1. ( Xanthomonas translucens pv. translucens )

2. Bacterial leaf streak (BLS) - Black chaff أهمية المرض:- فى بعض الحالات يسبب خسائر تصل لــ 40% فى ولاية idaho فى امريكا. ايضا يسبب عقم للسنابل بنسبة 5-10% عند الرى بالرش. خطورة المرض تكمن فى : من الامراض الكامنة فى البذور(الحبوب)- مداه العوائلى واسع حيث يصيب جميع النباتات التى تنتج حبوب(الشعير – الشوفان – القمح – بعض الحشائش المصاحبة لهذه النباتات) – درجات الحرارة المناسبة له هى 15-30 درجةـــ المناطق التى بها رطوبة و دافئة ذات ليالى باردة – كذلك ينتشر فى المناطق التى بها تغير فجائى فى درجات الحرارة الدول الذى ينتشر بها:- أمريكا- كندا- المكسيك- الارجنتين- البرازيل- بيرو- الصين- باكستان- ايران- الهند- سوريا- اسرائيل- اليمن- تركيا-تنزانيا- ليبيا- مدغشقر- زامبيا- موروكو- استراليا. لا ينتشر فى وسط اوروبا لشدة البرودة

3. Symptoms Bacterial leaf streak (BLS) - Black chaff

4. ( Disease cycle of Xanthomonas translucens pv. translucens)

5. Condensed summary of the Zadoks two-digit code system for growth staging in wheat with corresponding Feekes scale Zadoks codeDescriptionCorresponding Feekes code Principal stage Secondary stage 3Stem elongation 1First node detectable6 2Second node detectable7 3Third node detectable 7Flag leaf just visible8 9Flag leaf collar just visible9 4Boot 1Flag leaf sheath extending 3Boot just beginning to swell 5Boot swollen10

6. 7Flag leaf sheath opening 9First awns visible 5Head emergence 1First spikelet of head just visible10.1 3One-fourth of head emerged10.2 5One-half of head emerged10.3 7Three-fourths of head emerged10.4 9Head emergence complete10.5 6Flowering (not readily visible in barley) 1Beginning of flowering10.5.1 5Half of florets have flowered10.5.2 9Flowering complete 7Milk development in kernel 1Kernel watery ripe10.5.4 3Early milk

7. 5Medium milk11.1 7Late milk 8Dough development in kernel 3Early dough 5Soft dough11.2 7Hard dough, head losing green color 9Approximate physiological maturity 9Ripening 1 Kernel hard (difficult to divide with thumbnail) 11.3 2 Kernel cannot be dented by thumbnail, harvest ripe 11.4

8. مرحلة التسميد فترة المعاملة بالمبيدات الفطرية

9. Head at approximately physiological maturity when the kernels have attained maximum dry weight. Note the green color is gone from the peduncle and head parts Soft doughHard doughKernel watery ripe MilkDough Stage (10.5.4 – 11.2)

10. Relationship between the grain weight per spike and the severity of bacterial streak at GS 10.5.4 caused by Xanthomonas translucens pv. translucens in the winter wheat cultivar Savannah in Baton Rouge, Louisiana, in 1993 and 1994.

11. Relationship between the number of kernels per spike and the severity of bacterial streak at GS 10.5.4 caused by Xanthomonas translucens pv. translucens in the winter wheat cultivar Savannah in Baton Rouge, Louisiana, in 1993 and 1994.

12. Relationship between the grain weight per spike and the severity of bacterial streak at GS 10.5.4 caused by Xanthomonas translucens pv. translucens in the winter wheat cultivar Florida 304 in Alexandria and Baton Rouge, Louisiana.

13. Data were analyzed with the GLM procedure of SAS(SAS Institute, Cary, NC) using the fixed model : Y ijk = µ+R(L) ij + L j +T k + TL kj + E ijk Y ijk is the response of treatment (T) k in replication (R) i within location (L) j ; µ is the overall mean: TL kj is the interaction between treatments and locations ; and E ijk is the residual.

14. Severity(%)of leafrust on theflag leaf 10254065100 Growth stage… …………… …………%Yield loss… ……………………………… Flowering10151520203035 Milk2581420 Soft dough134710 Hard dough11135 Approximate percent loss of yield caused by leaf rust at combinations of leaf rust severity and growth stage of wheat