1 Jan., 1902.] QUEENSLAND AGRICULTURAL JOURNAL. 41 
Viticulture. 
COULURE; OR NON-SETTING OF GRAPES. 
By E. H. RAINFORD, Instructor in Viticulture. 
A certain amount of loss will be experienced by Queensland vignerons this 
season from coulure or non-setting of some varieties of grapes, which are more 
subject to this defect than others, and a few lines on this subject will not be 
out of season. 
Coulure appears under two different forms—one, the failure of the flower 
to set the fruit in all or part of the cluster; another, in which the fruit sets 
and increases in size, shortly to fall off the bunch in greater or less quantities as 
the attack may be severe or mild. ‘The causes of this serious defect are two— 
constitutional and accidental. 
Constitutional coulure is attributable either to defective sexual organs of 
the flower, by which fecundation is impeded, or to degeneration of the plant. 
In this latter phase the flower clusters form and blossom in the ordinary 
manner, with the sexual organs apparently perfectly normal and healthy; but, 
instead of the fruit setting in the ordinary manner, the cluster dries up to the 
yery point of attachment to the cane, subsequently falling off, leaving no trace 
of its existence ; sometimes one or two berries are fecundated, which attain a 
large size. The varieties most subject to this form of cowlure are the Clairettes 
and Terrets, the former erroneously called in this State Verdeilho. The cause 
of this class of coulure is, apparently, cultivating the vine in badly-drained 
land, as it is on this class of soil the defect more frequently appears. That it 
is constitutional and not accidental coulure is proved by the fact that if cuttings 
of these degenerated vines are planted elsewhere they are found to possess 
subsequently the same defect as the parent vines. The only cure for both 
forms of constitutional coulure is to graft the affected vmes with other 
varieties. ; 
Accidental coulure is caused by—1. Adverse meteorological conditions at 
flowering time. 2. Too great a vigour of vegetation. 3. Fungus attacks of the 
flower and immature berries. 
1. This class of accidental coulure may be caused by a continuation of rain, 
brusque changes of temperature, or prevalence of a hot wind during the 
blossoming pore: The non-setting is observable on the more exposed side 
of the bunch, and on those bunches more exposed than others. The organism 
of the flower or its sexual organs are so extremely delicate that the above- 
mentioned causes are often sufficient to interfere with fecundation or to blight 
the immature berry. The disease does not attack all varieties alike, some 
resisting atmospheric changes more than others. At Gatton College this season, 
the Alicante and B. Prince grapes were practically annihilated, while other 
varieties in close proximity.were spared. Accidental cowlwre when due to 
adverse meteorological conditions, has generally the appearance of a perfect 
cluster of minute berries, with few or many large berries intermixed according 
as the attack has been severe or not. The small berries, after a time, dis- 
appear, some few remaining aborted and not larger than shot. (See Plate I.) 
There is practically nothing to be done for this class of cowlure beyond 
avoiding excessive topping, which causes over-exposure of the flower clusters. 
2. The non-setting due to too great a vigour of vegetation may be caused 
by the vines being planted in too rich a soil, whereby very vigorous growth 
of wood is induced, or by an unusual amount of rain during the spring and 
early summer months. ‘The effect of excessive vegetation is to draw away from 
the clusters the sap required for their nourishment; if this drain can be 
checked in time, the cowlwre will also be checked. Pinching, which will stop 
