Resource Guide for Organic Insect and Disease ... - Cornell University

MATERIAL FACT SHEET
Copper products
MATERIAL NAME: Copper products
MATERIAL TYPE: Mineral-based fungicide/bactericide
U.S. EPA TOXICITY CATEGORY: Varies by form. Copper hydroxide and copper sulfate are
Category I, “Danger.” Basic copper sulfate and copper oxychloride are Category II, “Warning.”
Copper oxide and copper octanoate are Category III, “Caution.”
USDA-NOP:
Considered synthetic, allowed with restrictions. The following forms are permitted for use in
plant disease control:
1. Coppers, fixed - copper hydroxide, copper oxide, copper oxychloride, copper
octanoate, includes products exempted from EPA tolerance. Use as an herbicide is not
permitted (NOP: 7CFR 205.601(i)(1)).
2. Copper sulfate (NOP: 7CFR 205.601(i)(2)).
3. Copper sulfate is also permitted for use as an aquatic algaecide and for tadpole shrimp
control in rice production. (NOP: 7CFR 205.601(a)(4) and (e)(3)).
Copper-based materials must be used in a manner that minimizes accumulation in the soil
(NOP: 7CFR 205.601(i)(1) & (2)). It is recommended, and some certifiers require, that soil testing
is done to establish a baseline for background levels of copper in the soil and that subsequent
testing be done to monitor any accumulation. See below for a discussion of copper in soil.
MATERIAL DESCRIPTION:
Copper fungicides can be described as insoluble compounds, yet their action as fungicides
and bactericides is due to the release of small quantities of copper (Cu++) ions when in
contact with water. Copper hydroxide is more water soluble at low pH (high acidity). This
product should be applied in a spray solution (such as water) at a pH above 6.0; if the solution
is more acidic, phytotoxicity could occur. Bordeaux mixes are preparations of copper sulfate
and calcium hydroxide (hydrated lime), working in much the same way as the newer copper
fungicides, which are effective at lower rates of application.
HOW IT WORKS:
Toxic copper ions are absorbed by germinating spores. Following absorption into the fungus
or bacterium, the copper ions link to various chemical groups present in many proteins (e.g.,
imidazoles, phosphates, sulfhydryls, hydroxyls) and disrupt their function. Thus, the mode-ofaction
of copper hydroxide (or any other copper fungicide) is the non-specific denaturation
(disruption) of cellular proteins. For best results, copper must be on the plant surface before
the spore germinates and reapplied as plants grow to maintain coverage and prevent disease
establishment.
OMRI LISTED PRODUCTS (NOT INCLUDING COPPER FERTILIZERS):
Badge X2 (Isagro USA)
Camelot O Fungicide/Bactericide (SePRO Corporation)
Basic Copper 53 (Albaugh, Inc.)
Champ WG (NuFarm Americas, Inc.)
Chem Copp 50 (American Chemet Corporation)
COC WP (Albaugh, Inc.)
Copper Sulfate Crystals (Chem One Ltd.)
CS 2005 Algaecide/Bactericide/Fungicide (Magna-BonII, LLC)
CSC Copper Sulfur Dust Fungicide (Martin Operating Partnership, L.P.)
Organic Resource Guide 123