First report of root-knot nematode Meloidogyne enterolobii on guava in Vietnam.

In southern Vietnam, citrus is interplanted with guava (Psidium guajava L.) for the management of citrus greening disease. Guava seedlings exhibited decline symptoms including leaf browning, growth inhibition, leaf drop, and death. These symptomatic seedlings were accompanied by severely galled roots, possibly attributable to root-knot nematodes. We collected second-stage juveniles from the soil and picked adult females from roots to perform morphological observations. The perineal patterns of most specimens were similar to those in the original description of Meloidogyne enterolobii (3). However, some were similar to that of M. incognita. Such variability among perineal patterns precluded unequivocal identification. Therefore, DNA was extracted from these nematodes and their sequences were compared with those in the DNA sequence database. For the comparison, we employed the primer sets of Powers and Harris (1) to amplify a region between cytochrome oxidase II and the 16S ribosomal DNA gene of mitochondri...