I was told to mix at a rate up to 16 - 20 drops
per gallon. Also told not to use a surfactant. Finally, I was told that
it remains active in the plant for up to 6 weeks. The following is some
additional info I found on the net someplace.
Trade and Other Names: Abamectin is also known as Avermectin B1a. Trade
names include Affirm, Agri-Mek, Avermectin, Avid, MK 936,
Vertimec, and
Zephyr.
Regulatory Status: Abamectin is a General Use Pesticide
(GUP). It is
classified as toxicity class IV - practically nontoxic,
and has no
precautionary statement on its label.
Chemical Class: antibiotic
Introduction: Abamectin is a mixture of avermectins containing
about 80%
avermectin B1a and 20% avermectin B1b. These two components,
B1a and B1b,
have very similar biological and toxicological properties.
The avermectins
are antibiotic compounds derived from the soil bacterium
Streptomyces
avermitilis. Abamectin is a natural fermentation product
of this bacterium.
It acts as an insecticide by affecting the nervous system
of and paralyzing
insects. Abamectin is used to control insect and mite
pests of citrus,
pear, and nut tree crops, and it is used by homeowners
for control of fire
ants.
Formulation: Not Available
Toxicological Effects:
* Acute toxicity: Abamectin is highly toxic to insects
and may be highly
toxic to mammals as well [141]. Emulsifiable concentrate
formulations
may cause slight to moderate eye irritation and mild skin
irritation
[8]. Symptoms of poisoning observed in laboratory animals
include
pupil dilation, vomiting, convulsions and/or tremors,
and coma
[141,142]. Abamectin acts on insects by interfering with
the nervous
system. At very high doses, it can affect mammals, causing
symptoms of
nervous system depression such as incoordination, tremors,
lethargy,
excitation, and pupil dilation. Very high doses have caused
death from
respiratory failure [143]. Abamectin is not readily absorbed
through
skin. Tests with monkeys show that less than 1% of dermally
applied
abamectin was absorbed into the bloodstream through the
skin [141].
Abamectin does not cause allergic skin reactions [142].
The oral LD50
for abamectin in rats is 10 mg/kg, and in mice ranges
from 14 mg/kg to
greater than 80 mg/kg [141,142]. The oral LD50 for the
product Avid EC
in rats is 650 mg/kg [8]. The dermal LD50 for technical
abamectin in
rats and rabbits is greater than 330 mg/kg [144].
* Chronic toxicity: In a 1-year study with dogs given
oral doses of
abamectin, dogs at the 0.5 and 1 mg/kg/day doses exhibited
pupil
dilation, weight loss, lethargy, tremors, and recumbency
[141].
Similar results were seen in a 2-year study with rats
fed 0.75, 1.5,
or 2 mg/kg/day. Rats at all the dosage levels exhibited
body weight
gains significantly higher than the controls. A few individuals
in the
high dose group exhibited tremors [141]. When mice were
fed 8
mg/kg/day for 94 weeks, the males developed dermatitis
and changes in
blood formation in the spleen, while females exhibited
tremors and
weight loss [142].
* Reproductive effects: Rats given 0.40 mg/kg/day of abamectin
had
increased stillbirths, decreased pup viability, decreased
lactation,
and decreased pup weights [142]. These data suggest that
abamectin may
have the protential to cause reproductive effects at high
enough
doses.
* Teratogenic effects: Abamectin produced cleft palate
in the offspring
of treated mice and rabbits, but only at doses that were
also toxic to
the mothers [141]. There were no birth defects in the
offspring of
rats given up to 1 mg/kg/day [142]. Abamectin is unlikely
to cause
teratogenic effects except at doses toxic to the mother.
* Mutagenic effects: Abamectin does not appear to be mutagenic.
Mutagenicity tests in live rats and mice were negative.
Abamectin was
shown to be nonmutagenic in the Ames test [1].
* Carcinogenic effects: Abamectin is not carcinogenic
in rats or mice.
The rats were fed dietary doses of up to 2 mg/kg/day for
24 months,
and the mice were up to 8 mg/kg/day for 22 months [141].
These
represent the maximum tolerated doses.
* Organ toxicity: Animal studies indicate that abamectin
may affect the
nervous system.
* Fate in humans and animals: Tests with laboratory animals
show that
ingested avermectin B1a is not readily absorbed into the
bloodstream
by mammals and that it is rapidly eliminated from the
body within 2
days via the feces [142]. Rats given single oral doses
of avermectin
B1a excreted 69 to 82% of the dose unchanged in the feces.
The average
half-life of avermectin B1a in rat tissue is 1.2 days
[144]. Lactating
goats given daily oral doses for 10 days excreted 89%
of the
administered avermectin, mainly in the feces. Less than
1% was
recovered in the urine [144].
Ecological Effects:
* Effects on birds: Abamectin is practically nontoxic to
birds [142].
The LD50 for abamectin in bobwhite quail is >2000 mg/kg.
The dietary
LC50 is 3102 ppm in bobwhite quail [145]. There were no
adverse
effects on reproduction when mallard ducks were fed dietary
doses of
3, 6, or 12 ppm for 18 weeks [145].
* Effects on aquatic organisms: Abamectin is highly toxic
to fish and
extremely toxic to aquatic invertebrates [142]. Its LC50
(96-hour) is
0.003 mg/L in rainbow trout, 0.0096 mg/L in bluegill sunfish,
0.015
mg/L in sheepshead minnows, 0.024 mg/L in channel catfish,
and 0.042
mg/L in carp. Its 48-hour LC50 in Daphnia magna, a small
freshwater
crustacean, is 0.003 mg/L. The 96-hour LC50 for abamectin
is 0.0016
mg/L in pink shrimp, 430 mg/L in eastern oysters, and
153 mg/L in blue
crab [145]. While highly toxic to aquatic organisms, actual
concentrations of abamectin in surface waters adjacent
to treated
areas are expected to be low. Abamectin did not bioaccumulate
in
bluegill sunfish exposed to 0.099 ug/L for 28 days in
a flow-through
tank. The levels in fish were from 52 to 69 times the
ambient water
concentration, indicating that abamectin does not accumulate
or
persist in fish [145].
* Effects on other organisms: Abamectin is highly toxic
to bees, with a
24-hour contact LC50 of 0.002 ug/bee and an oral LD50
of 0.009 ug/bee
[145].
Environmental Fate:
* Breakdown in soil and groundwater: Abamectin is rapidly
degraded in
soil. At the soil surface, it is subject to rapid photodegradation,
with half-lives of 8 hours to 1 day reported [142,145].
When applied
to the soil surface and not shaded, its soil half-life
is about 1
week. Under dark, aerobic conditions, the soil half-life
was 2 weeks
to 2 months [142]. Loss of abamectin from soils is thought
to be due
to microbial degradation. The rate of degradation was
significantly
decreased under anaerobic conditions [145]. Because abamectin
is
nearly insoluble in water and has a strong tendency to
bind to soil
particles, it is immobile in soil and unlikely to leach
or contaminate
groundwater [145]. Compounds produced by the degradation
of abamectin
are also immobile and unlikely to contaminate groundwater
[145].
* Breakdown in water: Abamectin is rapidly degraded in
water. After
initial distribution, its half-life in artificial pond
water was 4
days. Its half-life in pond sediment was 2 to 4 weeks
[145]. It
undergoes rapid photodegradation, with a half-life of
12 hours in
water [142]. When tested at pH levels common to surface
and
groundwater (pH 5, 7, and 9), abamectin did not hydrolyze
[145].
* Breakdown in vegetation: Plants do not absorb abamectin
from the soil
[145]. Abamectin is subject to rapid degradation when
present as a
thin film, as on treated leaf surfaces. Under laboratory
conditions
and in the presence of light, its half-life as a thin
film was 4 to 6
hours [145].
Physical Properties:
* Appearance: Abamectin is a colorless to yellowish crystalline
powder
[1].
* Chemical Name: avermectin B1
* CAS Number: 71751-41-2 (avermectin B1a and avermectin
B1b) [1]
* Molecular Weight: 873.11
* Water Solubility: Insoluble [1]
* Solubility in Other Solvents: v.s. in acetone, methanol,
toluene,
chloroform, and ethanol [1]
* Melting Point: 150-155 C [1]
* Vapor Pressure: Negligible [1]
* Partition Coefficient: Not Available
* Adsorption Coefficient: 5000 (estimated) [53]
Exposure Guidelines:
* ADI: 0.0001 mg/kg/day [12]
* MCL: Not Available
* RfD: 0.0004 mg/kg/day [13]
* PEL: Not Available
* HA: Not Available
* TLV: Not Available
Basic Manufacturer:
Merck Agvet
Division of Merck and Co., Inc.
P.O. Box 2000
Rahway, NJ 07065
* Phone: 908-855-4277
* Emergency: Not Available
References:
References for the information in this PIP can be found
in Reference List
Number 10
------------------------------------------------------------------------
DISCLAIMER: The information in this profile does not in
any way replace or
supersede the information on the pesticide product labeling
or other
regulatory requirements. Please refer to the pesticide
product labeling.