DEPARTMENT OF AGRICULTURE. 



' rol. Spray with lime-sulphur solution diluted 1 to 9 before the buds break. 

 Repeat with a dilution of 1 to 25 or 30. after the fruit is set, and at intervals after- 

 wards, depending on weather conditions. When the lime-sulphur becomes objection- 

 able through forming a deposit on the maturing fruit, liver of sulphur (potassium 

 sulphide), % oz. to a gallon of water, may be substituted. This does not adhere 

 as well, but leaves no deposit. Badly diseased shoots should be pruned out and 

 burned. 



The same disease also attacks the curraut, but is rarely serious on this host. 



HOLLYHOCK. 

 RUST (Puccinia nmlvacearum) . 



This is generally distributed on both hollyhocks and the wild round-leaved 

 mallow, being often very serious on the former. It is one of the comparatively few 

 fungus-diseases conspicuously abundant in the Dry Belt. The disease shows first 

 as orange spots on the part attacked. Later these spots bear large, firm, dark-brown 

 masses of spores. On the leaves these spore-masses (sori) are on the lower side. 

 They may be so numerous that the leaves are practically destroyed and the plant 

 severely injured. The leaf-stalks, stems, calyx, and fruit may also be attacked. 



Control. Destroy wild mallows in immediate vicinity. Burn remains of attacked 

 plants. Spraying with Bordeaux mixture helps to prevent the disease, but renders 

 ornamental plants somewhat unsightly. 



OAT. 

 LOOSE SMUT (Ustilago aremr). 



This disease is almost universally present where oats are grown. The chaff 

 and kernel are destroyed by the fungus and replaced by a black powder of fungus- 

 spores, hence the name " smut." These are later blown away until at harvest-time 

 nothing but bare stalks and the remnants of some of the chaff are left. Although 

 the disease only manifests itself when the ear is out of the sheath, the fungus has 

 been present in the plant since the seedling came above ground. When the srnut- 

 scattered they are carried by the wind to the ears of neighbouring healthy 

 plants which are developing kernels. Some of these spores will find their way into 

 the crevices about the hulls, and will remain there until after the seed is threshed. 

 Should such seed be sown the next year, these spores germinate at the same time as 

 the seed, and produce a second kind of spore. These in turn germinate, each pro- 

 ducing a delicate fungus-thread (germ-tube) which can enter the oat seedling through 

 the cotyledon or first leaf, which encloses the other leaves as the seedling comes 

 through the ground. Once the fungus is established in the plant it remains near 

 the growing-point. Since the branches formed in stooling also arise at this point, 

 these generally become invaded by the fungus. Hence it usually happens that when 

 a plant later shows the smut, every ear on the plant shows it. The fungus does not 

 apparently injure the plant until flowering-time, being confined to the region near 

 the tip of the shoot. When the ear is forming, however, large quantities of food 

 substances are being conducted there to nourish the flowers and developing grain. 

 and this seems to stimulate the fungus into great activity. It extends rapidly at 

 the expense of the food substances and the tissues of the ear, producing enormous 

 numbers of black spores which form the " smut " with which we started. 



Control. Infection only takes place during the earliest stages of the seedling, 

 and practically always from spores adhering to the seed when sown. By treating 

 the seed with certain substances these spores can be killed without injuring the seed, 

 which will then produce a disease-free crop. The best substance for this purpose is 

 a 40-per-cent. solution of formaldehyde, diluted at the rate of 1 Ib. to 40 gallons of 

 water. The seed is spread out in a layer on a smooth, hard floor or canvas, and 

 the mixture sprinkled over it with a watering-pot, or in any other way that may be 

 convenient, the seed being at the same time shovelled over to secure uniform moisten- 

 ing. It should then be piled and covered with bag?, canvas, or other material to 

 keep in the fumes of the formalin and left six to twelve hours (usually overnight). 



