Diseases of Lentil

Rust, Wilt

1. W e l come

2. Lentil crop Diseases, Symptoms, Etiology, Disease cycle and Their Management. R u s t W i l t : U r o m y c e s v i c i a e - f a b a e : F u s a r i u m o x y s p o r u m f . s p . l e n t i s

3. 1 : . R ust : Uromyces viciae-fabae Symptoms: Rust pustules can be seen on leaf blade, petiole & stem. Rust starts with the formation of yellowish-white pycnidia and aecial cups on the lower surface of leaflets and on pods, singly or in small groups in a circular form. Later, brown uredial pustules emerge on either surface of leaflets, stem and pods. Pustules are oval to circular and up to 1 mm in diameter. They may coalesce to form larger pustules. In severe infections leaves are shed and plants dry prematurely, the affected plant dries without forming any seeds in pods or with small shrivelled seeds.

4. Etiology: Pycniospores: Pycnia (spermogonia) and the spore form pycniospore (spermatia). Pycnia were small, flask shaped and produced on the upper as well as lower surface of leaves and possess flexuous hyphae and nectar drop at the mouth. Aeciospores Designates aecia (aecidia) with aecisopores. Aeciospores were round to angular or elliptical with fine warts, yellowish in colour and 14-22 m in dia. Uredospores Uredospores are light brown, spiny, elliptical, single called, pedicillate, 20-30 x 18-26 mm and possess 3-4 germ pores. Teliospores Teleutospores were subglobose, ovate or elliptical, single called, pedicillate, thick walled with flattened apex and 25-38 x 18-27 mm in diameter. They were light brown with papillate apex. Basidiospores: Basidia with basidiospores. The teleutospore germinates and forms a 4- celled basidium on which four, single celled hyaline basidiospores were formed.

5. Disease Cycle: Uromyces viciae-fabae is an autoecious fungus. The pathogen survives in the volunteer sunflower plants and in infected plant debris in the soil as teliospores. b y win d - b o r n e uredos p o r es fro m The disease spreads (Secondary) infected crop Management: Use of foliar fungicides as Hexaferb and Dithane M-45 give best control. Fungicides as Mancozeb (0.2% a.i.), Bayleton (0.05% a.i) and Calixin (0.2% a.i.) are found effective against the pathogen. Foliar spray of benomyl, carboxin, metalaxyl, oxycarboxinthiram, triademafon either alone or in combination of Dithane M-45 are also effective. Lentil varieties Pant L-639, Pant L-406, Pant L-6, pant L-7 and Pant L-8 are resistant

6. 2 : . W ilt : Fusarium oxysporum f.sp . lentis Symptoms: The disease appears in the field in patches at both seedling and adult stages. Seedling wilt is characterized by sudden drooping, followed by drying of leaves and seedling death. The roots appear healthy, with reduced proliferation and nodulation and uslly no internal discoloration of the vascular system. Adult wilt symptoms appear from flowering to late pod-filling stage and are characterized by sudden drooping of top leaflets of the affected plant, leaflet closure without premature shedding, dull green foliage followed by wilting of the whole plant or individual branches. Seeds from plants affected in mid-pod-fill to late pod-fill are often shrivelled.

7. Wilt of lentil :

8. Etiology: The pathogen is known to produce three kinds of asexual spores; micro conidia, macro conidia and chlamydospores. Microconidia are usually single celled, ovoid or kidney-shaped and hyaline. Macroconidia are usually 2-7 celled, long with pointed apical cell and notched basal cell. Chlamydospores are single celled, oval or spherical shaped and thick walled, formed singly in macroconidia or apical or intercalary in the hyphae . Disease cycle The disease is seed and soil borne. The primary infection is through chlamydospores in soil, which remain viable upto next crop season. The secondary spread is through irrigation water, cultural operations and implements Management: Ploughing of the field during summer. The best method of controlling lentil wilt is to use resistant varieties, a number of which are now available as Pant L-4, Pant L-6, Pant L-8 and Noori. Following crop rotation with cereal crops which are not affected by wilt pathogen. Using antagonistic microflora like B. subtilis, T. harzianum, T. viride @ 4 g/kg seed etc Seed treatment with benornyl (0.3%) or thiram + benomyl (1:1, 0.3%) reduces wilt incidence and increases grain yield. Soil amendment with organic matter enhances antagonism with other soil microflora.