66 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the wintering of the fungus, the attack of the leaves, and the conditions 

 that favour susceptibility or immunity. Finally, he gives methods of 

 combating the disease, through soil-treatment, selection of immune 

 stocks, spraying with fungicides, etc. 



In a full account of diseases of rice, E. J. Butler* gives a description 

 of several which are due to fungoid attacks. Tilletia horrida is allied 

 to the well-known bunt of wheat. It is believed that it enters the seed- 

 ling while still below ground, just as in wheat-bunt. Nothing is noticed 

 until the grains are formed, and then these are found to be a mere mass 

 of spores. The mycelium occurs in the stem tissues of the affected plants, 

 and in the grain it develops chiefly under the skin of the grain, that is, 

 below the outer wall of the ovary The spores adhere to healthy grains, 

 and so the new crop becomes contaminated. 



A false smut, Ustilar/onidea virens is an Ascomycete which forms a 

 green sclerotium on the maturing grain. Ascospores have not been 

 found, but conidia are formed freely, which reproduce the disease. 

 Sclerotia have also been found at the base of rice-stems, which prevent 

 any formation of flower or seed. The life-history or parasitism of the 

 fungus Sclerotium Oryzse is unknown. 



F. T. Brooks t contributes a paper on silver-leaf disease, wherein he 

 sums up all that is known as to the origin and nature of the disease 

 which is specially harmful to plum-trees in this country, though many 

 other trees are also attacked. It is mainly due to the fungus Stereum 

 purpureum, though other agencies also produce the same effect — either 

 other fungi or certain physiological conditions not rightly understood. 

 Possibly excessive pruning may account in some instances for the attack. 

 Grease-banding is another factor that seems to favour the disease ; the 

 bark becomes rotten under the grease, and the fungus settles on the 

 wounded area. Exposed surfaces should always be protected, and 

 affected trees or parts of trees should be removed. 



A parasite on grass new to this country has been described by 

 G. Massee4 Gladochytrium yraminis ; it has been notified from various 

 localities. At present it has only been observed on species of Festuca 

 and other grasses with small leaves, and in consequence is most pre- 

 valent on lawns, tennis-grounds, etc. The fructification is borne on the 

 leaves but falls to the soil, where it continues to mature, and finally 

 attacks the roots. 



Carlo Ghirlando § publishes an account of a diseased condition of 

 oranges and lemons, due to a form of the fungus Gladosporium herbarum. 

 It formed rather wide-spreading dark spots on the skin, and on micro- 

 scopical examination it was found that the mycelium had penetrated 

 through the skin down to the pulp of the fruit. He also found a form 

 of Altemaria constantly present. 



* Agric. Res. Inst. Pusa, Bull. No. 34 (1913) pp. 28-36 (1 pi. and 2 figs.), 

 t Journ. Board Agric, xx. (1913) pp. 882-90 (2 pis.). 

 X Journ. Board Agric, xx. (1913) pp. 701-3 (1 pi.). 

 § Atti Soc Tosc Sci. Nat., xxii. (1913) pp. 27-32. 



