Classification

Pyraloidea: Crambidae: Crambinae: Diatraea lineolata (Walker)

Common name

Neotropical cornstalk borer

Synonyms

Chilo culmicolellus, Chilo neuricellus, Diatraea pallidostricta

Larval diagnosis (Detailed)

The larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
of D. lineolata, the Neotropical cornstalk borer, was described in detail by Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp.; this setal mapsetal map:
a flat, diagrammatic drawing of the arrangement of the setae on one side of a larva
later redrawn by Coto (1997)Coto (1997):
Coto, D. 1997. Lepidoptera en cultivos anuales y perennes: manual de reconocimiento. Manual tecnico numero 26. Centro Agronomico Tropical de Investigacion y Ensenanza, Costa Rica. 63 pp.. Color photographs of the late instar larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
can be found in King and Saunders (1984)King and Saunders (1984):
King, A. B. S. and J. L. Saunders. 1984. The invertebrate pests of annual food crops in Central America. Overseas Development Administration. 166 pp., Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp., Ortega (1987)Ortega (1987):
Ortega, C. A. 1987. Insect pests of maize. A guide for field identification. Centro Internacional de Mejoramiento de Maiz y Trigo. Mexico. 106 pp., and Rodriguez del Bosque (2009)Rodriguez del Bosque (2009):
Rodriguez del Bosque, L. A. 2009. Los barrenadores del tallo de la cana de azucar en Mexico. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias. Unpublished presentation. 65 pp..

Typically, the two most common corn feeding Diatraea (saccharalis and lineolata) have a small inner tooth (notch) on the mandible (Passoa 1985: fig. 331, Parada et al. 2007Parada et al. 2007:
Parada, S., E. Ebratt and M. A. Benavides. 2007. Diferenciacion de especies Diatraea spp. que afectan los cultivo de cana en la region del Gualiva. Revista Inventum 3: 69-78.); both the L and SV setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
anterior to the prothoracic spiracle; a prespiracular group that extends below the prothoracic spiracle but not behind it; a bisetosebisetose:
two setae
SV group on the thoracic segments; crochetscrochets:
sclerotized, hooklike structures, usually arranged in rows or circles on the prolegs of Lepidoptera larvae
of A3-6 in a triordinaltriordinal:
crochets arranged so the tips are of three alternating lengths
circle, and in the non-diapausing form, an obvious elongate extra pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
lacking setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
on the mesothoraxmesothorax:
the second thoracic segment
(Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp.).

Deckle (1976) used the paraproct setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
to separate D. grandiosella from D. saccharalis and D. crambidoides. Largely because D. lineolata and D. grandiosella have nearly identical larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
(Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp., Riley and Solis 2005Riley and Solis 2005:
Riley, D. R. and M. A. Solis. 2005. Keys to immatures of the sugarcane borer and Neotropical cornstalk borer from Mexico intercepted on corn in southeastern Texas. Southwestern Entomologist 30: 35-39.), Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp. applied the same character set to separate D. lineolata from D. saccharalis in Honduras. The paraproct setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
are never more than half as long as SV1 in D. lineolata whereas in D. saccharalis these two setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
are approximately equal in length. Riley and Solis (2005)Riley and Solis (2005):
Riley, D. R. and M. A. Solis. 2005. Keys to immatures of the sugarcane borer and Neotropical cornstalk borer from Mexico intercepted on corn in southeastern Texas. Southwestern Entomologist 30: 35-39. confirmed the utility of the paraproct setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
by using them to separate D. lineolata and D. saccharalis specimens intercepted from Mexico. They did not mention the SV1 setaseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
by name, instead calling it the "next lateral setaseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
". Deckle (1976), Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp., Riley and Solis (2005)Riley and Solis (2005):
Riley, D. R. and M. A. Solis. 2005. Keys to immatures of the sugarcane borer and Neotropical cornstalk borer from Mexico intercepted on corn in southeastern Texas. Southwestern Entomologist 30: 35-39. and Parada et al. (2007)Parada et al. (2007):
Parada, S., E. Ebratt and M. A. Benavides. 2007. Diferenciacion de especies Diatraea spp. que afectan los cultivo de cana en la region del Gualiva. Revista Inventum 3: 69-78. all illustrated the paraproct and SV setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
of Diatraea.

Weisman (1974)Weisman (1974):
Weisman, D. M. 1974. Some lepidopterous larvae of plant quarantine significance. U. S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine unpublished training aid. 22 pp. noted the bisetosebisetose:
two setae
thoracic SV group in Diatraea and mentioned the shape of the SD1 pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
and position of SD2 on A3-6 as useful characters. He did not study D. lineolata. On A3-6, the SD1 pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
extends to the middle of the spiracle and SD2 is below the spiracle in D. lineolata (Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp.). This is similar to D. grandiosella (Weisman 1974Weisman 1974:
Weisman, D. M. 1974. Some lepidopterous larvae of plant quarantine significance. U. S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine unpublished training aid. 22 pp.).

Based on Peterson (1962: L44), Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp. suggested that the substemmatal setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
often separate D. lineolata and D. grandiosella. The SS2 setaseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
usually lies closer to stemmastemma:
a simple eye of holometabolous larvae
6 than stemmastemma:
a simple eye of holometabolous larvae
5 in D. grandiosella (Peterson, 1962Peterson, 1962:
Peterson, A. 1962. Larvae of insects: an introduction to Nearctic species. Part I: Lepidoptera and plant infesting Hymenoptera. Columbus, Ohio. 315 pp.). The opposite is often true for D. lineolata. Unfortunately, this setaseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
is midway between the two stemmatastemma:
a simple eye of holometabolous larvae
on many larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
. There are also minor differences in the pattern of spines below the anus (Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp.). The spines of D. grandiosella appear slightly thicker and usually cover a wider area than in D. lineolata. In both species the spines can be quite faint. Combining these two features with host and orgin can be helpful.

Identification of D. lineolata is complicated by larval color variation. Early instars do not resemble the mature larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
. In addition, non-diapausing larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
have pigmented pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
that are pale in diapausing individuals. These are often called summer and winter forms, respectively, in the United States literature (e.g. Peterson 1962Peterson 1962:
Peterson, A. 1962. Larvae of insects: an introduction to Nearctic species. Part I: Lepidoptera and plant infesting Hymenoptera. Columbus, Ohio. 315 pp., Weisman 1986Weisman 1986:
Weisman, D. M. 1986. Keys for the identification of some frequently intercepted lepidopterous larvae. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine series 81-47. 64 pp.). Nevertheless, color of living larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
can be an important clue for identification (see Hensley 1960Hensley 1960:
Hensley, S. D. 1960. A comparative study of the immature stages of three species of the Diatraea complex. Oklahoma State University Ph.D thesis. Stillwater, Oklahoma. 82 pp., Peairs and Saunders 1980Peairs and Saunders 1980:
Peairs, F. B. and J. L. Saunders. 1980. Diatraea lineolata y Diatraea saccharalis: una revision en relacion con el maiz. Agronomia Costarricense 4: 123-135., Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp.). Early instar D. lineolata have the prothoracic shieldprothoracic shield:
the dorsal shieldlike covering of the first thoracic segment
dark brown whereas in D. grandiosella the shieldshield:
a sclerotized plate covering part of the dorsum of a segment
is honey-colored.

Late instars of Diatraea lineolata have a light reddish to golden brown head color with black pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
on a cream to white body color. This is similar to D. grandiosella but different from D. saccharalis. The head of D. saccharalis is a dark red brown, the pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
are light brown and the body is off white with a light yellow to brown tint. Ortega (1987)Ortega (1987):
Ortega, C. A. 1987. Insect pests of maize. A guide for field identification. Centro Internacional de Mejoramiento de Maiz y Trigo. Mexico. 106 pp. and Rodríguez del Bosque (2009) are readily available on line examples of these differences. The comparison of D. lineolata to D. saccharalis in Rodriguez del Bosque (2009, 2012) shows typical forms, however, the specimen of D. saccharalis next to D. grandiosella requires confirmation because of the pink longitudinal stripes. Hensley (1960)Hensley (1960):
Hensley, S. D. 1960. A comparative study of the immature stages of three species of the Diatraea complex. Oklahoma State University Ph.D thesis. Stillwater, Oklahoma. 82 pp. and Neunzig (1987)Neunzig (1987):
Neunzig, H. H. 1987. Pyralidae (Pyraloidea), pp. 464-494. In F.W. Stehr (ed.). Immature Insects. Kendall Hunt Publishing Company. Dubuque, Iowa. said that living larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
of D. saccharalis have a pale area around the body pinaculapinaculum:
a small, flat, or slightly elevated chitinized area bearing a seta or setae
, a useful character if present. Weisman (1986)Weisman (1986):
Weisman, D. M. 1986. Keys for the identification of some frequently intercepted lepidopterous larvae. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine series 81-47. 64 pp. and Solis (2011)Solis (2011):
Solis, M. A. 2011. Key to selected Pyraloidea (Lepidoptera) larvae intercepted at U. S. ports of entry: revision of Pyraloidea in "Keys to some frequently intercepted lepidopterous larvae" by Weisman 1986 (updated 2006). added that Diatraea lacks a middorsal pink stripe, indeed no common pest species of Diatraea has a middorsal stripe. The diapusing forms of D. lineolata and D. saccharalis are both pale cream but differ in head color.

Identification Authority (Detailed)

There are really only a few situations where identification of D. lineolata is justified; otherwise it is more accurate to stop at the genus level. Origin and host information are critical for accurate identification of Diatraea. Inspectors must get specific origins from Mexico, photograph the larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
or remember details of the head and body color before preservation. Ports must be prepared to send occasional specimens to quarantine facilities for rearing to the adult stage to be sure assumptions on the intercepted fauna have not changed. This is especially important because several species of Diatraea have unknown life histories. The literature often cannot be trusted; see comments by Agnew et al. (1988)Agnew et al. (1988):
Agnew C. W., L. A. Rodriguez del Bosque and J. W. Smith. 1988. Misidentifications of Mexican stalkborers in the subfamily Crambidae (Lepidoptera: Pyralidae). Folia Entomologica Mexicana 75: 63-75. for Mexico and Passoa (1985)Passoa (1985):
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp. for Central America. Even observations on larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
from experts like Box require caution (Solis pers. comm.).

Corn is the principal host of D. lineolata, but records also exist for Coix lachrymajobi, teosinte (Euchlaena mexicana), sorghum and Johnson grass, rice, Tripsacum, wheat, and rarely sugarcane (Peairs and Saunders, 1980Peairs and Saunders, 1980:
Peairs, F. B. and J. L. Saunders. 1980. Diatraea lineolata y Diatraea saccharalis: una revision en relacion con el maiz. Agronomia Costarricense 4: 123-135., Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp., Rodriguez del Bosque et al. 1988Rodriguez del Bosque et al. 1988:
Rodriguez del Bosque, L. A., J. W. Smith Jr. and H. W. Browning. 1988. Bibliography of the Neotropical cornstalk borer, Diatraea lineolata (Lepidoptera: Pyralidae). Florida Entomologist 71: 176-186.). Because of numerous sibling species with unknown immatures, it is very difficult to go past genus on Diatraea immatures except for those on crop plants. The original native host of D. lineolata is unknown, and no doubt there are new foodplants to discover, but for the present it is best to restrict authority for D. lineolata to just corn.

There are two issues with regard to origin. Diatraea lineolata occurs from south Texas to Mexico, Central America and northern South America (Solis 2004Solis 2004:
Solis, M. A. 2004. Systematics of Mexican stalkboring Crambine Pyraloidea. In: L. A. Rodriguez del Bosque, G. V. Cota and E. Cortez Mondaca (eds.). Taller Internacional sobre Barrenadores del Tallo de Cana de Azucar. Sinaloa, Mexico. Sociedad Mexicana de Control Biologico. 1004 pp.) including parts of the Caribbean (Rodriguez del Bosque et al. 1988Rodriguez del Bosque et al. 1988:
Rodriguez del Bosque, L. A., J. W. Smith Jr. and H. W. Browning. 1988. Bibliography of the Neotropical cornstalk borer, Diatraea lineolata (Lepidoptera: Pyralidae). Florida Entomologist 71: 176-186.). Thus, interceptions from central and southern South America cannot be D. lineolata even if on corn.

A bigger problem is that are five species of Diatraea recorded from corn in Mexico (Riley and Solis 2005Riley and Solis 2005:
Riley, D. R. and M. A. Solis. 2005. Keys to immatures of the sugarcane borer and Neotropical cornstalk borer from Mexico intercepted on corn in southeastern Texas. Southwestern Entomologist 30: 35-39.). They are D. grandiosella (parts of northern, western and southern Mexico), D. postlineella (only from Veracruz), and D. muellerella (from Morelos and Guerrero). Diatraea lineolata and D. saccharalis are generally considered the most widespread members of the genus (e.g. van Huis 1981:18) and can be expected throughout Mexico. Given the known distributions from Riley and Solis (2005)Riley and Solis (2005):
Riley, D. R. and M. A. Solis. 2005. Keys to immatures of the sugarcane borer and Neotropical cornstalk borer from Mexico intercepted on corn in southeastern Texas. Southwestern Entomologist 30: 35-39. and Rodriguez del Bosque (2009, 2012) (pending further collecting), the following guidelines are offered. With the exception of Chihuahua (where D. grandiosella occurs), D. lineolata and D. saccharalis can be identified from Sonora, Coahuila, Nuevo Leon and Tamaulipas. Identifications from the latter two eastern states are the most accurate because they are farther from the overlap zone with D. grandiosella. Anything south of the Border States but north of Veracruz or Oaxaca is probably best left at genus unless the origin is very well documented and sibling species can be eliminated as possibilities. There should be no sibling species of D. lineolata south of Veracruz, so if the host is corn, a species identification can be made from extreme southern Mexico.

Sporadic studies throughout Central America make identification of D. lineolata from corn possible in a few areas because adults were reared and genitalia examined. Surprisingly, neither Passoa (1983, 1985) working in corn fields or Miller's et al. (2012) list from light trapping and review of collections were able to find any species of Diatraea in Honduras except for D. lineolata and D. saccharalis. The situation is similar in Nicaragua. Van Huis (1981)Van Huis (1981):
Van Huis, A. 1981. Integrated pest management in the small farmer's maize crop in Nicaragua. Mededelingen Landbouwhogeschool Wageningen 81: 1-221. found that D. lineolata, and more rarely D. saccharalis, were the only species in corn. A current checklist from Nicaragua (Maes 1999) did not add any corn feeding Diatraea. Thus, identification of D. lineolata from Honduras and Nicaragua seems safe. King's survey of Central America (King and Saunders 1984King and Saunders 1984:
King, A. B. S. and J. L. Saunders. 1984. The invertebrate pests of annual food crops in Central America. Overseas Development Administration. 166 pp.) implies that Costa Rica might also be added to the list as there are active surveys in that country. There are too many sibling species of Diatraea in other parts of Latin America to expand the authority. The situation is the Caribbean needs to be evaluated on a country by country basis.

Weisman (1986)Weisman (1986):
Weisman, D. M. 1986. Keys for the identification of some frequently intercepted lepidopterous larvae. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine series 81-47. 64 pp. separated Chilo and Diatraea by the presence or absence of a middorsal stripe. This character can fade in preserved larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
. In addition, some Chilo are spotted and lack stripes like Diatraea (for example C. partellus, see Hutchison et al. 2008Hutchison et al. 2008:
Hutchison, W. D., R. C. Venette, D. Bergvinson and J. van den Berg. 2008. Pest Name: Chilo partellus (Swinhoe) (Lepidoptera: Crambidae). Pest Profile HC001V05. Centro Internacional de Mejoramiento de Maiz y Trigo. Harvest Choice Workshop (June, 2007). 5 pp.). Identifiers might encounter examples of the less common corn borers on occasion, especially in stems or roots. Some of them are striped (Xubida, Eoreuma) (Passoa 1985Passoa 1985:
Passoa, S. 1985. Taxonomy of the larvae and pupae of economically important Pyralidae in Honduras. Master's Thesis. University of Florida. Gainesville. 486 pp., Agnew et al. 1988Agnew et al. 1988:
Agnew C. W., L. A. Rodriguez del Bosque and J. W. Smith. 1988. Misidentifications of Mexican stalkborers in the subfamily Crambidae (Lepidoptera: Pyralidae). Folia Entomologica Mexicana 75: 63-75.).

Morphological guide to known species of Diatraea intercepted at U.S. ports of entry from Mexico

Guide to species of Diatraea intercepted or potentially encountered at U.S. ports of entry using morphology and origin

Origin records

Diatraea lineolata has been intercepted from the following locations:

Mexico

Host records

Diatraea lineolata has been intercepted on the following hosts:

Zea mays

Several other hosts are listed in PestID; however these records must be verified.