Feeding and Oviposition Behaviour of Trioza erytreae (Hemiptera: Triozidae) on Different Citrus Rootstock Material Available in Europe

SIMPLE SUMMARY: The Mediterranean Basin is the second largest citrus-producing region in the world. Huanglongbing (HLB) is the most important and devastating citrus disease worldwide, the causal agents of which are three bacteria species that belong to the genus Candidatus Liberibacter. The main transmission of these three bacteria is by two psyllid vectors, Diaphorina citri and Trioza erytreae. Trioza erytreae is a specific pest of plants from the Rutaceae family, which includes cultivated citrus. This insect has recently been detected in Mediterranean Basin countries, such as Spain and Portugal, but none of the causal agents of HLB have been described as infecting citrus plants in this region. The potential risk of HLB emergence has increased concern in the Spanish and Portuguese citrus industries, which require novel methods for controlling/eradicating populations of T. erytreae that are environmentally sound under new pesticide restrictions from European Union authorities. Hence, psyllid rootstock feeding preferences could play an important role in pest management. Thus, different citrus rootstocks have been tested for feeding, oviposition, and survival of T. erytreae. This study reports that the most commonly used citrus rootstocks (Carrizo citrange and Citrus macrophylla) are the favorite choices for the development of T. erytreae, and by contrast Poncirus trifoliata is the least suitable for this insect vector. ABSTRACT: Trioza erytreae (Del Guercio, 1918) (Hemiptera: Triozidae) is a vector of Candidatus Liberibacter spp., the causal agent of Huanglongbing disease (HLB). This study evaluates the preference of T. erytreae in different citrus seedlings. Thus, six different non-grafted citrus rootstocks were used for these experiments: (a) Carrizo citrange; (b) Citrus macrophylla; (c) ‘Cleopatra’ mandarin; (d) Forner-Alcaide No. 5; (e) Forner-Alcaide No. 517, and (f) Poncirus trifoliata (‘Flying Dragon’). The behaviour and survival of this psyllid was evaluated through the feeding preference of T. erytreae adults for different rootstocks (in a choice trial under greenhouse conditions) and oviposition and survival of T. erytreae adults on the different citrus material (in a no-choice trial under laboratory conditions). Trioza erytreae showed a clear preference for hosting and feeding on C. macrophylla, and Carrizo citrange was the most suitable rootstock for insect reproduction and survival followed by C. macrophylla. Conversely, Poncirus trifoliata was the least attractive rootstock to T. erytreae adults in the greenhouse trial and led to significantly lower T. erytreae survival. Our results suggest that conventional citrus rootstocks, such as Carrizo citrange and C. macrophylla, could increase T. erytreae populations.