L. S. SUBRAMANUM 193 



from the same as is common in the latter. I had Pythium monos'permum 

 Prings. under observation along with the present one. From Pythium 

 IndigqfercB Butl. it differs equally in the characters of the sexual organs. 

 A new name is therefore proposed for the parasite here studied : — Pytldum 

 Butleri n. sp. (After Dr. Butler, Imperial Mycologist, who first studied the 

 disease on ginger.) 



Pythium Butleri, n. sp. 



Mycelium composed of much branched hyphae, sometimes showing fal-^e 

 dichotomy, the main strands being 3 to 8/* broad and the lateral ramifications 

 thinner. Irregular swellings quite common on the mycelium, which is septate 

 in old stages. Sporangia lateral, elongated, slightly swollen at the tip. Zoo- 

 spores few to 35 in number, bean-shaped, bi-ciliate, measuring when moving 

 8 to 12/i, 6 to 8fji in diameter, and after coming to rest 7 to lift. Oogonia lateral 

 or intercalar, spherical or subspherical, thin- walled, and measuring 18 to 33 

 (average 26/a). Antheridia terminal or intercalar (when they are usually on a 

 different hypha from that bearing the oogonium) or hypogynal (when they 

 are on the same hypha as the oogonium), knob-shaped. Oospores, round, 

 smooth, hyaline or light yellowish when fully mature, thick-walled, never 

 filling the oogonium completely, 13- 5 to 25"3/>i in diameter (average 21 fi). 

 Oospores germinate by a germ tube, not by zoospores. Parasitic on Nicotiana 

 Tahacum, Zingiber officinale, Carica Papaya, Capsicum annuum, and capable 

 of attacking, when artificially inoculated, Solarium tuberosum and Ricinus 

 communis. 



Remedial Measures. 



Ginger. 



McRae^ has given detailed information on the lines of treatment against 

 this disease at Eangpur. The propagation of the disease is chiefly through 

 the use of unhealthy rhizomes for planting, and in rare cases through soil 

 where there is much water-logging. Some seed rhizomes were got from 

 Kangpur, and planted near a crop of local ginger. The Rangpur variety 

 developed the disease and the local one was free. Both had the same 

 treatment. Since the local variety was free, it is evident that the seed 

 rhizomes of the other variety were diseased before planting. So far the 

 disease has been recorded only from Surat (Bombay) and Rangpur (Easterq 

 Bengal). McRae estimated the loss in low lands from 10 to 15 per cent, as 



^ MoRae, W. Loo. eit. 



