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 snout 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 larva 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