Evaluation of the Efficacy of Some Pesticides and Chemical Compounds in Improving the Lateral Bud Death of Almond (cv. Shahroud 12) Cultivated along Zayandehrood

The lateral bud death disorder in almond (cv. Shahroud 12) is observed in some replanted orchards in Chaharmahal and Bakhtiary province. The abundance of plant parasitic nematodes, phytophthora species and zinc deficiency were more in trees with symptoms than the asymptomatic trees. Experiment was performed in a randomized complete block design with seven treatments including pesticides like fluopyram (Velum Prime®; EC, 41.5%), Abamectin (Vertimec®; EC, 1.8%), Fosetyl-Al + Propamocarb (Previcur Energy®; SL, 840), Fosetyl-Al (Elite®; WDG, 80%), Diazinon (Bazodin®; EC, 60%) , Zinc sulfate (ZnSO4H2O, 33%) and control with five replications on Shahroud 12 cultivar almond trees along Zayandehrood during 2018-2020. A week before the application of chemical treatment and three months later, soil and root samples were collected for the measurement of plant-parasitic nematode population and isolation of Phytophthora species and the zinc content. Four branches per tree were selected from different directions, a week before the chemical treatment and five months later, and  healthy (containing leaf and fruit) and dead buds were counted. The results show the treatments of Velum Prime, Abamectin, Diazinon, Zinc sulfate, Previcor and Elite reduced the bud death and improved the disorder of the almond trees by 66.1%, 53.2%, 36.3%, 33%, 19.3% and 16.9%, compared with the control, respectively. Although compounds with nematicidal properties were more effective in improving this disorder; other treatments were also significantly different compared with control in terms of reducing the symptoms of bud death. The role of other factors in causing this disorder can not be ignored; therefore, the interactional effects of these factors in causing or exacerbating  the symptoms of  bud death of almond (Shahroud 12 cv.) may be more effective than a single cause alone.