. The more important fruit tree diseases of Ontario [microform]. Fruit; Pulvérisation et poudrage en agriculture; Spraying and dusting in agriculture; Fruits; Exploitations agricoles. •t«in, Bftriy Harveit and St. Lawrence; (6) moderately subject to Scab—Spy, Bhodfl laland Greening, King, Baldwin and Beu Davi*; slightly subject to Scab—Dachess of Oldenburgh, Blenheim Pippin, Yellov. i miparent, Tolman Sweet and Golden Bnsset Lift Hiitory. The fungus which causes Scab passes the vmtc chiefly on the fallen leaves beneath the trees. If these are examined in tlie spri'-j, small black d. cs or pimp
. The more important fruit tree diseases of Ontario [microform]. Fruit; Pulvérisation et poudrage en agriculture; Spraying and dusting in agriculture; Fruits; Exploitations agricoles. •t«in, Bftriy Harveit and St. Lawrence; (6) moderately subject to Scab—Spy, Bhodfl laland Greening, King, Baldwin and Beu Davi*; slightly subject to Scab—Dachess of Oldenburgh, Blenheim Pippin, Yellov. i miparent, Tolman Sweet and Golden Bnsset Lift Hiitory. The fungus which causes Scab passes the vmtc chiefly on the fallen leaves beneath the trees. If these are examined in tlie spri'-j, small black d. cs or pimples will be seen projecting above the skin of the leaf on one or both sides. They vary in size from a mere speck to a pin head. Each is a fruiting body (perithecium) of the fungus, and contains numerous lu. sec-lik- . tructares (asci), (See Illustration), each of which in turn contains eight tw -c .ii^d '.porea (aacospores). When mature the fruiting bodies (perithecia) open by * of a minute r-^re, through which the spores are shot out from the sacs by a peculiar arrangement. Moisture is necessary for the discharge of the spores, which takes place chiefly during the spring rains from about the time the leaf buds burst until the blossoms are open- ing. Some, however, are discharged much later than this. The spores which are shot up for a short distance from the leaf are extremely light, and ere scattered here and there by the wind. Some of them reach the unfolding leaves or blossoms, and here, if there is rain or heavy mist for abo't two days, they germinate and send out a tiny thread- like ctmcture (germ-tube), which pene- trates beneath the skin of the leaf or the calyx of the blossom, which afterwards becomes the flesh of the apple. Moisture is essential not only for the germination _ ^, ,.^.. of the spore but also for the further de- aS, . « ... \ ^ ' ' velopment and penef .-on of th. germ- 'T\Sl^!l^^'rn^Z, K^lSft^^dS tube. It 18, therel • only
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectsprayinganddustingin
