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PDF Text
Text
ftomD Number
°3124
Author
Minarik, Charles E.
D not Scanned
^'ant Sciences Laboratory, Department of Defense
RBDOrt/ArtlClB TltlB Typescript: Report of Cambodian Rubber Damage
Journal/Book Title
Year
1969
Month/Day
December 1 1
Color
D
Number of Images
18
DBSCrbtOn NOtBS
Documents were filed together by Alvin Young under the
label, "Review of Vietnam Program". SMUFD-PSL
Friday, November 16, 2001
Page 3124 of 3140
�DEPARTMENT OF THE ARMY
FORT DETSiCK
FREDERICK, MARYLAND
21701
SMUFD-PSL
SUBJECT:
11 December 1969
Report of Cambodian Rubber Damage
SEE DISTRIBUTION
Inclosed is a copy of the report of damage to Cambodian rubber plantations prepared by the four-man survey team following a survey in June
1969. This version of the report has been released to the press by
the State Department.
FOR THE COMMANDER:
1 Incl
C. E. MINARIK
as
Director, Plant Sciences Laboratories
DISTRIBUTION:
Mr. A. E. Hayward, OSD, DDR&E
Dr. K. C. Emerson, OASA (R&D)
MAJ M. L. Sanches, OACSFOR
LTC William J. Henderson, OCRD
Mr. E. M. Hamory, USAMC
Mr. Werner Beyth, USAMUCOM
COL B. M. Whitesides, Cml Ops Div, MACV J-3
Mr. C. R. Heineman, JTCG/CB, Naval Air Sys Cmd
Mr. W. Vandeventer, SAOQT, SAAMA, Kelly AFB
Mr. M. G. Solomon, ATCB, Eglin AFB '
"tJPT R. Richter, AFATL, Eglin AFB
Mr. Mitchell Modrall, USA Cml Center & School
CO, Ft Det
Sci Dir, Ft Det
Mr. K. Irish, PP&C Ofc, Ft Det
Ch, Pit Physiol Div, Ft Det
f
.
�TABLE OF CONTENTS
INTRODUCTION
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Purpose
Saigon Briefings
Cambodia: Itinerary and Contacts Made
ANALYSIS OF DAMAGE AND CAUSES
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Area and Pattern of Damage
Severity of Damage
Causes of Damage
Permanence of Damage
Mitigation of Herbicide Effects
SUMMARY AND
CONCLUSIONS . •
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ACKNOWLEDGEMENTS
APPENDIXES
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A. Programme de Sejour et de Visite des Experts Americains
B. ,Map Showing Principal Cambodian Rubber Plantations* ;.,
Maximum Extent of Herbicide Effect, and; Boundary
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of Tay Ninh Spray Target
C. Maps Showing Areas and Severity of Herbicide Effect
: | at Chalang-Prekchlong and Mimot-Kantroy Plantations
D. Rapport du Comite Charge du Constat et de 1'Evaluation_
. des De"gats Dus aux Epandages des Produits Defoliants
par les Avions Americano-Subvietnamiens
E. Selected Photographs
�INTRODUCTION
On June 2, 1969 the United States Government received notice
of a. charge by the Cambodian Government that major defoliation
damage to Cambodian rubber plantations near the border of the
Republic of Viet-Nam (RVN) had occurred as the result of U.S.
defoliation activity. In replying to this charge, the U.S. State
Department offered to send a team of experts to examine the
area of alleged damage and the Cambodian Government agreed.
The team members were selected and met in Saigon on June 27,
1969 for a.formal briefing.
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-..-'•'Members of the four-man team included:
Dr. Charles E, Minarik, Director. .
Plant Sciences Laboratories
Department of Defense
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Jack B. Shumate, Chief
Forestry Branch
Office of Commercial and Capital Assistance
Agency for International Development
Saigon, Viet-Nam
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Dr. Fred H. Tschirley, Assistant, Chief;"
Crop Protection Research Branch
Agricultural Research Service
Beltsville, Maryland
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Purpose
Dr. NaderL_G. Vakili, Agronomy Adviser
: .Office of Development and Domestic Production
Agency for International Development
Saigon,;Viet-Nam
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The purpose of the trip was to determine the cause, severity,
origin, and extent of reported damage to rubber and fruit trees>
�Saigon Briefings
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Team members received a briefing from military and State .
Department personnel on June 27. .They were provided with
pertinent information on military operations—especially
defoliation activity--near the Cambodian; border.' Three of the
team members went via helicopter to Xuan LOG on June 28 to
visit with. Mr. Poliniere of the Rubber Institute. On June 29,
the group travelled via helicopter to the defoliation target area
in Tay Ninh Province to observe the defoliated areas from which
drift of the herbicide may have caused damage to rubber and fruit
trees in Cambodia. On June 30, the four-man team left by
commercial.aircraft for Phnom Penh.
• ;
Cambodia; Itinerary and Contacts Made
\
Upon arrival in Phnom Penh, Cambodia, shortly after noon on ;::
June 30, the team was met by a representative of the Cambodian
Foreign Ministry, by Mr. Mack Williams, Australian Deputy
Chief of Mission, and by Mr. Neil Manton, Third Secretary and
Vice Consul. Mr. Manton handled all local arrangements and
served as liaison officer for the team during the entire stay in
Cambodia. After checking in at the Monorom Hotel, the team
went to the Australian Embassy for a briefing. Members of the
embassy staff contacted included Mr. Graham Feakes, Ambassador;Mr. Mack Williams; and Mr. Neil Manton.
On Tuesday July 1, a meeting was held with Cambodian
representatives who outlined conditions as they saw them and
presented a proposed schedule for field travel (Appendix A)., We
agreed with the schedule, and a general discussion followed.
Individuals attending th§_meeting in addition to team members and
Mr. Manton ', included:
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Mr. Min Sarim, Ministry of Agriculture,
Chairman of the committee appointed by the
. Cambodian Government to study and report
on damage to rubber trees, fruit trees and
farm crops.
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Mr".,'Ring Un, Director of Agriculture 'Committee member
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'Mr. Suon Kaset, Director of Water and
Forestry - Committee member
Mr. Ho long Lip, Research Agronomist,
Ministry of Agriculture - Committee member
Field travel began on July 2, with a visit to the Chup rubber
plantation and an overflight in small fixed-wing aircraft, of the
entire area of alleged damage. Purpose of the visit was to see an
undamaged plantation (Chup) in operation and get a general picture
of the damaged area. People contacted at Chup were: Mr. Meas
Keth Cairnira, Director General of SOKAR; Mr. Francis Ninane,
agronomist, Mr. Chai Kim Chun, chemist, and Mr. Gilbert
De Coninck, pathologist, of the Rubber Research Institute (IRCC);
and Mr. Digoy, manager of the Chup Plantation. Travel from and
to Phnom Penh was by Dakota aircraft and over the Chup, Mimot and
other holdings by small, single-engine aircraft, both furnished by
the Royal Cambodian Air Force. Ground transportation was
furnished by plantation officials and the Cambodian Government furnisl
security forces at all times. Team and committee members returned
to Phnom Penh each night.
' ' -'.-.
On July 3, 4 and 5, we travelled to Mimot via Dakota aircraft,
and then by car throughout the area of reported damage.. Major
rubber plantations visited included: Chipeang, Chipes, Dar, Chalang,
Mimot, Kantroy, Krek and Prek Chlong. The group also visited a ,
number of other areas to inspect fruit trees, farm crops, ornamental
plantings, a teak plantation, and natural forest area. Key personnel
contacted at the Mimot headquarters included: , Mr„ H. Say, Director
.General - Mimot; Mr. Audureau, Director of farm operations Mimot; Mr. Girandel, Administrative.Officer - Mimot. .
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July 6 -7. No formal schedule.
and forest areas.
•
Team visited undamaged farm
" A helicopter flight over the entire damaged area was scheduled
for July 8, but was postponed 'one day. The team took advantage of
�this time to meet with the French Ambassador, the Canadian members
of the International Control Commission, the Australian Embassy
staff and the Cambodian Minister of Agriculture, Mr. Chuon Saodi.
An Alouette II helicopter was made available on July 9 and
the investigating team made an overflight of the entire area under
study. We returned to Phnom Penh in the afternoon and left for
Viet-Nam, arriving in Saigon shortly after 1700 hours.
ANALYSIS OF DAMAGE AND CAUSES
Area and Pattern of Damage,:
Representatives of the Cambodian Government had prepared a
map showing the extent of the damaged area. The boundary
representing the perimeter of the damaged area is shown on the
enclosed map (Appendix B). In addition, we were also supplied v . ••
with maps of the Mimot and Prek Chlong plantations 'that showed
rubber trees severely damaged,, (more than 50 percent defoliation)
and slightly damaged (less than 50 percent defoliation). These maps
I(Appendix C) were prepared at the time of maximum defoliation-before refoliation had begun. Our own observations confirmed the
findings of the Cambodian investigating committee.
The total area on which damage occurred was approximately
700 square.kilometers or 70,000 hectares. The Cambodian Government claimed damage on about 15,000 hectares, which represents
the area in rubber and fruit.
The principal damage reported by the Cambodian investigating
committee, and confirmed by us, was through the Dar and Prek
Chlong plantations. Lessor damage was noted to the west on the
Krek plantation and to the east on the Mimot plantation. „
Severity o f Damage
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The degree of plant response to the herbicide varied from
a very slight reaction showing discoloration of older leaves and
atrophy of the young leaves, to 100 percent defoliation and die-back
of one to four years of branch, growth. We were told by the
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:ambodians that normal flower development was prevented in teak
(Tectona grandis), resulting in the failure to product seed. The,.
defoliant caused malformation of fruits of jackfruit, durian and
guava, and, in severe cases resulted in rot and fall of the fruits.
The vegetable crops mentioned below were either destroyed and re'planted by the time of this report or were left in the field and backyards unattended.
The degree of plant reaction to the herbicide differed among
species. Within a species, the degree of response was conditioned
by variation in varietal tolerance, age of the plant, stage of growth
(active or quiescent) of, the plant, and dosage receiyed.
Exceptions may be found for any general statement about the
nature of damage to crops. However, the following statements
are based on two years of surveys and experience with tropical
crops in Viet-Nam. Each crop is discussed separately with the
• •crops least tolerant to herbicides mentioned first, followed by the
more tolerant ones.
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pasurina Pine or Australian Pine (Casurina equi s e t ifo1ia). This
lant is used as a shade tree. It is the species most.sensitive to
Befoliants used in Viet-Nam. After treatment its foliage turns brown
and falls, branches die back, and bark peels away from 'the trunk.
One treatment with a heavy dosage is sufficient to cause die-back of
most branches and often the tree is killed.
•
Jackfruit (Artocarpus integra). This fruit tree is easily grown
and popular in this region. It is highly sensitive to defoliants,
responding with very rapid defoliation and die-back of branches.
Young fruit may be malformed and fall. However, trees refoliate
rapidly and within 6 to 3 months begin to look normal. Because
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fruit buds originate fronvthe trunk and limbs of the tree, die-back
of the small branches does not result in fruit loss during the next
season, but may cause a reduction in yield.
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Rubber (Heyea brasiliensis). The rubber tree is highly sensitive
to defoliants, but the degree of response varies among varieties. A
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heavy rate of defoliant, such as is used normally in Viet-Nam, causes
complete defoliation and die-back of several years' growth. Refoliation
usually begins within a month, but the speed of refoliation is dependent
�pon 'the sensitivity of the variety. The less sensitive a variety,
'faster it refoliates. New leaves often show leaf malformation
for a period of two to four months, depending on the dosage ,
receivedo After six months, growth begins to appear normal
and the plantation canopy is essentially uniform within 3 to 12 months.
Wood-rotting fungi may enter limbs.and trunks by way of dead
branches. Young (3 to 5-year old) trees on the Dar plantation were
severely defoliated and showed extensive die-back. This was due
at least in part to the openness of the canopy in the young planta-..
tion, which permitted coverage of the entire plant by the defoliant
droplets. At Prek Chlong plantations, 5-year old trees of the
variety SPRM-1 suffered 13 feet of branch die-back. Seedlings
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5 to 7 months old were killed by the herbicides.
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The most common rubber varieties in Cambodia are PR-107,
PB-36, and AVROS-50, each representing about 30 percent of the
total acreage. The variety PB-86 is most tolerant to defoliants.
PR-107 is quite .sensitive and AVROS-50 most sensitive. Other .
varieties are variably sensitive, but are of such minor importance
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that they are not discussed here.
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or Star-apple (Chryspphyllum cainitp). This is a
.olorful fruit tree with purplish-brown foliage and fruit. Affected
'plants defoliate and young branches die back. However, this tree
begins- to refoliate within a month. The die-back of the terminal"
branches results in complete loss of the next season's fruit crop.
Kapok (Ceiba sp.). The cotton-like fibers developed in the
large pods borne by this tree are used as stuffing for pillows and.-,
mattresses. This tree is abundantly planted in back yards and in
hedgerows. It is highly sensitive to defoliant. Leaf malformation,
discoloration and defoliation follows even after a small dose of
herbicide. Kapok production during the next season is severely
affected by death of the terminal bran'dies.
Pineapple (Ananas comosus). The high dosage of the herbicide
in some areas visited had resulted in leaf folding and discoloration
with malformation and loss of fruits.
Bananas (Edible Musa_ varieties) . The high defoliant dosage
received in some areas visited had resulted in reduction in size "••'"
�and malformation of leaves, splaying of the .leaf sheaths, elongation
.of the fruits and brittleness of the plants. Plants treated while.in
fruit develop abnormal fruits and that condition may persist for
approximately six months to a year and a half. Plants treated, before
they are in fruit do not produce fruit
Teak (Tectona grandis). This species is intermediate in its
response to defoliants. The young leaves are malformed, turn brown.
and fall, and flower development is impeded. The teak plantation
in the Mimot area was infested heavily by leaf-eating insects. The .
damage caused by the defoliants was relatively small in comparison to
the damage caused by the leaf-eating insects.
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Coconut (Cpcos nucif.era). Coconut is one of the least sensitive
crops. However, 'once the growing tip of this plant is affected,
recovery is slow and sometimes trees die.
Papaya (Carica papaya). This is a sensitive plant that easily
loses its flowers and fruits. Even though a plant may survive a
moderate dosage of the herbicide, fruiting usually does not occur.
ava
(P&id.ium guajava).. Guava is moderately sensitive. ' .
The death of young branches results in yield reduction during the
next season's growth. Refoliation occurs rather rapidly.
Custard Apple (Annona re_ticulata) . This fruit tree is
moderately tolerant and recovers quickly.
Sapodilla or Chicle (Achras zapota). Slightly sensitive. It
can withstand heavy herbicide dosages without suffering defoliation.
Citrus, spp.. All citrus species are only slightly sensitive to
defoliants and the loss, ilSany, is negligible. The main loss in
citrus is due to diseases and insect damage.
Mango (Mangifera indie a ) Very tolerant. Flower development
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may be affected if defoliants are applied between the time of flower
bud initiation and fruit set.
Spur sop (Annona mur icatia) . Very tolerant.
�toffee. (Coffea rgbusta). Very tolerant.
Tomato family (Solanum sp.).
sensitivity.. '
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Complete loss due to extreme-
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Bean family (Phaseolus spp.). Extremely sensitive. Complete
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Cabbage family (Brassica sp.). Moderately sensitive.
to complete loss.
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Partial.
Cucumber family (Cucumis sp.). Moderately sensitive.
Partial to complete loss.
Cassava or Manioc (Manihot ut.illsima). Highly sensitive. ,
The above-ground portion of the .plant may.recover from defoliant
applications, but root formation is retarded. The extent of the
damage to the crop is dependent upon the stage of growth at.which
plants are sprayed with herbicide.
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Peanuts (Arachis hypogaea.) . This is a moderately sensitive
rop. Defoliants cause curling of the leaves and reduction in pod
brmation. The extent of damage to the crop is dependent upon the
-stage of growth at which plants are affected.
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Causes of Damage
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For the.purpose of analyzing the causes of damage, a number
of hypotheses were established and the available evidence brought
to bear on each. The hypotheses considered were: (1) Drift occurred
from defoliation operations in RVN, (2) direct overflight of the Dar
and Prek Chlong plantations for the purpose of defoliation, (3) damage
caused by drift from ground spraying operations in Cambodia,
(4) damage caused by disease, and (5) damage caused by poor
environmental conditions for growth of trees. Each of the hypotheses
will be discussed separately.
To obtain information on the possibility of the damage in
Cambodia being caused by drift from defoliation operations in Tay
I Hinh Province, the team made a helicopter survey of defoliation •
�:argets in that province on June 29, 1969.. It was quite apparent
that defoliant had drifted across the border into Cambodia,
particularly on the central and western portions of the Tay Ninh
target. A similar survey on July 8, 1969 on the Cambodian side
of the border confirmed the earlier observation,, The defoliation
reported immediately north,of the border undoubtedly resulted ;
from the Tay Ninh defoliation operations of April-May, 1969.'
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Defoliation missions in Tay Ninh Province were flown on
March 29 (7 aircraft), March 30 (5 & 7), April (7), April 16 (3),
•April 19 ( ) April 21 (5 & 5), April 24 (5), April 25 (6), April 29 (7)
7,
April 30 ( ) May 2 ( ) May 4 (6), May 6 ( ) May 9 ( ) May 13 ( )
6,
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May 14 ( ) May 16 (9), May 18 ( ) May 21 ( ) May 22 ( ) May. 23 (6),
6,
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May 27 ( ) June 1 (5), and June 9 ( ) Discussions with the
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• Cambodian committee elicited the information that the herbicidal
effect was first noted in the period from April 20 to 25, 1969.
Although the,Cambodian committee believed that-drift may have
come from several missions in RVN, we disagree because .
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manioc and bougalnvillea" both "indicated" herbicidal damage at only
on$ time or within a period of, a few days. Thus, drift from missions
in RVN could only include the first five missions listed above.
xamination of the meteorological data provided by the 12th
Special Operations Squadron for April 19, 1969 discloses that
at 1119 hours, when the spray run was made, the temperature was
90° F and the winds were "light and variable." Meteorological
data from Chup, furnished by the Rubber Research Institute of
'Cambodia for the.same day (at 1000 hours Cambodian time) shows
temperature as 89° F and wind speed of 10 mph from the southsoutheast. The data from Chup are given in Table 1.
Such meteorological conditions are unfavorable for spray
operations and undoubtedly-^were responsible for the spray drift '
that crossed the border on that date and resulted in defoliation
of the area immediately north of the border. We do not feel,
however, that drift from the Tay Ninh missions caused damage to a
distance of 18 to 20 km above the Cambodian border. If spray
drift were responsible for all of the damage observed, one would
expect to see a reduction in severity of plant response with increasing
•distance from the point of application. This is not the: case,
because rubber varieties 15 km north of the border were as severely
affected ,as .similar varieties closer to the border. Tapering off
�of effects was noted east and west of the severely affected area.
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Our second hypothesis was that a direct overflight was'made •
of the Dar-Prek Chlong plantations for the purpose of defoliation.
The pattern of extent and degree of herbicidal effect fits this
hypothesis more closely than any other. The response of a
rather resistant species, such as banana at coordinates XU225045,
XU095045, and XU190135, were indicative of heavier doses than .
one would expect from spray drift from south of the border.
.Some drift from the Tay Ninh operations up to and slightly
beyond the border was evident. However, there was then a zone
of somewhat lesser damage and still farther north there was
once again severe damage. In addition, considerable herbicidal
effect was noted on native forest trees in an area centering
approximately at coordinates XU110140. That this was caused by
drift from RVN is highly unlikely.
Only minor damage was noted on the Krek plantation.' If the
damage in Cambodia were the result of drift from RVN, Krek
and Chipeang would be directly on course for prevailing SSE winds.
Thus, the RVN missions on the west portion of the spray target
would be ideally located for drift, damage to Chipeang and Krek.
However, the light damage at Krek is further circumstantial
evidence that drift from RVN did not cause the major portion of
the damage in Cambodia.
The area of heavy rubber damage is about 60 sq km or 15,000
acres, principally in the Bar and Prek Chlong plantations.' Assuming
that a does of approximately 0.5 - 1,0 Ibs. .per acre was required .
to produce the severity of plant responses noted, this would mean
a deposit of 750 to 1500 gallons of defoliant, or 1 to 2 UC-123 plane
loads. It is highly unlikely that this quantity could have drifted
over the border from the Tay Ninh defoliation operations. This
strengthens the view that damage was due to herbicide spray during
a. direct flight over the affected plantations.
Thus, the evidence we have seen, though circumstantial, suggests
strongly that damage was cuased by direct overflight., We do not.
deny that the damage could have been caused by drift. But the
meteorologic conditions necessary to cause the damage pattern
observed forces us to accept this as only a remote possibility.
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The third hypothesis, drift from ground spray applications
in Cambodia,, cannot. ,be considered seriously as a cause of the
damage. As, far as could be determined, no ground sprays with .
herbicides similar to Orange or White have been used in the
rubber plantations. Limited spraying with dalapon, a herbicide
used 'to "control grass, is practiced on one of the plantations,
However, dalapon does not produce the plant responses noted, nor
<loes it affect broadleaf plants at the usual dosage rates. Weeds
In 'the young plantings are normally controlled mechanically
'by cutting. Weeds are not a problem in the older plantings since
the dense shade of the rubber trees does not permit them to thrive.
The uniformity of plant responses throughout this large area
would preclude ground spray operations as the cause. Moreover,
we did not see drums or Orange, or White during our visit. :
The hypothesis of disease as a cause of the damage can be
readily discounted. No disease organism attacks such a broad
spectrum of plant species as was observed in the area of interest...
Moreover., the plant responses prevalent throughout the area were,
typical of those induced by Orange and White. Undamaged rubber
trees adjacent to damaged ones; showed minor disease symptoms
but nothing approaching the epidemic proportions .that would have
been necessary to cause the widespread defoliation.
Our final hypothesis was that the damage in Cambodia may
foave been caused by environmental conditions unfavorable for
growth. Environmental conditions that prevailed in Cambodia
during 1969 are believed to be unimportant with respect to the
defoliation of rubber and other trees in Cambodia. Neither rubber
cor fruit trees in areas adjacent' to the damaged area give an
indication that edaphic or climatic factros were -responsib le» In
addition, the refoliation that is now occurring suggests that environmental factors are favorable for satisfactory growth and production.
Permanence of Damage
There is no indication that the damage to rubber or fruit trees
is permanent. Current observations in Cambodia lead only to the
conclusion that recovery is occurring. The rate and degree of
recovery among the various rubber varieties complicates the
situation to the extent that a.generalization is not possible. A highl
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susceptible variety such 'as AVROS-50 was completely defoliated,
and refoliation at this time varies from 5 to 20 percent. A
variety of moderate susceptibility may or may not have been
completely defoliated and foliage on the trees at time of
observation ranged from 20 to 70 percent. In the intermediately
affected areas of the plantations resistant varieties now have.
70 percent or more of their normal foliage. In the final
analysis, the degree and permanence of damage can only be
equated in terms of latex production. Personnel at the Rubber
Research Institute maintain records on production by varieties
for the large plantations. There are no good production data
for the small holdings, but extrapolation of data, from the
large plantations should provide a reasonable estimate. These
figures indicate that recovery is occurring and normal yields
may ultimately be obtained; however, appreciable-production
losses will be suffered in the interim.
An example of damage and recovery experienced in Viet-Nam
is the Gallia Plantation in Phuoc Tuy Province where one plane
sprayed herbicide.ORANGE directly over rubber trees in 1967.
One year later the French manager of the plantation stated that
the 'trees' had refoliated 100 percent and production had
returned to 90 percent.
In the Herbicide Policy Review issued by the American Embassy,
Saigon, 28 August 1968, a report by the CORDS Agricultural
Adviser in Binh Long Province is quoted as follows: "The
effects of defoliation have not been as disastrous as anticipated; refoliation has begun and blocks of trees marked off
as lost will be able to be tapped again. The Policy Review
continues, "Other preliminary evidence tends to substantiate
further the view that herbicides may be less toxic to rubber
trees than was previously thought."
Rubber trees on the island of Phu Quoc have reportedly been
sprayed intentionally three times with herbicide ORANGE
and have not been killed.
�IS
The inspection team feels that an assessment of damage in
terms of decreased latex production and decreased fruit
production can best be made in July or August, 1970. . The.
timing of the final assessment is important --it should
occur several months after the beginning of the 1.970
rainy season. Ideally, the final assessment should be
made by some of the same -- but not necessarily all -members of this inspection team plus an agricultural economist.
One item of great concern to French plantation managers
and to the Cambodians was the cost of support for the
unemployed rubber tappers. There is no question but that. .
the herbicide damage has disrupted the normal plantation
operations and there must be a cost associated with that.
Mitigation of Herb icicle Effects
Several practices to mitigate the long-term effects of
defoliation had already been instituted. One severely
damaged area, tapping was stopped because the 'net return
exceeded production costs. Cessation of tapping would,
in essence, husband the food reserves necessary for
refoliation. Trees on less severely damaged areas were
being tapped, but at 6-day rather than 3-day"intervals.
Tapping is proceeding as usual on trees that were only
lightly.damaged.
Fertilization with a complete fertilizer was being practiced
at one location. We encouraged this practice because we
believe it will increase the rate of refoliation.
At one location on the^Dar plantation, the tops of 3-year
old trees of Variety PR-107 were being removed in the
hope that this would prevent further translocation of the
herbicide. Topping done soon after treatment (up to
three days) would probably be effective, but downward translocation of the herbicide would certainly be completed
during a period of six weeks. Thus, topping at this time
would not affect herbicide translocation. A possible advantage
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from the topping would be a clean .wound (the subject
was coated with petroleum), that would be less subject ;
to attack by fungi than would be a wound caused by. rotting
of a dead branch.
The condition of the rubber trees before chemical defoliation is believed to have been good. There is no reason
to suspect that prior condition was a contributing factor
to the degree or duration of damage from herbicides. The
loss of production due to defoliation will vary with
varieties and cannot be satisfactorily assessed now. A
reliable estimate of loss should.be possible in July or
August, 1970.
' SUMMARY .AND CONCLUSIONS
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1. Herbicide damage in,the southeastern part' of'Kompong
Chara Province, Cambodia, was extensive due to a combination
of two factors: (a) Defoliation of. fruit trees on the
Cambodian side near the border was a result of. .drift, from
spray operations in JTay Ninh Province, and (b) Defoliation
,of" rubber, fruit, and forest trees farther north was
probably caused by a direct spray application by an unknown,
party on a north-south line running through the plantations
of par and Prek Chlong.
2. Defoliation of rubber trees on the Dar and Prek Chlong
plantations was complete, but refoliation is in progress.
3. Few, if any, rubber trees have been killed. The
degree and rate of refoliation will depend. oh the age of
the tree, variety, and dosage received.
4. The differential susceptibility of rubber varieties
to the herbicide applied is striking. All varieties are
defoliated from a heavy dosage such as is used in RW, . .
but low dosages as would be expected from drift result
in a marked differentia^ response.
,
•
�5. Species of fruit trees also vary in. their response
to the herbicide.' A decreasing rank of susceptibility
Is: jackfruit, cainito., durian, pineapple, papaya,
guava, and mango.
6. A final assessment of damage should be made in July
or August, 1970.' Damage 'to rubber must be assessed on
the basis of decreased latex production. Data on latex
production can be obtained from the Rubber Research Institute of Cambodia.
7. Damage to fruit trees is temporary. Loss of.production
from the trees should not continue for more than one year.
ACKNOWLEDGEMENTS
Many individuals were helpful to the investigation team 'in
carrying out its mission. Australian Ambassador Feakes
and his staff, particularly Deputy Chief of Mission Mack
Williams, and Third Secretary and Vice Consul'Neil Manton,
were most"helpful in making arrangements for us in Cambodia
and providing wise and appropriate counsel.
Among the Cambodians, Mr. Thach Phiem of the Foreign Ministry
provided many services and accompanied us on all tours. The
members of the Cambodian Committee appointed by the Minister
of Agriculture to assess damages were factual and objective
In their assessment of da:nages. They generated a feeling
.of trust in terms of both accuracy of observation and honesty
In reporting, which made our job much easier. Members of the
Committee who accompanied us were:
?
v
••
.Mr. Min,. Sarim, Director General
• . ' • of the Office of Land Development
in charge of State Plantations
. '. • :
Mr. Ring Un, Director of Agriculture
Mr. Suon Kaset, Director of Water
and Forests
�r; Ho Tong Lip, Research Agronomist,
The'se men were with us on. all tours and provided much
necessary background information. Also helpful were
"Mr. Francis Ninane'and Mr. Gilbert De Coninck of the
'
Rubber Research Institute. Lunches were provided on
three days by SOKHAR, the Cambodian Government Tourist
Information Agency.
JLastly, personnel of the American Embassy and' MACV
provided us with accommodations, assisted in travel
arrangements, and provided necessary background briefings.
We are grateful and owe our thanks to all.
�
Dublin Core
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Title
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Alvin L. Young Collection on Agent Orange
Description
An account of the resource
<p style="margin-top: -1em; line-height: 1.2em;">The Alvin L. Young Collection on Agent Orange comprises 120 linear feet and spans the late 1800s to 2005; however, the bulk of the coverage is from the 1960s to the 1980s and there are many undated items. The collection was donated to Special Collections of the National Agricultural Library in 1985 by Dr. Alvin L. Young (1942- ). Dr. Young developed the collection as he conducted extensive research on the military defoliant Agent Orange. The collection is in good condition and includes letters, memoranda, books, reports, press releases, journal and newspaper clippings, field logs and notebooks, newsletters, maps, booklets and pamphlets, photographs, memorabilia, and audiotapes of an interview with Dr. Young.</p>
<p>For more about this collection, <a href="/exhibits/speccoll/exhibits/show/alvin-l--young-collection-on-a">view the Agent Orange Exhibit.</a></p>
Text
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Box
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114
Folder
The folder containing the original item.
3124
Series
The series number of the original item.
Series VI Subseries I
Dublin Core
The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/.
Creator
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Minarik, Charles E.
Jack B. Shumate
Fred H. Tschirley
Nader G. Vakili
Description
An account of the resource
<strong>Corporate Author: </strong>Plant Sciences Laboratory, Department of Defense
Date
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December 11 1969
Title
A name given to the resource
Typescript: Report of Cambodian Rubber Damage