Olive Production Threatened by a Resurgent Pest Liothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) in Southern Italy

The Tubulifera (Hexapoda, Thysanoptera) of the Maltese Islands

This work records the presence of 13 species of tubuliferan thrips from the Maltese Islands. Eleven of these species, namely Bolothripsdentipes, B.insularis, Priesneriellamavromoustakisi, Gynaikothripsuzeli, Haplothripsacanthoscelis, H.aculeatus, H.setiger, H.tritici, Karnyothripsflavipes, Liothripsreuteri and Neoheegeriadalmatica are new records for the Maltese Islands. Two species: Gynaikothripsficorum and Karnyothripsflavipes can be described as subcosmopolitan in distribution, another three species: Haplothripsaculeatus, H.setiger and H.tritici are distributed across the Holarctic and Palaearctic regions, while a further seven: Bolothripsdentipes, B.insularis, Haplothripsacanthoscelis, Liothripsoleae, L.reuteri, Neoheegeriadalmatica and Priesneriellamavromoustakisi have a European and/or Mediterranean distribution. Gynaikothripsficorum and G.uzeli are considered as alien species. A key to the Tubulifera of the Maltese Islands as well as chorological data for these recorded species are provided in this work.

A Preliminary Survey of Olive Grove in Biskra (Southeast Algeria) Reveals a High Diversity of Thrips and New Records

Simple Summary

The diversity of thrips from olive trees in Algeria is unknown. According to the Ministry of Agriculture, thrip species have caused economic damage to the olive yield in the region of Biskra throughout the history of this crop, although the thrips pest species was unknown. To solve this question, we studied the thrips composition of one olive orchard over three years and the seasonal abundance of the species responsible of the damage of the olives in relation to the phenologic development of the olive tree

Abstract

This study was conducted to determine Thysanoptera species composition associated with olive trees, fruit injury, fluctuations in the abundance of the most phytophagous species relative to the phenological stages of the olive tree, and the temporal variations in the species Neohydatothripsamygdali in relation to environmental variations in Biskra province between 2018 and 2020. The olive orchard chosen for this study is located at the Experimental Station of the Technical Institute for the Development of Saharan Agriculture (ITDAS) in El Outaya (Biskra, a Saharan region of Algeria). Five trees were sampled each week, and thrips were collected by shaking 20 twigs (4 twigs per tree). Identification of thrips species was based on morphological characters of adults. Microscopic observation of the collected thrips specimens made it possible to report nine thrips species. Among them, four are reported for the first time in Algeria. Three taxa, namely Haplothrips tritici, Neohydatothrips amygdali, and Frankliniella occidentalis constituted the eudominant groups, representing 28.65%, 27.98%, and 23.39% of total specimens collected during the study, respectively. Thrips injury appeared as scaring and silvering of the fruit. The most abundant species was H. tritici, but N. amygdali was most common in the last two years of the survey. The influence of phenological stages of olive trees on the total number of H. tritici and F. occidentalis was significant. The highest numbers were recorded in flowering stage. The highest number of N. amygdali had two peaks: April (2020) and May (2018, 2019), as well as September (2020) and October (2018, 2019), when temperatures fluctuated between 20 °C and 30 °C. N. amygdali was totally absent during the other months (in winter and summer). During the three years of investigation, N. amygdali reproduced by thelytoky, with only females present.

Problems with the Concept of "Pest" among the Diversity of Pestiferous Thrips

Almost all of the thrips species that are considered pests are members of a single subfamily of Thripidae, the Thripinae, a group that represents less than 30% of the species in the insect Order Thysanoptera. Three of the five major Families of Thysanoptera (Aeolothripidae, Heterothripidae, Melanthripidae) are not known to include any pest species. The Phlaeothripidae that includes more than 50% of the 6300 thrips species listed includes very few that are considered to be pests. Within the Thripidae, the members of the three smaller subfamilies, Panchaetothripinae, Dendrothripinae and Sericothripinae, include remarkably few species that result in serious crop losses. It is only in the subfamily Thripinae, and particularly among species of the Frankliniella genus-group and the Thrips genus-group that the major thrips species are found, including all but one of the vectors of Orthotospovirus infections. It is argued that the concept of pest is a socio-economic problem, with the pest status of any particular species being dependent on geographical area, cultivation practices, and market expectations as much as the intrinsic biology of any thrips species.