investigation on the efficacy of some fungicides in controlling alternaria late blight of pistachio

The efficacy of pyradim ® df with pyraclostrobin+dimetomorf active ingredient was evaluated in comparison with fungicides captan, nordox, mishocap in the control of pistachio alternaria late blight. the experiment was carried out in markazi (zarandieh), kerman and semnan in a randomized complete block design (rcbd) with 8 treatments and 4 replications. treatments were applied at two stages (before bud swelling and after the petals fall and fruit set). the data were analyzed using sas software and mean comparison of disease severity and disease incidence percentages were done by duncan's multiple range test (p =5%). the results showed that pyradim with dosage of 1 and 0.75 per thousand has a good efficacy in disease control. so that the efficiency of dosage 1g l^-1 in reducing the severity of the disease compared to the control without spraying was about 88% in zarandieh and about 77% in kerman and semnan. the efficacy of pyradim at the dose of 0.75g l^-1 in zarandieh, kerman and semnan was about 76%, 72% and 74%, respectively, but the dose of 0.5g l^-1 pyradim was not acceptable and in the three studied areas was between 52 to 55%. captan fungicide also had acceptable efficacy in controlling pistachio alternaria late blight disease, so that its efficiency was more than 70% in kerman and semnan and 68% in zarandieh. in contrast, nordox and mishocap fungicides did not have good efficiency. therefore, 0.75g l^-1 pyradim is recommended for controlling pistachio alternaria late blight disease.