Pezothrips kellyanus a new citrus thrips: addition to the EPPO Alert List
During bibliographic search, the EPPO Secretariat noticed several publications about the presence of a new pest, Pezothrips kellyanus (Thysanoptera: Thripidae), in Sicilian citrus orchards. As significant fruit damage (scarring) was reported, the EPPO Secretariat felt that it was useful to add this species to the EPPO Alert List.
Pezothrips kellyanus (Thysanoptera: Thripidae - Kelly’s citrus thrips)
Why: The EPPO Secretariat noticed several publications mentioning the presence of a new thrips species, Pezothrips kellyanus, causing problems in citrus orchards in Sicilia (IT). Although it is not entirely clear whether this species originates or not from the Mediterranean region, it is indeed an emerging problem, and the EPPO Secretariat felt that it was useful to draw citrus-growing countries attention to this ‘new’ thrips.
Where:
EPPO region: Italy (Southern Italy, first reported in 1998 in Sicilia), Greece (first reported in 1987, Peloponese), Spain (Cataluña), Turkey (Province of Izmir).
Oceania: Australia (widespread), New Caledonia, New Zealand (first recorded in 1950). P. kellyanus was first observed in Australia and as a consequence it was thought to originate from this part of the world. But P. kellyanus has recently been re-designated from Megalurothrips which is a tropical genus mainly from South East Asia, to Pezothrips which so far included only Mediterranean and Southern European species. It was then hypothetized that P. kellyanus did not originate from Australia but most probably from the Mediterranean area.
On which plants: Citrus (all citrus can be attacked but lemons (C. limon) and Navel oranges (C. sinensis) are particularly susceptible). P. kellyanus has also been found in flowers of many other plant species, but further studies would be needed to know whether these are incidental or breeding hosts (e.g. Acmena, Brassica, Camellia, Chrysanthemum, Helianthus, Lonicera, Lycopersicon esculentum, Mangifera indica, Medicago sativa, Passiflora, Prunus, Rosa, Sparmannia africana, Zantedeschia, and weeds such as Ranunculus repens and Rumex crispus).
Damage: Adults are black and 2-3 mm long. Life cycle consists of eggs, 2 larval stages, pre-pupa, pupa and adult.
Pictures can be viewed on Internet:
http://www.agric.new.gov.au/reader/cit-thrips.htm
http://www.ento.sciro.au/aicn/name_s/b_2769.htm
P. kellyanus feeds on young tissues (flowers and fruits), particularly near the calyx, producing a circular stem-end scar. Damage is often restricted to a thin ring but heavy infestations can led to complete scarring of the fruit. Damage to mature fruit is less common but usually more severe, initially showing a silvering which leads to thin scarring over most of the fruit surface. Heavy scarring can render fruits unmarketable. It was observed that fruits were most susceptible to thrips infestations in the period shortly after petal-fall. In Sicilia, P. kellyanus is considered as a key pest in citrus orchards and during recent surveys it was found to be the predominant species (it was found in mixed populations with Thrips tabaci and T. flavus, which appeared to be secondary pests). In New Zealand, it is considered as the most serious pest affecting citrus production.
Dissemination: Adults can fly and are probably carried by winds (but no data is available on how they can disseminate within an orchard). Over long distances trade of infested plants can ensure pest dissemination.
Pathway: Plants for planting of citrus (other hosts?), cut branches of citrus, citrus fruits (?)
Possible risks: Citrus is a major crop in several EPPO countries around the Mediterranean basin. Although data is lacking on its economic impact, P. kellyanus is reported as a pest which can seriously reduce fruit quality. Control measures are available (several chemicals can be used, predatory mites such as Iphiseius (Amblyseius) degenerans were found in infested orchards but their efficacy is not known yet) and research is being carried out on adequate IPM strategies. As for many other thrips species, detection, identification and control are likely to be difficult in practice. More surveys would seem desirable to better know the geographical distribution of P. kellyanus within the EPPO region.
EPPO RS 2004/137
Panel review date - Entry date 2004-09
Sources
Conti; F.; Tumminelli, R.; Fisicaro, R.; Perrotta, G.; Marullo, R.; Liotta, G. (2003) An IPM system for new citrus thrips in Italy. OIBC wprs Bulletin, 26(6), 203-208.
Conti; F.; Tumminelli, R.; Amico, C.; Fisicaro, R.; Frittitta, C.; Perrotta, G.; Marullo, R.; (2001) Monitoring Pezothrips kellyanus on citrus in eastern Sicily. Proceedings of the 7th International Symposium on Thysanoptera (2001-07-02/07, Reggio Calabria, IT), 207-210. Also available on Internet: http://www.ento.csiro.au/thysanoptera/Symposium/Section7/31-Conti-et-al.pdf
Froud, K.J.. Stevens, P.S.; Steven, D. (2001) Survey of alternative host plants for Kelly’s citrus thrips (Pezothrips kellyanus) in citrus growing regions. New Zealand Plant Protection, 54, 15-20. Also available on Internet http://www.hortnet.co.nz/publications/nzpps
Marullo, R. (1998) Pezothrips kellyanus, un nuovo tripide parassita delle colture meridionali. Informatore Fitopatologico, 48(10), 72-74.
INTERNET
NSW Department of Primary Industries – Agriculture - Pezothrips (New South Wales, Australia). http://www.agric.new.gov.au/reader/cit-thrips.htm
CSIRO and Department of Agriculture, Fisheries and Forestry. Australia. Pezothrips kellyanus. http://www.ento.sciro.au/aicn/name_s/b_2769.htm