2018 SCIENCELINE  
Journal of Life Science and Biomedicine  
J Life Sci Biomed, 8(5): 77-83, 2018  
ISSN 2251-9939  
Controlling Powdery Mildew; Use of Arbuscular  
Mycorrhizal Fungi as Biocontrol Agent instead of  
Chemical Fungicides  
Zohreh Yousefi1, Sima Zanganeh2, Hossein Riahi3 and Yusuf Kaya4  
1 Ph.D. candidate of Plant Biosystematics, Faculty of Biological Sciences, Shahid Beheshti University, Tehran, Iran  
2 Assoc. Dr. of Plant Biosystematics, Faculty of Biological Sciences, Shahid Beheshti University, Tehran, Iran  
3 Assoc. Dr. of Plant Biology, Department of Botany, Plant Pests & Diseases Research Institute, Shahid Beheshti University, Tehran, Iran  
4 Prof. Dr. of Plant Biosystematics, Department of Biology, Faculty of Sciences, Ataturk University, P.O.Box 25010, Erzurum, Turkey  
Corresponding author’s Email: zohreh.yousefi12@ogr.atauni.edu.tr  
ABSTRACT  
Original Article  
PII: S225199391800012-8  
Plant protection based solely on modern fungicides could lead to genetic changes in neurons  
of animal and humans that contribute to cases of autism and Alzheimer disease, unless the  
bio control agents is applied or replaced. Most researches is focused on the strongest  
Rec. 22 Apr. 2018  
Rev. 30 Aug. 2018  
Pub. 25 Sep. 2018  
chemical fungicides, dangerous to human health, for effective plant disease control and we  
believe that non-chemical control methods such as biological agents like AMF are of great  
importance. The aim of study was to investigate whether the soil inoculation with Glomus  
isolates of arbuscular mycorrhizal fungi (AMF) affected control of powdery mildew disease  
of apple MM111 and its survival and growth instead of use of chemical fungicides such as  
Flint and Stroby. Twenty apple seedlings were randomly arranged to 4 treatments, each  
with 5 replicates (T1, control = no AMF, no fungicide, T2= Flint fungicide, T3= Stroby  
fungicide and T4 = only AMF mixture) and were monitored throughout 9 weeks. All  
seedlings were exposed to powdery mildew on week 6 and only T2 and T3 plants treated by  
fungicides after developing mildew colonies on the leaves. Results showed that, seedling  
length in plants cultivated in AMF-inoculated-soil was significantly higher than other  
treatments especially in weeks 1-4 and weeks 6-9. Leaf growth rate of all plants during the  
experimental growth period non-significantly increased between treatments with the  
exception of first week that did show a significant increase in leaf growth rate of group 4  
plants, even after exposure to disease. T4 samples showed a high average of leaves numbers  
(P<0.05) in compared to other groups followed by T3 samples during the experimental  
growth period. The data from this study confirmed the response of seedling and leaf growth  
rates of apple seedlings to mycorrhizal colonization. It was concluded that plants cultivated  
in soil inoculated to AMF throughout 6 weeks had higher resistance and growth rates  
against Podosphaera leucotricha fungi as an agent of powdery mildew disease in apple  
seedling and it can be considered as an applicable strategy in biocontrol measures against  
pathogens when most researches is focused on chemical fungicides.  
Keywords  
Arbuscular mycorrhizal  
Fungi,  
Fungicide,  
Powdery Mildew,  
Apple Seedling,  
Leaf  
INTRODUCTION  
Podosphaera leucofricha is an obligate, parasite that overwinters on apple as mycelium in dormant buds infected  
during the previous growing season [1]. The “primary infection phase” of the disease is initiated by conidia  
produced on overwintering mycelium at bud break, which infect young leaves, flowers and shoots. Newly  
formed conidia from these sources are inoculum for the “secondary infection phase”, which is the infection of  
healthy leaves during the growing season [2]. The reduction of primary inoculum and the protection of leaves,  
fruit and buds from secondary infections are two areas of concern for effective disease control measures.  
Timely application of fungicides is widely used to prevent new infections and to reduce the number of spores  
produced on new lesions.  
Powdery mildew (PM), caused by P. leucofricha (Ell. & Ev.) Salm., is an important disease of apple in the  
interior of British Columbia. Disease severity and need for control measures are related to host susceptibility  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
and to the intended market for the cultivar [3]. The pathogen may cause death of vegetative shoots or flower  
buds, and russetting of fruit [4]. The grower’s primary concern with mildew is the russet symptoms that  
markedly reduce fruit quality [4]. Infected young trees of susceptible cultivars may be seriously damaged or  
become poorly shaped because of retarded vegetative growth or loss of terminal buds. In British Columbia the  
very susceptible apple cultivars, such as Mclntosh and Golden Delicious, are treated regularly with fungicides  
for control of fruit russet. The fungicides most commonly used for powdery mildew. Several new cultivars have  
been recently introduced, which also will require regular fungicide treatments [5]  
The most promising new fungicides for control of powdery mildew are the broad-spectrum, sterol-  
inhibiting compounds [6]. With the exception of the morpholines, all sterol inhibitors have a common site of  
action within the biosynthesis pathway and are grouped together as demethylation inhibitors or DMls [7].  
Stroby and Flint are often called stroby fungicides and are very effective for controlling Black Spot (scab),  
mildew, and black rot. They provide adequate control of rust diseases when applied ahead of rains, but they  
have very little post-infection activity against rust diseases. For apple scab and mildew, they can provide  
roughly 48 hr of post-infection activity, but they are not effective for arresting apple scab after lesions are  
visible on foliage.  
All stroby-containing fungicides carry labels stating that combined usage for any product in this group is  
limited to four applications per year. Thus, one can apply a maximum of four sprays per year that contain  
Stroby, Flint, or Pristine, otherwise controlling disease, not guarantee. For example, if Flint is applied three  
times to control mildew, then Pristine can be used only one time during summer. Based on using methods and  
rates of sprays of mentioned fungicide for control powdery mildew, it is detected that the additional time is  
required for a good controlling plants against types of pathogens that markedly reduce fruit quality, while there  
is several biological solutions for improving resistance of plants via boosting mineral nutrition against different  
pathogens or the attacker lifestyle [8]. For example, colonization of the original soil by AMF can boost  
resistance/tolerance of plant such as apple seedling against powdery mildew in an uninterrupted manner  
without spending additional costs to fungicides, sprays times and labor costs.  
Biological control of plant pathogens is currently accepted as a key practice in sustainable agriculture  
because it is based on the management of a natural resource. Arbuscular mycorrhizal (AM) associations have  
been shown to reduce damage caused by soil-borne plant pathogens. This prophylactic ability of AM fungi could  
be exploited in cooperation with other rhizospheric microbial antagonists to improve plant growth and health.  
The most important roles and benefits [9-11] of the Arbuscular Mycorrhiza (AM) are: 1- Increasing plant  
nutrition by exploring and deploying soil volumes; 2- Increase plant nutrition by obtaining a form of nutrition  
that is not available to the plant; 3- Increasing the tolerance of plants against dirt pathogens such as  
phytophthora, fusarium and pityum; 4- Improve water and plant relationships, plant hormonal changes; 5-  
Increased plant crop, increased food supply and reproduction; 6- Mycorrhiza can cause changes in the form of  
growth and root and vascular tissues; 7- The network of mycorrhiza fungi and plant roots provide a reasonable  
level of nutritional for a population of soil bacteria that increases host growth; 8. Hyphae of mycorrhiza  
arbuscular fungi contributes to the soil structure, their role in the physical aggregation of the soil is  
questionable, but sticky secretions such as Glomalin may be important; 9. Mycorrhizal fungi affect carbon  
storage in soil due to their impact on the quantity and quality of organic matter; 10- Arbuscular mycorrhiza  
increases plant resistance to environmental stresses such as dryness, cold and root pathogens; 11. Mineral  
absorption of soil, especially low-mobility elements such as phosphorus, zinc and copper, is considered to be the  
main function of mycorrhiza.  
Common benefits for the plant are improved plant nutrition and/or increased capability to cope with  
adverse conditions. In the case of arbuscular mycorrhizal (AM) associations, the symbioses alter plant  
physiology, leading to a better mineral nutrition and to increased resistance/tolerance to biotic and abiotic  
stresses and or pathogens. Enhanced resistance/tolerance to soil-borne pathogens has been widely reported in  
mycorrhizal plants [12]. Although it is clear that the symbiosis may also impact plant interactions with  
aboveground attackers, the outcome of those interactions is less clear and seems to depend largely on the  
attacker lifestyle [8]. This finding points to a differential regulation of plant defense signaling pathways.  
Although Flint and Stroby was registered for the control of powdery mildew on apples and grapes in Iran,  
it is unclear whether soil inoculated by AMF are comparable to these DMI fungicides, which are used to control  
powdery mildew on apples in Iran. Hence, this study compares the activities of arbuscular mycorrhizal fungi in  
compared to DMI fungicides on seedling and leaf growth rates of apple seedlings infected to powdery mildew  
disease under controlled conditions in the greenhouse.  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
MATERIAL AND METHODS  
The study was conducted during the 2011/04 season in Iran on Maling merton (MM111) apple seedlings which  
cultivated in soil with and without AMF, infected to powdery mildew (Podosphaera leucotricha) and treated by  
fungicides or AMF-inoculated soil. The fungicides used in these experiments [Flint and stroby, Kersoxim-  
methyl & Trifloxy strobin (% 50) WG, are a pre-mix products containing the strobilurin trifloxystrobin; registered  
in pome and stone fruits] were commercial formulations provided by the manufacturers.  
MM111 apple seedlings were planted through tissue culture to free from any contamination by  
microorganisms in institute of tissue culture, Pishtaz Bldg., Karaj/Safadasht, Iran then all seedlings replaced in  
10-cm dia. pots in a soil mixture containing equal volumes of loam, sand and vermiculite, perlite and coco-pit.  
Selected seedlings for trial were transferred to larger pots (35-cm dia.) containing 50% sterile sand and 50%  
AMF-inoculated soil. Prior to starting the experiment inoculation concentration of AMF were cleaned from soil  
of all new pots with the exception of those selected as maycorrhizal treatment (5 pots).  
The symbiosis of the roots of apple seedlings of control group and treatment 4 (plants inoculated with  
Mycorrhiza) has been studied. Forty-two days after inoculation of apple seedlings with inoculum containing  
mycorrhizal fungi, apple rootstocks were sampled to determine if they have been able to coexist. The  
investigation of the seedlings showed that there was no fungal organ in the root of the control plants that had  
not received any inoculum, whereas the plants that were planted in the soil containing the mycorrhizal  
inoculum were created fungal structures (Figure 1). The rate of mycorrhizal symbiosis in these roots was  
moderate (less than 30%).  
Figure 1. Mycorrhiza spp. in the roots of inoculated seedlings with Mycorrhiza  
Therefore, twenty apple seedlings were selected and randomly arranged to four groups and five replicates  
including Treatment 1 as control group= without AMF mixture and fungicide; T2= Flint fungicide in 6th week;  
T3= Stroby fungicide in 6th week; and T4 = AMF mixture, which were monitored throughout 9 week. All groups’  
seedlings were exposed to Powdery Mildew on 6th week. Only T4 plants were cultivated in soil inoculated to  
AMF while only T2 and T3 plants treated by fungicides after developing mildew colonies on the leaves. The  
active ingredient (a.i.) dosages applied for the DMI materials were those recommended by the manufacturer.  
The experimental pots were placed in the greenhouse (22°C day, 18°C night, 77- 84% RH) for germination and  
subsequent growth for approximately 9 weeks so that plants protected against pesticides for disease or insect  
up to 6th week.  
The inoculum source was infected apple shoots from an eight year old Jonagold tree in Research Station  
orchard in the Iranian Research Institute of Plant Protection. The fungus was identified as Podosphaera leucotricha  
(Ell. & Ev.) Salm. on the basis of symptom development and a comparison of the morphological characters of the  
conidia and fruiting bodies with those described for P. leucotricha by Ogawa and English [7]. The infected shoots  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
were placed in a 1°C cold storage room for approximately 4 hrs while the fungicide suspensions were being  
prepared. Maling merton (MM111) seedlings were sprayed to runoff using a hand operated mister. The leaves  
were allowed to dry for 30-min before inoculation with P. leucotricha conidia. Each treatment consisted of 5  
seedlings (replicates). A conidial suspension was prepared by brushing conidia from diseased shoots into sterile  
water containing 20 pl/mL of Triton X 100 according to used method of Dekker [13]. The concentration was  
adjusted to 8.0 x 1011 conidi d.m.l. with a haemacytometer. Within 15-min of preparation the suspension was  
sprayed on the leaves. Seedlings length and leaves numbers of experimental apple seedlings were monitored  
and measured in day 1 and weekly during a 9-wks trial (Figure 2).  
All data from the trial were analyzed by ANOVA using the GLM procedure of SAS software [14], which was  
appropriate for a randomized complete block design. When significances were detected (P < 0.05), values were  
compared post-hoc using the Duncan test. The results are expressed as averages and their Standard Error (SE).  
Figure 2. Seedlings length in control and mycorrhizal plants after 4 weeks of Mycorrhiza inoculation  
RESULTS AND DISCUSSION  
Results of seedling length and leaves number of apple seedlings of treatments are shown in Tables 1 and 2,  
respectively. Seedling length in apple seedlings cultivated in AMF-inoculated-soil was higher than other  
treatments so that significant differences were observed in weeks 1-4 and weeks 6-9. Leaf growth rate of all  
experimental plants in weeks of plant growth non-significantly increased between treatments with the  
exception of first week that did showed a significant increase in leaf growth rate of group 4 plants (grown in  
AMF mixtures) compared to other treatments, even after infecting to disease. The data confirmed the response  
of seedling and leaf growth rates of apple seedlings to mycorrhizal colonization.  
In the present study, results related to seedling length in different treatments indicated that apple  
seedlings cultivated in AMF-inoculated-soil did showed a higher continuous growth than control groups or  
those treated with fungicides. Hence, it seems mycorrhizal soil resulted in boosting seedling growth in apple  
seedling (MM111). Our findings are agreement with results of Hause and Fester [15], Xu and Madden [16] and  
Stevens et al. [17]. Fortuna et al. [18] reported that soil contain arbuscular mycorrhizal fungi (AMF) via an  
beneficial interactions between plant and AMF improved plant nutrition and/or increased capability to cope  
with adverse conditions [19]. In the case of arbuscular mycorrhizal (AM) associations, the symbioses alter plant  
physiology, leading to a better mineral nutrition and to increased seedling and leaf growth rates and  
resistance/tolerance to biotic and abiotic stresses and or pathogens [20, 21].  
Comparison of average of seedlings length revealed that in spray fungicides to T2 and T3 plants in 6th  
week, had no deterrent effect on seedlings in the subsequent weeks (seventh, eighth, ninth). Researchers  
reported that Flint and Stroby fungicides that were used against Podosphaera leucotricha, had no effect on the  
seedlings length or leave numbers [22, 23]. Average of leave numbers in different treatment significantly (P<  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
0.05) increased between treatments in first week that did show highest leaf effects in group 4 plants (fertilized  
by AMF mixtures) compared to other treatments, even after infected to disease.  
These results could be due to boosting nutritional minerals of plants planted in soil inoculated by AMF  
which finally lead to a fast growth and leaf effects compared to those grown in AMF-deficient-soils [20, 24-26].  
Table 1. Comparing the average of seedlings length during the experimental growth period  
Treatment  
Standard Significant  
T1  
T2  
T3  
T4  
Date  
errors  
level  
Day 1  
17.40  
21.60b  
24.00b  
26.20b  
29.40ab  
35.00  
42.20ab  
46.40ab  
48.60ab  
52.20ab  
17.00  
22.40b  
23.60b  
25.40b  
27.80b  
32.20  
37.60b  
39.80b  
42.20b  
43.80b  
18.60  
24.20b  
28.80ab  
32.40ab  
35.00ab  
38.80  
43.20ab  
48.40ab  
54.60ab  
60.20ab  
19.20  
33.00a  
38.20a  
42.60a  
46.40a  
54.40  
66.60a  
71.20a  
74.20a  
78.60a  
0.815  
2.866  
3.789  
4.793  
5.499  
6.912  
8.202  
8.571  
8.587  
8.467  
NS  
*
*
Week 1  
Week 2  
Week 3  
Week 4  
Weed 5  
Week 6  
Week 7  
Week 8  
Week 9  
*
NS  
NS  
*
*
*
*
a,b Values in the same row and variable with no common superscript differ significantly; Values are means of 5 observations per treatment  
and their standard errors. Treatment 1 (T1) = control (non-AMF mixture, non-fungicide); T2 = non-AMF mixture + fungicide Flint in 6th  
week; T3 = non-AMF mixture + fungicide Stroby in 6th week; T4 = AMF mixture; NS= p>0.05; *= p<0.05; **= p<0.01.  
Table 2. Comparing the average of leaves numbers during the experimental growth period  
Treatment  
Standard Significant  
T1  
T2  
T3  
T4  
Date  
errors  
level  
Day 1  
13.20  
15.00b  
16.60  
17.20  
19.60  
21.60  
26.60  
28.40  
30.80  
32.80  
11.20  
14.80b  
15.60  
16.60  
18.60  
21.60  
24.00  
25.80  
28.00  
29.60  
14.00  
18.20ab  
20.80  
22.00  
22.60  
24.60  
26.80  
30.60  
34.20  
38.00  
13.80  
23.00a  
24.00  
25.00  
27.60  
31.40  
35.40  
38.20  
39.00  
43.60  
1.185  
2.143  
2.704  
3.033  
3.136  
3.991  
4.622  
4.693  
5.137  
5.146  
NS  
*
Week 1  
Week 2  
Week 3  
Week 4  
Weed 5  
Week 6  
Week 7  
Week 8  
Week 9  
NS  
NS  
NS  
NS  
NS  
NS  
NS  
NS  
a,b Values in the same row and variable with no common superscript differ significantly; Values are means of 5 observations per treatment  
and their standard errors. Treatment 1 (T1) = control (non-AMF mixture, non-fungicide); T2 = non-AMF mixture + fungicide Flint in 6th  
week; T3 = non-AMF mixture + fungicide Stroby in 6th week; T4 = AMF mixture; NS= p>0.05; *= p<0.05; **= p<0.01  
CONCLUSION  
The data confirmed the response of seedling and leaf growth rates of apple seedlings to mycorrhizal  
colonization. From the results of this study, it was concluded that plants cultivated in soil inoculated to AMF  
throughout 6 weeks had higher resistance and growth rates against Podosphaera leucotricha fungi as an agent of  
Powdery Mildew disease in apple seedling and it can be considered as an applicable strategy in bio control  
measures against pathogens.  
Nowadays, many works has been performed for improving plant growth and crop production. Most  
researches is focused on the strongest chemical fungicides, dangerous to human health, for effective plant  
disease control and we believe that non-chemical control methods such as biological agents like AMF are of  
great importance. Meanwhile, our work suggested that the combined use of both arbuscular mycorrhizal fungi  
and most safely fungicides is an effective strategy to management of diseases such as powdery mildew; so that,  
using AMF-fertilized-soil at the foot of the trees in early spring and then use fungicides only once (instead of  
three phases) in order to decline additional sprays times and labor costs is recommended.  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
DECLARATIONS  
Acknowledgements  
The manuscript was summarized from the master thesis in faculty of biological sciences, Shahid  
Beheshti University, Tehran. We would like to thank Prof. Dr. Hossein Riahi for directing us with his  
experiences in research. The authors are also grateful for valuable support and the skilled technical assistances  
throughout the experimental analyses from Hossein Khabbaz-Jolfaei, Assistant Professor in biological control,  
iranian research institute of plant protection, Tehran, Iran and Sima Zanganeh, Assistant Professor in Botany,  
Plant Pests & Diseases Res. Institute, Shahid Beheshti University, Tehran, Iran.  
Authors’ Contributions  
All authors contributed equally to this work.  
Competing interests  
The authors declare that they have no competing interests.  
REFERENCES  
1.  
Hickey KD and Yoder KS. 1990. Powdery mildew. Pages 9- 10 in: A.L. Jones and H.S. Aldwinckle, eds. Compendium of  
Apple and Pear Diseases. APS Press, St. Paul, MN.  
2.  
Burchill RT. 1960. The role of secondary infections in spread of apple powdery mildew, Podosphaera leucotricha (Ell. &  
Ev.) Salm. J. Hort. Sci., 35366-72.  
3.  
4.  
Yoder KS and Hickey KD. 1983. Control of apple powdery mildew in the Mid-Atlantic region. Plant Dis. 67:245-248.  
Jones AL and Sutton TB. 1984. Diseases of Tree Fruits. Cooperative Extension Service, Michigan State University, East  
Lansing, MI.  
5.  
6.  
7.  
Spotts RA, Covey RP and MacSwan IC. 1981. Apple powdery mildew and scab control studies in the Pacific Northwest.  
Plant Dis. 65: 1006-1009.  
Anon. 1992. Tree Fruit Production Guide for Commercial Growers, Interior Districts. Province of British Columbia,  
Ministry of Agriculture, Fisheries and Food, Victoria, British Columbia, Canada.  
Ogawa JM and English H. 1991. Powdery mildew of pome fruit. Pages 50-53 in: Diseases of Temperate Zone Tree Fruit  
and Nut Crops. University of California, Division of Agriculture and Natural Resources, Publication 3345, Oakland, CA.  
8.  
9.  
Pozo MJ, Azcَn-Aguilar C. 2007. Unravelling mycorrhiza induced resistance. Curr Opin Plant Biol, 10 : 393 – 398  
Sylvia DM, and Williams SE. 1992. Mycorrhizae and environmental stresses. In: Bethlenfalvay, G.J., and Linderman, R.G.  
(Eds.), Mycorrhizae in Sustainable Agriculture. Madison, WI: ASA Special Publication No. 54, pp. 101-124.  
10. Linderman RG. (1992). Vesicular-arbuscular mycorrhizae and soil microbial interactions. pp. 45-70 In: Mycorrhizae in  
Sustainable Agriculture. Bethlenfalvay, G. J. and Linderman, R. G. eds., ASA Special Publication No. 54, Madison, WI.  
11. Linderman RG and Davis EA. (2002). Vesicular-arbuscular mycorrhiza and plant growth response to soil amendent  
with composed grape pomace or its water extract. Phyton-Annales botanicae, 11(3):446-450.  
12. Whipps JM. 2004. Prospects and limitations for mycorrhizas in biocontrol of root pathogens. Can J Bot 82 : 1198 – 1227  
13. Dekker J. 1982. Method of fungicide resistance in powdery mildew of cucumber - FA0 Method No. 27. Food and  
Agriculture Organization of the United Nations. FA0 Plant Prot. Bull. 3059-61.  
14. SAS Institute Inc. SAS User’s Guide: Statistics. SAS Institute Inc., Cary, NC. 1998.  
15. Hause B and Fester T. 2005. Molecular and cell biology of arbuscular mycorrhizal symbiosis. Planta, 221: 184–196.  
16. Xu, X.M. and Madden, L.V. 2002. Incidence and Density Relationships of Powdery Mildew on Apple. Epidemiology, 92 (9):  
1005-1014.  
17. Stevens KJ, Wall CB, Janssen JA. 2010. Effects of arbuscular mycorrhizal fungi on seedling growth and development of  
two wetland plants, Bidens frondosa L., and Eclipta prostrata (L.) L., grown under three levels of water availability.  
Mycorrhiza. 21(4):279-88.  
18. Fortuna P, Citernesi AS, MORINI S, Vitagliano C and Giovannetti M. 1996. Influence of arbuscular mycorrhizae and  
phosphate fertilization on shoot apical growth of micropropagated apple and plum rootstocks. Tree Physiology 16, 757-  
763.  
19. Wehner J, Antunes PM, Powell JR, Mazukatow J, Rillig MC. 2009. Plant pathogen protection by arbuscular  
mycorrhizas: A role for fungal diversity?. Pedobiologia, 53: 197-201.  
20. Brundrett M, Bougher N, Dell B, Grove T, Malajczuk N. 1996. Working with mycorrhizas in forestry and agriculture.  
Aust Cent Int Agric Res Monogr 32:1–374.  
21. Smith SE, Read DJ. 1997. Mycorrhizal symbiosis. 2d ed. Academic Press, San Diego, Calif.  
22. Wilcox WF, Wasson DI and Kovach J. 1992. Development and evaluation of an integrated, reduced-spray program  
using sterol demethylation inhibitor fungicides for control of primary apple scab. Plant Dis. 76:669-677.  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com  
23. Sholberg PL and Haag P. 1994. Control of apple powdery mildew (Podosphaera leucotricha) in British Columbia by  
demethylation-inhibiting fungicides. Canadian Plant Disease Survey 74:1.  
24. Fortin JA, Becard G, Declerck S, Dalpe Y, St-Arnaud M, Couglland A, Piche Y. 2002. Arbuscular mycorrhizaa and root-  
organ cultures. Canadian Journal of Botany, 80:1-20.  
25. Turk MA, Assaf TA, Hameed KM and Al-Tawaha AM. 2006. Significance of Mycorrhizae. World Journal of Agricultural  
Sciences, 2 (1): 16-20.  
26. Daft MJ and Nicolson TH. 2011. Effect of Endogone Mycorrhiza on Plant Growth. III. Influence of Innoculum  
Concentrationon Growth and Infection in Tomato. New Phytologist, 68 (4): 953-961.  
Yousefi Z, Zanganeh S, Riahi H and Kaya Y. 2018. Controlling Powdery Mildew; Use of Arbuscular Mycorrhizal Fungi as Biocontrol Agent  
instead of Chemical Fungicides. J. Life Sci. Biomed. 8(5): 77-83; www.jlsb.science-line.com