Skip to main content

Pseudomonas for biological control of Dutch elm disease. III. Field trials at various locations in the Netherlands

Abstract

The prophylactic effect in elm of one treatment with aPseudomonas isolate was monitored in two types of field trials. In one type only natural Dutch elm disease infections were monitored and hence large numbers of trees were necessary due to the low incidence of natural occurring infections. In the other type trees were artificially infected.

The large-scale field trials in which only natural infections were monitored, were based on expected annual losses due to Dutch elm disease of approximately 2%. As a result of the Dutch sanitation program, which was based on the prompt removal of every weakened or diseased elm, the actual losses were generally threefold lower. Dutch elm disease incidence was 22–45% lower in the trees treated with aPseudomonas isolate in the year of treatment and the year after. The results of the biocontrol treatment were negatively influenced because on several locations trees were felled that showed initial signs of Dutch elm disease, which probably would have disappeared during the season.

The advantage of artificial infections withOphiostoma ulmi was a reproducable development of symptoms and the possibility to maintain diseased trees, at least till the first signs of elm bark beetle breeding. For ‘Commelin’ elms an increase in symptoms was observed with increasingO. ulmi dose till 3000 conidia per tree; the standard 500 000 conidia used for most experiments was well above this critical value. No decrease in effectiveness of the bacterial pre-treatment was observed with increasingO. ulmi inoculum. Different bacterial treatments suggested that injections at a smaller interval (i.e. more injections per tree) may result in a better prophylactic effect, but the significance of the correlation remained doubtful. A comparison of several elm species and clones showed the importance of the host tree. Prophylaxis as a result of one bacterial treatment was shown repeatedly in ‘Commelin’ elms; the numbers of trees showing symptoms by the end of the second year were 10 to 85% lower in the bacteria-treated groups in comparison with the controls. Also in one experiment with ‘Belgica’ elms prophylaxis was observed, resulting in a 84% decrease in the number of trees showing symptoms by the end of the second year after the prophylactic treatment followed by inoculation withO. ulmi. In ‘Vegeta’ symptom development was only less severe and in field elms (Ulmus carpinifolia) some prophylactic effect was observed in one experiment, but no effect in two others.

Samenvatting

De mogelijke bescherming tegen de iepeziekte, verkregen door injectie van de boom met bacteriën van het geslachtPseudomonas, werd gemeten in twee soorten experimenten. In het ene soort werden natuurlijke infecties gemeten, waardoor grote proefgroepen nodig waren. In het andere soort werden de iepen kunstmatig geinfecteerd.

De grootschalige veldexperimenten waarbij natuurlijke iepeziekte-infecties werden gemeten, waren gebaseerd op een verwachte jaarlijkse uitval van 2%. Als gevolg van de landelijke bestrijdingscampagne bleken de verliezen slechts ongeveer een derde hiervan te zijn. Er kwam minder iepeziekte voor in de metPseudomonas geïnjecteerde bomen in het jaar van injectie en in het jaar daarna. Een storende invloed op de resultaten had het effect dat ook met bacteriën geïnjecteerde bomen soms beginnende symptomen vertonen na infectie metOphiostoma ulmi, symptomen die in de loop van het seizoen soms weer verdwijnen. Als gevolg van de bestrijdingscampagne werden zulke bomen toch geveld.

Het voordeel van kunstmatige infecties metO. ulmi was een voorspelbaar verloop van de symptoomontwikkeling en de mogelijkheid om zieke bomen te laten staan tot er iepespintkevers in kwamen. In ‘Commelin’ iepen bleken de symptomen toe te nemen met een tot 3000 conidiën per boom toenemende dosisO. ulmi. De gebruikelijke 500000 conidiën die in de meeste experimenten werden gebruikt lagen ver boven deze kritische waarde. Er werd geen effect van een toenemende dosisO. ulmi op de effectiviteit van een bacteriebehandeling waargenomen.

Uit variaties in de diverse bacteriebehandelingen kwam naar voren dat injecties met een kleinere tussenruimte (dus meer injecties per boom) mogelijk het effect verbeterden, maar de significantie van deze correlatie bleef twijfelachtig.

Vergelijken van diverse iepen toont dat soort en kloon type een belangrijke rol speelt bij deze bestrijdingsmethode. Bescherming tegen de iepeziekte als gevolg van een bacteriebehandeling werd diverse malen aangetoond in ‘Commelin’ iepen; het aantal bomen met iepeziekte-symptomen was aan het eind van het tweede seizoen in de met bacteriën behandelde groepen 10 tot 85 % lager dan in de controlegroepen. Ook in een experiment met ‘Belgica’ iepen werd een goede bescherming gemeten. In ‘Vegeta’ werd slechts een verminderde symptoomontwikkeling gemeten en in veldiepen (U. carpinifolia) werd enige bescherming gevonden in één experiment, maar geen effect in twee andere.

This is a preview of subscription content, access via your institution.

References

  1. Conover, W.J., 1971. Practival nonparametric statistics. John Wiley & sons, Inc., New York.

    Google Scholar 

  2. Dunn, O.J., 1964. Multiple comparisons using rank sums. Technometrics 6: 241–251.

    Google Scholar 

  3. Elgersma D.M. & Heybroek, H.M., 1979. Spread and survival of an aggressive and a non-aggressive strain ofOphiostoma ulmi in elms. Netherlands Journal of Plant Pathology 85: 235–240.

    Google Scholar 

  4. Geels, F.P. & Schippers, B., 1983a. Selection of antagonistic fluorescentPseudomonas spp. and their root colonization and persistence following treatment of seed potatoes. Phytopathologische Zeitschrift 108: 193–206.

    Google Scholar 

  5. Geels, F.P. & Schippers, B., 1983b. Reduction of yield depressions in high frequency potato cropping soil after seed tuber treatments with antagonistic fluorescentPseudomonas spp.. Phytopathologische Zeitschrift 108: 207–214.

    Google Scholar 

  6. Hollander, M. & Wolfe, D.A., 1973. Nonparametric statistical methods. John Wiley & sons, Inc., New York.

    Google Scholar 

  7. Jeng, R.S., Bernier, L. & Brasier, C.M., 1988. A comparative study of cultural and electrophoretic characteristics of the Eurasian and North American races ofOphiostoma ulmi. Canadian Journal of Botany 66: 1325–1333.

    Google Scholar 

  8. King, E.O., Ward, M.K. & Raney, D.E. 1954., Two simple media for the demonstration of pyocyanin and fluorescin. Journal of Laboratory and Clinical Medicine 44: 301–307.

    PubMed  Google Scholar 

  9. Mukerji, K.G. & Garg, K.L., 1988. Biocontrol of plant diseases. CRC Press, Inc., Boca Raton, FL.

    Google Scholar 

  10. Murdoch, C.M., Campana, R.J. & Hoch, J., 1986. Development of Dutch elm disease inhibited by fluorescent pseudomanads. Biological and Cultural Tests 1: 71.

    Google Scholar 

  11. Myers, D.F. & Strobel, G.A., 1983.Pseudomonas syringae as a microbial antagonist ofCeratocystis ulmi in the apoplast of american elm. Transactions of the British mycological Society 80: 389–394.

    Google Scholar 

  12. Scheffer, R.J. 1983a. Biological control of Dutch elm disease byPseudomonas species. Annals of Applied Biology 103: 21–30.

    Google Scholar 

  13. Scheffer, R.J., 1983b.Pseudomonas treatments as a possible control method for Dutch elm disease Proceedings 24e Colloque de la Société Française de Phytopathologie, Bordeaux, May 26–28, 1983. Les Colloques de l'INRA no. 18, p. 131–136.

    Google Scholar 

  14. Scheffer, R.J., Elgersma, D.M., Weger, L.A. de & Strobel, G.A, 1989a.Pseudomonas for biological control of Dutch elm disease. I. Labeling, detection and identification ofPseudomonas isolates injected into elms; comparison of various methods. Netherlands Journal of Plant Pathology 95: 281–292.

    Google Scholar 

  15. Scheffer, R.J., Elgersma, D.M. & Strobel, G.A., 1989b.Pseudomonas for biological Dutch elm disease. II. Further studies on the localization, persistence and ecology ofPseudomonas isolates injected into elms. Netherlands Journal of Plant Pathology 95: 293–304.

    Google Scholar 

  16. Shi, J.L. & Brasier, C.M., 1986. Experiments on the control of Dutch elm disease by injection ofPseudomonas species. European Journal of Forest Pathology 16: 280–292.

    Google Scholar 

  17. Strobel, G.A. & Myers, D.F., 1982. Bacterial antagonism as a strategy for the treatment of Dutch elm disease. In: Kondo, E.S., Hiratsuka, Y. & Denyer, W.B.G. (Eds), Proceedings of the Dutch Elm Disease Symposium and Workshop, October 5–9, 1981, Winnipeg, Manitoba, p. 46–54. Manitoba Department of Natural Resources, Winnipeg.

    Google Scholar 

  18. Tchernoff, V., 1965. Methods for screening and for the rapid selection of elms for resistance to Dutch elm disease. Acta Botanica Neerlandica 14: 409–452.

    Google Scholar 

  19. Water, J.K., 1983. Dutch elm disease control in the Netherlands. In: Burdekin, D.A. (Eds), Research on Dutch elm disease in Europe, p. 17–18. Her Majesty's Stationery Office, London.

    Google Scholar 

Download references

Author information

Affiliations

Authors

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Scheffer, R.J. Pseudomonas for biological control of Dutch elm disease. III. Field trials at various locations in the Netherlands. Netherlands Journal of Plant Pathology 95, 305–318 (1989). https://doi.org/10.1007/BF01976618

Download citation

Additional keywords

  • Ophiostoma ulmi
  • Ulmus