The Reaction of Apple Cytospora Canker to Nutrient Nitrogen and Potassium

In An assessment,52 Golden delicious gardens(7-10 years old , 5000 m2 area) randomized selected for determination the role of macro and micro elements on incidence and development of Cytospora spp. associated with apple trees , and 5 trees randomized selected in each garden , and sampled from 50 leaves and 0-30 , 30-60 cm deep soil in Junuary.Sample compound prepaired in laboratoary , macro and micro elements based on Wet Digestion method analyzed and the results based on Deviation from Optimum Percentage(DOP) method in infected gardens to recent index concentration in non infected ones, were subjected to analyzed and required discussious.Potassium deficiency and high level of Nitrogen was observed in infected gardens, research on the role of these elements was performed on the fungus. This part of invastigation was done in Isfahan agricultural research greenhouses on seedlings of the two-years-old Golden Delicious apple cultivars (disease incidence is higher in the cultivar) and in a factorial randomized block design with two factors (16 treatments) and four replications. After 6 weeks, seedlings were inoculated with high virulence isolate.In most treatments in late spring and along summer callus tissue was formed around the site of inoculation. But the invasion of healthy tissues began in the fall, and cankers caused seedlings were dead.The results showed that only tissue callus was formed around the replications: N0K0, N0K1, N0K2, N0K3, N1K2.N1K3 while none of the treatmens were dried.,% 25 replications were dried. In treatments K0N1, K0N2, N1K1, N2K2, N2K3, N3K325%of replications were dried .In treatments K0N3, N2K1, N3K2 .% 50 repetitions While in treatment N3K1,% 100 repetitions were dried. Is characterized by increasing potassium intake and reduce the amount of nitrogen in treatments dring percentage variable and the trend is increasing. This results with the results obtained from healthy and infected apple trees leaves and soil are similar.