Tundu disease of wheat

 Tundu disease of wheat

 Pathogen:- Corynebacterium ratharyi.

Systematic position of disease:- Class- schizomycetes

Distribution :- The yellowing rot or tundu disease of wheat has been recorded from the Punjab, Haryana, Rajasthan. This disease was first reported from the Punjab by Hutchinson in 1908. The disease has also been recorded from Australia, china and Egypt.

 Symptoms:- at first, a wrinkling of the lower and twisting of the central leaves is seen. Simultaneously,a bright yellow slime exudates on the affected leaves. Later on, the yellow slime appears on stem and inflorescence. In humid atmosphere, the yellow slime can be trickling down, but when it dries up, it become sticky and afterwards hard and dry. Ultimately the spikes become curled and twisted. The bacterium alone cannot cause the disease, and it is always associated with nematode, anguina tritici. In association with the nematode, the kernels are replaced by nematode galls and yellow rot sets in.

Nature and recurrence of disease:-This disease is a seed-borne disease. If the infected seeds are sown, the galls absorb moisture from the soil, and the larvae of the nematodes are released out from the ectoparasites on the growing apex of the seedling. At the time of flowering, the ovaries of the flowers are being infected by the nematodes already present on the growing apex. Once again the galls are formed. In the mean time, the bacterial infection also takes place and the yellow ear rot sets in.

Control measures:-

Sanitation- As soon as the symptoms appear, the plant should be uprooted and destroyed by burning them, out of the field.

Proper drainage- it has been suggested that if the fields are well drain aged, there are less chances of the disease.

Sowing of clean seeds- the galls free seeds should be sown. The seeds can be freed from galls by soaking in strong solution of common salt at the rate of 40 lbs per twenty-five gallons of water. By doing so the galls float on the surface of solution.

Crop rotation- crop rotation with barley and oats for 2-3 years is quite effective. During rotations, seasonal wetting of galls ensure release of larger which die in the absence of host.

 Resistant varieties- Same varieties are resistant against this disease. They are, Sonora 63, lerma roja, NP 908, S 227.