Evaluation of Effect of Different Fungicides on Fungus Podosphaera leucotricha, the Causal Agent of Apple Powdery Mildew Disease

Document Type : Research Article


1 Ardabil Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Ardabil, Iran

2 Research Assistant Professor, Iranian Research Institute of Plant Protection, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran


Introduction: Apple (Malus domestica, Borkh) is considered one of the most common popular and favorite deciduous fruit trees cultivated in Iran. Various harmful factors affect the performance of this fruit. Apple powdery mildew disease is one of the most important apple diseases that has a worldwide distribution and causes disease and is caused by the fungus Podosphaera leucotricha Ell. Et Ev. This fungus is an obligate parasite and it can attack to leaves, flowers, fruits and twigs. In the beginning of spring the disease appeared on leaves which are the most susceptible organs. The disease appears on the upperside of infected leaf as powdery white lesions and eventually the infected part of leaf turn brown and infections on the underside of infected leaf result in chlorotic patches. Infected leaves become crinkle, curl and drop prematurely. Although blossom and fruit infections are less common, they are important because infected fruits are small and stunted if they do not drop. P. leucotricha survives the winter as mycelium in vegetative tissues or in infected flower buds. The primary infection starts when infected buds break dormancy and fungus resumes growth and colonizes developing shoots. Spores growing on infected shoots spread nearby and initiate secondary infections. Also it causes early loss of leaves and stop the growth of diseased branches and as a result, the loss of yield. In heavily infected trees, rust can be seen on fruit surface. Powdery mildew infection usually occurs at relative humidity above 70%, and on days when humidity is low, the infection usually occurs at night or in the early morning hours when the humidity is high. Although the use of effective fungicides can control the disease well but appearance of resistant strains of pathogens to reduce fungicide efficiency in controlling disease and producers' access to effective fungicides from various chemical groups, while helping gardeners to reduce the economic damage caused by the disease, reduces the possibility of pathogen resistance to fungicides. The aim of this study was to determine the efficacy of Boscalid + Pyraclovastrobin (Bellis ® WG38%) (Manufactured by BASF Co.) (With doses of 0.4, 0.7 and 1 ml L-1) compared with Tri-floxystrobin + Fluopyram (Luna Sensation ®) (with a dose of 0.2 ml L-1), Tri-floxystrobin (Flint ® WG50%) (0.2 ml L-1) and Tri-floxystrobin + Teboconazol (Nativo ® WG50%) (With a dose of 0.2 ml L-1) to control apple powdery mildew disease.
Materials and Methods: For the experiment, the apple orchard of Golden Smooth cultivar with a history of powdery mildew in Ardabil province was selected. The experiment was carried out in a randomized complete block design (RCBD) with 8 treatments and 4 replications. Control treatments were without any spraying and with water spraying. Treatments were applied at three stages (full green bud stage and followed up at pink flowers stage and 10 days after the 2nd spraying). Ten days after the first symptoms of the disease were observed on the control treatments, samples were taken from the sheets and the percentage of the disease incidence and disease severity percentage were calculated. After calculating the incidence and disease severity of apple powdery mildew for each plot, the corresponding values in SAS statistical software were analyzed and the means of both traits were compared by Duncan's multiple range test at one percent probability level.
Results and Discussion: The results of analysis of variance of the data obtained from the evaluation of the leaves of the treated trees showed that the effect of treatments on reducing the percentage of disease severity and disease incidence is statistically significant. The results showed that Bellis ® fungicide with a concentration of 0.1 and 0.7 ml L-1, Luna Sensation ® 0.2 ml L-1, Nativo ® 0.2 ml L-1 and Flint ® with a concentration of 0.2 ml L-1 had a high efficiency of controlling apple powdery mildew disease. The efficacy of new Bellis ® fungicide with concentrations of 1 and 0.7 ml L-1 was 76 and 60 percent, respectively. According to the obtained results, Bliss fungicide with a dose of 0.4 per thousand had poor efficacy in controlling the severity and occurrence of the disease and was not statistically significantly different from the control treatments. The results also showed that there was no significant difference between the control treatments (treatment with water spraying and treatment without spraying).
Conclusion: Because both Bellis ® concentrations are effective in controlling the disease, therefore in order to protect the health of the fungicide users, the consumer of sprayed products and the environment as well as reduction in costs, the preferred dose is 0.7 ml L-1.


Main Subjects

  1. Al-Rawashdeh Z. 2013. Ability of mineral salts and some fungicides to suppress apple powdery mildew caused by the fungus Podosphaera leucotricha. Asian Journal of Plant Pathology 7: 54-59.
  2. 2009. FRAC cod list: Fungicides sorted by mode of action (including FRAC code numbering), Fungicides Resistance Action Committee, in: http:// www.frac.info/ [Accessed on 2018- 8-10].
  3. 2015. UK safety data sheet. In: https://www.agricentre.basf.co.uk/go/Bellis [Accessed on 2018- 10-1].
  4. 2016. Agricultural Statistics, Ministry of Jihad Agriculture .http://www.agri-jahad.ir
  5. Behdad E. 1990. Diseases of Fruit Trees in Iran. Neshat Isfahan Publications. Pp. 293.
  6. Berrie A.M., and Xu X.M. 2003. Managing apple scab (Venturia inaequalis) and powdery mildew (Podosphaera leucotricha) using AdemTM. International Journal of Pest Management 49(3): 243-249.
  7. Cacaj I., Kelmendi B., Shala N., and Rexhaj B. 2015. Chemical protection of apple against leaf powdery mildew and sustainability to pathogen cultivars according to EU standards. Academic Journal of Interdisciplinary Studies 4: 117-122.
  8. Fernández O.D., Torés J.A., de Vicente A., and Pérez G.A. 2010. The QoI Fungicides, the Rise and fall of a Successful Class of Agricultural Fungicides. pp. 203-220 In: Carisse, O. (ed.), Agriculture and biological science “fungicides”. Janeza Trdine, Rijeka. Inc. INTECH Open Access Publisher.
  9. Filsouf F., Behdad A., and Hassanpour H. 1998. Study of apple powdery mildew disease and its chemical control in Semirom, 13th Iranian Plant Protection Congress, Karaj, P. 234.
  10. Gupta D., and Sharma, J.N. Chemical control of powdery mildew of apple in warmer climates of himachal pradesh India. Acta Horticulture 696: 355-358.
  11. Hanifeh S., Afzali H., and Yeganeh Kh. 2014. Evaluation of the effect of Nativo (Nativo WG 75%) on apple powdery mildew in comparison with common pesticides in West Azerbaijan province. Twenty-first Congress of Plant Protection, 1 to 4 September. Orumiyeh.
  12. Holdsworth R.P. 1972. European red mite and its major predators: Effects of sulfur. Journal of Economic Entomology 65: 1098-1099.
  13. Irani H., and Ashkan M. 1998. The effect of several fungicides to control powdery mildew on apple in West Azerbaijan province. 13th Iranian Plant Protection Congress, Karaj, P. 216.
  14. Karimi-Shahri M., and Heydarian A. 2010. Investigation of the effect of tetraconazole fungicide on apple powdery mildew. Final report of Khorasan Razavi Agricultural and Natural Resources Research Center research project, Pp. 12.
  15. Keliaei R., Khabbaz Jolfaei H., and Mirkamali H. 2002. Handbook of Pests, Diseases and Weeds, Agricultural Education Publishing, Karaj, Iran, Pp. 144.
  16. Khabbaz Jolfaei H., and Azimi Sh. 2011. Guidelines for the correct use of Iranian pathogens in the control of plant diseases (scientific and applied), Iranian Plant Protection Research Institute, Pp. 311.
  17. Khabbaz Jolfaei H., Karimi-Shahri M.R., Irani H., and Zaker M. 2016. Evaluation of the efficacy of Luna Sensation® 500 SC fungicide against Podosphaera leucotricha, the disease agent of apple powdery mildew. Final report of the research project of the Iranian Plant Protection Research Institute, Pp. 16.
  18. Khabbaz Jolfaei H., Irani H., Karbalaei Khiavi H., Farrokh Eslamloo E., and Abidi A. 2002. Evaluation of the effect of Flint (WG 50%) and Strobi (WG 50%) fungicides and their comparison with common pesticides against apple powdery mildew. Final report of the research project of the Iranian Plant Protection Research Institute, Pp. 10.
  19. Marine S.C., Yoder K.S., and Baudoin A. 2010. Powdery Mildew of Apple. The Plant Health Instructor. DOI:10.1094 (PH). J- 1010 – 1021 01. Virginia Polytechnic Institute and State University.
  20. Pscheidt J.W., and Ocamb, C.M. 2016. Pacific Northwest Plant Disease Management Handbook [online]. Corvallis, OR: Oregon State University. http://pnwhandbooks.org/plantdisease.
  21. Rather T.R., Bhat Z.A., Pandit B.A., Sheikh K., Malik A.R., and Ganai M.A. 2019. Bioefficacy studies of new fungicide molecules (Proquinazid 20 EC) against powdery mildew of apple. Journal of Pharmacognosy and Phytochemistry 8(1): 1963-1965.
  22. Turechek W.W., Carroll J.E., and Rosenberger D.A. 2004. Powdery Mildew of Apple. nysipm.cornell.edu/factsheets/treefruit/diseases/pm/apple_pm.pdf.
  23. Wang Y., Liu Y., He P., Chen J., Lamikanra O., and Lu J. 1995. Evalution of foliar resistance to Uncinula nacator in China wild Vitis Vitis 34(3): 159-164.
  24. Wurms K.V., and Chee A.A. 2011. Control of powdery mildew (Podosphaera leucotricha) in apple seedlings using anhydrous milk fat and soybean oil emulsions. New Zealand Plant Protection 64: 201-208.
  25. Yeganeh M. 2017. Pesticides Registered in Iran. Basir Shimi Pars. Pp. 47.