Plant-parasitic nematodes associated with almond (Prunus dulcis Mill.) orchards

Plant-parasitic nematodes are one of the main causes of yield loss in agricultural products. During a survey of almond (Prunus dulcis Mill.) orchards in the central part of Iran, seven species of plant-parasitic nematodes were identified from the soil and root samples in five orchards; ChamAli, Chelvan, Saman, Kharaji and Teshneez. The most common nematodes observed were Scutylenchus rugosus (168/100 g soil), Boleodorus thyllactus (58/100 g soil), Helicotylenchus pseudorobustus (36/100 g soil), and Helicotylenchus digonicus (34/100 g soil). We analysed pH, Zn, Mn, Fe and physical properties of the soils including percentages of sand, silt and clay. At Kharaji and Teshneez (soil texture sand 72%; silt 8%; clay 20% and low Fe), Pratylenchus thornei, Merlinius brevidens, and H. digonicus were observed more than at other localities, although levels were not as high at Teshneez, where Mn was lower, as they were at Kharaji. S. rugosus was dominant in soils with high levels of Fe in Saman, Chelvan, and ChamAli orchards, but this species was not observed at Kharaji and Teshneez. In conclusion, the almond-producing regions had various types of plant-parasitic nematodes, with six and five species found in Kharaji and Teshneez orchards, respectively. However, further studies are required to evaluate the tree damage caused by plant-parasitic nematodes on the almond orchards.