''Trichobaris trinotata'', commonly known as the potato stalk borer, is a species of weevil in the family

Curculionidae The Curculionidae are a family of weevils, commonly called snout beetles or true weevils. They are one of the largest animal families with 6,800 genera and 83,000 species described worldwide. They are the sister group to the family Brentidae. Th ...

. It is found in North America where it is a pest of

potato The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade famil ...

plants, the larvae tunnelling inside their stems.

Description

The adult weevil is a small species with a length of about and a width of about . The

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit ** podium * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ...

or beak bends sharply downwards at the base. The insect is inconspicuous; it is black in color but appears gray as most of the surface is covered by minute gray scales; scales are absent from the head and from three spots at the base of the

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

, one at the front and one on either side, and these appear dark. These three bare spots give the insect its scientific name of "trinotata".

Ecology

This weevil feeds on plants in the family

Solanaceae Solanaceae (), commonly known as the nightshades, is a family of flowering plants in the order Solanales. It contains approximately 2,700 species, several of which are used as agricultural crops, medicinal plants, and ornamental plants. Many me ...

. The potato is its most economically-important food plant, but it sometimes feeds on the

eggplant Eggplant (American English, US, Canadian English, CA, Australian English, AU, Philippine English, PH), aubergine (British English, UK, Hiberno English, IE, New Zealand English, NZ), brinjal (Indian English, IN, Singapore English, SG, Malays ...

(''Solanum melongena''), the

Carolina horsenettle ''Solanum carolinense'', the Carolina horsenettle, is not a Urtica, true nettle, but a member of the Solanaceae, or nightshade family. It is a Perennial plant, perennial herbaceous plant, native to the southeastern United States, though its rang ...

(''Solanum carolinense''), the buffalo bur (''Solanum rostratum''), the

European black nightshade ''Solanum nigrum'', the European black nightshade or simply black nightshade or blackberry nightshade, is a species of flowering plant in the family Solanaceae, native to Eurasia and introduced in the Americas, Australasia, and South Africa. Rip ...

(''Solanum nigrum'') and several species of groundcherry (''Physalis''). Adults emerge from reproductive

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

in spring and the females start to lay their eggs in May. These are deposited singly in holes made in stems and leaf stalks by the insect's rostrum, or in the axils of terminal leaves. The eggs hatch in about a week and the white, legless larvae eat their way through the stem tissues, creating tunnels up to in length. Having passed through five or six

instar An instar (, from the Latin '' īnstar'' 'form, likeness') is a developmental stage of arthropods, such as insects, which occurs between each moult (''ecdysis'') until sexual maturity is reached. Arthropods must shed the exoskeleton in order to ...

s over a period of up to 106 days, the larvae pupate in the stem, with the adults emerging about twelve days later. There is a single generation each year and the adults overwinter inside the dead potato haulms or the stems of other members of the Solanaceae such as ''Solanum carolinense''. Few enemies of this weevil have been identified, but it is sometimes parasitised by the

braconid wasp The Braconidae are a family of parasitoid wasps. After the closely related Ichneumonidae, braconids make up the second-largest family in the order Hymenoptera, with about 17,000 recognized species and many thousands more undescribed. One analysis ...

, ''

Nealiolus curculionis ''Nealiolus curculionis'' is a species of parasitic wasp in the family Braconidae. It is a parasitoid of the sunflower stem weevil '' Cylindrocopturus adspersus'', and a number of other species of stem-boring weevils. Description ''Nealiolus cur ...

'' and less frequently by the eurytomid wasp, '' Eurytoma tylodermatis''.

Damage

The adults feed on leaves producing ragged holes, but it is the larvae that cause most damage to the potato crop with their tunnelling activities. At one time this weevil was considered a serious pest of potatoes, however modern management practices have reduced its impact. The burning or removal of crop residues destroys the overwintering adults.

References

* Poole, Robert W., and Patricia Gentili, eds. (1996). "Coleoptera". ''Nomina Insecta Nearctica: A Check List of the Insects of North America, vol. 1: Coleoptera, Strepsiptera'', 41-820.

External links

NCBI Taxonomy Browser, ''Trichobaris trinotata''
{{Taxonbar, from=Q48972322 Baridinae Agricultural pest insects Beetles described in 1831 Beetles of North America Taxa named by Thomas Say

Description

Ecology

Damage

References

Further reading

External links