Powdery mildew of green gram (dhanendra kumar)

Powdery mildew of green gram dhanendra kumar

1. POWDERY MILDEW OF GREEN GRAM SBUMITED BY DHANENDRA DHANUKA Classification:- Kingdom - Mycetae Division - Eumycota Class - Hemiascomycetes Order - Erysyphales Family - Erysyphaceae Genus - Erysiphe species - Polygoni

2. Economics Importance:- Powdery mildew is one of the wide spread disease of several legumes including green gram.

3. Symptoms:- Small,irregular powdery spots appear on the upper surface of the leaves. These spots gradually increase in size and become circular covering the lower surface also. When the infection is severe,both surfaces of the leaf are completely covered by whitish powdery growth.

4. In severe infection, foliage becomes yellow causing premature defoliation. The disease become severe during flowering and pod development stage. The white powdery spots completely cover the petioles, stem and even the pods. The plant assumes grayish white appearance. Often pods are malformed and small with few ill – filled seeds. The disease causes forced maturity of infected plants which results in heavy yield losses.

5. Pathogen:- The fungus is ectophytic, spreading on the surface of the leaf , sending haustoria into the epidermal cells . Conidiophores arise vertically from the leaf surface ,bearing conidia in short chains . Conidia are hyline, thin walled elliptical or barrel shaped cylindrical and singal celled. Latter in the season, cleistothecia appear as minute, black, globose structures with myceloid appendages. Each cleistothecium contains 4-8 asci and each ascus contains 3-8 ascospore which are elliptical, hyaline and singal celled.

6. Disease cycle:- The fungus is an obligate parasite and survive as cleistothecia in the infected plant debris. Primary infection is usually from ascospores from perennating cleistothecia . The secondry spread carried out by the air –borne conidia.rain splash also helps in the spread of the disease.

7. Favourable conditions:- Warm humid weather favours disease developed.the disease is severe generally during late kharif and rabi season.

8. Managenet:- Remove and destroy infected plant debris. Sowing of seed selection of disease free area. Sowing of certified seed. early sowing and use of early maturity variety. Spray twice with carbendazim or thaophanate methyl @0.1% one immediately after disease appearance and the second after 15 days. Use of resistant variety like PRAGYA,PUSA-105