RHIZOCTONIA ROOT AND CROWN ROT OF PISTACHIO IN KERMAN AND IT’S BIOLOGICAL CONTROL

Document Type : Short Article

Authors

Abstract

In this study, 99 Rhizoctonia solani isolats were isolated from some pistachio nurseries in Kerman province. Fungus was isolated from infected plant tissues and soils. Isolates were identified according to the morphological characters of the hyphae, cellular nuclei number of young hyphae, and their anastomosis groups. Results revealed that 96 isolates were multinucleate (MNR) and 3 of them binucleate (BNR). MNR isolates belonged to AG-4, and BNR isolates to AG B-I. Pathogenicity of the isolates was carried out on pistachio plants and the MNRs were pathogenic on pistachio but their virulence levels were significantly different. None of BNR isoltes were pathogenic on pistachio. The applicability of biological control as a method for combating disease was investigated in lab and greenhouse experiments using BNR isolates. In dual culture tests,  no hyphal lysis was observed and the only interaction  was coiling of the bc agent hyphae around the R. solani hyphae. In greenhouse experiments, coinoculation of the plants by BNR and  R. solani did not control the disease. On the other hand, when plants were inoculated by BNR, two weeks before inoculation with R. solani,thedisease was reduced considerably.

Keywords