374 the farmers' handbook. 



Where the attack is comparatively light it will only be necessary to grow 

 a crop of oats occasionally in rotation with wheat. 



In the above rotation, if it be decided to sow a fodder crop on the land 

 instead of bare-fallowing, this crop would be sown in February, fed off with 

 sheep throughout the winter months, and the land ploughed in spring and 

 fallowed as a preparation for the main crop the following autumn. Such 

 treatment to a paddock over a period of three years should help very 

 materially in stamping these diseases out. Oats are a valuable crop to sow 

 for sheep feed, but for this purpose the sowing should be done not later 

 than February or early March. 



Diseases and Pests of Oats. 



Loose Smut (Ustilago Avenw (Pers.) Jens). — This smut occurs on the 

 flowers of the oat, and is readily recognised because affected spikelets present 

 a black sooty appearance, without any skin or covering membrane to enclose 

 the smut spores. It is related to Loose Smut of wheat, but has a somewhat 

 different life history. The spores are known to be very long-lived and to 

 persist in the soil for seven years. They germinate in the soil and infect 

 the young growing seedling. The fungus grows with the plant to maturity 

 and then, instead of grain, there is produced in the spikelets a mass of smut. 

 The smut spores are blown from a diseased plant to healthy plants by the 

 wind and may become entangled between the glumes and the seed. Seed so 

 affected gives rise to a proportion of smutted plants on germinating the 

 following season. A certain amount of infection may take place by 

 adherence of the spore to the outside of the seed, and, probably, but very 

 rarely, by infection from spores of the smut in the soil. 



As the spores of the fungus are often entangled within the glumes, which 

 adhere to the oat seed, the Milestone treatment used for Stinking Smut of 

 wheat is only effective after prolonged action by the bluestone. This is 

 liable to interfere with germination. The hot water treatment has been us.d 

 successfully, but the satisfactory control of temperature is troublesome. Many 

 investigators favour the use of one per cent, formalin sprayed over the seed, 

 which is then covered with a bag and allowed to be exposed to the formalin 

 vapour for about four hours. It should be sown shortly afterwards in a 

 moist seed-bed. Seed should always be obtained from clean crops. 



Mildew (Erysiphe graminis). — A biologic form of this fungus sometimes 

 attacks oats in moist seasons. See article under the heading of "Wheat 

 Diseases" on page 346. 



Rusts (Puccinia spp.). — Rusts are exceedingly common in oats, but- 

 systematic cross-breeding and selection has resulted in the production of 

 some varieties showing immunity. The best method of combating these 

 diseases is to select varieties which are normally free from serious or epidemic 

 attack when grown in that particular district. 



Take-all (Ophiobolus yraminia) is relatively rare in oats under New South 

 Wales conditions. 



Foot-rot (Helminfhosporium). — A condition resembling the Foot-rot of 

 wheat has been met with in oats in this State. The introduction of a clean 

 fallow into the rotation is the best method of controlling the disease in both 

 wheat and oats. 



Insect Pests. 



The insect pests of oats — wireworms, cutworms, grasshoppers, and grain 

 weevils — are dealt with in the section on maize. 



