232 FUNGOID PESTS OF CULTIVATED PLANTS. 



RED MOULD OF WHEAT. 

 Fusarium culmorum (W.G.S.), PL XXII. fig. 6. 



This is one of the gelatinous red moulds which Worthington Smith 

 contends are more injurious to growing corn than has been supposed. It 

 forms a pale orange-yellow gelatinous stratum over the ears, or some por- 

 tion of the ears, of growing Wheat, and glues the spikelets together. 



The mycelium is effused, gelatinous, yellow or orange, and sparingly 

 septate. The conidia are fusiform, or spindle-shaped, attenuated towards 

 each end, and slightly curved, with from three to five transverse septa, and 

 of an orange colour (40 x 7/u). 



In common with most other species the conidia will sometimes germi- 

 nate from any one of the. cells whilst still in position, or the cells will 

 separate and each assume a globose form (8/z diam.). 



Smith, Field Crops, p. 208, figs. 91-92 ; Sacc. Syll. xi. ; Mass. PL 

 Dis. p. 333. 



Wheat is also subject to Bacteriosis, caused by Micrococcus Tritici, 

 which is indicated externally by a rose or purple colour. 

 Mass. PI Dis. p. 339. 



WHEAT LEAF-SPOT. 

 Septoria Tritici (Desm.), PL XXII. fig. 7. 



This leaf-spot occurs on the leaves of Wheat, and also several grasses, 

 especially of Festuca and Glyceria fluitans. The spots occur on both 

 surfaces and are elongated and linear, whitish, with a dark purple margin. 

 The receptacles are very minute and scattered over the spots, almost in- 

 conspicuous. The sporules are cylindrically fusoid, and slightly curved 

 (60-65 x 3j-5/u) with from three to five septa. Ejected when mature in 

 flesh-coloured tendrils through the mouths of the receptacles. 



Known in Britain, France, and Italy. Probably not injurious to the 

 Wheat crop. 



Sacc. Syll. iii. 3042. 



WHEAT KNOT SPOT. 

 Septoria nodorum (Berk.). 



This spot was first observed by Berkeley on the nodes of Wheat straw 

 previous to the maturing of the grain. The spots are pallid ochraceous, 

 with a brownish line or margin. The receptacles are at first reddish - 

 brown, becoming black. The sporules, elongated, slightly curved or 

 irregular. 



Sacc. Syll. iii. 3044 ; Gard. Chron. 1845, p. 601 ; Cooke, Hdbk. 

 No. 1304. 



GRASS LEAF- SPOT. 

 Septoria graminum (Desm.), PL XXII. fig. 8. 



This was called by Berkeley Depazea graminicola, and occurs on the 

 leaves of Wheat, as well as on some of the common grasses. The spots 



