and Integrated Pest Management - part - usaid

352 PESTICIDE MANAGEIEN'Ir AND HPM IN SOUIIIAST ASIA
(1983) also found out that washing removed 50-80% of the residues.
Subsequent degradation studies showed that residue problems wCre unlikely to
arise if a preharvest interval of two weeks was followed.
Besides vegetables, analysis of cocoa beans for residues of the isomers of
HCH and DDT were also ,done by the Department of Agriculture with the
assistance of the GTZ laboratory in Darmstadt. Results showed that
levels
only
of
trace
DDT and less than 0.1 ppm of grnima-HCH was present in the cocoa
beans; other lC-I isomers in Malaysian cocoa were also not a problem.
Nevertheless, the Pesticides Board decided not to register pesticides containing
mixed isomers of HCH, with the exception of the granular formulation, which is
mainly used by paddy farmers.
To date little is known about pesticide residues in water, soils, and animals
in this country. Water samples taken from a river flowing through vegetable
areas in tho Cameron t-tighlands, when analyzed, (lid not show the presence of
organochlorine intsccticidcs such as HCH and its isomers, chlordane, heptachlor,
heptachlorepoxide, aldrin, dieldrin, endrin, and DDT (Anonymous 1984). Water
collected from paddy fields where dead fish were found often contained significant
levels oi endosulfan but not alpi-- or gamnma-HC- (Lee & Ong 1983).
Analysis of dead fish tissues showed high levels of endosulfan. However,
endosulfan is not recommended for use in paddy fields where fish production is
important.
Fish caught in rivers flowing through industrial zones were also reported
contain
to
fron 0.1 ppm to 0.241 ppm mercury (Chia & Tong 1981).
levels
These
are below the maximum permissible levels of 0.5 ppm set by the United
States Food and Drug Administration. No significant results were found in seawater
fish when they were analyzed for organochlorine pesticides.
STUDIES ON PESTICIDE DEGRADATION
Degradation studies to detennine the preharvest interval for some commonly
used pesticides have been carried out on vegetables. The results of the studies
(Lim et al. 1983, l-tatzo!l et al. 1986) are as follows:
Pesticide,' (%a.i.)
Methamidophos (0.06%)
Endosulfan (0.02%)
Permethrin (0.02%)
EBDC (0.4%)
('ypermethrin (0.01%)
EBDC (0.2%)
Velables
Preharvest interval (days)
B. rapa
14
B. oleracca
14
B. rapa
7
B. rapa
7
tomatoes
14
B.oleracea
3
B.rapa
3
Chrysanthemum
14
coronariun
L.var.spatiosumn Bailey
More studies are being carried out to determine the preharvest intervals for
other pesticides on other crops and this information will be incorporated on
pesticide labels for farmers to follow.