Lower reproductive rates of Asian citrus psyllid (Hemiptera: Psyllidae) on 'Tahiti' acid lime than on 'Valencia' sweet orange

In Brazil, ‘Tahiti’ acid lime is usually found growing near sweet orange orchards, the main citrus grown in the country. As all citrus types, ‘Tahiti’ is susceptible to Candidatus Liberibacter asiaticus (CLas), the pathogen associated with huanglongbing (HLB), the most devasting citrus disease, and hosts the vector of CLas, the Asian citrus psyllid (ACP) Diaphorina citri. ‘Tahiti’ could then be contributing to spread CLas between ‘Tahiti’ and sweet orange orchards. Given the lack of comparative studies on the suitability of ‘Tahiti’ and sweet oranges to reproduce ACP a study was undertaken inside an acclimatized room (AR) and greenhouse (GH) involving healthy ‘Tahiti’ and ‘Valencia’ sweet orange plants. Daily temperature and relative humidity averaged 22ºC and 60% inside AR and 24°C and 70% inside GH. Two ACP couples were kept caged for 3 days on new shoots. Egg number and time for egg to hatch nymphs were assessed in AR and GH, and survival rates and time for nymphs to become adults in GH. Overall, ‘Tahiti’ was 3.5 times less suitable to ACP than ‘Valencia’. Egg number and nymph survivals were 27% and 59% lower, and the life cycle 34% longer on ‘Tahiti’ than on ‘Valencia’. Potential impacts of the results on CLas spread and HLB control are discussed.