powdery mildew of red gram, black gram, green gram

symptoms,pathogen, management

1. STUDENT COURSE TEACHER PAVITHRA. E Dr. PARTHASARATHY.S ID . No. 2016021029 Assistant Professor (Plant Pathology ). COLLEGE OF AGRICULTURAL TECHNOLOGY Affiliated to Tamil Nadu Agricultural University, Coimbatore Kullapuram , Via Vaigai dam, Theni-625 562 POWDERY MILDEW OF RED GRAM, BLACK GRAM, GREEN GRAM

2. POWDERY MILDEW OF RED GRAM SIGNIFICANCE It was caused by Leveillula taurica . It is an oidiopsis type. It is also known to infect other allium, solanaceous , and cucurbit species. It leads to pre-mature shedding of leaves and plants become barren.

3. ECONOMIC LOSS The yield loss accounts for about 21-31% in pod number and 26-47% in pod weight.

4. DISTRIBUTION World: Ethiopia , India, Kenya, Malawi, Tanzania, Uganda and Zambia.

5. SYMPTOMS Dull red spot, irregular in outlines limited by leaf veins on the upper surface of the leaf are the most important symptoms of this disease. White powdery mildew patches appear on the upper surface of leaf and the affected leaf dries up and fall off.

6. POWDERY MILDEW OF RED GRAM www.picswe.com

7. Kingdom Fungi Phylum Ascomycota class Leotiomycetes order Erysiphales Family Erysiphaceae Genus Leveillula Species L.taurica SYSTEMIC POSITION

8. PATHOGEN - CHARACTERS The fungus is intercellular and absorbs nutrition through haustoria . The conidiospores , which arise through stomata, are hyaline, long, non septate , slender and rarely branched and bear single conidium at the tip. The conidia are hyaline, single celled and elliptical or clavate .

9. The fungus also produces black, globose cleistothecia with simple myceloid appendages . They contain 9-20 cylindrical asci . Each ascus contains 3-5 ascospores which are also hyaline and unicellular.

10. MYCELIUM CHARACTERS The mycelium of L.taurica found on the plant is both extra cellular and inter cellular.

11. Conidia of L.taurica www.topsimages.com

12. DISEASE CYCLE www.slideshare.net

13. EPIDEMOLOGY MODE OF SPREAD Primary spread The primary infection in soil through cleistothecia and ascospores from asci infect the first lower most leaves near the soil level. m the infected heads land on the later emerging florets and infect the frequent rain showers , high humidity and temperature. The disease is internally seed borne, where pathogen infects the embryo in the seed.

14. Secondary spread The secondary spread is by air borne conidia.

15. FAVOURABLE CONDITIONS Dry humid weather following rainfall.

16. MANAGEMENT The stubbles of previous crop and disease affected plants should be collected and destroyed by burning. Late sowing should be avoided. Dusting sulphur 80 WP @ 30.0 kg/ha checks the spread of the disease. The disease can be controlled by spraying any one of following fungicides starting just on the appearance of the disease.

17. POWDERY MILDEW OF BLACK GRAM AND GREEN GRAM SIGNIFICANCE: This disease causing considerable reduction in the yield. The losses proportional to the disease severity various considerably d epending on the stage at which it occurs. This pathogen reduces the photosynthetic activity thereby reducing the yield.

18. ECONOMIC LOSSES Yield losses ranging from 9-50% The losses to the grain is both quantitative and qualitative.

19. DISTRIBUTION World: Japan, South E ast Asian countries, India, Pakistan, Middle East countries, Europe, South Africa and the U.S.A. India: Haryana, Madhya pradesh , Delhi, Rajasthan and Himachal Pradesh.

20. SYMPTOMS In the early stages, small irregular powdery spots appear on the upper surface of leaves. When plants are in the flowering and pod stage , the disease assumes epiphytotic proportions. The powdery whitish spots completely cover the leaves, petioles, stem, and even the pods, the plant assumes a greyish white appearance, and the leaves turn yellow and are finally shed. The yield from the crop may be greatly reduced.

21. POWDERY MILDEW OF GREEN GRAM AND BLACK GRAM www.alamy.com

22. SYSTEMIC POSITION Kingdom Fungi Phylum Ascomycota Class Leotiomycetidae Order Erysiphales Family Erysiphaceae Genus Erysiphe Species polygoni

23. PATHOGEN -CHARACTERS Conidiophores arise vertically from the leaf surface. Conidia usually form singly (rarely in chains), are ellipsoid. Later in the season, cleistothecia appear as sharp, black specks scattered on the surface of the white mucelium ; globose . Appendages very variable in number and length, myceloid , sometimes knotty and frequently geniculate, rarely irregularly branched, brown, to broadly ovate or subglobose .

24. MYCELIUM CHARACTERS: Mycelium consists of delicate and persistent hyphae which are attached to the leaves by means of appressoria . Hyphae penetrate the epidermis and swell into a lobed and round sac in the epidermal cells.

25. CONIDIA OF E.polygoni www.discoverlife.org

26. DISEASE CYCLE www.reseaechgate.net

27. EPIDEMOLOGY MODE OF SPREAD PRIMARY SPREAD The primary infection is usually from ascospores released from penetrating cleistothecia .

28. SECONDARY SPREAD The secondary spread is caried out by the air borne conidia produced in the season. Rain splash also helps in the spread of the disease.

29. FAVOURABLE CONDITIONS This disease is particularly severe in late sown kharif crop and it occurs through out the year.

30. MANAGEMENT The affected plants should be collected and burnt. Late sowing should be avoided. The affected plants should be sprayed with any one of the following fungicides as soon as the appearance of the disease is noticed. A second spray may be given, if necessary, after 15 days of the first spraying.

31. REFERENCES Das,P.C.2018.Plant Diseases. Kalyani Publishers,New Delhi . Mehrotra,R.S and Ashok Aggarwal.2017.Plant Pathology.McGraw Hill Education (India) Private Limited,Chennai .