THE AGRICULTURAL NEWS. 



FeBRUABI -i 



1915. 



FUNGUS NOTES. 



RUSTS AND SMUTS OF INDIAN CORN. 



The increased attention riow being given t<> Indian < 



production in some of the Lesser Antilles has alreadj resulted 

 in the recording of observations concerning the diseases 

 the plant. Undei the conditions of the some 

 it desultoi crop vi hich has bil herto 



been the rule, these d o have been negligible 



in their effects, bul ii is bj do means certain or probable I 

 tln\ will so remain if the ana of cultivation is increased. 

 \\ In]', however, the question of diseases maj require more 



ntion than it h past, experience in 



large corn-growing countries does not suggest any und 

 imount of trouble fro i urce. 



Of the diseases known to be present in the West Indies, 

 the rusts (Uredii -units (Ustilagineae) are most 



likelj i" attracl earlj a tention, and to them this article 

 will I"' confined Their synonymy is so complicated thai 

 somi intj in.", be who consult thi 



articles concerning them in hand books and periodicals, and 

 30 the alternative nami iei which they have been 'Irs 

 scribed or discussed are gi\ i to prevent confusion. 



1:1 STB. 



The species ol Sorghum (or Andropogon) such a 

 imphee and Guinea corn an rerj commonly attacked in 

 these islands by the rust fungus, Puccinia purpurea, Cke. 

 rUredo Sorghi, Fckl.). This is also one of the rusts which 

 icks maize. It may be shed on that plant bj 



the deep purplishred discolors produced on the leaves, 



like that familiar on imphee, and it has received the name of 

 Red R 



I i writer do aber to have met with it or 



to li. it recorded as occurring on maize in the West 



Indies, and it wo in from the literature consulted 



it appears rarely, ii al i II, on maize in the United Stairs. 

 Sir. I. B Pole-Evans, in the. Report of the Department of 

 Agricultt Union of South Africa, 1910-11, records it 



■lit apparently only in the 

 province of Natal. 



The maize ru •■ ol] referred to in the American 



literature is Puccinia MaydU, Bereng {!'. Sorghi, Schwein.), 

 called by Pole Evans the Brown Bust of Maize, in distinction 

 from tin- previous species. Although identified with the 

 species described as P. Sorgkx by Schweinitz, there appears to 

 i.r no established record of its occurrence on sorghum, and 

 attempts to infect sorghum with spores produced on maize 

 '• failed. 



Leaves ol maize, heavily infested with this fungus, 

 v ere recently forwarded to this < >ffice bj Mr. Ro 



"i tic Bo ■ nat, wh ported that it was 



very pi £ i M planted some t. u « 



previously, and had been non there from the time the 



nt- flowered. 



Comparatively little discoloratioi leafisprodu 

 but the brown pustules of the fung more or less con- 

 spicuous, " ling to tl of it ion. 



In the I r nited Stat i usl is not regarded as ha 



much economic import Usually it becomes common too 



in the season to do much damage. Winn I bj 



e\- | and have 



a considet ield. 



In South Africa, I I ■'.•■ in sun s that althi 

 i ious, then is no doubt that 

 ..vn i ust will 



of the most enemies of maize. The more that corn 



rown the mo the disease will manifest itself. Serio 



outbreaks havi rred in certain districts, where 



in many in I it a large proportion of the plants were so 



severely attacked that they set no cobs 



In South i- in Aim', ira. ' i ' hosts if 



this fungu • of Oxalis, and ii was noticed that 



a severe epidemii it Pretoria was preceded bj and 



most noticeable infestation ol a species of Oxalis by its 

 "t ( txalis an i ncommon in the 



West Indies. They are low tender herbs' with trifolia 

 leaves, arid ma) occur on waste land, or a weedsof cultiva- 

 tions. 



The cereal r ■ far provi I ifficult to deal 



with in temperate climates, and the problem ol their control 

 has practical!} resolved itself into one of breedi taut 



varieties. The life history ol the rusts which have beei 

 examim I in the West Indies differs frqm the course followed 



countries with a cold winter, in that the think walled 

 resting spores, the teleutospores, appear to be seldom formed. 

 Whether this n rsthe fungus more vulnerable nan only be 



iinineil wh method bj which the disease is carried 



. M'i' has been st m ied. 



-\n i - 

 The Am rican corn smut, Ustilago Ztae, (Beck.) Ung. 

 (U. Main j u, U. Maydis) is widel] distributed in the West 

 Indies as in Nbrtli America, without assuming any serious 

 proportions. Tt is distinguished by the swellings to which 

 it gives rise on th leaves, the ears, or the tassels, which 



may attain on tl ars to an enormous size. The pustules are 



covered at first with a greyish envelope, which later bursts 

 and reveals thi blacfc ma — ol spores. Am young and 

 growing part of thi plant is liable to infection. The leaves 

 are usually first attacked, and the disease may be recognized 

 at an earlj stage '". the whitish swellings there arising. 



Whehthes] s are released a certain amount of direbt 



infection may tak place, but the capacitj of the spores to 

 germinate apart from the host plant on any moist nutritive 

 material very greatly increases the possibilities of infection. 

 In rich soil, for instance, or in manure heaps, a yeast-like 

 growth takes place, with the result that myriads of conidia 

 are formed, which .oe easily distributed by the wind, and are 

 able to .start the disease on an\ growing pan of thecorn plant 

 tin \ happen to reach. When the original spores do not 

 attain to u situation which favours their growth they 

 remain dormant, and are capable of germinating at any 



time, should the conditions become favourable, during a period 



usually to 1"' measured in years. 



It will be seen that the deposition of smutted material 

 in cattle pens or manure heaps, or, since the Spores can pass 

 uninjured through the alimentary can the feeding of 

 diseased plants to cattle, is a sure w n sing and 



distributing thi 



The idea that the smutted ear-, ol ■■Inch cattle are 

 . fond, are unwholesome as foi orne out 



by experiments n liich have bei 



Certain sum I diseases, in which infection is confined 

 to the young sei i fective control by 



w ith the 



disease under i St ill, sp verj well be 



.. id wlnrc land is free from smut, and 

 seed from an outside source is being used, disinfection may 

 be worth whili . ' ma bed on p 



316 Of Vol. Mil of this journal. 



Where thi spi cies "i smut i ; -. the best me 



introl lies in id ion ol 



plai their affected parts, before the -pore- ., ■ 



