Crambus
The genus Crambus includes around 155 species of moths in the family Crambidae, distributed globally. The adult stages are called crambid 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. 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. 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. 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, 1961Crambus acyperas Hampson, 1919Crambus agitatellus Clemens, 1860Crambus ainslieellus Klots, 1942Crambus albellus Clemens, 1860Crambus albifrons Schaus, 1913Crambus alexandrus Kirpichnikova, 1979Crambus alienellus Crambus angulatus Barnes & McDunnough, 1918Crambus angustalatellus Maassen, 1890Crambus angustexon Błeszyński, 1962Crambus archimedes Błeszyński, 1961Crambus argyrophorus Butler, 1878Crambus aristophanes Błeszyński, 1961Crambus arnaudiae Rougeot, 1977Crambus athamas Błeszyński, 1961Crambus attis Bassi, 2012Crambus autotoxellus Dyar, 1914Crambus averroellus Bassi, 1990Crambus awemellus McDunnough, 1921Crambus bachi Bassi, 2012Crambus bellinii Bassi in Bassi & Trematerra, 2014Crambus bellissimus Błeszyński, 1961Crambus berliozi Bassi, 2012Crambus bidens Zeller, 1872Crambus bidentellus Hampson, 1919Crambus bigelovi Klots, 1967Crambus bipartellus South in Leech & South, 1901Crambus boislamberti Rougeot, 1977Crambus brachiiferus Hampson, 1919Crambus braunellus Klots, 1940Crambus brunneisquamatus Hampson, 1919Crambus caligula Błeszyński, 1961Crambus claviger Staudinger, 1899Crambus coccophthorus Błeszyński, 1962Crambus cockleellus Kearfott, 1908Crambus cormieri Błeszyński, 1961Crambus coryolanus Błeszyński, 1961Crambus cypridalis Hulst, 1886Crambus cyrilellus Klots, 1942Crambus cyrnellus Schawerda, 1926Crambus daeckellus Haimbach, 1907Crambus damotellus Schaus, 1922Crambus dedalus Bassi, 2000Crambus delineatellus Hampson, 1896Crambus descarpentriesi Crambus dianiphalis Hampson, 1908Crambus diarhabdellus Hampson, 1919Crambus dimidiatellus Grote, 1883Crambus ellipticellus Hampson, 1919Crambus elongatus Hampson, 1919Crambus erechtheus Bassi, 1992Crambus ericella Crambus erostratus Bassi, 1992Crambus eurypides Błeszyński, 1961Crambus falcarius Zeller, 1872Crambus frescobaldii Bassi, 2012Crambus gausapalis Hulst, 1886Crambus geleches Błeszyński, 1967Crambus girardellus Clemens, 1860Crambus guerini Błeszyński, 1961Crambus hamella Crambus hampsoni Błeszyński, 1961Crambus harrisi Klots, 1967Crambus hastifer Staudinger, 1899Crambus hemileucalis Hampson, 1896Crambus heringiellus Herrich-Schäffer, 1848Crambus humidellus Zeller, 1877Crambus icarus Błeszyński, 1961Crambus isshiki Matsumura, 1925Crambus johnsoni Klots, 1942Crambus jupiter Błeszyński, 1963Crambus kazitaellus Bassi, 1986Crambus kumatakellus Shibuya, 1928Crambus kuzakaiensis Okano, 1960Crambus lacteella Janse, 1922Crambus laqueatellus Clemens, 1860Crambus lascaellus Druce, 1896Crambus lathoniellus Crambus leachellus Crambus leuconotus Zeller, 1881Crambus leucoschalis Hampson, 1898Crambus lyonsellus Haimbach, 1915Crambus magnificus Błeszyński, 1956Crambus melanoneurus Hampson, 1919Crambus mesombrellus Hampson, 1919Crambus microstrigatus Hampson, 1919Crambus midas Błeszyński, 1961Crambus moeschleralis Schaus, 1940Crambus monostictus Hampson, 1919Crambus mozarti Bassi, 2012Crambus multilinellus Fernald, 1887Crambus multiradiellus Hampson, 1896Crambus narcissus Błeszyński, 1961Crambus nephretete Błeszyński, 1961Crambus netuncus Bassi, 2012Crambus neurellus Hampson, 1919Crambus nigriscriptellus South in Leech & South, 1901Crambus nigrivarialis Gaede, 1916Crambus niitakaensis Marumo, 1936Crambus nivellus Crambus nolckeniellus Zeller, 1872Crambus occidentalis Grote, 1880Crambus okinawanus Inoue, 1982Crambus ovidius Błeszyński, 1961Crambus palustrellus Ragonot, 1876Crambus paris Bassi, 2012Crambus pascuella Crambus patulellus Walker, 1863Crambus pavidellus Schaus, 1913Crambus perlella Crambus perspicuus Walker, 1870Crambus praefectellus Crambus pratella Crambus prometheus Błeszyński, 1961Crambus proteus Bassi & Mey in Mey, 2011Crambus pseudargyrophorus Okano, 1960Crambus psychellus Maassen, 1890Crambus puccinii Bassi, 2000Crambus pythagoras Błeszyński, 1961Crambus quinquareatus Zeller, 1877Crambus racabellus Druce, 1896Crambus reducta Janse, 1922Crambus richteri Błeszyński, 1963Crambus rickseckerellus Klots, 1940Crambus rossinii Bassi, 2012Crambus sachaensis Ustjuzhanin, 1988Crambus saltuellus Zeller, 1863Crambus sanfordellus Klots, 1942Crambus sapidus Błeszyński, 1967Crambus sargentellus Klots, 1942Crambus satrapellus Crambus sebrus Błeszyński, 1961Crambus sectitermina Hampson, 1910Crambus sibirica Alphéraky, 1897Crambus silvella Crambus sinicolellus Caradja, 1926Crambus sjoestedti Aurivillius, 1910Crambus sparselloides Bassi, 1986Crambus sparsellus Walker, 1866Crambus sperryellus Klots, 1940Crambus sudanicola Strand, 1915Crambus tenuis Bassi, 1992Crambus tenuistriga Hampson, 1898Crambus tessellatus Hampson, 1919Crambus themistocles Błeszyński, 1961Crambus thersites Błeszyński, 1961Crambus theseus Bassi, 2000Crambus tomanaellus Marumo, 1936Crambus trichusalis Hulst, 1886Crambus tutillus McDunnough, 1921Crambus uliginosellus Zeller, 1850Crambus uniformella Janse, 1922Crambus unistriatellus Packard, 1867Crambus vagistrigellus de Joannis, 1913Crambus varii Bassi, 2012Crambus viettellus Błeszyński & Collins, 1962Crambus virgatellus Wileman, 1911Crambus vittiterminellus Hampson, 1919Crambus vulcanus Bassi, 2000Crambus watsonellus Klots, 1942Crambus whalleyi Błeszyński, 1960Crambus whitmerellus Klots, 1942Crambus xonorus Błeszyński, 1963Crambus youngellus Kearfott, 1908Crambus zelator Bassi, 1992