Short communication. Identification of the Poncirus biotype of Tylenchulus semipenetrans in Valencia, Spain

High population densities of Tylenchulus semipenetrans Cobb were detected on mature Poncirus trifoliate (L.) Raf. rootstocks in a commercial citrus orchard in Rafelguaraf, Valencia, Spain. Until now, this rootstock was considered resistant to populations of T. semipenetrans. The biotype of the nematode was characterised according to its host range. Under greenhouse conditions, it proved to be very capable of reproduction on the Bennecke and Rubidoux cultivars of P. trifoliate and on rough lemon (Citrus jambhiri Lush) at seven months post-infestation. It was also able to infest grapevine 141-R (Vitis berlandieri xV. rupestris), but not cv. Arbequina olive (Olea europaea L.). These results suggest this Valencia population of T. semipenetrans behaves similarly to the Poncirus biotype.