EFFECT OF POLYVERSUM AND FUNGAZIL 100 SL ON THE GROWTH OF HELMINTHOSPORIUM SOLANI 1. Abstract. Introduction

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1 Hugo Kołłątaj Agricultural University, Cracow, Poland EFFECT OF POLYVERSUM AND FUNGAZIL 100 SL ON THE GROWTH OF HELMINTHOSPORIUM SOLANI 1 I. Gajda and H. Kurzawińska Abstract An effect of biopreparate Polyversum and fungicide Fungazil 100 SL used for potato seed tuberdressing on control of Helminthosporium solani and in vitro growth inhibition of this pathogen was investigated. Both preparations showed high fungistatic activity to Helminthosporium solani. Key words: Helminthosporium solani, silver scurf, potato tubers, Polyversum, Fungazil 100 SL Introduction Potato diseases belong to factors causing losses in the production cycle. According to Kapsa (1999) the diseases developed on stored tubers cause not only storage losses and wastage but also affect both the market value of potatoes and the quality of seeds. Among pathogens causing potato skin blemish diseases, Helminthosporium solani Dur. et Mont. is the one responsible for silver scurf. The sources of infection include diseased seed potatoes (Kurzawińska 1989, Rudkiewicz and Sikorski 1986), soil (Hall 1996, Szutkowska 1999) and storage dust (Carnegie et al. 1996). The fungus looses tuber skin from the underneath tissues. The symptoms are visible in the form of irregular brownish-silver spots of various sizes that spread over the entire tuber surface. The damaged tuber skin increases evaporation, thus leading to tuber fading and drying. In the next step parenchyma darkens which results in decreasing market value of potatoes. The infected seeds could not sprout or its germination is very poor, thus reducing crops (Kapsa 1993, Kurzawińska 1990). 1 This work was supported by the State Committee for Scientific Research, grant No. 3 P06R Phytopathol. Pol. 32: The Polish Phytopathological Society, Poznań 2004

2 76 I. Gajda and H. Kurzawińska However, the mechanism of activity of Pythium oligandrum Drechsler is based on mycoparasitic faculty and antybiosis (Benhamou et al. 1999). Drechsler discovered mycoparasitic abilities of P. oligandrum in He found in in vitro tests that hyphae of this fungus growing on agar in the vicinity of P. ultimum Trow., rounded the pathogen mycelium and penetrated it. Therefore, the aim of this study was to investigate the efficiency of biopreparate Polyversum (containing P. oligandrum oospores) and fungicide Fungazil 100 SL in field and in vitro growth inhibition of H. solani. Materials and methods The field plot experiment was carried out with seven potato cultivars (four medium early: Balbina, Kolia, Maryna, Triada and three medium late: Ania, Beata, Bryza ) in the years Usefulness of biopreparate Polyversum (containing P. oligandrum oospores) in comparison to fungicide Fungazil 100 SL (imazalil active substance) was studied (recommendation of Institute of Plant Protection). The experiment was randomized (in three repetitions of 10 tubers) according to the following combinations: 1) seed tubers before planting with Polyversum biopreparate dressed, 2) seed tubers before planting with Fungazil 100 SL suspension (15 ml per 100 kg of tubers) dressed, 3) control untreated tubers. Immediately after harvesting, and then during and after storage the degree and percentage of diseased tubers were estimated in scale of 1 to 9, where: 1 healthy tuber, 3 up to 15% of tuber infected area, % of tuber infected area, % of tuber infected area, 9 above 60% of tuber infected area. The obtained results were subjected to statistical computation by variance analysis. The laboratory tests were carried out, by employing the poisoned agar method with the accordance to Kowalik and Krechniak (1961). The fungus H. solani was isolated from potato tubers showing silver scurf symptoms. The dissolved biopreparate Polyversum and fungicide Fungazil 100 SL were added to liquid PDA. The three concentrations of biopreparate (0.025, 0.05 and 0.1%) and fungicide (1, 10, 100 l/l of agar) were used. After pouring agar into dishes and allowing it to concentrate, in central dish an inoculum of 14-day pathogen cultures was laid. Dishes containing H. solani growing on agar without any additives were used as a control. The test was carried out in five repetitions (10 dishes in each). The measurements were started from the moment the first mycelium growth was observed in

3 Effect of Polyversum and Fungazil 100 SL control dishes and were continued until entire dish was covered with mycelium. The colony diameter was measured in two perpendicular directions and then the mean value was calculated for each repetition. The gathered data enabled the test fungi growth (T) and coefficient of linear growth inhibition (I) to be determined by using the formulae given by Burgieł (1979). Results Both Polyversum and Fungazil 100 SL have shown fungistatic activity to H. solani in field and laboratory tests (Tables 1, 2). For Polyversum the best effects of H. solani growth inhibition activity was observed on tubers of Ania, Bryza and Kolia cultivars in two years, whilst in the second year an effect on Beata potato cultivar was also indicated (Table 1). The use of Fungazil 100 SL indicated the strongest inhibition of silver scurf on tubers of Bryza potatoes. For this preparation the fastest fungicidal activity was observed on Triada. The tubers of this cultivar in various control combinations compared to other cultivars, were of the highest degree. The analysed data, cultivars and the combination used on tuber infestation by H. solani indicated a significant effect in the statistical analysis (Table 1). In laboratory test Fungazil 100 SL inhibited the growth of H. solani to the greatest extent in concentration of 100 l/l of agar. The coefficient of linear growth inhibition was 97%, while fungi linear growth index was 0.1 (Table 2). The lower concentration (10 l/l) of this fungicide also lead to remarkable growth inhibition of this pathogen on agar. Similar effects were observed for Polyversum in concentration of 0.1% (Table 2). Fungazil 100 SL in concentration of 1 l/l introduced into substratum showed the lowest activity in growth inhibition of H. solani (growth inhibition coefficient was 53%). Discussion Based on the obtained results it was found that Fungazil 100 SL is a good growth inhibitor of H. solani both in field and laboratory tests. Such powerful effect of Fungazil on the pathogen responsible for silver scurf, was reported by Bernat (2003). The author wrote that autumn treating of tubers with this preparation had an effect on disease inhibition after the end of storage season. Also studies carried out by Cayley et al. (1981, 1983) confirmed an effect of autumn tuber dressing with Fungazil 100 SL on the amount of diseased tubers and intensity of silver scurf. The performed test indicated fungistatic properties of Polyversum to this pathogen. Drechsler discovered mycoparasitic abilities of P. oligandrum in He found in in vitro tests that hyphae of this fungus growing on agar in the vicinity of P. ultimum, rounded the pathogen mycelium and penetrated it.

4 78 I. Gajda and H. Kurzawińska Effect of potato seed tuber dressing with Polyversum biopreparate and Fungazil 100 SL fungicide on Helminthosporium solani occurrence Combination Cultivar 2001/ / IX 02 I 02 III 02 IX 03 I 03 III a b a b a b a b a b a b Table1 Polyversum Ania abc a ab abc a abcd Balbina bcd cdefg ab abcd abc abc Beata bcd abc ab abc a abcd Bryza abc bcde ab ab a cd Kolia abc abcd ab abc abc abcd Maryna bcd bce ab cde a abcd Triada bcd bcdefg ab abcd ab cd Fungazil 100 SL Ania bcd ab ab abc a abcd Balbina a bcdef a abc abc ab Beata abc bcdefg ab abc abcd abcd Bryza ab ab b abc a d Kolia bcd defg b abc cde d Maryna bcd abc ab de ab abcd Triada def bcdef ab bcd a cd Control Ania bcd abcd ab cde abc abcd Balbina ef efg b de ef d Beata cde efg ab de ef d Bryza cde efg b de bcde d Kolia ef fg b de def d Maryna bcd ghi b de def d Triada f gh b e cde d Degrees of liberty a average degree of infection, b percentage of potato tubers infected. Means in columns bearing the same letters do not differ significantly.

5 Effect of Polyversum and Fungazil 100 SL Table 2 Effect of Polyversum biopreparate and Fungazil 100 SL fungicide on the growth of Helminthosporium solani Preparation, concentration Inhibition growth of fungus Index of linear growth of fungus Polyversum 0.025% % % 85 1 Fungazil 100 SL 1 l l l Control 6.1 Martin and Hancock (1987) reported that P. oligandrum occupied the ecological niche in soil and effectively competed with plant pathogens. By introducing this mycoparasite into soil, the population of microorganisms on seeds, tubers and rhizomes could be reduced, thus enhancing plant health. Applying Polyversum into the Chinese aster substratum improved health of these plants and the number of plants showing fusarium wilt symptoms was reduced considerably (Saniewska 2001). Summary The aim of work was comparison of Polyversum biopreparate and Fungazil 100 SL fungicide in potato protection against Helminthosporium solani. In field experiment conducted with seven cultivars of potato tubers, biopreparate Polyversum and fungicide Fungazil 100 SL were used. On the other hand, in laboratory experiment, biopreparate (in three concentrations: 0.1, 0.05, 0.025%) and fungicide (also in three concentrations: 100, 10, 1 l/l of medium) were introduced into medium, where later H. solani was grown. Results obtained showed the effect of biopreparate and fungicide in limitation growth of H. solani both in the field and laboratory experiment.

6 80 I. Gajda and H. Kurzawińska Streszczenie WPŁYW POLYVERSUM I FUNGAZILU 100 SL NA WZROST HELMINTHOSPORIUM SOLANI Celem pracy było porównanie biopreparatu Polyversum i fungicydu Fungazil 100 SL w ochronie ziemniaka przed Helminthosporium solani. W doświadczeniu polowym, które przeprowadzono na bulwach siedmiu odmian ziemniaka, zastosowano biopreparat Polyversum i fungicyd Fungazil 100 SL. Z kolei w doświadczeniu laboratoryjnym do pożywki, na której rósł H. solani, wprowadzano Polyversum (w trzech stężeniach: 0,1, 0,05, 0,025%) oraz Fungazil 100 SL (również w trzech stężeniach: 100, 10, 1 l/l pożywki). Uzyskane wyniki wykazały ochronne działanie biopreparatu i fungicydu przed H. solani zarówno w warunkach polowych, jak i laboratoryjnych. Literature Benhamou N., Picard K., Trilly Y., 1999: Ultrastructural and cytochemical aspects of the interaction between the mycoparasite Pythium oligandrum and soil-borne plant pathogens. Phytopathology 89: Bernat E., 2003: Możliwość ograniczania rozwoju chorób grzybowych w okresie przechowywania. In: Materiały z Konferencji: Nasiennictwo i ochrona ziemniaka. Kołobrzeg. IHAR, o. Bonin: Burgieł Z.J., 1979: Wpływ herbicydów stosowanych w pszenicy ozimej na występowanie chorób podsuszkowych. Manuscript. Doctor dissertation. Institute of Plant Protection, Agricultural University, Cracow. Carnegie S.F., Cameron A.M., Hadon P., 1996: The potato store a source of infection. In: Abstract 13th Trien. Conf. EAPR. Veldhoven. The Netherlands Cayley G.R., Hide G.A., Read P.J., Dunne Y., 1983: Treatment of potato seed and ware tubers with imazalil and thiabendazole for control of silver scurf and other storage diseases. Potato Res. 26: Cayley G.R., Hide G.A., Tillotson Y., 1981: The determination of imazalil on potatoes and its use in controlling potato storage diseases. Pestic. Sci. 12: Drechsler C., 1943: Two species of Pythium occurring in southern states. Phytopathology 33: Hall S.M., 1996: Sources of Helminthosporium solani inoculum during the potato crop cycle and its importance in contaminating healthy tubers. In: Abstract 13th Trien. Conf. EAPR. Veldhoven. The Netherlands Kapsa J., 1993: Choroby skórki bulw ziemniaka. Ziemn. Pol. 1: Kapsa J., 1999: Choroby ziemniaka występujące na wszystkich etapach jego rozwoju. Ochr. Rośl. 9: 4 7. Kowalik R., Krechniak E., 1961: Szczegółowa metodyka biologicznych i laboratoryjnych badańśrodków grzybobójczych. In: Materiały do metodyki badańbiologicznej oceny roślin. IOR, Poznań: Kurzawińska H., 1989: Wpływ trzech terminów sadzenia i czterech poziomów nawożenia azotowego na porażenie bulw wybranych odmian ziemniaka przez Helminthosporium solani (Dur. et Mont.). Zesz. Nauk. AR Krak. 234, Ogrodn. 18: Kurzawińska H., 1990: Wpływ terminów i gęstości sadzenia na porażenie bulw ziemniaka przez Helminthosporium solani (Dur. et Mont.). In: Phytopathologia Polonica XI. Materiały z sympozjum odbytego w dniach września w Szczecinie na temat Niepatogeniczna mikoflora w patologii roślin. Wydz. V PAN, PTFit, Poznań: Martin F.N., Hancock J.G., 1987: The use of Pythium oligandrum for biological control of preemergence damping-off caused by P. ultimum. Phytopathology 77:

7 Effect of Polyversum and Fungazil 100 SL Rudkiewicz F., Sikorski J., 1986: Wpływ porażenia sadzeniaków parchem srebrzystym (Helminthosporium solani Dur. Mont.) na ich wartość nasienną. Biul. Inst. Ziemn. 34: Saniewska A., 2001: Możliwość wykorzystania biopreparatu Polyversum w ochronie astrów chińskich przed Fusarium oxysporum f.sp. callistephi. Progr. Plant Prot. / Post. Ochr. Rośl. 41: Szutkowska M., 1999: Wpływ pogody oraz rodzaju gleby na porażenie bulw ziemniaka parchem srebrzystym (Helminthosporium solani Dur. et Mont.). Zesz. Probl. Post. Nauk Roln. 469: Authors address: Dr inż. Iwona Gajda, Prof. dr hab. Halina Kurzawińska, Hugo Kołłątaj Agricultural University, Department of Plant Protection, Al. 29 Listopada 54, Kraków, Poland iwonagajda@wp.pl Accepted for publication:

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