Is the presence of Trioza erytreae, vector of huanglongbing disease, endangering the Mediterranean citrus industry? Survey of its population density and geographical spread over the last years

Abstract

Is the presence of trioza erytreae, vector of huanglongbing disease, endangering the mediterranean citrus industry? survey of its population density and geographical spread over the last years.

A Model to Predict the Expansion of Trioza erytreae throughout the Iberian Peninsula Using a Pest Risk Analysis Approach

“…Regarding the PRA models, the radial and radial random models did not represent the observed pattern of expansion of the area invaded by T. erytreae during the five years after its introduction in the Iberian Peninsula (see Figures S5 and S6 online). This finding agrees with the circumpeninsular distribution of the host, regardless of the local scattered distribution of citrus crops and trees in small orchards and gardens within the study area [30].…”

“…After the first detection of T. erytreae in the Iberian Peninsula in 2014, a series of delimiting surveys were carried out to assess its distributional range [30]. It was found that the population had spread from Vilanova de Arousa (Galicia, Spain) to the north, following the coastal line of Galicia, and to the south following the Portuguese coastal line, reaching the Lisbon region [31].…”

“…This strongly suggests that the kernel model with two entry points deserves further research and refinement. For instance, incorporating geographical effects such as outbreaks and hot spots for local transport (see [30]), the effect of density-related patterns such as the preference of T. erytreae for crop borders [41], physical barriers (e.g., rivers, mountain chains), and high-resolution local climatic data would lead achieving a detailed and accurate tool to predict the future spread of T. erytreae. Although the Mediterranean basin is still free of HLB [42], the inefficient control measures against T. erytreae and its high rate of spread represent a significant threat, and this raises the alarm among scientists and stakeholders, especially regarding key citrus-growing areas in southern Portugal and southern and eastern Spain [19].…”

‘Candidatus Liberibacter Solanacearum’ Is Unlikely to Be Transmitted Spontaneously from Infected Carrot Plants to Citrus Plants by Trioza Erytreae

“…Additionally, this species is commonly used as a rootstock for lemon and as a crop for the jam industry. All in all, it would be interesting to perform new feeding behavior assays with other citrus species, such as lemon, sweet orange or mandarin trees, since certain preference of T. erytreae have been seen in the fields where the most frequently grown citrus species are: lime, lemon, mandarins, sweet orange and grapefruit trees [60][61][62]. For our study, eight hours of EPG recording time was used as this is the standard time used in many previous similar EPG studies, e.g., in those involving B. trigonica, B. tremblayi and D. citri [45,54,63].…”

“…Nevertheless, under multiple choice conditions, which are actually like more real situations in the field, T. erytreae is unlikely to transmit the bacterium from one carrot plant to another because this species is not a host ( T. erytreae is not able to complete its life cycle on this species, although it can land or feed off of carrot plants). This fact could only occur sporadically; several reports have described rutaceous plants as the only hosts of T. erytreae [ 34 , 60 , 61 , 62 , 65 , 66 , 67 ]. In addition, previous studies using sampling methods at the level of the crop canopy have shown that the main psyllid species present in carrot fields is B. trigonica , followed by B. nigricornis in low proportions [ 27 , 29 ].…”