PROPARGITE JMPR 1978
Explanation
Propargite was evaluated in 1977 (FAO/WHO, 1978b), when a
temporary ADI was allocated and a number of maximum residue limits
were recommended. The compound is due for reevaluation in 1981, but
some of the information recorded as desirable by the 1977 Meeting
has been received and is reviewed in the following monograph
addendum.
IDENTITY
The data given below supplement the information given in the
1977 evaluation.
Synonym
Proparigite
Information on identity and properties
Molecular weight: 350
Physical form: Light to dark brown viscous liquid
Odor: Faint solvent odor. A strong odor of SO2 may mean
that partial decomposition has occurred.
Volatility: Low
Specific gravity 25°C: 1.085 - 1.115
Flash point: 28°C (min.) Pensky Martens
Stability: Between 0.5 and 1.0% propylene oxide is added
to stabilize Omite Technical. Shows no
degradation after 12 months storage.
Water, max.%:Less than 0.1
Solubility: Water - about 0.5 mg/kg 25°C. Miscible with
organic solvents such as acetone, benzene,
ethanol heptane and methanol.
Assay Method
Infrared spectroscopy based on the propargyl absorption at
3.03 microns in comparison with a standard of known purity.
Formulation
OMITE - 4D 4% Dust
OMITE - 3OW 30% Wettable Powder
OMITE - 57E 57% Emulsifiable Concentrate
OMITE - 6E 68% Emulsifiable Concentrate
OMITE 75% Emulsifiable Concentrate
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Propargite is a specific acaricide which, when used at
recommended rates, is relatively safe to honey bees and many
beneficial parasitic and predaceous insects. Predaceous mites will
not be eliminated from treated areas and it can be successfully
used in integrated control programmes.
Pre-harvest treatments
In countries other than the United States formulations are
registered for use on apples, apricots, cherries, citrus, maize,
cotton, grapes, hops, nectarines, peaches, pears, plums, prunes,
raspberries, strawberries, tea, vegetables such as beans and
cucumbers and ornamentals.
Propargite has provided effective control of the following
mite species: apple rust mite, Banks grass mite, brown mite, citrus
red mite, citrus rust mite, clover mite, cyclamen mite, European
red mite, McDaniel spider mite, Pacific spider mite, peach silver
mite, six-spotted mite, strawberry spider mite, Texas citrus mite,
two-spotted spider mite, Willamette mite.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Residues in crops
Residue data were available from Field Tests conducted in the
Netherlands, South Africa, Canada and India. Results are summarized
in Table 1.
FATE OF RESIDUES
In plants
Propargite - 14C (Phenyl), formulated as Comite(R), was
applied to defined areas in the upper surfaces of mature leaves on
two Blue Lake Bush Bean plants (Wong et al., 1978). After seven
days, 68% of the applied radioactivity was recovered from the
treated area as propargite. no significant translocation of
radioactivity to untreated areas of the treated leaf or to
TABLE 1. Propargite residues from supervised trials
Crop Country Application Residues, mg/kg,
Days after application
Apples Netherlands Omite 30W 0 7 14 21
Var. 1 0.79 0.79 0.84 0.78
Var. 2 0.73 0.82 0.60 0.93
S. Africa 0 2 6 13 20
Omite 30W 1.03 0.94 0.87 0.62 -
Omite 57E 0.99 1.08 0.82 1.02 0.84
Ontario, Canada 0.61 lbs. ai/acre 14
MacIntosh 0.33
Spy 0.59
Golden Del. 0.59
0.54 lbs. ai/acre
MacIntosh 0.43
Spy 0.20
Golden Del. 0.47
Tomatoes Netherlands Aerosol 0 3
1.21 1.23
S. Africa Omite 30W 0 3 7 14 21 28
1.11 1.29 1.44 0.35 0.43 0.30
Cucumbers Netherlands Aerosol 0 3
Site 1 0.32 0.18
Site 2 0.23 -
Tea leaves Borbhetta, India Omite 57E 7
Manufactured 0.75 kg. ai/ha 0.5
0.5
TABLE 1. (Cont'd)
Crop Country Application Residues, mg/kg,
Days after application
0.5
1.5 kg. ai/ha 1.1
1.0
0.97
Sun dried 0.75 kg. ai/ha 0.7
0.5
0.5
1.5 kg. ai/ha 0.9
0.9
0.9
Manufactured Cinchona District, 1.50 kg. ai/ha 7
S. India 2.04
2.04
2.24
Sun dried 1.52
1.24
1.16
Manufactured Assam, N. India 0.75 kg ai/ha 7
0.50
0.46
0.52
1.50 kg ai/ha 1.14
1.00
0.97
Sun dried 0.75 kg ai/ha 0.66
0.45
0.46
1.50 kg ai/ha 0.89
0.90
0.90
TABLE 1. (Cont'd)
Crop Country Application Residues, mg/kg,
Days after application
Manufactured Madras, India 0.75 kg ai/ha 0 7 14 28
67 4 <0.1 <0.1
61 3.8 <0.1
48 4.2 <0.1
Sun dried 161 2.6 0.2 <0.1
174 1.1 <0.1
178 1.8 <0.1
Manufactured Coimbatore District 0.31 kg ai/ha 7 14
<0.1 0.2
Sun dried 0.3 <0.1
untreated portions of the whole plant was observed by autoradiography
(sensitivity: 0.1% of applied 14C). Thus, residues of propargite and
its degradation products found in beans are unlikely to result from
translocation.
In another experiment, two Blue Lake Bush Bean plants were
treated with two applications of propargite - 14C, formulated as
Comite(R), according to field usage. After harvest 1.8% of the
applied radioactivity remained on the beans (5.6 mg/kg calculated as
propargite). The majority (60.4%) of the radioactivity associated with
the beans was characterized as propargite - 14C and the remainder
consisted mainly of polar material (29.3%) and unextractable residues
(5.5%).
APPRAISAL
Propargite in a specific acaricide with registered uses on a wide
variety of agricultural crops in many countries. It was first
evaluated by the Joint Meeting in 1977. In response to questions
arising from that meeting information was received and evaluated on
residues resulting from supervised trials in countries other than the
U.S.A. and on the translocation and fate of residues in plants.
Summary data on the results of field trials on apples were
received from Canada, the Netherlands and South Africa, on tomatoes
from the Netherlands and South Africa and on cucumbers from the
Netherlands. These data indicated that it would be unlikely for
residues to exceed 2 mg/kg on apples, 2 mg/kg on tomatoes, or 0.5
mg/kg on cucumbers.
Detailed data were received an field trials on tea in various
regions in India. Since it is common practice in tea culture to pick
leaves repeatedly from the same bush at a desired stage of growth, it
is possible to have some leaves harvested as soon as 1 day after
treatment, especially if repeated treatments are required. However, in
the absence of information on the need for repeated treatments, it was
assumed that control over the pre-harvest interval could be exercised
by growers and an interval of 7 days was selected on which to base
recommendations. Data on residues on manufactured tea at a pre-harvest
interval of 7 days show that values of 5 mg/kg would not be exceeded.
Experiments with 14C-labelled propargite, formulated as
COMITE(R), applied either to defined areas of Blue Lake Bush Bean
leaves or according to field usage indicated that no significant
translocation of propargite or its degradation products took place and
that the residue on beans consisted mainly (60.4%) of propargite, the
remainder being polar material (29.3%) and unextractables (5.5%).
RECOMMENDATIONS
The following temporary maximum residue limits are recommended.
Those for tea, tomatoes and cucumbers are new. Those for apples, figs
and peers are amended on the basis of new data and to comply with the
usual manner of expressing limits.
Commodity Limit, mg/kg
Tea (dried, manufactured) 5
Apples 2
Figs 2
Pears 2
Tomatoes 2
Cucumbers 0.5
FURTHER WORK OR INFORMATION
Desirable
1. Additional data from supervised trials in countries other than
U.S.A.
2. Information on the occurrence of residues on commodities in
commerce.
REFERENCES
Uniroyal, Technical Data Sheet on OMITE(R) Acaricide
Uniroyal, Residue Data obtained from Field Tests conducted
(1978) outside the USA.
Wong, D.T.L., Tortora, N.J., Fuller G.B. and Cardona, R.A.
(1978) Translocation and Fate of Propargite - 14C on
Blue Lake Bush Beans. Report on Project No. 7834,
Uniroyal Chemical.