Sod Webworm

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

Life cycle

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.

Egg

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.

Larva

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 at the first instar and 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.

Pupa

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 long by wide.

Imago

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 long, with wingspans of . 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.

Management

To be considered a serious infestation of sod webworms, 12 larvae must be found in a 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 genus ''Crambus'' now are:

* '' Crambus achilles'' Błeszyński, 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'' Błeszyński, 1962
* '' Crambus archimedes'' Błeszyński, 1961
* '' Crambus argyrophorus'' Butler, 1878
* '' Crambus aristophanes'' Błeszyński, 1961
* '' Crambus arnaudiae'' Rougeot, 1977
* '' Crambus athamas'' Błeszyński, 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'' Błeszyński, 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'' Błeszyński, 1961
* '' Crambus claviger'' Staudinger, 1899
* '' Crambus coccophthorus'' Błeszyński, 1962
* '' Crambus cockleellus'' Kearfott, 1908
* '' Crambus cormieri'' Błeszyński, 1961
* '' Crambus coryolanus'' Błeszyński, 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'' Błeszyński, 1961
* '' Crambus falcarius'' Zeller, 1872
* '' Crambus frescobaldii'' Bassi, 2012
* '' Crambus gausapalis'' Hulst, 1886
* '' Crambus geleches'' Błeszyński, 1967
* '' Crambus girardellus'' Clemens, 1860
* '' Crambus guerini'' Błeszyński, 1961
* '' Crambus hamella'' (Thunberg, 1794)
* '' Crambus hampsoni'' Błeszyński, 1961
* '' Crambus harrisi'' Klots, 1967
* '' Crambus hastifer'' Staudinger, 1899
* '' Crambus hemileucalis'' Hampson, 1896
* '' Crambus heringiellus'' Herrich-Schäffer, 1848
* '' Crambus humidellus'' Zeller, 1877
* '' Crambus icarus'' Błeszyński, 1961
* '' Crambus isshiki'' Matsumura, 1925
* '' Crambus johnsoni'' Klots, 1942
* '' Crambus jupiter'' Błeszyński, 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'' Błeszyński, 1956
* '' Crambus melanoneurus'' Hampson, 1919
* '' Crambus mesombrellus'' Hampson, 1919
* '' Crambus microstrigatus'' Hampson, 1919
* '' Crambus midas'' Błeszyński, 1961
* '' Crambus moeschleralis'' Schaus, 1940
* '' Crambus monostictus'' Hampson, 1919
* '' Crambus mozarti'' Bassi, 2012
* '' Crambus multilinellus'' Fernald, 1887
* '' Crambus multiradiellus'' Hampson, 1896
* '' Crambus narcissus'' Błeszyński, 1961
* '' Crambus nephretete'' Błeszyński, 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'' Błeszyński, 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'' Błeszyński, 1961
* '' Crambus proteus'' Bassi & Mey in Mey, 2011
* '' Crambus pseudargyrophorus'' Okano, 1960
* '' Crambus psychellus'' Maassen, 1890
* '' Crambus puccinii'' Bassi, 2000
* '' Crambus pythagoras'' Błeszyński, 1961
* '' Crambus quinquareatus'' Zeller, 1877
* '' Crambus racabellus'' Druce, 1896
* '' Crambus reducta'' Janse, 1922
* '' Crambus richteri'' Błeszyński, 1963
* '' Crambus rickseckerellus'' Klots, 1940
* '' Crambus rossinii'' Bassi, 2012
* '' Crambus sachaensis'' Ustjuzhanin, 1988
* '' Crambus saltuellus'' Zeller, 1863
* '' Crambus sanfordellus'' Klots, 1942
* '' Crambus sapidus'' Błeszyński, 1967
* '' Crambus sargentellus'' Klots, 1942
* '' Crambus satrapellus'' (Zincken, 1821)
* '' Crambus sebrus'' Błeszyński, 1961
* '' Crambus sectitermina'' Hampson, 1910
* '' Crambus sibirica'' Alphéraky, 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'' Błeszyński, 1961
* '' Crambus thersites'' Błeszyński, 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'' de Joannis, 1913
* '' Crambus varii'' Bassi, 2012
* '' Crambus viettellus'' Błeszyński & Collins, 1962
* '' Crambus virgatellus'' Wileman, 1911
* '' Crambus vittiterminellus'' Hampson, 1919
* '' Crambus vulcanus'' Bassi, 2000
* '' Crambus watsonellus'' Klots, 1942
* '' Crambus whalleyi'' Błeszyński, 1960
* '' Crambus whitmerellus'' Klots, 1942
* '' Crambus xonorus'' Błeszyński, 1963
* '' Crambus youngellus'' Kearfott, 1908
* '' Crambus zelator'' Bassi, 1992

Former species

* '' Crambus argyrostola'' Hampson, 1919
* '' Crambus xebus'' Błeszyński, 1962

References

External links

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{{Taxonbar, from=Q1941887

Crambini
Agricultural pest insects
Crambidae genera
Taxa named by Johan Christian Fabricius