1 Ocr., 1898.] QUEENSLAND AGRICULTURAL JOURNAL. 309 
2. Plant Susceptibility—Again it may be remarked that certain varieties 
of strawberries are especially liable to be attacked by Leaf Blight; whilst, on 
the other hand, others enjoy a comparative immunity from its onslaught. 
Observations in Queensland have not as yet been conducted by the writer for 
a sufficient length of time to enable him to state which varieties are to be 
included in one or other of these two categories; though a locally 
raised seedling—Pink’s Prolific—seems to be generally regarded as being little 
subject to the presence of the disease. There are, however, grounds for 
concluding that « particular strawberry’s susceptibility—or non-susceptibility— 
to Leaf Bhght will be found to vary in different seasons and especially under 
different soil conditions. This feature connected with the disease has been 
especially commented upon by W. Trelease. He writes, too, as follows:—“ From 
my observation, and from the testimony of correspondents of the station 
(Wisconsin Agricultural Experiment Station), I should give the following list 
as spotting most in this section:—Downing, Wilson, Russell’s Prolific, Big 
Bob, Bidwell, Captain Jack, Forest) Rose, and Manchester. The Crescent is 
one of the varieties least affected, though by no means entirely exempt. 
. . . . The Windsor Chief and Sharples are also noticeably free from 
‘rust.’”? [(3), pp. 48-9]. -'T. L. Brunk, writing after many years’ experience 
some six years later, gives a table showing the susceptibility of a large number 
of varieties of strawberries to the Leaf Blight, and concludes that the varieties 
Bidwell, Van Dieman, Anna Forest, Haverland, Daisy, Ruby, and Bubach No. 5 
are the five least susceptible varieties, when growing upon the Maryland 
Agricultural Experiment Grounds [e.f: (15), pp. 104-8]. 
Again although Briosi and Cavara (8) mention the Chilian Strawberry 
(Fragaria chinensis) as being one of the species on which the Leaf Blight 
occurs, more than one American authority has pronounced itimmune. The 
Fruit Fxpert, A. H. Benson, has also pointed out to the writer, as being blight- 
proof, a white-fruiting strawberry (with a blush on the sun-exposed side), 
occasionally locally regarded as one of the Hautbois (Ff. elatior) group. This, 
he states, is grown in the Zillmere and Bald Hills districts,.and adds that it is 
the result of a cross between FP. chilensis and another species of Fragaria. 
Iragaria chinensis has been described as being “a large and hardy species, with 
thick leaflets, soft silky on the underside.” Downing [Fruit and Fruit-trees 
of America, 1892”’] assigns the following varieties to it:—Patagonia, Green- 
well’s New Giant, Greenwell’s French. From it are stated also to have been 
derived the numerous Pine (Ananas) varieties of strawberries, by crossing 
with other species of Fragaria. 
NATURE AND CAUSE. 
On examining the leaf-spots, whose presence, as it has been already stated, 
are characteristic of the occurrence of the disease, it will be found that the 
pale-brown, or whitish-coloured, centres that exist in connection with them are 
composed of dead tissue that is already both dry and brittle. If one of these spots 
be cut through, and a thin slice or section of the tissue of the leaf thus exposed 
(suitably prepared) be examined by the aid of a microscope, the appearances 
illustrated on Plate LVIL., fig. 8, will be remarked. In this a represents the 
cellular leaf-substance that is as yet structurally unaffected, but here the cells 
have their contents already of a purple colour, corresponding as they do in 
position to the purple border bounding each leaf-spot externally whose presence 
they account for. Further, d marks the position of the central pale area of 
the spots. Here, as will be observed, the leaf-tissue is shrunken, being dry or 
sapless. Further, at c occur in tufts little erect threads having oblong bodies 
at their extremities. These tufts are constituted by the external growth of a 
special fungus named Ramularia Tulasnei, Sacc.; and the oblong bodies are its 
spores or conidia. (These highly magnified are represented by Fig. 6a.) Again, 
at d will be remarked little thread-like bodies, that pass from the base of the 
tufts into the tissue (a) occupying the intervals between adjacent leaf-cells. 
