68 1 



TIIK FARMERS HANDBOOK. 



formaldehyde to 2 gallons), in which the seed is soaked for twenty 

 minutes, is also useful. This method of disinfection is also of great service 

 in checking other diseases. 



A rotation of crops is useful and also good farm practice. It affords 

 time for the spores in the soil to die out. 



Spraying helps to keep the growing crop clean. Bordeaux mixture, made 

 according to the 6 — 4 — 100 formula (described in this Handbook in connec- 

 tion with Late Blight of potatoes on page 498) should be sprayed on when 

 the first true leaves are unfolding; a second spraying should be given about 

 two weeks later, and a third when the young pods are being formed. The 

 pods, stems, and leaves should be well drenched with the fungicide. 



Soil well fertilised with stable manure some time previous to planting 

 has been beneficial in promoting active plant growth and also reducing 

 disease. The grower should also be on the lookout for resistant varieties — 

 selecting seed from any plants that show resistance to the disease at any 

 time. The wax variety has proved susceptible, while Lima beans have been 

 quite resistant. 



Rusts. 

 Several species of rust fungi, belonging to the genus Uromyces, affect 

 varieties of beans and peas. In New South Wales our commonest species is 

 probably Uromyces phaseolorum, De Bary (= U. appendiculatus (Pers.) 

 Link), which occurs upon the ordinary varieties of our garden beans 

 {Phaseolus vulgaris) and also on the cowpea. The fungus usually appears 

 late in the season and is destructive to foliage and may thus result in an 



earlier ripening of the crop as well as a 

 reduced crop. Spots appear on the leaves 

 (especially on the -under surface though 

 occasionally on the upper), at first blister-like 

 and small. These rupture and the spores 

 produced give an iron rust colour to the 

 mass. The fungus is harboured by the old 

 leaves and vines. 



Control. — Burn all refuse. Neither throw 

 any on the manure heap to be returned 

 later to the field, nor turn any under 

 with the soil. Early spraying with Bordeaux 

 mixture should be given. Later, when the 

 pods are well developed the English practice 

 is to use permanganate of potash, about 1 oz. 

 in 8 to 10 gallons of water. The grower 

 should always be on the lookout for selecting 

 seed from an} r resistant varieties. Climbing 

 varieties are most generally attacked. 



Another species that has been recorded in 



New South Wales is Uromyces ' fabo? (De 



Bary) on broad beans (Vicia /aba). This 



attacks pods, leaves, and stems, and in 



other parts of the world occurs on garden 



peas (Pisum sativum) and several species 



of vetch, e.g., common vetch or tare 



( Vicia Sativa). If it be remembered that 



these rust fungi commence their attacks 



from germinating spores that have hibernated on parts of old plants, it 



will be evident what benefit will be derived from collecting and burning all 



old refuse. 



Bean Rust (Uromyces phaseolomm). 



