Thrips species composition and seasonal dynamic populations in an organic citrus orchard in the central eastern coast of Tunisia

Abstract: In Tunisia, citrus hold an important place in the agricultural sector, and is considered a strategic product to which the state attaches great importance. Thrips species composition in an organic citrus orchard in the region of Chott-Mériem, in the central eastern coast of Tunisia, was studied during the years 2010 and 2011. Twelve thrips species were identified and monitored. The most abundant species were Frankliniella occidentalis Pergande (32.97% in 2010 and 27.93% in 2011), Melanthrips fuscus Sulz. (18.56% in 2010 and 21.71% in 2011), Thrips tabaci Lindemann (11.14% in 2010 and 11.84% in 2011) and Pezothrips kellyanus Bagnall (8.2% in 2010 and 10.4% in 2011). Dynamic populations of those eudominant species was also studied showing that they occurred especially during spring and hot summer except for M. fuscus whose population developed the most during the cold season. On the other hand, three predatory thrips species were identified and monitored, Aeolothrips tenuicornis Bagnall, the eudominant thrips predator species (18.46% in 2010 and 18.64% in 2011), A. fasciatus L. and Franklinothrips megalops Trybom that were both subdominant species in 2010 (3.21% and 3.62%, respectively) and subrecedents in 2011 (2.03% and 1.97%, respectively). It must be noted that two thrips species were absent during 2010 and occurred only in 2011: Microcephalothrips abdominalis Crawford, whose presence was recedent with a percentage of about 1.43%, and Ceratothrips frici Uzel (1895), a subrecedent species with only 0.3% of total thrips population in the citrus orchards.