Cultural and physiological studies of phytophthora parasitica dast. var. macrospora ashby,causing fruit rot of anona squamosa L.

Summary This paper gives an account of some cultural and physiological studies of an isolate ofPhytophthora parasitica Dast. var.macrospora Ashby, the causal agent of fruit rot ofAnona squamosa L. Among the various culture media studied, non-synthetic ones like oat meal agar, corn meal agar, lima-bean agar, carrot extract agar, soya-bean extract agar and steamed rice agar were the best, on which the organism showed marked growth and sporulation. Non-synthetic types were poor in this direction. Regarding the effect of various carbon sources, sucrose, lactose, maltose, raffinose, inulin, dextrin, dulcitol, glycogen, rhamnose and xylose supported growth and sporulation of the organism. Sodium nitrate, ammonium nitrate, magnesium nitrate, potassium nitrate, ammonium lactate and asparagin were the best sources of nitrogen. 6.5 was found to be the best pH for the growth and sporulation of the organism.A portion of Senior Author's M.Sc. Agric. Thesis, University of Poona, India.     

An account of some physiological studies in two species of phytophthora

Summary The paper deals with some physiological studies of two typical strains ofPhytophthora palmivora Butl. andP. parasitica Dast. var.macrospora Ashby causing severe fruit rots ofAchras sapota L. andAnona squamosa L. respectively. The effect of temperature on the germination of sporangia had a marked effect. Maximum percentage of indirect germination (by formation of zoospores) occurred at 20° C, whereas direct germination of sporangia (by formation of germ tube) was at 30° C, which further continued upto 37° C. Maximum indirect germination at 20° C shows the favourable cool temperature for the epidemic of the diseases (Fruit rots) in nature. The best substrate (medium) for germination of sporangia was found to be tap water. Next to this was the host decoction or extract. Glucose solution also accelerated sporangial germination. The effect of two dyes viz., Malachite green and crystal violet was also studied in relation to growth and sporulation ofPhytophthora isolates. Their addition to the medium in various fractional dilutions had a profound influence in the rate of growth and sporulation. An interesting observation noted was that growth of the isolates was inversely porportional to the various concentrations of the dyes, under study. An attempt was also made to study the influence of various vitamins. In all, six vitamins were included in the study. Out of these, thiamine and riboflavin were found to be the best sources promoting good growth and sporulation of both the species ofPhytophthora under study.Forms a part of Senior author's M. Sc. (Agric.) Thesis, University of Poona, Poona (India).Respectively, Ex-Junior Research Fellow, I.C.A.R., New Delhi; Professor of Plant Pathology and Principa, College of Agriculture, Junagad (Gujarat); Plant Pathologist, Wheat Rust Research Station, Mahabaleshwar, Poona, India.     

Some physiological studies in two species of phytophthora

Summary The paper deals with some physiological studies viz., (1) Production of enzymes (2) Effect of chemicals and sugar solutions and (3) Utilization of amino acids, by two species ofPhytophthora i.e.,Phytophthora palmivora Butler andP. parasitica Dast. var.macrospora Ashby., isolated from rotten fruits ofAchras sapota andAnona squamosa respectively.In the study of production of extra-cellular enzymes, it was found that both the isolates ofPhytophthora produced enzymes like inulase, amidase, emulsin and diastase in small quantity.Among the various chemicals and salt solutions used to study their effects in the formation of sporangia; it was observed that these were remarkably produced in abundance by both the species ofPhytophthora specially in the chemical solutions like sodium chloride, potassium nitrate, sodium thiosulphate and potassium permanganate. On the other hand, chemical solutions like strontium sulphate, potassium chromate, ammonium oxalate, zinc sulphate, copper sulphate, potassium sulphate, strontium nitrate and ferrous sulphate completely ceased the sporangial development. Among the various sugar solutions tried, dextrose, galactose, glucose, laevulose and fructose accelerated sporangial formation.An attempt was also made to study the effect of various amino acids singly or in combination on growth and sporulation. Both the isolates under study, utilized L-Arganine monohydrochloride and DL-Aspartic acid, hence these were growth promoters. It is interesting to note that the growth of the isolates was good, only when DL-Norleucine and DL-Methionine (both growth inhibitors) were provided in combination.Forms a part of Senior author's M.Sc. (Agriculture) Thesis, University of Poona, (Poona) India.Respectively, Ex-Jr. Res. Fellow, I.C.A.R. New Delhi; Professor of Plant Pathology and Principal, College of Agriculture, Junagad (Gujarat); and Plant Pathologist, Wheat Rust Research Station, Mahabaleshwar (Poona), India.     

Nitrogen utilization of highly and weakly virulent isolates of Colletotrichum falcatum Went

Nine inorganic nitrogenous compounds and sixteen amino acids were used to study the growth and sporulation of highly and weakly virulent isolates ofColletotrichum falcatum Went. Potassium nitrate, sodium nitrate and calcium nitrate supported good growth, while ammonium phosphate, potassium nitrate and sodium nitrate supported good sporulation of both isolates. Among the amino acids tested, glycine and DL-alanine were best for growth, and DL-threonine, L-leucine, DL-tyrosine, DL-serine, DL-phenylalanine and L-cystine for sporulation. No correlation existed between virulence and growth but the highly virulent isolate sporulated significantly more than the weakly virulent isolate.This work is a part of the author's Ph. D. Dissertation submitted to the Faculty of the Graduate School of the College of the Agriculture, University of the Philippines (1969).     

Factors influencing formation of acervuli and conidia by Collectotrichum graminicola

Summary Abundant sporulation of certain isolates ofColletotrichum graminicola (Ces.)Wils., occurred when sufficient aeration was provided to their liquid culture either by reducing the quantity of the media or by forcing air into them. Certain carbon and nitrogen compounds caused more sporulation of only orchard grass isolate of the fungus. When sufficient aeration was provided to the culture media more sporulation also occurred at a temperature range of 20–30°C. Glucose content of the media did not have any influence on sporulation.Portion of a Ph.D. thesis, Department of Botany and Plant Pathology, The Ohio State University, Columbus 10, Ohio, U.S.A.     

Factors influencing pathogenicity of three isolates of colletotrichum graminicola on wheat

Summary Factors such as varieties of wheat, hydrogen ion and various mineral salts concentrations of soil having possible influence on the pathogenicity of certain isolates ofColletotrichum graminicola (Ces.)Wils. on wheat were studied. Of the six varieties of wheat studied, the variety Dual was highly susceptible, and the variety Knox highly resistant. The percentage seedling blight was greatest in soil at the highest pH values, 7.0–9.0. Concentrations of potassium nitrate, ammonium nitrate and magnesium sulfate in soil greatly influenced disease development.Portion of a Ph. D. thesis, Department of Botany and Plant Pathology, The Ohio State University, Columbus-10, Ohio, U.S.A.     

Sulphur and phosphorus requirements of Curvularia pallescens Boed

The effect of different sulphur and phosphorus compounds on the growth and sporulation ofCurvularia pallescens Boed. has been studied. Nine different sulphur sources were tried but among them only magnesium sulphate yielded the best dry weight of the fungus. Zinc sulphate, sodium sulphate, sodium thiosulphate, potassium sulphate and calcium sulphate supported good growth. Poor growth was recorded on sodium bisulphite, ammonium sulphate, sodium sulphide and control. Sporulation was excellent on magnesium sulphate. It was good on zinc sulphate, sodium sulphate and potassium sulphate. On sodium thiosulphate, calcium sulphate, sodium bisulphite and control it was fair. Sodium sulphide and ammonium sulphate had inhibitory effect as sporulation was poor and nil on these two compounds respectively.Six phosphorus compounds were studied. Tripotassium phosphate gave best growth and excellent sporulation. Good growth and excellent sporulation was recorded on monobasic potassium phosphate and magnesium phosphate. Growth and sporulation were good on dibasic potassium phosphate and sodium dihydrogen phosphate. Ammonium phosphate was poorly utilized.     

Alternaria tenuis Auct. in Bombay-Maharashtra

Summary This paper gives an account of distribution, host range and economic importance of the speciesAlternaria tenuis Auct, as it occurs in Bombay-Maharashtra (India). The species has been collected on 51 hosts distributed among 23 host families of which 5 are new host records not previously reported in literature.Part of the author's Ph. D. (Agri.) thesis approved by the University of Poona, Poona (India), 1964.Junior Research Fellow of the University Grants Commission, New Delhi, (India) in Mycology and Plant Pathology.     

Nitrogen and sulphur requirements of Colletotrichum inamdarii Lal

Summary Nitrogen and sulphur requirements ofColletotrichum inamdarii Lal isolated from the leaves ofCarissa carandas L. have been studied. DL-serine, L-asparagine and L-phenylalanine have been found to be of good nitrogen source followed by potassium nitrate, calcium nitrate, magnesium nitrate, DL-alanine, ammonium nitrate, glutamic acid, ammonium sulphate, DL-valine, aspartic acid, ammonium chloride, ammonium hydrogencarbonate, L-histidine and potassium nitrite. There was no growth in the absence of nitrogen.Sporulation was excellent on calcium nitrate and sodium nitrate, Very good on DL-serine, potassium nitrate, and magnesium nitrate. Good on L-asparagine, L-phenylalanine and ammonium oxalate. Fair on DL-alanine, DL-leucine, ammonium sulphate, DL-valine, ammonium chloride and L-histidine whereas poor on glutamic acid, aspartic acid, ammonium tartarate and ammonium nitrate. Few spores were observed on ammonium hydrogencarbonate but potassium nitrite did not show any sporulation.Amongst the sulphur compounds sodium bisulphate gave the best growth and good sporulation, followed by sodium thiosulphate, magnesium sulphate, ammonium sulphate and potassium sulphate. Thiourea gave negligible growth whereas it failed to grow on zinc sulphate and potassium persulphate.     

The epiphytology of spearmint rust in Indiana

Summary Field studies indicated that subterranean aecia ofPuccinia menthae Pers. are of little significance in the initiation of spearmint rust infection in undisturbed fields. Also, wild or escaped mints do not appear to be of significance. The primary source of inoculum comes either from fields that are not fall plowed or from infected rhizomes or transplants during spring planting. Temperatures during May appear to be critical in the development of rust epiphytotics. The predominant race of the pathogen occurring in Indiana corresponds to Race 1.Respectively, former graduate research assistant, Department of Botany and Plant Pathology, Purdue University, presently Assistant Plant Pathologist, University of Arizona, Mesa Branch Experiment Station, Mesa, Arizona; and Associate Plant Pathologist, Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana. Journal paper 2691. The authors thank Dr.M. J. Murray, A. M. Todd Company, Kalamazoo, Michigan, for species ofMentha used as race differentials. This research was supported, in part, by funds provided through the Mint Industries Research grant.     

Effect of different carbon and nitrogen sources on the growth and sporulation of Claviceps microcephal (Wallr) TUL.

The effect of different carbon and nitrogen compounds on growth and sporulation ofC. microcephala (Wallr.)Tul. causing ergot disease of Bajra has been studied. Nine different sources of carbon were used but cane sugar was found to be the best source for both, growth and sportulation of the fungus. Glucose, sucrose and maltose gave good growth but fair sporulation. Lactose and sorbitaol proved to be the poor sources. However, fungus failed to utilize starch, dextrin and mannitol.Nineteen nitrogen compounds were tried for the growth and sporulation of the fungus. Best growth and sporulation were supported by peptone and glycine. L-asparagine, DL-valine, Urea, magnesium nitrate and L-proline supported good growth and fair sporulation except DL-valine where it was excellent. Poor growth was obtained on L-isoleucin, ammonium sulphate, potassium nitrate,-alanine, ammonium chloride, DL-aspartic acid and DL-methionine. Fungus failed to utilize thio-urea.     

Studies on taphrina maculans butler,inciting leaf spot of turmeric (curcuma longa L.). I. Isolation of the pathogen

Summary T. maculans inciting leaf spot of turmeric is difficult to be isolated into a pure culture. The best stage of the spot development on turmeric which yielded successful isolations was either the initial or the middle stage expressing yellowish necrotic areas. The successful course of development of asci, ascospore and conidia has been worked out. By streaking ascospore and conidial suspensions, the spot bearing portions of leaves on the inner side of the lid thus placing them in hanging position above the plates poured with cleared and acidified potato dextrose agar or turmeric leaf decoction agar or by streaking sterile water washings from the chocolate brown spots on these media, it was possible to isolate successfully the pathogenic culture ofT. maculans at 20° C.Condensed from the thesis submitted by the senior author to the University of Poona for M. Sc. (Agri.) under the guidance of the junior author. Respectively Assistant Professor of Plant Pathology, College of Agri. Poona and Wheat Rust Mycologist, Mahabaleshwar, India.     

Studies on taphrina maculans butler inciting leaf spot of Turmeric (Curcuma Longa L.). III. Perpetuation and transmission of the disease

Summary The pathogenT. maculans inciting leaf spot of turmeric perpetuates in the form of ascospores and conidia and incites first infection on the lowermost leaves, in October and November when the atmospheric humidity prevails about 80 % with 21°–23° C temperatures. The secondary infection is due to availability of large potential of inoculum of ascospores and conidia frequently and periodically produced by the pathogen under cool temperature conditions (20°–24° C) with about 80 % atmospheric humidity. Plant debris, rhizomes etc. of the previously affected crop or soil from the fields where turmeric crop was taken in the previous season do not serve the primary source of infection.Condensed from the Thesis submitted by the senior author to the University of Poona for M. Sc. (Agri.) under the guidance of the Junior author.Respectively Assistant Professor of Plant Pathology.College of Agriculture, Poona and Wheat Rust Mycologist, Mahableshwar, India.     

An account of the fungus genus Alternaria nees from India

The paper deals with the taxonomy, distribution and host range of the fungus genusAlternaria Nees from India. The contributions made by various research workers in this country so far are also discussed.Taken from a Thesis submitted by the author for the degree of Doctor of Philosophy in the Faculty of Agriculture, Poona University, India.     

Influence of temperature upon growth and sporulation in two species of Phytophthora

The paper deals with the influence of temperature on the growth and sporulation of two species ofPhytophthora, viz.,P. palmivora Butl. andP. parasitica Dast. var.macrospora Ashby, the causal agents of fruit rots ofAchras sapota L. andAnona squamosa L. respectively. Germination of sporangia at different temperatures were also undertaken. There was marked variation in growth and sporulation of these two organisms. Isolate C (Phytophthora palmivora) showed no growth at 5° and 35°C, scanty growth at 10° and 32.5° with an optimum temperature between 26–28°C. On the other hand, Isolate S (Phytophthora parasitica var.macroscora) showed no growth at 10°C, but slight growth even at 37°C. Eight days exposure at 37°C completely stopped the growth of this Isolate. It showed best growth at 30°C and hence this was its optimum temperature. In general, Isolate C sporulated abundantly at all temperatures tested but reached its maximum at 25°C. On the other hand Isolate S showed best growth but failed to sporulate at any of the temperatures in 98 hours growth, although it sporulated freely when the incubation period extended up to two weeks. On the basis of temperature toleration the twoPhytophthora isolates are distinguished from each other as two different species. This confirms the earlier observations and nomenclature criterion as emphasized and formulated byTucker (1931). In the germination studies, it was observed that the indirect germination with the formation of abundant zoospores started from 5° and continued even up to 35°C, reaching maximum at 20°C. High temperature was not favourable for indirect germination. As the temperature proceeded increasing, the percentage of direct germination by formation of germ tubes also increased. Direct germination was observed from 10° which continued up to 37°C, with a maximum reach at 30°C. This confirms the epidemic of fruit rots in nature during monsoon season which is prevalent with the persistence of high humidity and rainfall.Taken from a thesis submitted by the author for the degree of Master of Science in the Faculty of Agriculture, Poona University, India.     

Some pathological studies in two species of Phytophthora

Summary The paper deals with some detailed pathological investigations with two species ofPhytophthora, viz.,Phytophthora palmivora andP. parasitica var.macrospora causing severe fruit rots ofAchras sapota andAnona squamosa respectively. Both the isolates were found pathogenic to a variety of fruits including papaya, tomato, chillis, banana, fig, apple, cucumber, guava, orange, onion bulb and potato tuber. They were, however, non-pathogenic to carrot, zinger, turmeric andColocasia corms. In the seedling inoculation experiment they showed pathogenic nature to castor bean, brinjal, cotton, sesamum, pea, French bean,Cactus sp. andBryophyllum leaves. It is interesting to note that only the Isolate S caused infection to the plants ofVinca rosea L., whereas the Isolate C failed to do so.This work frames up a part of Senior author's M.Sc. (Agri.) Thesis, approved by the University of Poona, India.Respectively, Ex-Junior Research Fellow (1958–60), Indian Council of Agricultural Research, New Delhi; Principal and Professor of Plant Pathology, College of Agriculture, Junagad, (Gujarat) and Mycologist, Wheat Rust Research Station, Mahabaleshwar (Satara Dist.) India.     

A new rust species ofRoestelia onSorbus collected in China

A rust species ofRoestelia onSorbus collected in China is newly described asR. echinulata. This species is morphologically different from the otherRoestelia spp. and aecial stages ofGymnosporangium species in surface structures of aeciospores and peridial cells. Contribution No. 141, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Some effects of organic acid supplementation on utilization of ammonium compounds by three pathogenic fungi

Utilization of ammonium nitrogen byFusarium moniliforme Sheld.,Curvularia verruciformis Agarwal &Sahni andSclerotium rolfsii Sacc., with and without organic acid supplementation was studied. Ammonium utilization by these organisms generally improved with small amounts of organic acid supplementation except in the case ofC. verruciformis on ammonium chloride where fumaric acid was observed to suppress utilization. Effects of supplementation were seen to be dependent on the nature of the organic acid, the ammonium source used and the organism employed. Further evidence obtained by varying the quantities of succinic acid in ammonium chloride media showed that higher levels of supplementation gave increased growth of the fungi and prevented the pH from falling. It seems that these acids play a dual role as pH buffers as well as nutritional compounds.     

Comparative studies on the effect of vitamins on sporulation in Fusarium oxysporum schlecht. ex. Fr. and Fusarium moniliforme V. subglutinans Wr. & Rg.

On the basis of sporulation (total output of all the three spore forms taken together) and fungal mat production bothF. oxysporum Schlecht ex.Fr. andF. moniliforme v.subglutinans Wr. &Rg. are auxoheterotrophic for thiamine, biotin, inositol, riboflavin and pyridoxine. The first three vitamins are selective in accelerating macro-conidial production also inF. moniliforme, which otherwise shows decrease with advance in days of incubation.F. moniliforme is an auxo-autotroph for nicotinic acid, Ca-pantothenate and folic acid and auxoheterotroph for ascorbic acid. Auxoautotrophy for Ca-pantothenate, folic acid, l-ascorbic acid and p-aminobenzoic acid cannot be suggested forF. oxysporum. Whereas nicotinic acid is a depressent of sporulation inF. oxysporum, inF. moniliforme another vitamin p-aminobenzoic acid depresses sporulation. As the two species ofFusarium show differences in preference as well as inhibition to at least five of the vitamins studied and also varied trends of pH changes exists there is full justification for their separate taxonomic placements.     

Urocystis tranzscheliana,a newly recorded smut fungus onPrimula sieboldii from Japan

A smut fungus onPrimula sieboldii was newly found in Japan and identified asUrocystis tranzscheliana by comparative morphology. This species causes systemic infection ofP. sieboldii and produces sori in its ovaries.Contribution No. 121, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba.