Sod Webworm

Taxobox
name = Crambus


image_width = 220px
image_caption =
regnum = Animalia
phylum = Arthropoda
subphylum = Hexapoda
classis = Insecta
ordo = Lepidoptera
unranked_familia = Obtectomera
superfamilia = Pyraloidea
familia = Crambidae
subfamilia = Crambinae
tribus =
genus = Crambus
genus_authority = Fabricius, 1798
subdivision_ranks = Species
subdivision =ManyThe Sod Webworm, "Crambus", is an insect that causes damage to turfgrass areas and is distributed practically worldwide, with approximately 100 species recognized in the United States alone. Life stages of the Sod Webworm consist of egg, larva, pupa, and adult. Sod Webworms in the adult life stage are often referred to as "snout moths", and are identified by their long labial palpi that extend in front of their heads. Another characteristic of identification comes from the position of the Sod Webworm's wings, which fold underneath its body, making it slender and harder to see while landed on a plant. [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Sod Webworms feed primarily on the family Gramineae. In turfgrass species, Sod Webworms’ primary host plants are cool season grasses. Warm season grasses can also be damaged by Sod Webworms, but there are few recorded cases of this. In addition to turfgrasses, some species are known to feed on corn, wheat, rye, oats, timothy, "Phleum" L., pastures, and meadows, with the most damage occurring in areas with permanent sod. In all cases, damage is more pronounced during times of drought. [Citation | last = Brandenburg | first = Rick L. | last2 = Villani | first2 = Michael G. | title = Handbook of Turfgrass Insect Pests | place = Lanham, New York | publisher = Entomological Society of America | year = 1995 | edition = 5th ]

Life Cycle

Sod Webworms have a bivoltine life cycle with four defined stages that include egg, larva, pupae, and adult. They overwinter as larva in their penultimate or ultimate instar stage in the thatch or soil. With the coming of warmer weather, the larva will pupate, and moths will appear in late spring or early summer. First generation eggs will then be laid in June, with larva appearing in June and lasting until July. When pupation occurs, adult moths will appear starting in July and will last until August. Under favorable conditions, a second generation will occur, with the adult stage laying eggs in early October. [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Egg

Eggs are found dry and nonadhesive, with an oval to elliptical shape. Most species have a white to creamy white color when first laid that later turns to a bright orange or red. Depending on the species, egg size can also vary between 0.598 mm to 0.503 mm (for species with larger eggs) and 0.390 mm to 0.300 mm (for species with smaller eggs). [ Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Larva

Larval color also varies from greenish to beige, brown, or gray, with most having dark circular spots that extend over the entire body. During the first to third instar, the head capsule will appear black, with mature larva appearing light-brown in color with varying shapes of black sculpturing. The size of the head capsule varies between 0.19 and 0.23 mm during the first instar and between 1.23 and 2.21 mm during the ultimate instar. Body length varies from 9 to 13 mm during the first instar and from 24 to 28 mm during the ultimate instar. [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Pupa

The pupa develops in a cocoon that is made from silk attached to soil particles, plant debris and fecal pellets. Often the cocoon will be mistaken for a lump of earth. The pupa itself will have a pale yellow color at first that will darken to a mahogany brown. Size of the pupae can range from 8 – 10 mm long and 2.5 mm wide. [ Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Adult

The moth that forms from Sod Webworms appears whitish or light gray to tan. Many have designs that have colors varying from silver, gold, yellow brown, to black. The size of the moth is approximately 12mm in length, with wingspans of 20 – 25 mm. [ Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

History

A wide scale drought occurred between 1928 – 34 that affected most of the United States. During this time, Sod Webworms became recognized as a serious lawn and golf course pest. In 1931, many states experienced damage of an unprecedented magnitude from this pest. Unlike many of the other more destructive turfgrass pests, the sod webworm is native to the United States and was not introduced [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ] . [Citation | last = Bohart | first = R.M. | title = Sod Webworms and other lawn pests in California | place = Lanham, New York | publisher = Hilgasdia ]

Distribution of Insect

The Sod Webworm, "Crambus" species is located across the United States with more specific species found in local areas. "Crambus praefectellus" is located in states that are east of the Mississippi River. "Crambus caliginosellus" is located in the Northern United States and along the east coast and extends as far south as North Carolina. "Crambus luteolellus" appears in the same region and in the same numbers as "Crambus caliginosellus". [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Damage from Insect

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 the nocturnal nature of the insect. 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 there is no damage done to the crown of the plant. In closely mowed turf and drought conditions, damage is more severe than in poorly maintained turf. In closely mowed 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, and the returns and the yellow and brown patches can be seen. [Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ]

Management of Insect

To be considered a serious infestation of Sod Webworms, 12 larva must be found in a 0.1 m2 [ Citation | last = Vittum | first = Patricia J. | last2 = Villani | first2 = Michael G. | last3 = Tashiro | first 3 = Haruo | title = Turfgrass Insects of the United States and Canada | place = Ithaca, New York | publisher = Cornell UP | year = 1999 | edition = 2nd ] . To test this, place hollow pans with a pyrethrum or detergent drench and let sit for 10 minutes, and then count the larva in the area. 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, the way to go about handling the problem is to attract predators of the Sod Webworms. Predators include birds and insect predators, such as ground beetles, robber flies, and predator wasps. The larva is also prone to infection from microorganisms such as "Beauveria bassiana" (Balsamo) and "Nosema" (microspordia). Parasitic nematodes such as "Steinernema carpocapsae" (Weiser) and "Heterorhabditis heliothidis" (Khan, Brooke, and Hirschmann), can also infect Sod Webworms. [ Citation | last = Brandenburg | first = Rick L. | last2 = Villani | first2 = Michael G. | title = Handbook of Turfgrass Insect Pests | place = Lanham, New York | publisher = Entomological Society of America | year = 1995 | edition = 5th ]

References

External links

* [http://www.ento.psu.edu/extension/factsheets/sodWebwormLawns.html Penn State Sod Webworm fact sheet]
* [http://ohioline.osu.edu/hyg-fact/2000/2011.html Ohio State Sod Webworm fact sheet]