Heliothrips haemorrhoidalis (Bouché)
Common name: Greenhouse thrips.
Geographical distribution: Almost world-wide; occurs outdoors in tropical and subtropical regions, in greenhouses in cooler areas.
Morphology: The larvae are initially pale-white, becoming yellowish after feeding, length up to about 1 mm. The adults are dark brown to black, body about 1.5 mm long.
Host plants: Polyphagous, attacking many ornamental plants in greenhouses and several tropical fruit trees.
Economic importance: The thrips feeds primarily on the foliage of ornamentals. The leaves become discolored, covered with black fecal material and may drop. On developing citrus fruit the pest causes ring spotting, blemishes or irregular russeting. It is a pest of several tropical fruit trees, such as avocado, mango and others.
Life cycle: The greenhouse thrips is parthenogenetic, and may live for several weeks. The eggs (about 25-50/female) are inserted into the leaf or fruit surfaces. The threshold of development is around 11oC and the pest requires about 500 day degrees for the development of a generation, raising 4-7 annual generations. It is a poor flier and usually remains in the shade.
Monitoring: The presence of black fecal globules on leaves indicates the presence of the pest.
Horticultural methods: The elimination of weeds and/or any alternate hosts in order to reduce the thrips populations.
Biological control: The hymenopterous parasitoids Thripobius javae and Megaphragma mymaripenne Timberlake (Trichogrammatidae) usually control the pest. Several predatory mites also attack the greenhouse thrips.
Bernardo, U., Viggiani, G. and Sasso R. 2005. Biological parameters of Thripobius semiluteus Bouček (Hym., Eulophidae), a larval endoparasitoid of Heliothrips haemorrhoidalis (Bouché) (Thysan., Thripidae). Journal of Applied Entomology 129: 250-257.
Stevens, P., Froud, K. and Mills, E. 1999. Effects of greenhouse thrips (Heliothrips haemorrhoidalis) life-stage, density and feeding duration on damage to avocado fruit. Revista Chapingo Serie Horticultura 5: 297-300.
Larral, P. and Ripa, R. 2007 Evaluation of pesticide effectiveness on the control of Heliothrips haemorrhoidalis (Thysanoptera: Thripidae) on avocado trees (Persea Americana Mill.). Proceedings VI World Avocado Congress, Viña Del Mar, Chile, without pagination (in Spanish with an English abstract).
Wysoki, M. (and 6 co-authors) 1997. Successful acclimatization of Thripobius semiluteus a parasitoid of Heliothrips haemorrhoidalis (Bouché) in Israel. Phytoparasitica 25: 155.