Tecia solanivora: addition to the EPPO Alert List
Tecia (Scrobipalpopsis) solanivora (Lepidoptera, Gelechiidae) is a serious pest of potato in Central and South America. T. solanivora larvae feed exclusively on potato tubers in the field and more particularly during storage. It is considered as a native species from Guatemala (reported there in 1956). It was later reported in Costa Rica (1971) and Panama (1973). Its introduction via infected potatoes into new areas was then reported in the following countries: in Venezuela, in 1983 (potatoes imported from Costa Rica); in Colombia, in 1985 (potatoes imported from Venezuela); and in Ecuador, in 1997 (potatoes imported from Colombia). In countries where T. solanivora has been introduced, it has rapidly spread to most potato-growing regions, essentially via infested seed potato tubers. Apparently, T. solanivora is still absent from Peru, it is considered there as a quarantine pest and a large-scale programme of survey has been initiated.
Little information is available on the biology of the pest. Eggs are mostly laid on the soil surface (a few on potato leaves and stems) or directly on tubers in storage. They can also be found on potato bags. First instar larvae then migrate towards potato tubers and enter them, making very small, almost invisible, entry holes. Larvae tunnel into the tubers making galleries which enlarged with the insect development and which are filled with excrement. Attacked tubers are more susceptible to secondary rots. Last instar larvae (4th instar) leave the tuber before pupation, making neat and circular exit holes. Prepupae and pupae are usually formed in the soil (although a few can be found inside tubers). In storage, they can also be seen attached to potato bags. Adults are small, brownish-grey moths. They are active at night (dusk and first night hours). They can fly over short distances from field to field. Females can lay 150 to 360 eggs. In the laboratory, the life cycle was completed in 94 days at 15.5 °C. It was estimated that T. solanivora could complete 2 generations per year at 10°C and 10 at 25°C. Optimum temperature for oviposition is 15°C. Development threshold is 9°C for larvae and 7°C for pupae.
In these equatorial and tropical regions, potato is cultivated at high altitude. In Costa Rica, potato crops which are attacked by T. solanivora are located between 1300 and 2300 m. In Colombia, T. solanivora is considered as the most damaging potato pest. In cases of heavy infestation, up to 100 % losses have been observed in the fields and stores. Tuber damage was so severe that potatoes could no longer be used for human or animal consumption. However, when fields are moderately infested, no symptoms are visible on the crop until the tubers are harvested. T. solanivora attacks potatoes in storage and several generations can develop, as conditions are favourable. For example, in 1996 in Colombia, it was estimated that the percentage of attacked potatoes varied from 0 to 43% in the field and from 0 to 37.5% in stores. It was also estimated that the introduction of this pest, which is now present in all Colombian potato-growing regions (i.e. 100.000 ha), has caused 75 million USD losses. In Ecuador, potatoes are produced between 2000 and 3000 m altitude. In 3 years time, it is reported that T. solanivora has spread to all potato-growing areas.
Control against T. solanivora is difficult because of several factors: adults are active at night, larvae are hidden in the tubers and no symptoms are visible on the crop until the harvest, it has been introduced into new countries without its natural enemies, it is disseminated by infested seed potatoes and potato bags, storage conditions are highly favourable to its development. Integrated pest management strategies are being developed based on: selection of healthy seed potatoes, treatment of seed potatoes (chemical, use of baculovirus), use of pheromone traps in the field and in storage for detection and monitoring of population levels, good storage practice (selection of tubers, tuber treatments with chemicals or baculovirus, disinfection of stores, permanent light in stores, avoidance of used potato bags). The EPPO Panel on European Phytosanitary Measures for Potato has prepared a Pest Risk Analysis on T. solanivora and the EPPO Secretariat has considered that this pest could usefully be added to the EPPO Alert List.
Tecia (Scrobipalpopsis) solanivora (Lepidoptera, Gelechiidae)
Why: The EPPO Panel on European Phytosanitary Measures for Potato has prepared a Pest Risk Analysis on Tecia solanivora. Considering the damage which is reported, in particular from countries where this pest has been introduced, the EPPO Secretariat felt that it should be added to the EPPO Alert List.
Where:
Central America: Costa Rica, Guatemala, Panama.
South America: Colombia, Ecuador, Venezuela.
On which plants: Solanum tuberosum.
Damage: Larvae feed exclusively on potato tubers, in the field and in storage. They make galleries within the tubers, which are filled with excrement. This also favours secondary rot. Quality of the tubers is much reduced and heavily infested tubers can no longer be used for human or animal consumption. Pictures of T. solanivora can be viewed on Internet (http://www.iicasaninet.net/pub/sanveg/html/tecia.html).
Pathway: Potato plants, seed and ware potatoes, potato bags (which can carry eggs and pupae), infested soil (which can carry eggs).
Possible risks: Potato is a very important crop in the EPPO region. T. solanivora causes problems on potato crops and stocks in countries where it is present (at least in Colombia and Ecuador), and it has apparently been introduced through international movement of seed potatoes. However, movement of potatoes from Central and South America to Europe is prohibited. Little data is available on the biology of the pest and its potential for establishment in the EPPO region if introduced. From past experience with Phthorimaea operculella (another potato tuber moth), it can be considered that the southern part of Europe may be more at risk.
EPPO RS 2001/037
Panel review date 2001- Entry date 2001-03
Sources
Notz, A. (1996) Influence of temperature on the biology of Tecia solanivora (Polvony) (Lepidoptera: Gelechiideae) on potato Solanum tuberosum L. tubers. Boletin de Entomologia Venezolana, 11(1), 49-54.
Povolny; D. (1973) Scrobipalpopsis solanivora sp. n. – a new pest of potato (Solanum tuberosum) from Central America. Acta Universitatis Agriculturae, Facultas Agronomica, 21(1), 133-146.
Torres, W.F.; Notz, A.; Valencia, L.; (1997) Life cycle and other aspects of the biology of Tecia solanivora (Polvony) (Lepidoptera: Gelechiideae) in Tachira state, Venezuela. Boletin de Entomologia Venezolana, 12(1), 95-106.
INTERNET
International Potato Center (CIP) CIP Annual Report 98. In Brief. Tecia solanivora: Threat to Andean potatoes. http://.www.cipotato.org/market/ARs/ar98/InBrief.htm
IRD (Institut de Recherches pour le Dévelopment). La teigne du Guatemala ravage la pomme de terre en Equateur. Septembre 2000. http://www.ird.fr/fr/inst/actualites/fiches/2000/fact_120.shtml
RedePapa
Boletín de la Papa. Vol. 1, No.4. Noviembre 30, 1999. Entrevista : la polilla guatemalteca by G. D. Sanchez L. http://redepapa.org/boletincuatro.html
La polilla guatemalteca de la papa. Biología, comportamiento y prácticas de manejo integrado (08/97) by F. Herrera Jacquelin http://redepapa.org/boletincuatro.html
SANINET
Ecuador. Confirma presencia de la polilla guatemalteca en la provincia del Carchi. 1997. http:// www.iicasaninet.net/noticias/anteriores/1997/ago15v.htm
Emergencia por la polilla: Ecuador vende papas a Colombia. 1998-07-07 http://www.iicasaninet.net/noticias/anteriores/1998/mar15v.htm
La polilla de la papa llega a Imbabura, Ecuador. 1998-08-22. http://www.iicasaninet.net/noticias/anteriores/1998/ago31v.htm
Ecuador. El control de la polilla de la papa es efectivo. 1998-10-24. http://www.iicasaninet.net/noticias/anteriores/1998/oct31v.htm