Page 15 - Volume 5, Issue 1, January 2012

1

Agricultural Research Council (CRA), Plant Pathology

Research Center, via C.G. Bertero 22, 00156 Rome, Ita-

ly

Corresponding author:

anna.latorre@entecra.it

Introduction

Downy mildew, caused by the oomycete

Plasmopara viticola

(Berk. & M.A. Curtis) Berl.

& De Toni, is one of the world’s most de-

structive grapevine diseases (2, 24, 12, 27,

23). In organic farming, the control of

P. viti-

cola

is based on the use of copper, together

with all preventive management measures

necessary to minimize the development of

disease. Copper is still a very important tool

to manage the diseases in conventional ag-

riculture and is actually indispensable in or-

ganic farming (24, 21).

With Commission Directive 2009/37/EC,

copper compounds have been included in

Annex I to Directive 91/414/EEC (concerning

the placing of plant protection products on

the market). “Therefore, it is necessary that

Hellenic Plant Protection Journal

5:

13-21, 2012

Natural alternatives to copper and low-rate copper

formulations to control grape downy mildew in organic

farming

A. La Torre

1

, C. Mandalà

1

, F. Caradonia

1

and V. Battaglia

1

Summary

To control plant diseases in organic farming, growers can use preventive measures togeth-

er with a few plant protection products. The control of downy mildew is based on the use of copper

compounds, however copper can cause environmental problems due to its accumulation in the soil.

In this study natural alternatives to copper and formulations with low rates of copper were evaluated

in organic farming in order to control

Plasmopara viticola

. All of the products tested ensured effective

control of grape downy mildew under the experimental conditions of the trial, characterized by mod-

erate disease pressure. The best levels of protection were observed with copper products. Low-copper

formulations (Glutex Cu 90 and Labicuper) with similar efficacy to the reference product offer benefits

including lower quantities of copper. This paper recommends a cultural management of downy mil-

dew in accordance with the risk of infection in order to reduce environmental copper input. We sug-

gest that organic growers can minimize the use of copper in organic viticulture by using copper-alter-

natives when downy mildew infection is intermediate or low. On the other hand in years with high dis-

ease pressure new copper formulations can be used to reduce the amount of copper.

Additional keywords

: copper, natural products, organic farming, plant protection,

Vitis vinifera

L.

Member States introduce monitoring plans

in vulnerable areas, where the contamina-

tion of the soil compartment by copper is a

matter of concern, in order to set, where ap-

propriate, limitations as maximum applica-

ble rates” (Commission Directive 2009/37/

EC) (7). In organic farming, limitations such

as maximum applicable copper rates have

already been defined (Regulation EC No

889/2008) (6). The use of copper, in fact, may

have long-term consequences due to its ac-

cumulation in the soil (4, 26, 28, 14, 9, 22) and

this is incompatible with the principles of or-

ganic farming. In the near future the current

legal amount of copper will probably be re-

duced, so that alternatives to copper com-

pounds need to be developed. Several re-

search programs have been carried out to

find appropriate alternative solutions (24, 8,

16, 17, 31, 18, 32, 30, 5, 35).

In order to evaluate the possibility of

replacing or reducing the use of copper, a

field trial in an organic vineyard was carried

out and the activity of natural products and