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Sciothrips Cardamomi (Ramakrishna)
Ronald F.L. Mau, Extension Entomologist
Jayma L Martin Kessing, Educational Specialist
Department of Entomology
Updated by: J.M. Diez April 2007
In Hawaii this thrips species has attacked red and pink ginger flowers. Outside of Hawaii this pest attacks cardamom and others in the family Zingiberaceae, edible ginger, and Pancium longipes.
The cardamom thrips is found in Hawaii and India. It was first found in Hawaii on pink flowering ginger in 1986. Cardamom thrips are now found on the islands of Hawaii and Maui but are probably present on all the major islands due to inter island movement of flowering ginger.
Injury is caused by thrips feeding in young leaf sheaths and basal ends of unopened flower bracts. Nymphs and adults feed with their piercing-sucking mouth parts, which lacerate young tissues and suck the juices that ooze from ruptured cells. First the injured area develops a silvery sheen because of air occupying the emptied cell cavities. Due to oxidation, this area becomes a mixture of white, yellow, and brown splotches and streaks.
Because of the secretive nature of feeding only within the sheaths and unopened bracts, its early presence usually goes undetected, until one actually looks down into the opened inflorescence and sees the feeding damage at the bottom of the flower bracts.
This thrips is suspected to be a vector of a mosaic disease that effect cardamom in India.
The life cycle (egg to adult) is 25 to 30 days. Reproduction is mostly sexual, though virgin females are able to lay viable eggs during the summer.
The white kidney shaped eggs are inserted in leaf sheaths or flower bracts by the sharp ovipositor of the adult. Eggs hatch in about a week.
The transparent larvae are approximately 1/25 inch in length. The larval stage consists of three larval stages separated by molts in the course of 15 to 21 days.
Pupae resemble the larvae except for the presence of wing pads (incompletely developed wings). There are 2 pupal stages, the prepupa and pupa, neither of which are feeding stages. Pupae become adults in 10 to 15 days.
The head and abdomen of this thrips are dark gray brown and the thorax and legs are pale yellowish brown. Females measure approximately 1/4 inch in length; males are slightly smaller. Refer to Ramakrishna (1935) for a comprehensive description of type species.
The cardamom thrips is difficult to find, since feeding is confined to young tissues in dark, confined areas such as the sheaths of young leaves, the base of unopened flower bracts, and possibly the spindle of top shoots.
The nymphal stages are sluggish in movement. Adults are also sluggish and rarely take to flight.
There are no reported natural enemies of this pest.
General cultural practices involving sanitation, such as the removal of alternative hosts and plant debris within and outside the field.
On cardamom, the removal of dried shoot peels at the base of the stem resulted in a reduction of thrips populations by one-third.
Chemical control is difficult because the thrips remain hidden under the cover of leaf sheaths and bracts.
Insecticide trials for the cardamom thrips performed in India on cardamom demonstrated that synthetic pyrethroids gave adequate control. Of the different synthetic pyrethroids, Permethrin was the most effective.
Anathakrishnan, T. N. 1971. Thrips (Thysanoptera) in Agriculture, Horticulture and Forestry - Diagnosis, Bionomics and Control. J. Scien. Ind. Res. 30(3): 113-146.
Chakravarthy, A. K. and M. M. Khan. 1987. Innovative Tools for Protecting Cardamom (Elettaria cardamomum Maton) from Herbivores: Plea for Crop Management. Quarterly Newsletter of the Plant Protection Commission. 30(3/4): 12-17.
Hansen, J. D., A. H. Hara, H T. Chan, V. L. Tenbrink. 1991. Efficacy of Hydrogen cyanide Fumigation as a Treatment for Pests of Hawaiian Cut Flowers and Foliage After Harvest. J. Econ. Ent. 84(2): 532-536.
Joseph, D. 1983. Effect of Two Synthetic Pyrethroid Insecticides on the Control of Cardamom Thrips (Sciothrips cardamomi Ramk.) Infesting Cardamom (Elettaria Cardamomum). Agric. Res. J. Kerala. 21(2): 77-78.
Nambiar, M. C., G. B. Pillai, and K. K. N. Nambiar. 1975. Diseases and Pests of Cardamom - A Resume of Research in India. Pesticides Annual. 122-127.
Rajan, S. V. 1965. Protect Your Cardamom Against Insect Pests. Indian Farming. 14(11): 21-24.
Ramakrishna, T. V. 1935. A New Species of Thysanoptera from S. India (Taeniothrips cardamomi, sp. Nov.). Bull. Ent. Res. 26(3): 357-358.
Ramakrishna, T.V. and M.S. Kylasam. 1935. A New Disease of Cardamom (Elatteria cardamomi) Apparently Due to Insect Damage in South India. Bull. Ent. Res. 26(3): 359-361.
Tsuda, D. M. and A. H. Hara. 1990. HITAHR Brief No. 083. Cardamom Thrips on Flowering Ginger. Hawaii Institute of Tropical Agriculture and Human Resources, College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa.