Problems with the Concept of “Pest” among the Diversity of Pestiferous Thrips

SIMPLE SUMMARY: The word “pest” can be interpreted in many ways, ranging from something that causes minor personal irritation to something that results in major economic losses. The various insects that are referred to as thrips are used to discuss the question “what is a pest”. Many species of thrips feed on young leaves and developing fruits, and we emphasize that crop loss and reduced financial yield are more significant than mere presence of a thrips on a crop. The diversity in biology among species of thrips is discussed within the context of their respective families and subfamilies, emphasising that pest behaviour is found in relatively few species of the insect Order Thysanoptera. ABSTRACT: 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.