Influence of Meteorological Factors on Date Bunch Fading Disorder

Date bunch fading disorder (DBFD) has been one of the major issues facing date palm growers in recent decades. This order has caused high and non-compensable losses to date palm product. Despite numerous studies, predominantly focusing on the causes and mitigation methods of this disorder, no precise influencing factors have been established and practices which can completely control it are not available. Increased temperature and low RH have been mentioned as factors responsible for inducing this disorder, other probable factors are biotic stresses, especially fungal infections. Present research was carried out to determine the effects of climatic factors on DBFD occurrence. For this purpose, ten orchards of ‘Kabkab’ cultivar of date palm with a history of previous symptoms of DBFD were selected in Bushehr province during 2012-13. 20 trees in each orchard were selected and 100 fruits on each tree were chosen. Numbers of faded and non-faded fruits were counted and disorder percentage was calculated. The daily meteorological data at meteorological stations near the experimental locations were recorded. Results showed that the damage rate was higher in the first year compared to the second one. Furthermore, in 2013, there was a decrease in temperature and concomitant increase in relative humidity from 2012. This condition leads to excess surface evaporation from the fruits and causes fruit wilting, which is referred to as DBFD.