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*Corresponding author: francesco.cavazza@astrainnovazione.it
Fungicide activity of milk and whey powders towards Erysiphe necator, the causal agent of
powdery mildew of grapevine
Bugiani1, R., Cavazza2, F., Landi2, M., Preti2, M.
1 Servizio Fitosanitario – Regione Emilia-Romagna - Via A. da Formigine, 3, 40129 Bologna, Italy
2 Astra Innovazione e Sviluppo Test Facility – Via Tebano, 45, 48018 Faenza, Italy
______________________________________________________________________________
1 Introduction
The fungus Erisyphe necator (syn. Uncinula necator)
(Schw.) Burr. is the causal agent of powdery mildew, a major
grapevine disease throughout the world. Control of powdery
mildew is traditionally based on the management of
secondary infections. According to a survey carried out by the
European Commission, in 2007 growers in Europe used
70,000 tons of fungicides for grapevine protection, of which
53,000 tons were used against E. necator (European
Commission, 2007). Despite this large use of fungicides,
powdery mildew epidemics are frequently difficult to control
due to the explosive nature of the infection cycles caused by
its clonal reproduction.
The directive on the sustainable use of the plant protection
products (EU Dir. 128/09) asks growers to implement disease
control strategies to go beyond the use of synthetic chemicals.
The means for bio-control are valuable technical tools that
can effectively complement good practices such as the
prevention and monitoring of plant diseases. Growers can use
two categories of plant protection substances as alternatives
to the ‘conventional’ plant protection products: the low-risk
substances and the basic substances. The basic substances
benefit from the following peculiarities: unlike a
phytosanitary product, no approval by the manufacturing
companies or licence for their purchase and use is required;
they are easily available in any market or supermarket; they
are not dangerous; some of these are allowed in organic
farming. The basic substances include, among others, the
dairy product whey. Whey has always been studied to be used
as source of nutrients to be potentially use in a circular
economy (Sharratt et al., 1959; Ahmed Hashim, 2019). More
recently, the activity of milk has been investigated on
pumpkin and courgette with respect to Sphaeroteca fuliginea,
demonstrating a certain activity in controlling the disease
(Bettiol, 1999; Ferrandino et al., 2006). Subsequently, the
milk was tested for its effectiveness for the first time in
Australia against the powdery mildew of the vine (Crisp &
Bruer, 2001), tomato (Khairy et al., 2018), and soybean
(Perina et al., 2013). Whey has also been found to be effective
in controlling Tomato Yellow Leaf Curl Virus (TYLCV) in
tomato (Abdelbacki et al., 2010). Finally, a study with
electron spin resonance and scanning electron microscopy
speculated that free radical production and the action of
lactoferrin are associated with the control of powdery mildew
by milk (Crisp et al., 2006). In Italy, a preliminary assessment
of the activity of the powdered milk against powdery mildew
was carried out with promising results in 2017, a year of
medium-high disease pressure (Cavazza et al., 2018). The
present preliminary investigation aimed to verify and confirm
the potential efficacy of powdered milk and whey, its
derivative, against Uncinula necator.
2 Materials and Methods
In 2018 and 2019, two efficacy field trials were carried out to
evaluate the activity of milk and whey powders against
Uncinula necator to control the powdery mildew disease on
grapevine. Two vineyards, one of cultivar Pinot Gris and the
other of cultivar Sangiovese, were selected in the hilly area of
Tebano (Ravenna province, Emilia-Romagna region, Italy), a
typical grapevine area usually affected by severe powdery
mildew infections due to the favourable environmental
conditions.
This study was realized in agreement with the most relevant
EPPO guidelines (PP1/152(4): design and analysis of efficacy
evaluation trials; PP1/181(5): conduct and reporting of
efficacy evaluation trials, including good experimental
practice; PP1/135(4): phytotoxicity assessment; and
PP1/004(4): Uncinula necator) (EPPO, 2022). Both trials
considered 4 repetitions per treatment and 5 plants per plot,
with a complete randomized blocks experimental design. The
treatments under study are reported in table 1 and included an
untreated control unsprayed with fungicides for the whole
season. The milk powder (Ferga Super Elevage, Ouest
Élevage, Ploudaniel, France) and the whey powder (Quality
Milk, Kalmi Italia) were both commercial calf feeds used for
animal nutrition. The products under study were distributed
with a backpack nebulizer sprayer (brand Stihl model SR420
with 1 nozzle of 2 mm in 2018 or model SR430 with 1 nozzle
of 2.3 mm in 2019), simulating a water volume ranging
between 500 L/ha and 1000 L/ha, according to the crop
phenological stage. The spray interval between applications
was of 6-8 days, according to the weather trend.
Formulated
product (f.p.)
Active
ingredient
concentration
Dosage
f.p.
in g/L
Year
2018
2019
Untreated
control
-
-
x
x
Tioflor
sulphur 80%
5
x
Tioflor
sulphur 80%
6
x
Milk powder
n.a.
10
x
Milk powder
n.a.
20
x
Milk powder
n.a.
30
x
x
Whey powder
n.a.
30
x
Whey powder
n.a.
45
x
Table 1: Treatments under study during 2018-2019 to
evaluate the milk powder and whey powder activity against
Uncinula necator in grapevine crop.
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0
(http://creativecommons.org/licenses/by/4.0/).
BIO Web of Conferences 50, 03009 (2022) https://doi.org/10.1051/bioconf/20225003009
GDPM 2022
*
The efficacy assessments were carried out on 50 bunches per
plot, observing the powdery mildew disease symptoms and
visually estimating the affected area. Each bunch was scored
using the following damage classes: 0 = no symptoms; 1 =
0.1÷5% of symptomatic surface; 2 = 5.1÷15% of
symptomatic surface, 3 = 15.1÷40% of symptomatic surface;
4 = 40.1÷70% of symptomatic surface; 5 = 70.1÷100% of
symptomatic surface. Disease incidence (percentage of
symptomatic grape bunches out of the total observed) and
disease severity (percentage of symptomatic grape bunch
surface according to the mean value of each damage class)
were calculated.
In the same date of the efficacy assessments, also the
phytotoxicity assessments were carried out. Any symptom
due to lack of crop selectivity was recorded both on leaves
and bunches, observing 100 and 50 organs per plot,
respectively. The same approach used to score the disease
symptoms was adopted for the phytotoxicity symptoms.
The collected data were analysed with the Analysis of
Variance (Anova) and subsequent S.N.K. test (p ≤ 0.05) for
the separation of the means, transforming the percentages
data with square root or arcsine of the root square percentage
if required to satisfy the Bartlett’s test. The degree of action
(percentage of efficacy) of the treatments under study was
calculated on the untreated control using the Abbott’s
formula. All the results are reported as mean values (± SEM).
3 Results and discussion
In both years, the disease pressure recorded in the vineyard
under study can be considered of medium level. During
spring, periods with temperatures above the norm have led to
an advance of crop vegetation, more marked in the 2019
vintage, and a consequent advance of susceptibility to
primary infections. In both years, the weather conditions
continued in a similar way, with a very rainy and cool period
during May (which in 2019 had exceptional characteristics of
precipitations above the norm) and which caused an obstacle
to the normal development of the disease. From June onward,
the establishment of a favourable weather trend with low
rainfall and high humidity parameters has allowed the
epidemic development of the disease.
The first disease symptoms on the grapevine leaves were
observed on May 23rd in 2018 and on May 27th in 2019. In
both years, the uneven disease occurrence on the leaves has
not allowed any evaluation of the tested products
performance on the leaves. The first disease symptoms on the
grape bunches were observed on May 30th in 2018, while only
on June 17th in 2019. The evolution of the disease on the grape
bunches, very rapid in 2018, was slower in 2019.
The results obtained in the 2018 trial are reported in figure 1
and figure 2 for the disease incidence and disease severity,
respectively. Similarly, in figure 3 and 4 the results obtained
in 2019 are presented.
In 2018, ten experimental applications were carried out
between April and June (4/24, 4/30, 5/7, 5/15, 5/23, 5/30, 6/7,
6/13, 6/20, 6/27). Two efficacy assessments were carried out
between late June (6/22) and early July (7/9). In both the
assessments, the milk powder was significantly different from
the untreated control, providing a disease control similar to
that provided by the sulphur-based plant protection product.
The efficacy in reducing the disease severity (figure 2) was
close to 95-99% regardless the tested concentration of the
milk powder, while concerning the disease incidence (figure
1) a numerical dose-effect was observed among the three
tested dosages (milk powder at 10 g/L, 20 g/L and 30 g/L, the
latter with the highest performance). In the second and last
assessment (7/9), when the crop was at BBCH 81 (beginning
of berries ripening), the milk powder applied at 30 g/L
provided a protection of the grape bunches numerically better
than the sulphur reference standard.
Figure 1: Disease incidence on grape bunches (histograms)
and tested products efficacy (lines) recorded in 2018.
Figure 2: Disease severity on grape bunches (histograms) and
tested products efficacy (lines) recorded in 2018.
In 2019, eleven experimental applications were carried out
between April and July (4/19, 4/26, 5/6, 5/16, 5/22, 5/30, 6/6,
6/13, 6/21, 6/29, 7/8). Two efficacy assessments were carried
out between late June (6/28) and mid-July (7/19). In this trial,
in terms of percentage of affected grape bunches, the sulphur-
based product provided a significantly better performance
compared to the two dairy products, which however were
significantly different from the untreated control. Regarding
the percentage of symptomatic grape bunch surface, both the
milk and whey powders provided a similar activity to the
sulphur-based reference standard. The two dosages of whey
powder (30 g/L and 45 g/L) provided a performance
comparable to that of the milk powder applied at 30 g/L, with
a numerical better control of the highest tested dosage.
Both 2018 and 2019 results confirm the good performance of
these dairy powders observed in mid-June 2017, where eight
applications of milk powder at 30 g/L provided a protection
of the grape bunches comparable to that of a sulphur-based
plant protection product. In that screening the milk powder
showed an efficacy higher than 90% in reducing the disease
incidence and an Abbott degree of action close to 99% in
reducing the disease severity (Cavazza et al., 2018).
Nevertheless, it has to be noted that in the 2017 screening a
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BIO Web of Conferences 50, 03009 (2022) https://doi.org/10.1051/bioconf/20225003009
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milk powder for human use (as food for new-borns) was
considered, while in the present study the milk powder tested
was chosen among the ones available for zootechnical uses.
Figure 3: Disease incidence on grape bunches (histograms)
and tested products efficacy (lines) recorded in 2019.
Figure 4: Disease severity on grape bunches (histograms) and
tested products efficacy (lines) recorded in 2019.
Regarding the phytotoxicity symptoms, no lack of crop
selectivity was observed in the grapevine plants repeatedly
treated with neither the milk powder not with the whey
powder.
4 Conclusions
During 2018-2019 seasons, in two vineyards characterized by
a medium pathogen pressure, the sulphur-based plant
protection product provided a good control of powdery
mildew disease when applied straight with weekly sprays.
The zootechnical milk and whey powders (dairy products
used as calf feeds) tested in this study on grapevine crop
provided significantly effective disease reduction (compared
to the untreated control), with a good performance when
tested at concentrations of 30 g/L and 45 g/L, respectively.
The present study allowed to define a preliminary minimum
effective dose of such basic substances that could be
potentially be exploited in crop protection. Further studies are
needed to better investigate and understand the role of milk
and whey powders in the control of powdery mildew on
grapevine. Similarly, new screenings are required to widen
the target plant pathogens (i.e., downy mildew disease caused
by Plasmopara viticola) that could be affected by these
substances and the crops potentially suitable for their usage
without causing adverse side-effects. In fact, the European
commission following the EFSA analysis, only recently
authorized whey and cow milk as basic substances for the
control of powdery mildew disease in grapevine. This
authorization indicates as period as suitable for application
the spring from 1st shoots occurrence to cluster tightening
(BBCH 10-57), at 7 to 10 days interval (EFSA, 2020;
European Commission, 2021), a phenological period more at
risk for downy mildew and powdery mildew primary
infections rather than for powdery mildew secondary
infections.
References
1. Abdelbacki A.M., Taha S.H., Sitohy M.Z., Dawood
A.I.A., Abd-El Hamid M.M., Rezk A.A., 2010. Inhibition
of Tomato Yellow Leaf Curl Virus (TYLCV) using whey
proteins. Virology Journal, 7:26.
http://www.virologyj.com/content/7/1/26.
2. Ahmed Hashim Abd AL-Razaq, 2019. Whey applications
in plants. Plant Archives Vol. 19, 1, pp. 45-48.
3. Bettiol W., 1999. Effectiveness of cow’s milk against
zucchini squash powdery mildew (Sphaerotheca
fuliginea) in greenhouse conditions. Crop Protection 18:
489-492.
4. Cavazza F., Preti M., Franceschelli F., Landi M.,
Montanari M., Antoniacci L., Bugiani R., 2018.
“Valutazione dell’attività antioidica di diversi prodotti a
basso impatto ambientale per il contenimento di Erysiphe
necator su vite in Emilia-Romagna”. ATTI Giornate
Fitopatologiche, 2018, 2, 551-558.
5. Crisp P., Bruer D., 2001. Organic control of powdery
mildew without sulfur. Australian Grapegrower and
Winemaker 452: 22.
6. Crisp P., Wicks T.J., Troup G., Scott E.S., 2006. Mode of
action of milk and whey in the control of grapevine
powdery mildew. Australasian Plant Pathology, 2006,
35, 487–493.
7. EFSA, 2020. European Food Safety Authority. Ouput of
the consultation with Member States and EFSA on the
basic substance application for approval of whey for the
extension of use in plant protection as a fungicide in
grapevines and vegetable crops. EFSA supporting
publication: EN-1868. 39, pp.
doi:10.2903/sp.efsa.2020.EN-1868.
8. EPPO, 2022. European Plant Protection Organization
database on PP1 Standards. Available on-line at the link:
https://pp1.eppo.int/. Latest access: January 24th 2022.
9. European Commission, 2007. The use of plant protection
products in the European Union - Data 1992-2003,
Luxembourg: Office for Official Publications of the
European Communities, 222 pp. ISBN 92-79-03890-7.
10. European Commission, 2021. EC SANTE/12354/2015–
rev3. Review report for the basic substance whey
finalised in the Standing Committee on Plants, Animals,
Food and Feed at its meeting on 8 March 2016 and
amended on 25 March 2021 in view of the approval of
whey as basic substance in accordance with Regulation
(EC) No 1107/20092 pp.1-8.
3
BIO Web of Conferences 50, 03009 (2022) https://doi.org/10.1051/bioconf/20225003009
GDPM 2022
11. Ferrandino F.J., Smith V.L., 2006. The effect of milk-
based foliar sprays on yield components of field
pumpkins with powdery mildew. Crop Protection 26(4):
pp.657-663.
12. Khairy Abdel-Maksoud Abada, Amany M.F. Attia and
Maryan M. Youssef., 2018. Role of chemicals for plant
resistance, Trichoderma bioagents and cow whey milk in
combination on management of tomato powdery mildew.
Journal of Biotechnology and Bioengineering, 2, 2, pp.
25-35.
13. Perina F.J., Alves E., Pereira R.B., Gilvaine C.L., Labory
C.L.G., De Castro H.A., 2013. Essential oils and whole
milk in the control of soybean powdery mildew. Ciência
Rural, Santa Maria, 43, 11, pp.1938-1944.
14. Sharratt W. J., Peterson E., Calbert H.E., 1959. Whey as
a source of nutrients and its effect on the soil. Journal of
Dairy Science, 42, 7, pp.1126-1131.
4
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