Crambus

The genus Crambus includes around 155 species of moths in the family Crambidae distributed globally. The adult stages are called snout moths (a name shared with the rest of the family Crambidae), while the larvae of Crambus and the related genus Herpetogramma are the sod webworms, which can damage grasses.

Life cycle


Crambus patella mating
Sod webworms have a bivoltine life cycle with four stages: egg, larva, pupa and imago (adult). They overwinter as larvae in their final or penultimate instar in the thatch or soil. With the coming of warmer weather, the larvae will pupate, and moths will appear in late spring or early summer. The first generation of eggs is laid in June, with larvae appearing in June and lasting until July. Adult moths appear from July until August. Under favorable conditions, a second generation will occur, with the adult stage laying eggs in early October.

The eggs of Crambus species are dry and nonadhesive, with an oval to elliptical shape. The eggs of most species are white to creamy white when first laid, but later turn bright orange or red. The size of the eggs varies between species, but ranges from 0.3 mm to 0.6 mm.

The color of the larvae also varies from greenish to beige, brown, or gray, with most larvae having dark, circular spots that extend over the entire body. From the first instar to the third instar, the head capsule will appear black, but later instars have a light brown head capsule with various black sculpturation. At the first instar, the head capsule is 0.19–0.23 mm wide, growing to 1.23–2.21 mm by the last instar. The length of whole larvae is 9–13 mm (0.4–0.5 in) at the first instar and 24–28 mm (0.9–1.1 in) at the last instar.

Crambus larvae, known as "sod webworms", feed primarily on grasses. In turfgrass species, their primary host plants are cool-season grasses, with fewer records on warm-season grasses. Some species also feed on maize, wheat, rye, oats, timothy-grass, and other grasses in pastures, and meadows, with the most damage occurring in areas with permanent sod. The damage caused is more pronounced during times of drought.

The pupa develops in a silken cocoon attached to soil particles, plant debris and fecal pellets. The cocoon resembles a small lump of earth, while the pupa itself is pale yellow at first, darkening to a mahogany brown. The pupae are 8–10 mm (0.3–0.4 in) long by 2.5 mm (0.1 in) wide.

The adult moth is whitish or light gray to tan. Many species have patterns of colors, including silver, gold, yellow, brown and black. The moths are approximately 12 mm (0.5 in) long, with wingspans of 20–25 mm (0.8–1.0 in). Like other snout moths, they have long labial palpi that extend in front of their heads, and fold their wings underneath their bodies, making them slender and harder to see while resting on plants.

Damage

Sod webworms were first recognized as a serious pest of lawns and golf courses during the drought of 1928–1934 that affected most of the United States. Unlike many of the other more destructive turfgrass pests, the sod webworm is native to the United States and was not introduced.

Most damage occurs during the first instar, when the sod webworm only feeds on the foliage of the turfgrass. Damage is often seen as a small area of leaves that are yellow to brown. Sod webworms themselves will not be seen because of their nocturnal nature. During the day, the sod webworm can be found in its burrow in the center of the damaged area. Even though damage can be an eyesore, it does not hurt the turf because no damage is done to the crown of the plant. In closely mown turf and drought conditions, damage is more severe than in poorly maintained turf. In closely mown turf, symptoms will appear more quickly and prominently. During drought conditions, damage is more severe because the damage is often not seen until rainfall occurs.

To be considered a serious infestation of sod webworms, 12 larvae must be found in a 0.1 square metres (1.1 sq ft) area. To test this, hollow pans are placed with a pyrethrum or detergent drench and allowed to sit for 10 minutes, then the larvae in the area are counted. During peak growing periods, the grass will often be able to recover by itself and not show serious damage. For high-end turf that cannot show any damage or serious infestations, predators of the sod webworms must be attracted, including birds and insect predators, such as ground beetles, robber flies, and predatory wasps. The larva is also prone to infection from microorganisms such as Beauveria bassiana and Nosema (Microsporidia). Parasitic nematodes such as Steinernema carpocapsae and Heterorhabditis heliothidis can also infect sod webworms.

Systematics and taxonomy

The genus Crambus was erected by Johan Christian Fabricius in 1798, and was originally used to cover species which are now considered to belong to the Noctuidae. The type species was designated by John Curtis in 1826 as Phalaena pascuella (now Crambus pascuella). Fabricius originally included 62 species, a number which had increased by 1940 to 116, of which only 98 were thought to be valid. A 1986 estimate suggested there were "perhaps 400" species of Crambus.

Species in the Crambus genus now are:


Crambus pascuella
Crambus achilles Bleszynski, 1961
Crambus acyperas Hampson, 1919
Crambus agitatellus Clemens, 1860
Crambus ainslieellus Klots, 1942
Crambus albellus Clemens, 1860
Crambus albifrons Schaus, 1913
Crambus alexandrus Kirpichnikova, 1979
Crambus alienellus (Germar E. F. & Fr. Kaulfuss, 1817)
Crambus angulatus Barnes & McDunnough, 1918
Crambus angustalatellus Maassen, 1890
Crambus angustexon Bleszynski, 1962
Crambus archimedes Bleszynski, 1961
Crambus argyrophorus Butler, 1878
Crambus aristophanes Bleszynski, 1961
Crambus arnaudiae Rougeot, 1977
Crambus athamas Bleszynski, 1961
Crambus attis Bassi, 2012
Crambus autotoxellus Dyar, 1914
Crambus averroellus Bassi, 1990
Crambus awemellus McDunnough, 1921
Crambus bachi Bassi, 2012
Crambus bellinii Bassi in Bassi & Trematerra, 2014
Crambus bellissimus Bleszynski, 1961
Crambus berliozi Bassi, 2012
Crambus bidens Zeller, 1872
Crambus bidentellus Hampson, 1919
Crambus bigelovi Klots, 1967
Crambus bipartellus South in Leech & South, 1901
Crambus boislamberti Rougeot, 1977
Crambus brachiiferus Hampson, 1919
Crambus braunellus Klots, 1940
Crambus brunneisquamatus Hampson, 1919
Crambus caligula Bleszynski, 1961
Crambus claviger Staudinger, 1899
Crambus coccophthorus Bleszynski, 1962
Crambus cockleellus Kearfott, 1908
Crambus cormieri Bleszynski, 1961
Crambus coryolanus Bleszynski, 1961
Crambus cypridalis Hulst, 1886
Crambus cyrilellus Klots, 1942
Crambus cyrnellus Schawerda, 1926
Crambus daeckellus Haimbach, 1907
Crambus damotellus Schaus, 1922
Crambus dedalus Bassi, 2000
Crambus delineatellus Hampson, 1896
Crambus descarpentriesi (Rougeot, 1977)
Crambus dianiphalis Hampson, 1908
Crambus diarhabdellus Hampson, 1919
Crambus dimidiatellus Grote, 1883
Crambus ellipticellus Hampson, 1919
Crambus elongatus Hampson, 1919
Crambus erechtheus Bassi, 1992
Crambus ericella (Hübner, 1813)
Crambus erostratus Bassi, 1992
Crambus eurypides Bleszynski, 1961
Crambus falcarius Zeller, 1872
Crambus frescobaldii Bassi, 2012
Crambus gausapalis Hulst, 1886
Crambus geleches Bleszynski, 1967
Crambus girardellus Clemens, 1860
Crambus guerini Bleszynski, 1961
Crambus hamella (Thunberg, 1794)
Crambus hampsoni Bleszynski, 1961
Crambus harrisi Klots, 1967
Crambus hastifer Staudinger, 1899
Crambus hemileucalis Hampson, 1896
Crambus heringiellus Herrich-Schäffer, 1848
Crambus humidellus Zeller, 1877
Crambus icarus Bleszynski, 1961
Crambus isshiki Matsumura, 1925
Crambus johnsoni Klots, 1942
Crambus jupiter Bleszynski, 1963
Crambus kazitaellus Bassi, 1986
Crambus kumatakellus Shibuya, 1928
Crambus kuzakaiensis Okano, 1960
Crambus lacteella Janse, 1922
Crambus laqueatellus Clemens, 1860
Crambus lascaellus Druce, 1896
Crambus lathoniellus (Zincken, 1817)
Crambus leachellus (Zincken, 1818)
Crambus leuconotus Zeller, 1881
Crambus leucoschalis Hampson, 1898
Crambus lyonsellus Haimbach, 1915
Crambus magnificus Bleszynski, 1956
Crambus melanoneurus Hampson, 1919
Crambus mesombrellus Hampson, 1919
Crambus microstrigatus Hampson, 1919
Crambus midas Bleszynski, 1961
Crambus moeschleralis Schaus, 1940
Crambus monostictus Hampson, 1919
Crambus mozarti Bassi, 2012
Crambus multilinellus Fernald, 1887
Crambus multiradiellus Hampson, 1896
Crambus narcissus Bleszynski, 1961
Crambus nephretete Bleszynski, 1961
Crambus netuncus Bassi, 2012
Crambus neurellus Hampson, 1919
Crambus nigriscriptellus South in Leech & South, 1901
Crambus nigrivarialis Gaede, 1916
Crambus niitakaensis Marumo, 1936
Crambus nivellus (Kollar in Kollar & Redtenbacher, 1844)
Crambus nolckeniellus Zeller, 1872
Crambus occidentalis Grote, 1880
Crambus okinawanus Inoue, 1982
Crambus ovidius Bleszynski, 1961
Crambus palustrellus Ragonot, 1876
Crambus paris Bassi, 2012
Crambus pascuella (Linnaeus, 1758)
Crambus patulellus Walker, 1863
Crambus pavidellus Schaus, 1913
Crambus perlella (Scopoli, 1763)
Crambus perspicuus Walker, 1870
Crambus praefectellus (Zincken, 1821)
Crambus pratella (Linnaeus, 1758)
Crambus prometheus Bleszynski, 1961
Crambus proteus Bassi & Mey in Mey, 2011
Crambus pseudargyrophorus Okano, 1960
Crambus psychellus Maassen, 1890
Crambus puccinii Bassi, 2000
Crambus pythagoras Bleszynski, 1961
Crambus quinquareatus Zeller, 1877
Crambus racabellus Druce, 1896
Crambus reducta Janse, 1922
Crambus richteri Bleszynski, 1963
Crambus rickseckerellus Klots, 1940
Crambus rossinii Bassi, 2012
Crambus sachaensis Ustjuzhanin, 1988
Crambus saltuellus Zeller, 1863
Crambus sanfordellus Klots, 1942
Crambus sapidus Bleszynski, 1967
Crambus sargentellus Klots, 1942
Crambus satrapellus (Zincken, 1821)
Crambus sebrus Bleszynski, 1961
Crambus sectitermina Hampson, 1910
Crambus sibirica Alphéraki, 1897
Crambus silvella (Hübner, 1813)
Crambus sinicolellus Caradja, 1926
Crambus sjoestedti Aurivillius, 1910
Crambus sparselloides Bassi, 1986
Crambus sparsellus Walker, 1866
Crambus sperryellus Klots, 1940
Crambus sudanicola Strand, 1915
Crambus tenuis Bassi, 1992
Crambus tenuistriga Hampson, 1898
Crambus tessellatus Hampson, 1919
Crambus themistocles Bleszynski, 1961
Crambus thersites Bleszynski, 1961
Crambus theseus Bassi, 2000
Crambus tomanaellus Marumo, 1936
Crambus trichusalis Hulst, 1886
Crambus tutillus McDunnough, 1921
Crambus uliginosellus Zeller, 1850
Crambus uniformella Janse, 1922
Crambus unistriatellus Packard, 1867
Crambus vagistrigellus Joannis, 1913
Crambus varii Bassi, 2012
Crambus viettellus Bleszynski & Collins, 1962
Crambus virgatellus Wileman, 1911
Crambus vittiterminellus Hampson, 1919
Crambus vulcanus Bassi, 2000
Crambus watsonellus Klots, 1942
Crambus whalleyi Bleszynski, 1960
Crambus whitmerellus Klots, 1942
Crambus xonorus Bleszynski, 1963
Crambus youngellus Kearfott, 1908
Crambus zelator Bassi, 1992
^ a b "Crambus Fabricius, 1798". Butterflies and Moths of the World: Generic Names and their Type-species. Natural History Museum. Retrieved July 20, 2010.
^ H. D. Oliver Miller (1940). "Observations on sod webworms (Crambus spp. Lepidoptera) in Kansas" (PDF). Transactions of the Kansas Academy of Science. 43: 267–281. doi:10.2307/3625521. JSTOR 3625521.
^ Gaden S. Robinson (1986). "Edward Meyrick: an unpublished essay on phylogeny". Journal of Natural History. 20 (2): 359–367. doi:10.1080/00222938600770261.
Former species

Crambus argyrostola Hampson, 1919
Crambus xebus Bleszynski, 1962

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