Nematodes as a Possible Cause of Damage to Opuntia ficus-indica in the Province of Santiago del Estero, Argentina

Abstract

In the summer of 2000/2001 in Santiago del Estero, Argentina, we encountered problems with rotting and
breaking of main stems of cactus, which was associated with nematodes. When the plant material was
first processed, we found nematodes of the orders Aphelenchida, Dorylaimida, Monochida and
Rhabditida. (It is important to point out that the nematodes may have been in the plant tissues and in the
soil attached to the tissues). When a second extraction was performed only from deteriorated plant tissues,
nematodes of Rhabditida were observed. As representative of the first order, the species Aphelenchus
avenae Bastian, 1865 was detected. This species of cosmopolitan distribution is often found on
decomposing tissues and can grow easily on nutrient agar where it feeds on the hyphae of various fungi
(Goodey, 1963). It is considered a typically mycophagous species. We found representatives of at least
two families of the second order: one of them is the family Longidoridae, which was represented by a
phytophagous species. The other species (as well as the family to which it belongs) is in process of
identification.