Peridroma saucia, the pearly underwing or variegated cutworm, is a moth of the family Noctuidae.

[2] The variegated cutworm has a number of wasp and fly parasites, which account for most of the larval deaths each year.

The larvae cause considerable damage to common garden vegetables and fruits, destroying large amounts of crops every year.

However, the moth was first observed in North America in 1841, where today it primarily inhabits Southern Canada and Northern United States.

[1] P. saucia was discovered in Japan in the 1970s, where it is dubbed "nise-tamanayaga", which directly translates to "false black cutworm moth".

As Japanese populations of the variegated cutworm continue to grow, studies are still being conducted to identify the distribution areas in the region.

One of the reasons why P. saucia is such a common pest is because of its very high reproductive potential and the difficulty in controlling the moth's mass egg-laying.

However, studies have shown that this is due to an extension of the oviposition period, rather than an increase in the number of eggs the female moth lays per day.

The larvae are generally colored brownish-gray to grayish-black, with a distinctive yellow or white spot on the dorsal side of their first four to six abdominal segments.

The front wings of P. saucia are grayish-brown with a red undertone, with darker brown shades centrally and along the edges.

[1] The subspecies margaritosa includes the more strongly marked and varied specimens, wholly grey in color.

nigrocosta is greyish fuscous, sometimes tinged with reddish or ochreous, with a broad black shade along the costal area which sometimes encloses the stigmata.

[7] These data suggest the moth does not overwinter in the cold northern Canadian extent of their geographic range.

[2] The common infestations seen in the spring are believed to be because of the migration of adults returning to the north from overwintering areas in the Southern United States.

The complete overwintering range is unknown, but it is suggested to be from the lower Mississippi valley to the southern Great Plains.

Some of the most common organisms that attack the larvae include: Apanteles xylinus, Chelonus insularis, Chelonus militaris, Meteorus autographae, Meteorus leviventris, Microplitis feltiae, Rogas perplexus, Rogas rufocoxalis, Campoletis sonorensis, Enicospilus merdarius, Nepiera fuscifemora, Ophion flavidus, Dibrachys canus, Archytas aterrimus, Archytas cirphis, Bonnetia comta, Carcelia spp., Chaetogaedia monticola, Clausicela opaca, Eucelatoria armigera, Euphorocera claripennis, Euphorocera omissa, Gonia longipulvilli, Gonia porca, Gonia sequax, Lespesia archippivora, Madremyia saundersii, Peleteria texensis, Periscepsia helymus, Periscepsia laevigata, Voria ruralis, Winthemia leucanae, Winthemia quadripustulata, Winthemia rufopicta.

[1] The Winthemia rufopicta, Voria ruralis, Archytas apicifer, Lespesia archippivora, Apanteles marginiventris, Campoletis sonorensis, and Peleteria texensis are species that have been found to parasitize P. saucia.

[2] These larvae are common in low-growing herbage, but what makes them especially dangerous to crops is their ability to climb trees to feed on foliage.

Damage can happen extremely quickly, with entire gardens and fields being destroyed in a matter of days.

Removing weeds and rubbish from gardens reduces the number of variegated cutworm larvae in the area.

Painting tar or pitch around the tree is effective for a short time, but a fresh coat must be applied every few days.