Study on causal agent(s) of date bunch fading disorder

Date palm is one of the important fruit crops of Iran vs ,role in food security, national economic, environment sustc income. Kerman, Hormozgan, Pars, Sistan and Bluechestan, ] Provinces with over than 99% of total date production are t areas in Iran. Date bunch fading disorder has been the most important \\ growers in recent years. It first was reported from Kahn province and gradually distributed to the other main date proi commercial cultivars, such as, Mozafti in Kerman, Kabkab in Hormozgan and Khasi and Kabkab in Khuzestan (Behbehan) disorder. It has not been reported from other main date produc Increasing the rate of disorder damage was accompank continuation of drought year during several years in coun percent of date yield was lost during the last years. There wei about the casual agent(s) of disorder, but four hypothesis including interfering of diseases agents specially fungi, interf agents, nutrient deficiency and no consideration to the agro date plantations. These hypothesizes were studied in Kern and Khuzestan provinces during 2000-2004. To determining the probable role of fungi-agents on incidei disorder, different parts of infected bunches including fruit,different cultivars were sampled and cultivated on WA and P 2004. After separating, purifying and raising of fungi isolates justified mycology keys. Pathogenesis tests of prevalent iso laboratory and field condition on date palm CVs. Mozafti, S order to determining of probable role of climaticall fac development of disorder, the effects of several climaticc temperature (Temp) and relative humidity (RH) were studi August during 2002-2003. A thermometer and hygrometer v date plantation in Jiroft area and data were recorded I1 appearing to harvesting time. Samples were taken from 20 with 5-6 days interval for determining the rate of cumulativ Also real damage percent (rdp) was determined by calcula frequent two cdp. Thirty-six parameters of RH and Temp hygrograph and thermograph and simple correlation was sti real damage percent by statistical soft ware. Effects of foliar sulfate and calcium chloride with or without using micron disorder, was • studied in randomized completely block c treatments and 4 replicates in Jiroft region during 2002-20C Ti:Control(Only nitrogen fertilization application)T2:mi application of pure calcium chloride (5 kg/lOOOL)T4: T2 + ' of pure potassium sulfate (5 kg/lOOOL)T6: T2 + T5. The irrigation method was basin (pan), and the trees we interval. Foliar applications were carried out at 2,4, 10 and 1 One half of N- fertilizer (as urea) was used in January wit next half was used in May. The effects of two agro mana. different thinning methods: thinning one third of inflorescen (Tl), one third of inflorescence tip + 10 percent of central str one third of central strands at Kimri stage (T3) and control Aluminum foil(Cl), mat-like basket(C2), wax(C3) and cor factorial experiment in form of randomized completely treatments and 4 replications on Mozafti, Kabkab and Khas Behbehan regions during 2002-2003. The two years data wei the means of treatments compared, using Duncan multiple ra: In Hormozgan and Kahnoudj, a species of genus 1 species of Aspergillus spp. were identified on infected bunc species of Aspergillus, a species of Alternaria and a speci identified on infected bunches too. Two species of Aspe Alternaria were identified on infected bunches fron pathogenicity tests, Thielaviopsis sp. and two species of Hormozgan, two species of Aspergillus and Thysanophora species of. Aspergillus from Jiroft made tissues necrosis of fruits that were inoculated by injection of spore suspension Pathogenicity tests only Thielaviopsis sp. increased the rate ( climatical condition (high temperature and low relative \\ Another isolates not showed the symptoms of disorder ii Khouzestan. One or two week before disorder incidence, blowin started in the region, and RH was decreased and temp increa: Subsequently, the disorder was appeared on 20,29 and 28 respectively. Correlation coefficient for the Tmxi were det (2003) and 0.69(2004) and for d factor were determined -and -0.59 (2004) respectively. Foliar application of potas: chloride with (or without) micronutrients application, decreasing the damage of the disorder. Potassium treatment of faded fruits and bunches, subsequently increased the yield Foliar application of potassium sulfate with (or witho decreased the percent of faded bunches from 69% in control faded fruits from 66.5% in control to 7.5% and 10.4% and ii and 65%, respectively. For the first time, these results re1 potassium sulfate application with (or without) micronutriei bunch fading disorder in Iran. covering and thinning of Kabkab cultivar in Bou effects on disorder damage (p0.01) covering treatments, mean damage percents 7.9, 8.6, 19.5 and 29.8 were placed respectively and thinning treatments Tl, T2 , T3 and T4 w: 10, 11.5 , 14 and 21.8 were placed A. A,B and C classes, n thinning on weight, length and diameter of fruits and the e weight and diameter of fruits and pulp to seed ratio were sigi covering and thinning of Khasi cultivar in Beht effects on disorder damage (p0.01). covering treatments, mean damage percents, 3.84, 8.66, 33.54 and 17.21 wen respectively. Thinning treatmentsTl, T2, T3 and Tz percent, 12.28, 10.25, 16.54, 24.17 were placed in B, B, AB, Thinning treatments, Tl and T2 showed the most positive volume, pulp to seed ratio and diameter of seed. The effects of both mentioned factors on Mozafati cul significant (p0.05). Covering treatment, C2, Cl, C3 and percents, 6.78, 10.64, 16.92, 20.74 were placed in B, AB, A and thinning treatments Tl, T2 , T3 and T4 with mean dam .14.02 and 19.3 were placed in B, AB, AB and A respectivi factors on fruit weight, length, diameters, volume and seed dia Finally, thinning of inflorescence tip at pollination stage a bunches with mate-like basket are recommended as the best t: damage of the date bunch fading disorder and improving t fruits.