Description
Azoxystrobin is
a second broad-spectrum strobilurin fungicide (28,29).
It forms white solids with a mp = 116 ?C; vp = 1.1 ×
10?7 mPa at 25 ?C; logP = 2.5 at 20?C; water solubility =
6 mg/L; and a half-life of 11 to 17 days for aqueous
photolysis.
Chemical Properties
White to beige crystalline solid or powder.
Uses
Strobilurin fungicide; inhibits mitochondrial respiration by blocking electron transfer between cytochromes b and c1. Agricultural fungicide.
Uses
Azoxystrobin has a very broad spectrum of activity and is active
against fungal pathogens from all four taxonomic groups, the Oomycetes,
Ascomycetes, Deuteromycetes and Basidiomycetes. It controls diseases
on cereals, rice, vines, apples, peaches, bananas, citrus, curcurbits,
potatoes, tomatoes, peanuts, coffee and turf.
Uses
Agricultural fungicide.
Definition
ChEBI: An aryloxypyrimidine having a 4,6-diphenoxypyrimidine skeleton in which one of the phenyl rings is cyano-substituted at C-2 and the other carries a 2-methoxy-1-(methoxycarbonyl)vinyl substituent, also at C-2. An inhibitor of mitochondrial respiration by b
ocking electron transfer between cytochromes b and c1, it is used widely as a fungicide in agriculture.
Hazard
Moderately toxic by inhalation.
Agricultural Uses
Fungicide: Azoxystrobin has been processed as a Reduced
Risk pesticide for Turf uses. Azoxystrobin is a systemic,
broad-spectrum fungicide that was first introduced in
1998. It inhibits spore germination and is used on grape
vines, cereals, potatoes, apples, bananas, citrus, tomatoes
and other crops. Largest crop uses in California are on
almonds, rice, pistachios, wine grapes, raisins and garlic.
Among the diseases it controls are rusts, downey and
powdery mildew, rice blast and apple scab. A U.S. EPA
restricted Use Pesticide (RUP)
Trade name
ABOUND®; AMISTAR®; AMISTAR
OPTI; AMISTAR PRO; BANKIT®; HERITAGE®;
ICIA5504 80WG®; OLYMPUS®; ORTIVA®;
PROTEGE®; PROTEGE-ALLEGIANCE WP®;PROTEGE-FL SEED APPLIED FUNGICIDE®;
QUADRIS OPTI®; QUILT®; SOYGARD WITH
PROTEGE®
Safety Profile
Moderately toxic by inhalation.When heated to decomposition it emits toxic vapors ofNOx.
Potential Exposure
A β-methyoxyacrylate, Strobilurin is
an agricultural fungicide.
Metabolic pathway
Azoxystrobin is a recently developed fungicide with a novel mode of
action (see Overview for relevant references). It was first registered in
1996. It has been and is being subjected to the full range of studies to meet
current regulatory requirements for toxicology, metabolism and
environmental fate. Information on its metabolism and environmental
fate was presented as a lecture at the 9th International Congress of
Pesticide Chemistry (IUPAC) in 1998 and this will be published in the
Proceedings. The information presented below is derived from this source
(Joseph, 1998).
Azoxystrobin is a carboxylic acid methyl ester and one of its pathways
of metabolism is via hydrolysis to its carboxylic acid. The latter is not
biologically active (see Overview) and the favourable selective toxicity of
the fungicide is due to this and other metabolic reactions in non-target
species. Azoxystrobin is readily degraded in soil and ultimately mineralised
and it is metabolised in plants and animals. Metabolism is complex
because the molecule possesses several functional groups. Five different
pathways have been identified in plants and animals. Biotransformations
occurring on the parent molecule include hydrolysis, aromatic hydroxylation,
cleavage of both phenoxy linkages, nitrile to amide hydrolysis and
fragmentation of the acrylate double bond. Some photo-induced changes
also occur, including conversion to the (Z)-isomer.
Metabolism
Metabolites are also rapidly degraded in soil.
Photolysis studies show a DT
50 of 11 days. Due to the rapid
degradation and low soil mobility, no leaching is found in
field studies.
Shipping
UN2811 Toxic solids, organic, n.o.s., Hazard
Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name
Required. UN3082 Environmentally hazardous substances,
liquid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous
hazardous material, Technical Name Required.
Degradation
Azoxystrobin is degraded under conditions of aqueous photolysis with a
DT
50 of 11-17 days (PM).
Soil surface photolysis of azoxystrobin (
14C-labelled separately in each
of the three rings) was studied on a sandy loam for a period of 30 days.
The fungicide was degraded with a DT
50 measured as a mean of the three
radiolabels, of 11 days in natural summer sunlight. The degradation was
complex, affording many initial products, all at 40% of the applied
radiocarbon. These products were themselves readily photolysed and no
product accumulated during the course of the experiment. The yield of
14CO2 in 30 days was between 17% (phenylacrylate label) and 29%
(cyanophenyl label). Thus soil surface photodegradation is likely to
be an important mechanism for the removal of azoxystrobin from the
environment.
Toxicity evaluation
Azoxystrobin has an acute oral LD
50 > 5,000 and an
acute dermal LD
50 > 2,000 mg/kg in rats. Azoxystrobin
gives only slight skin and eye irritation and is nonmutagenic
and nonteratogenic. Its NOEL is 18 mg/kg
bw/day. It has no toxicity to birds in acute studies
(LD
50 > 2,000 mg/kg). It is harmless to other nontarget
organisms (honey bees, earthworms, beneficial arthropods)
due to low toxicity and rapid degradation in the
environment, which minimizes exposure.
Incompatibilities
Combustible; dust may form explosive
with air. Incompatible with oxidizers (chlorates, nitrates,
peroxides, permanganates, perchlorates, chlorine, bromine,
fluorine, etc.); contact may cause fires or explosions. Keep
away from alkaline materials, strong bases, strong acids,
oxoacids, epoxides.
Waste Disposal
Recycle any unused portion
of the material for its approved use or return it to the manufacturer
or supplier. Dispose of contents and container to
an approved waste disposal plant. Use a licensed professional
waste disposal service to dispose of this material.
Ultimate disposal of the chemical, product, and waste containers
must consider: the material’s impact on air quality;
potential migration in soil or water; effects on animal and
plant life; and conformance with public health, local, state,
and federal health and environmental regulations. Never
reuse or recycle used product containers unless the recycling
program specifically accepts pesticide containers and
you follow the program’s instructions for preparing the
empty containers for collection
