep rose to violet forewings with yellow borders along the leading edge and the fringes of the wing, as well as some mottled yellow markings.
If rosemary is for culinary use, it would be well to use insecticidal soap or insecticides with Bacillus thuringiensis as the active ingredient.
- Descriptions of American Lepidoptera, no. 1.Grote, A.R. and C.T. Robinson. 1867. Transactions of the American Entomological Society, 1: 1-34.
- Northward expansion of two mint-feeding species of Pyrausta in California (Lepidoptera: Pyraloidea: Crambidae). Powell, J. A. et al. 2000. Holarctic Lepidoptera 7 (2): 55-58.
- Species Pyrausta laticlavia - Southern Purple Mint Moth - Hodges#5070. Balaban, J. and J. Balaban. 2019 (update). Iowa State University Department of Entomology.
- Extension Plant Pathology Publications and Factsheets
- Horticultural Science Publications
- North Carolina Agricultural Chemicals Manual
For assistance with a specific problem, contact your local Cooperative Extension Center.
This Factsheet has not been peer reviewed.
Publication date: Nov. 4, 2019
Revised: Nov. 4, 2019
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