NORTHERN AND SOUTHERN CORN LEAF BLIGHT

symptoms,pathogen,and mangement

1. STUDENT COURSE TEACHER JANANI.V Dr. S. PARTHASARATHY ID . No. 2016021015 Asst . Professor (Plant Pathology ) COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 NORTHERN & SOUTHERN CORN LEAF BLIGHT

2. NORTHERN CORN LEAF BLIGHT SIGNIFICANCE Northern corn leaf blight (NCLB) is a foliar disease of corn (maize) caused by Exserohilum turcicum . With its characteristic cigar-shaped lesions, this disease can cause significant yield loss in susceptible corn hybrids. The endemic areas of the disease identified in India, which are Karnataka, Maharastra , Andhra Pradesh, Bihar and Uttarkhand .

3. SIGNIFICANCE In dry weather, the disease rarely occurs or does not spread enough to cause significant economic damage . NLB development persisted at most in the US and canada . As a result, NLB found at economically significant levels in many areas.

4. ECONOMIC IMPORTANCE It is one of the important diseases affecting photosynthesis with severe reduction of grain yield to an extent of 28 to 91% India  too, severe losses of 25–90% in grain   yield. to an extent of 28 to 91%.

5. GLOBAL DISTRIBUTION WORLD: Northeastern United S tates Sub Saharan Africa China Latin America

6. DISTRIBUTION INDIA: Bihar Lalmardi Himachal Pradesh S ikkim M eghalaya T ripura Assam

7. SYMPTOMS OF NLB Early symptoms are oval, water-soaked spots on leaves. Mature symptoms are characteristic cigar shaped lesions that are 3 to 15cm long. Lesions are elliptical and tan in color , developing distinct dark areas as they mature that are associated with fungal sporulation.

8. SYMPTOMS Lesions typically first appear on lower leaves, spreading to upper leaves and the ear sheaths as the crop matures. Under severe infection, lesions may coalesce, blighting the entire leaf .

9. @ @ Pioneer.com

10. @ @ Purdue Extension.com l Long , Narrow lesions O Oblong lesions

11. SYSTEMATIC POSITION KINGDOM Fungi PHYLUM Ascomycota SUB PHYLUM Pezizomycotina CLASS Dothideomycetes SUB CLASS Dothideomycetidae ORDER Pleosporales FAMILY Pleosporaceae GENUS Exserohilum SPECIES turcicum AUTHORITY K.J.Leonard & Suggs

12. PATHOGEN CHARACTER Setosphaeria turcica is the causal agent of NCLB in maize . Large cigar shaped necrotic lesions that develop on the leaves due to the polyketide metabolite monocerin . Conidia germination, the fungus forms an appressorium , which penetrates the corn leaf cell directly using an infection hypha. Once below the cuticle, the infection hypha produces infection pegs to penetrate the epidermal cell wall .

13. Researchers have found that a small peptide called the  E.t.  toxin allows a non-pathogenic isolate of  E. turcicum  to infect corn when suspensions of conidia and the toxin were in contact with the leaves . This toxin has also been shown to inhibit root elongation in seedlings and in chlorophyll synthesis . Another toxin produced by E. turcicum , called monocerin , is a lipophilic toxin known to cause necrosis of leaf tissue.

14. Conidia and conidiophore of Exerohilum turcicum @ Wikipedia.com

15. DISEASE CYCLE OF NLB

16. EPIDEMOLOGY MODE OF SPREAD PRIMARY INFECTION: Rain splash Air currents SECONDARY INFECTION: Crop residue

17. FAVOURABLE CONDITIONS Optimum Temperature –18 to 27 ̊ C Sporulation – 14 hrs Dew period – 20 and 25 ̊ C Cool, moist conditions in late summer Early autumn

18. MANAGEMENT CULTURAL CONTROL : Deep ploughing reduces the amount of initial inoculum carried over. Crop rotation with crops such as soybean, sunflower and beans will effectively reduce the inoculum levels. ughing reduces the amount of initial inoculum carried over.

19. CHEMICAL CONTROL Picoxystrobin [ Aproach ®] Tetraconazole [ Domark ®] Pyraclostrobin [ Headline ® AMP] Propiconazole [ Tilt®] Azoxystrobin [ Quadris ®]

20. HOST RANGE PRIMARY HOSTS: Sorghum [ Sorghum bicolor] Pearl millet [ Pennisetum glaucum ] WILD HOSTS: Johnson grass [ Sorghum halepense ] Elephant grass [ Pennisetum purpureum ] Sudan grass [ Sorghum sudanense ]

21. SOUTHERN CORN LEAF BLIGHT SIGNIFICANCE Southern corn leaf blight is the foliar disease in maize caused by Bipolaris maydis or Helminthosporium maydis . It causes the significant yield losses in cultivars developed from subtropical or temperate germplasm ranging from 9.7% to 11.7% depends upon the weather conditions.

22. SIGNIFICANCE Two races are include in this disease. Race O and Race T are responsible for causing this disease in Pakistan. Race C have been reported in China. In 1970, epidemic was caused by Race T in maize with Texas male sterile cytoplasm in most maize growing areas of USA.

23. ECONOMIC IMPORTANCE Nisikado & Miyake evolved from a minor disease that causes an average annual loss of less than 1%, to one that caused more than the 12% average expected from all diseases of corn in US. It reaches epidemic status in 1970 & destroyed about 15% of the corn belt’s crop production that year.

24. GLOBAL DISTRIBUTION IN WORLD Nepal Kampuchea Philippines Indonesia Vietnam China

25. IN INDIA Jammu & Kashmir Himachal Pradesh Rajasthan Andhra Pradesh Uttar Pradesh Karnataka Tamil Nadu

26. SYMPTOMS OF SCLB Small yellowish round or oval spots appear on the leaves. These spots enlarge, become elliptical and the center becomes straw coloured with a reddish brown margin. Conidia and conidiophores are formed in the center.

27. Southern corn leaf blight @ Purdue extension.com

28. SYSTEMATIC POSITION Kingdom Fungi Division Ascomycota Sub division Pezizomycotina Class Dothideomycetes Order Pleosporales Family Pleosporaceae Genus Bipolaris Species maydis Authority Nisikado & Miyake

29. PATHOGEN CHARACTER Cochliobolus heterostrophus is found in many tropical regions. Race T destroyed more than 15% of the U.S corn crop. Race T differed from race O in the sense that it produced T-toxin [ host selective toxin]. T- toxin is considered to be related to a family of linear polyketides .

30. eplantdisease.blogspot.com

31. DISEASE CYCLE

32. EPIDEMOLOGY MODE OF SPREAD PRIMARY INFECTION: Broken stalks, and malformed or completely rotten cobs covered with greyish powder. SECONDARY INFECTION: Phytotoxins , pathotoxins and mycotoxins

33. FAVOURABLE CONDITIONS Warm, moist climate Warm temperature – 68 to 98 ̊̊ F Long and sunny growing areas Dry conditions are highly favourable

34. MANAGEMENT CULTURAL CONTROL: Do not grow maize on the same land, one crop after another. Plant at wider than normal spacing to reduce humidity in the crop. Collect leaves, stalks, and other debris, and use to make compost, or feed to livestock, rather than leaving them in the field to produce spores to infect new crops.

35. CHEMICAL CONTROL Mancozeb Chlorothalonil Seed treatments are not advisable.

36. HOST RANGE Maize, including sweet corn, is the main host. The fungus also infects sorghum and many grasses.

37. REFERENCES Das,P.C ., 2018. Plant diseases. Kalyani Publishers, New Delhi. https://www.pioneer.com https://www.apsnet.org.com