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Influence of Fungicides on Vesicular-Arbuscular Mycorrhizae in Sesamum indicum L.
Zentralbl. Mikrobiol. 148 (1993), 483-486 Gustav Fischer Verlag lena [Department of Botany, Nagarjuna University, Guntur, India]
Influence of Fungicides on Vesicular-Arbuscular Mycorrhizae in Sesamum indicum L. Eintlu8 von Fungiziden auf die Vesikular-Arbuskulare Mycorrhizae in Sesamum indicum L. M. Vijayalakshmi and A. S. Rao Key words: Vesicular-arbuscular mycorrhizae, fungicides, Sesamum
Summary The effects of three commonly used commercial formulations of fungicides (carbendazim, captan and blitox) on vesicular-arbuscular mycorrhizal development of sesamum when applied with 50-500 ppm a.i. at different timings were studied. Carbendazim and blitox, when applied to soil after 30 days of seed sowing significantly inhibited mycorrhizal colonization. Drenching the soil with blitox and captan just before seed sowing tended to enhance mycorrhizal colonization.
Zusammenfassung Es wurde der Effekt von drei Fungiziden: Carbendazim, Captan und Blitox (handelsiibliche Formulierungen) auf die Vesikular-arbuskulare Mycorrhiza, die sich auf Sesam entwickelt hatte, studiert und zwar in den Konzentrationen 50-500 ppm (aktive Form) und nach verschiedener Anwendungszeit. Carbendazim und Blitox - wenn 30 Tage nach Aussaat appliziert - hemmten signifikant die Mycorrhiza-Kolonisation. Befeuchtung des Bodens mit Blitox und Captan kurz vor der Aussaat, schien dagegen eine Mycorrhiza-Kolonisation zu erhiihen.
The increasing use of fungicides to control soil-borne fungal pathogens has developed concern about their effects on beneficial organisms like mycorrhizal fungi. The effects of systemic and non-systemic fungicides on root colonization by vesicular-arbuscular mycorrhizal (VAM) fungi often exhibit variation - which may sometimes be inhibitory, sometimes stimulatory and neutral in some instances (Jalali and Domsch 1975; Nemec 1980). Despite the use of certain fungicides like captan, carbendazim, benomyl etc. to control charcoal rot, wilt and damping-off of sesame caused by Macrophomina phaseolina, Fusarium oxysporum f. sp. sesami and Pythium ultimum respectively (EI-Deeb et al. 1985; Patel and Patel 1990), not much is known about their effects on VAM colonization of this oil seed crop under semi-arid tropical conditions. Hence, an attempt was made to report the effects of three fungitoxic chemicals on the development of VA mycorrhizae in potted sesame plants raised in field soil. The fungicides were studied in concentrations, usually applied to soil and also in higher concentrations (till 500 ppm), to see the effects even in such higher concentrations.
Material and Methods The soil used in all experiments was a red laterite with pH 8.2, deficient in phosphorus (0.001 % total P), contained 790-830 chlamydospores of Glomus species per kg soil as determined by the wet-sieving and decanting method (Gerdemann and Nicolson 1963). Earthen pots (20 cm wide and 19 cm deep) were filled with
484
M. Vijayalakshmi and A. S. Rao
potting medium consisting of a 2: I soil-sand mixture. Aqueous solutions of three fungicides viz. Bavistin (Carbendazim 50% WP - Methyl-IH-benzimidazole-2-yl carbamate); Captaf (Captan 50% WP - N(trichloromethylthio)-4-cyclohexene-l,2-dicarboximide) and Blitox (Copper oxychloride 50% WOP) were applied to the soil mixture at concentrations (based on weights of air-dried potting medium) of 50, 100, 200 and 500 ppm taking into consideration the active ingredient. Two sets of pots were maintained, of which one set was drenched with fungicides before sowing the seeds and another set after 30 days of seed sowing. Five pots with a minimum of five healthy plants in each were considered as a treatment. Potted plants receiving only water served as control. Ten plants from each treatment were harvested 45 and 60 days after sowing. The per cent root length colonized by mycorrhizal fungi was determined from a random sample (90-100) of 1 cm root pieces by the root-slide technique (Nicolson 1960), after clearing the roots with 10% KOH and staining with trypan blue (Phillips and Hayman 1970). The average dry weight of ten plants was determined after drying to constant weight at 70°C, after 60 days of sowing. The data were analysed statistically using analysis of variance.
Results and Discussion Mycorrhizal colonization of sesame was affected to varying degrees by treating the soil with different fungicides (Table 1). Carbendazim, when applied to soil before raising the crop, was found to enhance mycorrhizal colonization at 50 ppm, but was inhibitory at 100,200 and 500 ppm levels. When applied after 30 days of sowing, this systemic fungicide reduced Table 1. Effect of soil application of three fungicides on development of VAM fungi in sesamum. Fungicide tested (ppm)
% mycorrhizal colonization after 45 days of sowing
% mycorrhizal colonization after 60 days of sowing
Average dry matter (glplant)
(i)
(ii)
(i)
(ii)
(i)
(ii)
Control
41 (40)
41 (40)
57 (49)
57 (49)
0.94
0.94
Carbendazim 50 100 200 500 Mean C.D.
57 (49) 28 (32) 26 (31) 21 (27) 35.8 3.92
38 (38) 27 (31) 20 (26) 21 (27) 32.4 3.47
73 (59) 52 (46) 50 (45) 37 (37) 47.2 5.17
32 (34) 27 (31) 22 (28) 18 (25) 33.4 4.87
0.97 0.94 0.92 0.84 0.92 0.06
0.94 0.93 0.88 0.81 0.90 0.06
Blitox 50 100 200 500 Mean C.D.
59 (50) 57 (49) 61 (51) 63 (52) 48.4 2.45
41 (40) 36 (37) 25 (30) 28 (32) 35.8 3.17
69 (56) 74 (59) 60 (51) 60 (51) 53.2 4.53
50 (45) 43 (41) 37 (37) 33 (35) 41.4 3.59
0.99 0.98 0.93 0.91 0.95
0.91 0.92 0.88 0.88 0.90
Captan 50 100 200 500 Mean C.D.
63 (52) 69 (56) 68 (55) 62 (52) 51 5.08
50 52 50 49 44
73 (59) 75 (60) 74 (59) 68 (55) 56.4 6.04
65 (54) 60 (51) 58 (50) 58 (50) 50.8
0.99 1.02 0.98 0.96 0.97
0.98 0.99 0.93 0.91 0.95
(45) (46) (45) (44)
(i) Fungicide applied to soil before seed sowing (ii) Fungicide applied to soil after 30 days of sowing % root colonization values after arcsin transformation are given in parenthesis
Influence of Fungicides on Mycorrhiza
485
mycorrhizal infection at the four concentrations tested. Similarly, carbendazim was shown to have toxic effect on the mycorrhizal formation of Allium cepa, Cicer arietinum, Triticum aestivum and Vigna radiata (Giovannetti and Riess 1980; Jalali and Thareja 1982). Other systemic fungicides like benomyl, calixin, topsin, vitavax etc. appear capable of reducing infection of mycorrhizal fungi (Jalali and Domsch 1975; Sutton and Sheppard 1976; De Bertoldi et al. 1977). Menge (1982) opined that systemic fungicides have more damaging effect to mycorrhizal symbiosis than nonsystemic ones since they can affect spore germination and infection as well as growth of VA mycorrhizae within the root. Plant growth was also adversely affected with this fungicide when applied at high concentrations. Application of blitox to the soil before raising the crop tended to increase mycorrhizal colonization at all the concentrations tested. But it became inhibitory when applied after 30 days of sowing. As it takes 2 - 3 weeks for the initial colonization of plant roots by mycorrhizal fungi (Vijayalakshmi and Rao 1988), this non-systemic fungicide may not have much effect by that time. Instead, by reducing root pathogens that compete with mycorrhizal fungi, it may ultimately increase mycorrhizal infection. But it seems to have direct effect on mycorrhizal colonization when applied after 30 days of seed sowing. Trappe et al. (1984) opined that the targeted site of application seems to be more important in that fungicides applied as foliage sprays may not affect mycorrhiza formation as much as those that are applied directly to soil. The inhibitory effect of this fungicide when applied after 30 days of sowing as observed in the present study may be the result of soil application of this chemical. A slight reduction in plant growth was noticed in the samples receiving the chemical after 30 days of sowing, which may be due to reduction in mycorrhizal colonization. The dicarboximide fungicide, captan, was found to increase mycorrhizal colonization particularly when applied to soil before sowing the crop, at all the concentrations tested. Such a stimulatory effect on mycorrhizal colonization was observed earlier with captan and captafol (Sutton and Sheppard 1976; Nemec 1980). Several fungicides can improve mycorrhizal colonization of plant roots by reducing the numbers of mycorrhizal hyperparasites and predators (Daniels and Menge 1980). But it did not have much effect when applied to soil after 30 days of seed sowing. Dry matter content of plants receiving this non-systemic fungicide was slightly high particularly at low concentrations when compared to the control. As mycorrhizae are necessary components of most plant systems, pesticides that affect mycorrhizal formation will affect system productivity. Since the effects of fungicides on mycorrhizal infection vary with the nature of the crop plant and the fungal endophyte as well as with the soil conditions, attention must be given to the three components to assess the real effect of chemicals.
References Daniels, B. A., Menge, J. A.: Hyperparasitization of vesicular-arbuscular mycorrhizal fungi. Phytopatho!. 70 (1980), 584-588. de Bertoldi, M., Giovannetti, M., Griselli, M., Rambelli, A.: Effects of soil application of benomyl and captan on the growth of onions and the occurrence of endophytic mycorrhizas and rhizosphere microbes. Ann. App!. Bio!. 86 (1977), 111-115. El-Deeb, A. A., Hilal, A. A., Radwani, I. A., Ali, A. A., Mohamed, H. A.: Varietal reaction and fungicidal effect to root rot and wilt disease of sesame. Ann. Agric. Sci. Moshtor, 23 (1985), 713-721. Gerdemann, J. W., Nicolson, T. H.: Spores of mycorrhizal Endogone species extracted from soil by wetsieving and decanting. Trans. Brit. Mycol. Soc. 46 (1963), 235-244. Giovannetti, M., Riess, S.: Effects of soil applications of systemic fungicides on bulb formation in onion. Plant Soil, 57 (1980), 463-465. Jalali, B. L., Domsch, K. H.: Effect of systemic fungitoxicants on the development of endotrophic mycorrhiza. In: Endomycorrhizas. (Eds.) F. E. Sanders, B. Mosse and P. B. Tinker, Academic Press, London, 1975, pp. 619-626.
486
M. Vijayalakshmi and A. S. Rao
Jalali, B. L., Thareja, M. L.: Studies on the plant growth responses to vesicular-arbuscular mycorrhiza. Haryana Univ. Dept. Plant Pathol. ICAR Rep., 1982, 31 pp. Menge, J. A.: Effect of soil fumigants and fungicides on vesicular-arbuscular fungi. Phytopathol. 72 (1982), 1125-1132. Nemec, S.: Effects of II fungicides on endomycorrhizal development in sour orange. Can. J. Bot. 58 (1980), 522-526. Nicolson, T. H.: Mycorrhiza in the Gramineae. II. Development in different habitats, particularly sand dunes. Trans. Brit. Mycol. Soc. 43 (1960), 132-145. Patel, K. K., Patel, A. J.: Control of charcoal rot of sesamum. Ind. J. Mycol. Plant Pathol. 20 (1990),62-63. Phillips, 1. M., Hayman, D. S.: Improved procedures for clearing roots and staining parasitic and vesiculararbuscular mycorrhizal fungi for rapid assessment of infection. Trans. Brit. Mycol. Soc. 55 (1970), 158-161. Sutton, J. c., Sheppard, B. R.: Aggregation of sand-dune soil by endomycorrhizal fungi. Can. J. Bot. 54 (1976), 326- 333. Trappe, J. M., Molina, R., Castellano, M.: Reactions of mycorrhizal fungi and mycorrhizal formation to pesticides. Ann. Rev. Phytopathol. 22 (1984),331-359. Vijayalakshmi, M., Rao, A. S.: Vesicular-arbuscular mycorrhizal associations of sesamum. Proc. Ind. Acad. Sci. (Plant Sci.), 98 (1988), 55-59. Authors' address: Dr. M. Vijayalakshmi and Prof. A. S. Rao, Department of Botany, Nagarjuna University, Guntur, A. P., India.
Zentralbl. Mikrobiol. 148 (1993), 486 Gustav Fischer Verlag Jena
Buchbesprechung Bomer, H., und Zunke, U.: Praktikum der Phytopathoiogie. Ein Farbatlas fiir Studium und Praxis (Pareys Studientexte 75) Verlag Paul Parey, Berlin und Hamburg 1992. 66 Seiten, 124 Farbabb. und 124 Zeichnungen. Kart. Preis DM 46,-. ISBN 3-489-61126-8. Das reich iIIustrierte Biindchen stell! eine Auswahl phytopathogener Viren, Bakterien und (ganz iiberwiegend) Pilze vor. Sowohl taxonomische Gruppen (Subphyla, Klassen) als auch einzeIne Arlen werden verbal charakterisiert. Symptome und namentlich lichtmikroskopische Merkmale werden einerseits (1 bis 6 pro Erreger), andererseits durch von diesen Fotos abgeleitete Zeichnungen iIIustriert. Diese Bilder, darunter viele gefarbte Schnitte, sind meist hervorragend gelungen und zeigen typische Merkmale in wiinschenswerter Klarheit. Die Anordnung folgt nicht den Wirtspflanzen und Symptomen, sondem dem aktuellen Pilzsystem. Viren und Bakterien kommen in diesem schmalen Buch sehr kurz weg. Was die Pi1ze betrifft, handelt es sich um eine zwar knapp gehaltene, aber gehaltvolle und kompetente Einflihrung in die mikroskopischtaxonomische Untersuchung pilzlicher Erreger von Pflanzenkrankheiten. Die Verfasser haben sich ihre Arbeit nicht leicht gemacht und mit didaktischem Geschick ein iibersichtliches Blindchen geschaffen, an welchem sowohl Studenten als auch Praktiker Nutzen und Freude haben werden. In zukiinftige Auflagen sollten auch einige Hinweise auf die verwendeten Schnitt- und Flirbemethoden eingearbeitet werden, darnit die Priiparation leichter nachvollzogen werden kann. H. Kreisel, Greifswald
Influence of Fungicides on Vesicular-Arbuscular Mycorrhizae in Sesamum indicum L. Eintlu8 von Fungiziden auf die Vesikular-Arbuskulare Mycorrhizae in Sesamum indicum L. M. Vijayalakshmi and A. S. Rao Key words: Vesicular-arbuscular mycorrhizae, fungicides, Sesamum
Summary The effects of three commonly used commercial formulations of fungicides (carbendazim, captan and blitox) on vesicular-arbuscular mycorrhizal development of sesamum when applied with 50-500 ppm a.i. at different timings were studied. Carbendazim and blitox, when applied to soil after 30 days of seed sowing significantly inhibited mycorrhizal colonization. Drenching the soil with blitox and captan just before seed sowing tended to enhance mycorrhizal colonization.
Zusammenfassung Es wurde der Effekt von drei Fungiziden: Carbendazim, Captan und Blitox (handelsiibliche Formulierungen) auf die Vesikular-arbuskulare Mycorrhiza, die sich auf Sesam entwickelt hatte, studiert und zwar in den Konzentrationen 50-500 ppm (aktive Form) und nach verschiedener Anwendungszeit. Carbendazim und Blitox - wenn 30 Tage nach Aussaat appliziert - hemmten signifikant die Mycorrhiza-Kolonisation. Befeuchtung des Bodens mit Blitox und Captan kurz vor der Aussaat, schien dagegen eine Mycorrhiza-Kolonisation zu erhiihen.
The increasing use of fungicides to control soil-borne fungal pathogens has developed concern about their effects on beneficial organisms like mycorrhizal fungi. The effects of systemic and non-systemic fungicides on root colonization by vesicular-arbuscular mycorrhizal (VAM) fungi often exhibit variation - which may sometimes be inhibitory, sometimes stimulatory and neutral in some instances (Jalali and Domsch 1975; Nemec 1980). Despite the use of certain fungicides like captan, carbendazim, benomyl etc. to control charcoal rot, wilt and damping-off of sesame caused by Macrophomina phaseolina, Fusarium oxysporum f. sp. sesami and Pythium ultimum respectively (EI-Deeb et al. 1985; Patel and Patel 1990), not much is known about their effects on VAM colonization of this oil seed crop under semi-arid tropical conditions. Hence, an attempt was made to report the effects of three fungitoxic chemicals on the development of VA mycorrhizae in potted sesame plants raised in field soil. The fungicides were studied in concentrations, usually applied to soil and also in higher concentrations (till 500 ppm), to see the effects even in such higher concentrations.
Material and Methods The soil used in all experiments was a red laterite with pH 8.2, deficient in phosphorus (0.001 % total P), contained 790-830 chlamydospores of Glomus species per kg soil as determined by the wet-sieving and decanting method (Gerdemann and Nicolson 1963). Earthen pots (20 cm wide and 19 cm deep) were filled with
484
M. Vijayalakshmi and A. S. Rao
potting medium consisting of a 2: I soil-sand mixture. Aqueous solutions of three fungicides viz. Bavistin (Carbendazim 50% WP - Methyl-IH-benzimidazole-2-yl carbamate); Captaf (Captan 50% WP - N(trichloromethylthio)-4-cyclohexene-l,2-dicarboximide) and Blitox (Copper oxychloride 50% WOP) were applied to the soil mixture at concentrations (based on weights of air-dried potting medium) of 50, 100, 200 and 500 ppm taking into consideration the active ingredient. Two sets of pots were maintained, of which one set was drenched with fungicides before sowing the seeds and another set after 30 days of seed sowing. Five pots with a minimum of five healthy plants in each were considered as a treatment. Potted plants receiving only water served as control. Ten plants from each treatment were harvested 45 and 60 days after sowing. The per cent root length colonized by mycorrhizal fungi was determined from a random sample (90-100) of 1 cm root pieces by the root-slide technique (Nicolson 1960), after clearing the roots with 10% KOH and staining with trypan blue (Phillips and Hayman 1970). The average dry weight of ten plants was determined after drying to constant weight at 70°C, after 60 days of sowing. The data were analysed statistically using analysis of variance.
Results and Discussion Mycorrhizal colonization of sesame was affected to varying degrees by treating the soil with different fungicides (Table 1). Carbendazim, when applied to soil before raising the crop, was found to enhance mycorrhizal colonization at 50 ppm, but was inhibitory at 100,200 and 500 ppm levels. When applied after 30 days of sowing, this systemic fungicide reduced Table 1. Effect of soil application of three fungicides on development of VAM fungi in sesamum. Fungicide tested (ppm)
% mycorrhizal colonization after 45 days of sowing
% mycorrhizal colonization after 60 days of sowing
Average dry matter (glplant)
(i)
(ii)
(i)
(ii)
(i)
(ii)
Control
41 (40)
41 (40)
57 (49)
57 (49)
0.94
0.94
Carbendazim 50 100 200 500 Mean C.D.
57 (49) 28 (32) 26 (31) 21 (27) 35.8 3.92
38 (38) 27 (31) 20 (26) 21 (27) 32.4 3.47
73 (59) 52 (46) 50 (45) 37 (37) 47.2 5.17
32 (34) 27 (31) 22 (28) 18 (25) 33.4 4.87
0.97 0.94 0.92 0.84 0.92 0.06
0.94 0.93 0.88 0.81 0.90 0.06
Blitox 50 100 200 500 Mean C.D.
59 (50) 57 (49) 61 (51) 63 (52) 48.4 2.45
41 (40) 36 (37) 25 (30) 28 (32) 35.8 3.17
69 (56) 74 (59) 60 (51) 60 (51) 53.2 4.53
50 (45) 43 (41) 37 (37) 33 (35) 41.4 3.59
0.99 0.98 0.93 0.91 0.95
0.91 0.92 0.88 0.88 0.90
Captan 50 100 200 500 Mean C.D.
63 (52) 69 (56) 68 (55) 62 (52) 51 5.08
50 52 50 49 44
73 (59) 75 (60) 74 (59) 68 (55) 56.4 6.04
65 (54) 60 (51) 58 (50) 58 (50) 50.8
0.99 1.02 0.98 0.96 0.97
0.98 0.99 0.93 0.91 0.95
(45) (46) (45) (44)
(i) Fungicide applied to soil before seed sowing (ii) Fungicide applied to soil after 30 days of sowing % root colonization values after arcsin transformation are given in parenthesis
Influence of Fungicides on Mycorrhiza
485
mycorrhizal infection at the four concentrations tested. Similarly, carbendazim was shown to have toxic effect on the mycorrhizal formation of Allium cepa, Cicer arietinum, Triticum aestivum and Vigna radiata (Giovannetti and Riess 1980; Jalali and Thareja 1982). Other systemic fungicides like benomyl, calixin, topsin, vitavax etc. appear capable of reducing infection of mycorrhizal fungi (Jalali and Domsch 1975; Sutton and Sheppard 1976; De Bertoldi et al. 1977). Menge (1982) opined that systemic fungicides have more damaging effect to mycorrhizal symbiosis than nonsystemic ones since they can affect spore germination and infection as well as growth of VA mycorrhizae within the root. Plant growth was also adversely affected with this fungicide when applied at high concentrations. Application of blitox to the soil before raising the crop tended to increase mycorrhizal colonization at all the concentrations tested. But it became inhibitory when applied after 30 days of sowing. As it takes 2 - 3 weeks for the initial colonization of plant roots by mycorrhizal fungi (Vijayalakshmi and Rao 1988), this non-systemic fungicide may not have much effect by that time. Instead, by reducing root pathogens that compete with mycorrhizal fungi, it may ultimately increase mycorrhizal infection. But it seems to have direct effect on mycorrhizal colonization when applied after 30 days of seed sowing. Trappe et al. (1984) opined that the targeted site of application seems to be more important in that fungicides applied as foliage sprays may not affect mycorrhiza formation as much as those that are applied directly to soil. The inhibitory effect of this fungicide when applied after 30 days of sowing as observed in the present study may be the result of soil application of this chemical. A slight reduction in plant growth was noticed in the samples receiving the chemical after 30 days of sowing, which may be due to reduction in mycorrhizal colonization. The dicarboximide fungicide, captan, was found to increase mycorrhizal colonization particularly when applied to soil before sowing the crop, at all the concentrations tested. Such a stimulatory effect on mycorrhizal colonization was observed earlier with captan and captafol (Sutton and Sheppard 1976; Nemec 1980). Several fungicides can improve mycorrhizal colonization of plant roots by reducing the numbers of mycorrhizal hyperparasites and predators (Daniels and Menge 1980). But it did not have much effect when applied to soil after 30 days of seed sowing. Dry matter content of plants receiving this non-systemic fungicide was slightly high particularly at low concentrations when compared to the control. As mycorrhizae are necessary components of most plant systems, pesticides that affect mycorrhizal formation will affect system productivity. Since the effects of fungicides on mycorrhizal infection vary with the nature of the crop plant and the fungal endophyte as well as with the soil conditions, attention must be given to the three components to assess the real effect of chemicals.
References Daniels, B. A., Menge, J. A.: Hyperparasitization of vesicular-arbuscular mycorrhizal fungi. Phytopatho!. 70 (1980), 584-588. de Bertoldi, M., Giovannetti, M., Griselli, M., Rambelli, A.: Effects of soil application of benomyl and captan on the growth of onions and the occurrence of endophytic mycorrhizas and rhizosphere microbes. Ann. App!. Bio!. 86 (1977), 111-115. El-Deeb, A. A., Hilal, A. A., Radwani, I. A., Ali, A. A., Mohamed, H. A.: Varietal reaction and fungicidal effect to root rot and wilt disease of sesame. Ann. Agric. Sci. Moshtor, 23 (1985), 713-721. Gerdemann, J. W., Nicolson, T. H.: Spores of mycorrhizal Endogone species extracted from soil by wetsieving and decanting. Trans. Brit. Mycol. Soc. 46 (1963), 235-244. Giovannetti, M., Riess, S.: Effects of soil applications of systemic fungicides on bulb formation in onion. Plant Soil, 57 (1980), 463-465. Jalali, B. L., Domsch, K. H.: Effect of systemic fungitoxicants on the development of endotrophic mycorrhiza. In: Endomycorrhizas. (Eds.) F. E. Sanders, B. Mosse and P. B. Tinker, Academic Press, London, 1975, pp. 619-626.
486
M. Vijayalakshmi and A. S. Rao
Jalali, B. L., Thareja, M. L.: Studies on the plant growth responses to vesicular-arbuscular mycorrhiza. Haryana Univ. Dept. Plant Pathol. ICAR Rep., 1982, 31 pp. Menge, J. A.: Effect of soil fumigants and fungicides on vesicular-arbuscular fungi. Phytopathol. 72 (1982), 1125-1132. Nemec, S.: Effects of II fungicides on endomycorrhizal development in sour orange. Can. J. Bot. 58 (1980), 522-526. Nicolson, T. H.: Mycorrhiza in the Gramineae. II. Development in different habitats, particularly sand dunes. Trans. Brit. Mycol. Soc. 43 (1960), 132-145. Patel, K. K., Patel, A. J.: Control of charcoal rot of sesamum. Ind. J. Mycol. Plant Pathol. 20 (1990),62-63. Phillips, 1. M., Hayman, D. S.: Improved procedures for clearing roots and staining parasitic and vesiculararbuscular mycorrhizal fungi for rapid assessment of infection. Trans. Brit. Mycol. Soc. 55 (1970), 158-161. Sutton, J. c., Sheppard, B. R.: Aggregation of sand-dune soil by endomycorrhizal fungi. Can. J. Bot. 54 (1976), 326- 333. Trappe, J. M., Molina, R., Castellano, M.: Reactions of mycorrhizal fungi and mycorrhizal formation to pesticides. Ann. Rev. Phytopathol. 22 (1984),331-359. Vijayalakshmi, M., Rao, A. S.: Vesicular-arbuscular mycorrhizal associations of sesamum. Proc. Ind. Acad. Sci. (Plant Sci.), 98 (1988), 55-59. Authors' address: Dr. M. Vijayalakshmi and Prof. A. S. Rao, Department of Botany, Nagarjuna University, Guntur, A. P., India.
Zentralbl. Mikrobiol. 148 (1993), 486 Gustav Fischer Verlag Jena
Buchbesprechung Bomer, H., und Zunke, U.: Praktikum der Phytopathoiogie. Ein Farbatlas fiir Studium und Praxis (Pareys Studientexte 75) Verlag Paul Parey, Berlin und Hamburg 1992. 66 Seiten, 124 Farbabb. und 124 Zeichnungen. Kart. Preis DM 46,-. ISBN 3-489-61126-8. Das reich iIIustrierte Biindchen stell! eine Auswahl phytopathogener Viren, Bakterien und (ganz iiberwiegend) Pilze vor. Sowohl taxonomische Gruppen (Subphyla, Klassen) als auch einzeIne Arlen werden verbal charakterisiert. Symptome und namentlich lichtmikroskopische Merkmale werden einerseits (1 bis 6 pro Erreger), andererseits durch von diesen Fotos abgeleitete Zeichnungen iIIustriert. Diese Bilder, darunter viele gefarbte Schnitte, sind meist hervorragend gelungen und zeigen typische Merkmale in wiinschenswerter Klarheit. Die Anordnung folgt nicht den Wirtspflanzen und Symptomen, sondem dem aktuellen Pilzsystem. Viren und Bakterien kommen in diesem schmalen Buch sehr kurz weg. Was die Pi1ze betrifft, handelt es sich um eine zwar knapp gehaltene, aber gehaltvolle und kompetente Einflihrung in die mikroskopischtaxonomische Untersuchung pilzlicher Erreger von Pflanzenkrankheiten. Die Verfasser haben sich ihre Arbeit nicht leicht gemacht und mit didaktischem Geschick ein iibersichtliches Blindchen geschaffen, an welchem sowohl Studenten als auch Praktiker Nutzen und Freude haben werden. In zukiinftige Auflagen sollten auch einige Hinweise auf die verwendeten Schnitt- und Flirbemethoden eingearbeitet werden, darnit die Priiparation leichter nachvollzogen werden kann. H. Kreisel, Greifswald