Document 6bRbYbj1VrEBqKN06vqdyJqX9

S'J ' A / /. / i > I t / t-. v/ . - V' \ *\ / / J .( 34 TV. SELECTION AND TEST EVALUATION OF CANDIDATE AGENTS A. CRITERIA. In the selection of candidates and the development of improved defoliant, agents and systems, the following criteria are recognized: 1) Broad spectrum of activity. The agent should be active on many kinds of plants, with emphasis or woody species. A continued search is being made for a universal defoliant effective on all kinds of plants.' ORANGE and WHITE, currently in use, exhibit selectivity in species response and are notably ineffective In the control of grasses and other monoeotyledenous plants. 2) Rapid in action Defoliation in 1 to 3 days after application is an accepted goal for improved defoliants. . Current defoliation agents in use are primarily systemic herbicides and exhibit a delay in attainment of full defoliation. WHITE is notably clever than ORANGE in causing defoliation under tropical conditions. In coniferous forest vegetation -Ce.g., Canada) defoliation with WHITE or pleloram is not fully achieved until the growing season following spray application. 3) Suitable for application with air or ground equipment Selected agents are preferably liquids with high concentrations of active ingredients. Physical properties of the agent such as viscosity, density, flaanabllity and compatibility with solvents and components of dissemination systems, should permit low-volume application of appropriate droplet or particle size at minimal pressures from available spray, devices. 4) Nontoxic to man and animals la the search for new or improved candidates, compasada of moderate toxicity may be included in the Initial screening programs because highly promising candidates may be modified Co minimize toxicity. Selected agents should present minimal toxicity to man, domestic animals, and all forms of fish.and wildlife both at the time of and subsequent coapplication. Preference is given to chemicals that decompose readily without toxic or harmful residues in soil or- created vegetation. 3) Stable in storage Selected chemicals should remain stable under storage conditions ranging from freezing temperatures to tropical heat and high humidity. ?referanca~may be given to concentrated liquids chat retain flowabie I i l 1/S9G I s a < I. ' / characteristics under a vide range of temperatures. Dry herbicides that absorb moisture from the environment are to be avoided. However, extremely stable chemicals resistant to microbial or hydrolytic decomposition on contact with the soil present disadvantages where a short-term response is needed. 6) Effective In low dosage ft Under optimum conditions, the selected defoliant agent should be effective at minimal dosage rates consistent with the requirements for adequate volume coverage of the target vegetation. In general, the volume requirements for effective defoliation may be less for a growth regulator or systemic herbicide in comparison with a contact herbicide or desiccant. Initial screening programs with seedling plants utilise dosage levels of 0.1 and 1.0 lb/acre as a basis for selection of active compounds. 7) Koacorroslve Selected agent should preferably be noncorrosive to storage containers, dissemination systems, and aircraft or mobile equipment used in application. The corrosive action of an agent may restrict its use or require rigid maintenance schedules to minimise damage or deleterious effects on equipment. 8) Low in cost Cost is of secondary Importance In the selection and improve ment of agents. Effectiveness and utility of the agent should begiven first consideration. 9) Readily available or capable of manufacture Selected agents should be producible In large quantities ac . an acceptable cost. B. SCREENING AMD FIELD TESTING CANDIDATE AGENTS Fort Detrlclc has tssted and evaluated 26,000 chemical compounds, including every herbicide that has been marketed in the United States . as veil as many from foreign sources. A continuing program of research on biological activity of chemicals has shown chat many chemical compounds exhibit growth regulating, desiceant 'or herbicide 1 activity but few satisfy military agent criteria. More eh*TM 200 chemicals are now marketed cosnereially as herbicides for agricultural and Industrial use. These represent selections from many thousands of-chemicals investigated by the chemical Industry and private and government research. > . < * :/y*. f i i j * { ! | | j j \ j i } I ^/ V* '' - 36 AC Fort Decrick, chemicals with known biological, activity and new candidates are studied in the continuing search for improved vegetationcontrol agents. Recently, 7.000 new chemicals, for testing worn obtained from Valter Reed Institute of Research.* . 1' ' * Initial screening is conducted on seedling plants (7 days old) of six species: Black Valentine beans, soybeans, morning glory, radish, oats, and rice. Evaluations are made of desiccant, herbicldal, and growth-regulating responses over a 2-veek period from foliar spray appli- cations at 0.1 and 1.0 lb./aero. Numerical ratings applied to each species on a 4-point scale as no, slight, moderate, or severe responses give a total maximum score of 24 points. Racings of the three principal agents In. this primary screening program are as follows: 0.1 lb1/acre 1.0 lb./acre ---- ORANGE WHUS BIDE. 20 13 10 20 20 22 Both ORANGE and WHITE are less effective on grasses than broad-leaved plants and the ratings of 20 at 1 lb/aere reflect the Halted' responses cn oats and rice of the six plants in this test. High-rating chemicals In the primary screening test are subjected to an intermediate screening for defoliation activity on lA-day-old Black Valentine bean plants at 0.1 and 1.0 lb/aere. Black Valentine bean, has been, selected as a test plant lor defoliation effect because of its characteristic leaf abscission. Typical responses of the three agents In this screening test are as follows: 0.1 lb./acre 1.0 lb./acre ORANGE Moderate desiccation Death at 10 days; growth regulator effects WHITE Death at 1A days; growth regulator effects. Death at 14 days; growth regulator effects BLUE Slight desiccation *Death at 14 days Candidate chemicals showing high activity In the Black Valentine bean 'defoliation screen then are subjected to evaluation for desiccation and herbicldal response on eight to 10 woody species under greenhouse conditions Species used in this test at Fort Decrick include: eastern hemlock, Norway sprues, Chinese elm, black locust, red maple, pin oak, California privet, * Division .of Medicinal Chemistry, Walter Reed Army Medical Center, Washington, D.C. l. J W- I i i, ift i ! i i tI i US GO cn G5 V. 37 Scotch piss, pittospona, and eucalyptus. Foliar sprays are applied to 2- to 3-year-old seedling plants at races of 1, 5, and 10 lb./acre of active Ingredient or acid equivalent. In the ease of GRANGE, WHITE, and BLUE, application rates are based on weight of acid equivalent rather than the total ester or salt in which the chemical Is formulated. Representative data for these three agents on the number of species (of a total of 10) shoving extreme desiccation or Will and defoliation at 30, 60, and 90 days follows ORANGE WHITE Ring Desiccation Kill and defoliation 30 days 60 days 90 days 1 1 . 10 1 Z4 333 1 1 HD 1 ND 3 1 t 10 - 1 ND 1 ND ' 2 1 10 57 24 5 1 11 2 1 3 HD ND ND 1 1 1 ND ND ND The primary responses of ORANGE and W H T OE as herbicides and that of BLUE as a dasiccant are evident in these ratings. Following Initial laboratory and greenhouse screening programs, chemicals selected as potential anticrop agents ire subjected to field screening and tasting on several major crop species. Promising defoliants end herbicides are evaluated in a series of field tests on native vegeta tion at CONUS and 0C0NDS sites representing various temperate and tropical plant types* 1* Field Tests of Chemicals on Crops Evaluations of chemicals, on specific crops are made In replicated teses at three dosage rates using a logarithmic sprayer or knapsack sprayer. Seasonal responses are obtained by treatment at two or three stages of growth. Effective rates of applldacion for control of selected crops by Che standard and candidate agents listed in Section Z H are as follows: t* l it i h \ f 5 CO CJT 39 Rce Tandex Bromad 1 BUJE Dluron Wheat (winter) WHITE Ptcloram eater Bromad I Tandex BISE Sugarcane Bromad 1 Tandex Com BUJE Da Upon Bromad 1 Tandex Dlron Rate. Ib./aere 0.5 0.5 to 1 0.5 to 1 2 to 4 2 to 4 2 to 4 2 to 4 2 to 4 2 to 4 5 to 15 5 to 15 l to 2 2 to 4 4 4 to 6 4 to 8 Potatoes Picioram ester WHITE ORANGE Soybeans * Picloram eseer WHITE ORANGE Tandex Bromacil ' Castorbeans Picloram ester ORANGE WHITE Manioc WHITE Picloram eater ORANGE Race. lb./acre C.5 1 4 to-8 0.25 0.25 0.5 to 1 L to 2 1 to 2 . 0.5 0.5 1 0.2 0.5 l 2* Field Teses of Defoliants Inicial field testing of defolianes on native woody vegetacin has .been eondueced by Fore Dc trick personnel with a vehicle-moon ted high**lift boon capable of overhead spray application on plots ranging In size froa 20 by 20 feet to circular areas 50 feec In diameter. Subsequent RAD tests have been conducted with aerial dissemination systems, principally the nrnAT.y using H-19 and H-34 aircraft and the UH-1B/D he licopcer-mounced sprayer, with 200-gal tank, developed by AGRXKAUTXCS. Both helicopter and fixedvlng agricultural aircraft spray systems also have been utilized for CONUS and OCQNUS tests. Application volumes In the test program have varied from 1 to lOgal/acre. Field tests of candidate defoliants are designed to evaluate such variables as rotes, volume of application, season, and vegetation composi tion, Three rates of application: are usually employed to develop dosageresponse data. Evaluation procedures vary with the objectives and Intensity level of cbe test program; these may include determinations of: 1) Defoliation on degree of canopy removal by one or more of the following: - (i) visual estmate of overa 11 defoliacin; C U ) ati nares of defo H a t ion based on repeated observatlon of individual marked planta of Importase apelas; speeies daca may be suoaaed for che vegeta cin type orease alte; (111) perceneage reduccin of vertical 39 obscuration as determined by repeated vertical photographs at permanent photo stations; (iv) percentage increase in horizontal visibility based on- changes in obscuration o targets at selected distances iron a central observation, point; and (v) aerial photography with color or camouflage detection film. 2) Desiccation or contact injury frets visual overall or individual species ratings* * 3) Plant kill, based on overall visual estimates or composited species racings iron sampled individala* Defoliation and desiccation may be evaluated periodically to -determine percentage and duration of response* Plant kill determinations should be made afear one complete growing season has elapsed following treatment. 3. Parameters for Effective Defoliation' ! Available data frea aerial application tests at several CONUS and OCONUS locations are presented in the following tables to illustrate the effects of variables such as vegetation type, vegetation structure, rata, and season of application of agent on defoliation response* a* Rate of Application Under tropicaL conditions, applications of ORANGE and UHITE at 3 gal/acra appear tn give optimum defoliation (Tables 1, 2, and 3). Tests with ORANGE over the range of 1.0 to 6*0 gal/acre shoved increased defoliation with higher rates of application. Under temperate zone condi tions, the 3 gal/acre rate of WHITE gives effective long-term defoliation (Table 4). > Increasing the rate of application of BLUE in excess of 9 to 12 lb*/acre did not appreciably Increase the efficiency of defoliation (Table 5). b. Season of Application Tests of ORANGE and its predecessor FURPIE in Thailand showed that applications were more effective during the rainy or growing season than In the dry season (Table 2)* A higher rate of application may* partially compensate for the difference In seasonal response* In the same tests, cacodylle aeld or BLUE showed no difference in defoliation with season of application. : CL3 CO 03 cn CO . II f % i \ / I 40 TABLE 1 DEFOLIATION RESPONSES FROM ORANGE Df TROPICAL FOREST SITES33 Location and Rata In gal/aere Loquillo, Puerto Rico: tropical rain forest 1.3 3.0 6.0 Defoliation at Period Indicated. T I m o 3 d o 6 u> 9 mo 1 2 m o 61 73 73 . April 1966 Aon lication 65 52 -a/ 38 79 66 55 91 71 . - 61 October 1966 Application 3.0 46 ' 62 75 - Hilo, Hawaii: ohla, trae fern forest 3 December 1966 Application 45 60 62 53 55 Kauai, Hawaii: ohla, guava, java plum 3 December 1967 Application 71 84 80 - - Thailand: dry evergrean forest 3 Kav 1964 Application * 90' 66 50 30 September 1964 Application 3 40 57 - 60 45 32 . December 1964 Application 3 15 52 52 37 27 ZNTERIRETATIOH OF TABLE 1: (i) Significant dsfo iiatlon cay occur at 1 taoneh fear spray application. (11) Mixlaana defoliation usually occurs at 2 to 3 months after spray application. (ill) Regrowth of vegetation occurs in 9 to 12 months as- shown by ths decrease in dsfoliation ratings, a*. - - no data. i. ! i ii .i I D 3- 9 G - H 8 i. 7 L. \\ fe * fr I i** t % \ i 4 \ .i Ni 41 TABLE 2. DEFOLIANT EFFECTIVENESS OF ORANGE^ I TROPICAL FOREST VEGETATION AS RELATED TO RATE, SEASON OF APPLICATION:, AND DENSITY OF FOREST CANOPES/ Spray Deposit, ga1/ecre * Mximum Defoliation. T Ralnv Season Application Drr Season Application Canoov Canoov Single Multiple Single . Multiple 5.0 2.5 2.0 1*5 1.0 8S 75 79 6676 59 76 52 76 49 82 71 64 58 52 67 6L 54 48 ' 42 INTERPRETATION OF TABX 2: (1) G c u i e r defoliation is achieved under all conditions at ebe higher rates of application of 2*5 to 3*0 gal/acre* (11) Createsc defoliacin occurs in vegetation, types with a light or moderate density typical of a singla canopy. Multiple layers of canopy foliage Interfere with penetra tion of pray to lower vegetation. (Ill) Treatment during the dry seeson reduces the maximum response especially at the lighter dosage rates. As a systemic herbicide, ORANGE is more effective during periods of active vegetative growth, (iv) The data may also indicate chat greatest overall effects may be obtained from two 1-gal/acre treatments, with the second at the peek of defoliation from the first application. . . .. e. Tests Included ORANGE and its predecessor PURPLE, b. Data based on 0C0NUS defoliation tests in Thailand.14 TABLE 3. DEFOLIATION EFFECTIVENESS OF ORANGE IN TROPICAL RAIN FOREST OF PUERTO RICO AS RELATED TO RATE OF APPLICATION33 Location and Rata In gal/acre Defoliation at Period Indicated. 2 1 mo 3 mo 6 no . 1 yr Luquillo National Forest, April 1966 1.5 3.0 6.0 61 65 52 38 73 79 66 55 75 91 71 61 INTERPRETATION OF TABLE 3: (i) Effective defoliation was obtained at 1 month after application at all races. (11) Increasing the rate of applica tion gave higher.rates of defoliation. However, over the period of evalua tion, the Increased defoliation at 6.0 gal/acre was not proportional to the increase in cost and logistics burden compered with the 3.0 ga 1/ecre rate. i *e I i i . f" ! 1 < i 1 i ! I i l\I Ii 1 ! I - f 42 TABLE 4. REPRESENTATIVE DATA ON DEFOLIATION AND VEGETATION CONTROL UITS ORANGE AND WHITE ONE YEAR AFTER TREATMENT^ Location and Vegetation Type Vevetafcion Control at 1 Year. 7. ORANGE WHITE New Brunswick, Canada, 1967: birch, maple, aspan, spruce, fir 51 32 Florida, 1967: water oak, magnolia, sweet gum, holly Georgia, 1967: blueJack, turkey, and post oaks 54 - y 57 72 Arkansas, 1367: pose oak, hickory, winged elm 63, 70 82 Kauai, Hawaii. 1967: ohia, m e lastoma, lantana, guava 56^ 71 Thailand, 1964: tropical dry evergreen forest 36/ 70/ INTERPRETATION OF TABLE 4: (1) la boch temperate and tropical foreacs, applications of ORANGE and WHITE at 3 gal/acre do not provide for com plote defoliation at 1 year following application. (11) WHITE appears to be more effective than ORANGE in defoliation on a long-term basis. However, peak defoliation from WHITE develops much later than that from ORANGE application. a. Applications at 3 gal/acre. b. No data* c. -Evaluation at 9 months. d. Application of ORANGE at 2.5 gal/acre; VHXXZ application consisted of 2.3 lb./acre of pleloraa + 5.3 lb./acre of 2,4-D (plcloraa equivalent to 4.6 gal/acre of WHITE ) it t ( ! ob i <> ds* cp fP k Wl * * ! i r t tt i : ;. .}, * t t rV. I9 43 TABLE 5. DERATION OF DEFOLIATION OF'TROPICAL VEGETATION WITH AERIALiX APPLIED BLUE' _____ _________ . _____________________ Location, Species,- and Rate In lb./acre Defoliation, Z, * at Indicated Davs after Treatment 7 14' 30 60 ISO Laa Karlas, Puerto Rico, 1967: semi-evergreen forest 12 Kauai, Hawaii, 1967: gauva, ohla, Java plum, staghorn fern 9 12 IS 51 60 70 57 * 43 37 40 45 56 54 62 51 * 54 "2 6Ir^/ 40 56 59 57 26E' Thailand. 1964-1965: tropical dry evergreen forest 3.4 6.0 15 42 52 37 30 55 65 43 15 25 * I .I . i* ! - i. f ; I > * i ! i : INTERPRETATION OF TABLE 5: (i.) Maximum dafoliation of tropical vegetac Ion occurs at Z Co 4 weeks after application of BLUE, (ii) BLUE causes short-term defoliation. Substantial regrowth occurs by 60 days or later as shown by marked reductions in defoliation ratings at 4 to 6 months. BLUE acts as a desiccant rather than a systemic herbicide as ORANGE and WHITE. a. Rate of 9 lb./acre is equivalent to 3 gal/acreof BLUE or Fhytar 560G. b. At 1Z0 months. c. Single- Versus Multiple-Canopy Vegetation Structure of vegetation influences the degree of coverage and penetration* of spray deposit in aerial application. Data on defoliation response In single and multiple canopy in Table 2 show that somewhat greatar defoliation was obtained in forest types with a single versus multiple canopy. In nwltiple-cano'*y vegetation, repeat spray application may be required tG 'obtain adequate defoliation of dense undergrowth after the upper foliage canopy has been reduced from the Initial spray treatment* ... 3 l o CO' CD CO V* , ,, * * I 1) . r\ * iI f i t i \ ii 1: (. / ? "7 \ 44 d. Vegetacin Type and Species Composition Overall .defoliacin response will be affected by che species compos 1cIon and type of vegetacin. Species vary widely In their response or suseeptibl U t y to the systemic herbicides ORANGE and WITTE, and the long-term effectiveness of defoliane treatments will be Influenced by cha proportion of resistant species In Che vegetation complex. Temperate zone vegecatlon appears to respond somevhac better Co agents GRANGE and WHITE than tropical vegecaclon (Table 4) K notable difference In effectiveness between the two agencs ORANGE and WHITE Is in the greater response of coniferous evergreen types co pleloraa or WHITE Chan co ORANGE. In Vletnao, the nlpa pa la Is much more susceptible co * ORANGE then to WHITE i* I. \ o CD to CTD 45 V. AERIAL DELIVERY SV5TCG A. C-123/MC-1 SPRAY SYSTEM The first pray system employed in Vietnam by the USAF was* developed at Langley AFB, Virginia, for dissemination of liquid insecticide*. The system consisted of the Fairchild C-123 aircraft, the modified HC-1 (Hourglass) spray device (1,000-gal tank, 10-hp gasoline engine, pump, and piping) with spray booms on each vlng extending from the wing d p to the outboard engine nacelle. Each spray boom was 1.5 inches In diameter and contained 42 teejet nozzles. The system was capable of spraying PURPLE at a rate adequate to deposit 1 gal agent per acre. Subsequent to use of the system, the QSD/ARPA evaluation team made a series of recoanendaelaia that included:u 1) Modify the spray system to provide for deposie of 1.5 gal/acre in a spray having a HMD of 300 u* 2) Apply 3 gsl of PURPLE per acre on upland forest targets ( n o passes at 1.5 gal/acre each). 3) Develop a system capable of depositing 3 gal/acre on target. 1. Modification and Calibration _ During the spring of 1962, ARPA sponsored a east and evaluation program on various spray configurations of the C - 123/MC-1 system as well as work on the USB HIDAL (Helicopter, Insecticide Dispersal Apparatus', Liquid) spray device.34 The second, major modification of the C-123/MC-I system was tested and evaluated at Eglln AFB, Florida, in 1963 (Fig, 2). Concurrently, additional studies were accomplished oh the HH3AL system and on a prototype USH FIDAL (Fixed-Wing, Insecticide Dispersal Apparatus, Liquid).34 The results of the 1962 spray'trials were, evaluated and a configuration was described that would produce an effective swath of approximately 300 feet with a deposit of L.5 gal PURPLE per acre in a spray having an HMD of 293 p. (release altitude 150 feet; airspeed 130 knots). The testing during 1963 was an extension of the 1962 effort on various modifications of the C - 123/MC-1 system to achieve 3 gal/acre deposits of PURPLE. Major changes in the test system included; two 20-hp engine-pump combinations per-unit as the power source; an added call boom; all new spray boons 3 inches in dlameeer# A total of 110 fe-lneh check valves were Installed in the three booms. Early in the test pro gram the 3"inch wing booms proved to be unsatisfactory and were replaced with booms 1.5 Inches In diameter. Conclusions from the results of the easts were: 1) Three-gs 1/acre deposits can be achieved on swaths 240 feet wide when' spraying at an airspeed of 130 knots at 150-foot altitude. 0319 665 l i '! i j { ] ` <A 0 ' v^/T . V _^ A cr jh V * f* 46 i\ '' m , /. IV K * A* >i *UlV-\" X< r.\ v"' ,v S S * S * * " *l S w Sr>t" " Mo,,ul*d * 03196GB t Eu! 47 1 i.- I i> Z) Two 20-hp pumps are needed Co achieve a required flou race of 430 gal/rain 0f PURPLE. 3) Using only che wing boosts, 2 gal/acre is che maximum practical deposit possible; using all booms, 3-gal deposies may be obtained. The reeouuendaCIons Included replacement of che 10-hp engines in Che I operational systems with the more versatile 20-hp units. After completion of these trials, numerous changes were made In t I .the.spray system, but no additional calibration studies vers accomplished until 1968. I I* 2. A/A457-1 InternaL Defoliant Dispenser \ The USAP development and adoption of the A/A45T-1 Internal Defoliant Dispenser represents a major step in che evolution of the defoliant system and is the unit currently in use by RAUCH BAUD (Fig. 3). The A/A45Y-1 defoliant dispenser is a modular spray system for internal carriage in cargo aircraft... The module consists of a 1,000-gal tank, pump, and ergine (20 hp) mounted on a frame pallet. An operator's console is an Integral part of the unit but is not mounted on the pallet. The C-123 aircraft has wing boons 1.5 inches in diameter and 22 feet long extending from the outboard engine nacelles coward the wing tips. -A short tall boom 3 inches in dianecer Is positioned centrally near the aft cargo door. There are 16 nozzles on each wing boom and eight on the tail boom. The nozzles are check valve bodies with 3/8-inch orifices (no nozzle tips). The system Is capable of spraying at the race of 275 gal/min, which when released at 150 feet altitude at 130 knots airspeed will produce a swath 240 feet wide with a mean deposit of 3 gal/acre in a coarse spray having an HMD of 320 to 350 u, Spraying Cline is approximately 3.5 to 4 minutes, which is adequate to dispense 950 gal of chemical on a line about 8.7 statute miles (14 ka) in length. In order to achieve predictable- deposits, it is raconmended 1 that th missions be conducted under inversion to neutral temperature lItI situations and calm wind conditions. B. ,HIDAL In 1961. when testing In Vietnam was proposed, th USN HIDAL was the only known military spray system suitable for use on the H-19 and H-34 helicopters (Fig. 4), then being used by the Vietnamese Air Force (VNAF). The unit had been designed and built by the Disease Vector Control Center. Naval Air Station, Jacksonville, Florida, for dissemination of aqueous solutions of insecticldes. One such unit was obtained and was i the flrse spray system put into operation in Vietnam. Later, a total of i six HIDAL units were made operational. The device consists of a 200-gal 9 cylindrical fiber- glass tank that is positioned inside the cabin? an ll CO I I CO l* o t 03 0319668 - : -' S i' yr\ tipf \l. \lV it 1*r. em t\ \ i ir t % 'V 49 electrically driven,' positive displacement pump capable of delivering 25 gal/ain, and cue spray booms 25 feet long that extend out and back from Che fuselage in a delta design. Each boom vas equipped with 21 spraying systems teejec nozzles capable of delivering 0.6 gal/ain of vacer ae 40 psl pump pressure. During use, a number of deficiencies were made apparent and several components failed or malfunctioned. Equipment modifications were accomplished by NAS, Jacksonville, and the modified unit was tested during 1962 to 1963. The reliability of the system was improved and the test results show: spraying PURPLE, the-unit can davelop sprays with an NMD of 365 u. in swaths of 190, 160, and 150 feet wide with deposits of 0.5. 1*0, and 1.5 gal/acre, respectively, when flown tnwind at 55 knots at an altitude of 100 feet.3* Extensive use of the system by VNAF was limited by their inability to maintain the- units in an operable condition. C. SELECTIVE AERIAL SPRAT SYSTEM Trobp units In Vietnam were quick to recognize the usefulness of the vegetation-control agents for maintaining vegetation-free perimeter defenses, helicopter landing sites, -and destruction of Viet Cong (VC) garden plots. These areas were considered to be coo small to justify the use of the RANCH HAND systems; further, the field units felt a need to have their own spray capabilities. A number of Jerry-rlggsd spray devices for use in helicopters were assembled and used. One such unit (SASS) was described In a letter from the Army Concept Team in Vietnam (ACTIV) to ' six airmobile units. The system was simply constructed with components available In the field and consisted of a 55-gal drum, a pressure unit from a portable flame thrower, connecting hoses, and a length of pipe with drilled holes as a spray boom. The unie could be installed easily in the UH-1B or (IH-1D helicopters without modification to the aircraft*. The spray boom was tied to the rear skid struts. The unit performed satisfactorily and vas reeonsnended for Interim use. Another such system .'consisted of two 55-gal drums welded together end-to-end; a frame was affixed to the bottom for tie-down; large (6 to 8 Inches) open tubes fastened to the top on each end of the tank were angled out of the heli copter doors into the alrstresm and served as ram air orifices to complement gravity flow of the chemical through the spray boos tied to the skids. (hie ocher unit utilizes a 400-gal engine shipping container in a CH-47 helicopter and a long boom fastened to the outer edge of the aft cargo door; f l w of agent Is by gravity feed. Each of these units has satisfied a need for a small spray device for use In available aircraft. The ACTIV letter also described the AGRXNAUTXCS (then ACAVENC0) spray units that ^iere .oeing used for mosquito control In Vietnam and recosraendedthat such a system be developed for use with vegetation-control agents. | i4 I 6 9 9 6 GO i l -*<. 51 d . u h -ib/d 'h e l i c o p t e r s p r a t s y s t e m (a g r t n a u t i c s ) The AGRXNAUTXCS (formerly AGAVENCO) spray unit a ae If-contained and Is suitable for us In Che UH-1B and UH-1D Army helicopters, the US Navy US-IE, and US Air Force UH-1F types. It can be Installed In or removed from the aircraft In a matter of minutes because It Is "tied down" to installed cargo shackles and no modifications are required for* its use. The sprayer was designed for the dissemination of Insecticides, and six of the units were deployed by medical troops In Vietnam early In 1966. Eight of the units* with modifications, were procured by the Army Mobility Equipment Command, late In 1967 for use In disseminating vegetation-control agents. Th* latter units were tested Intensively In Vietnam during 1968* and lata in ehe year 21 additional sprayers were ordered for Army use. The Model 3090-2 Sprayer-Pesticide Helicopter Mounted, UH-IB/D Is composed of a aix-bladed 7h* windmill pump drive, spray booms and nestles, a tank and support structure, sad a mechanically operated valve control. The sprayer tank Is a. 200-gal 5 * epoxy structure. The windmill ray be manually adjusted-on the ground to r any selected blade angle from 10 to 90 degrees. The spray boom is 32 feet, 2 Inches long sad has provisions for nozzles every 4 Inches. The unit Is operated by manual controls to the flow control valve and a windmill brake. The system has a usable.capacity of 195 gal and weighs approximately 2CC lb. empty. Limited tests by the manufacturer, on contract with the Army, shew chat with the maximum pitch setting (1.0) ca ehe windmill, airspeed 50 knots at 50.feet altitude, ORANGE Is deposited in a 100-foot swath at a race of. 2.5 gal/acre. The MMD of ehe spray may he expected tij be approximately I 300 u. Users in Vietnam have experienced difficulties in obtaining flow races of ehesdcal adequate to provide, in a,single pass, desired dosages of both agents BLUE and ORANGE. The manufacturer and the US Army M o b l U t y Equipment Cosmand have been a.dvised of limitations in th* spray device and corrective modifications may be expected. ? r t t* t rs V t it. i 52 i VI. GROUND DELIVEEV SYSTEMS A* BUFFALO TURBINE Engineering development of a ground delivery system for employment of vegetation-concro 1 agents has not been accomplished. Various dissemination devices, as field expedients, have been used in Vietnam for control of vegetation on 11artted areas* The Buffalo turbine la a unit that Is representative of one type of disseminator that la capable of disseminating either liquid or dry chemicals and Is available from agricultural supply houses in the United States. A number of different models may be obtained: towed or vehicular-mounted; powered by a gnaollile engine or from a power take-off assembly; also, various tank sizes are available. One unit that has been in operation In Vietnam since 1961 consists of a trailer-mounted, 100-gal stainless steel tank with agitator, pomp, turbine fan, and air cooled gasoline engine. In operation, the turbine fan serves to generate a high-volume, hlgh-velccity airscream that Is projected through a some*hat restricted orifice. Using an available fishtail nozzle, the machine will develop an air blast of a velocity up to 150 mph at 10,000 ft^/mln volume. The chemical Injected into the air blast Is "shot* at the foliage. Because the materials become finely atomized, care is taken to`avoid drift damage. The Buffalo turbine has been useful for roadside spraying and applications on perimeter defenses. B. MITT-HITE The MIty-Hite back pack sprayer-duster was Introduced Into Vietnam for study as a possible means of forcing riot-control agents `throughout enemy tunnel complexes. The device was developed by the Buffalo Turbine Co. and operates on the asm principle as their larger units. The unit weighs 21 3/4 lb. and consists of a'Homelite engine, blower assembly, tank, discharge equipment, and peck frame. .The .tank capacity is 0.3 ft^ of dust or 3.5 gal of liquid. In operation, the unit will' spray at the rate of 1 gal/tain in an. airstream of 135-mph velocity and 450-ft^/ain volume (at the hand-held nozzle). - The Mity-Mlts is suitable for dissemi nating liquid or dry chemicals for the control of plants in small garden plots and/or seedbeds. C. POWER-DRIVEN SECONEAMXNAXIKC APPARATUS The power-driven decontaminating apparatus (PDDA) is a self-contained spray system mounted on 6 by 6 military vehicles and is intended for employ ment of decontaminating chemicals for elimination of toxic antipersonnel agents. In the field, the units are used for many purposes, Including the dissemination of vegetation-control .'.gents. Several- different PDDA models are available in Vietnam and all are adaptable for use on vegetation-control problems. Tank capacities vary among the models and may be 200, 400, or 600 gal; the larger models have power take-off-driven pumps capable of delivering chemicals at Che race of -35 to 60 gal/mln at pump pressures up to 800 lb./ln.7* 53 Delivery is through two hoses, with adjustable nozzles, located at the rear of the unit. The EDDA units have been used effectively with available chetoica Is to control vegetation-on aloe fie Ids, periaeter defenses, road* sides, etc. i 1 : i i r I f i I ( i ii t j i 54 VTT. TARGET VEGETATION IN VIETNAM A. DESCRIPTION OF FORESTS The forests of Vietnam have been studied extensively over the past 60 years and the works are veil documented in botanlcaL and forestry literature According to publications prepared by Preach botanists, there are more than 1*500 speclas of woody plants In Vietnam and a vide range of forest types17 The botanist, taxonomist, and ecologist are concerned with each- specific forest formation; for the problem of defoliation, the military In the field recognises two principal types of forest: (1) upland forests, which Include the dense evergreen and fairly danse semi-evergreen types, and (11) the lowland or mangrove forests. The basis for this simplified classification la the general, overall response of each type to the available vegetation* control agents The upland forests are made up of complex associations of plants with varying degrees of sensitivity to defoliant agents and present a much sore variable target chan the mangrove forests that consist of one dominant plant type that is uniformly sensitive to GRANGE. Complete defoliaeion (lQOT) of upland forest targets has nr c been, accomplished ,1, Primary Upland Forest The primary upland forest usually consists of an overstory or dominant canopy made up of trees varying in height and crown sire and an intermediate layer or understory of smaller trees (Pig, 5). The two layers . together form a dense canopy as seen from the air. The overstory trees may attain a height of 60 to 125- feet In high-rain fa11 areas'; In .regions with a pronounced dry season, the dominant'species m a y b e somewhat* shorter in height and more widely spaced. Woody vines occur comonly In the top of the canopy and form a dense interwoven network The understory is made up.of shrubs, vines,,and smaller trees, ranging in height from 20 to 30 feet. This lover level may consist of bamboo, vines, cane,-grass, and rattan,' all close together In a tangled mass, hard to traverse, sad limiting visibility to a few yards. A fair evergreen species are deciduous in areas that have a dry season. t 2. Secondary Forest The secondary forests may have only remnants of the overstory tree canopy but have dense growth of small trees and shrubs. The understory vegetation is dense'and difficult to penetrate* The secondary forests may be represented by areas of tropical scrub on abandoned cropland or areas where timber has been removed. Thaae are made up of pn assortment of shrubs, vines, and grasses The shrubs may be 15 to 20 feet tall and are often covered with vines* -This type of vegetation affords cover for. men, animals, and equipment against observation from the air* V \ > /. s'/* */ I /.*m> 0m L FIGURE 5. MuId pi* Canopy Jungl* or Tropical Evergrc* ForaaC of SatiChcasS A sifi. ' 3. Lowland or Mangrove Forest Low land or mangrove forests are of two general kinds: those that grow in standing water, usually within the Units of the mean high tide, and those, that grow above the tidal limits but In marshy, poorly drained areas. In either ease, dense, puce stands of trees tend to form*. In each group, the trees tend to be of the same age, ranging from 25 to 60 feet in height. These trees have prop and aerial recta Chat 'mpede movement and visibility and crowns that ora a continuous canopy that affords protection from air observation. Ground cover is usually lacking, although in places nipa pels, water coconut, and some tall ferns occur (F1&. 6). *. 1 C O 33 -- c_n W r-TJ 56 FIGURE 6 . Hip P la , Cos Mekong D e lta Region o f RVN. Associate of Hsogrme la eh* 4. Growth Patterns It oust be remembered that many' different kinds of trees are la these tropical forests, and each has a different growth cycle and .r- ent sensitivity to herbicides, thus making uniform results with defoliants difficult to achieve. In general, the active growing season for upland vegetation .starts with the first rains Just before the onset of the rainy season, and most of the vegetative growth occurs during the early part of this season. The flowering and fruiting come later In the rainy season or at the start of the dry season. During the dry part of the veer, the trees tend to be dormant, but the varying rainfall patterns can vary the periods of active growth. The dormancy factor ham a definite Influence on the development of effects from an application of the growth-regulator chemicals; defoliation may be delayed until growth is resumed with the onset of the rainy season. The mangrove forest does not exhibit seasonal variation!. C\S CO CD on t B. SINGLE, DOMINANT PLANT TYPE The largest numbers of spray missions In Vietnam have been carried out on misted forest vegetation; however, there are a number of prime targets that consist largely of a single, dominant plane type* Outstanding examples include: (1) Nlpa pals, frequently found in association with mangrove, provides a dense screen along waterways, and may be controlled successfully only with ORANGE but It responds ouch more slcvly than adjacent vegetation. (11) Elephant grass is a serious problem In many, If not moat, of the so-called "open areas" la upland forests ami can be controlled only by BLUE when used, at high rates*, .(ill) Rice is severely damaged or destroyed by BLUE at low rates; the application of l gal/acre la more than adequate to caus 100Z yield reduction*. ORANGE and fanlfE are not recommended for use on rice; upward of 5 gal ORANGE per acre are required to damage the plants severely* (lv) Bamboos of various types flourish throughout Vietnam and present a formidable problem when their control Is required* Some species may be defoliated by high applications of BLUE, but the-plants are not hilled and Che clumps of stems, alone, provide effective screens* It is felt that*the development of a capability to control bamboo effectively may be dependent on use of a soil-applied compound (currently not approved for use in Vietnam)* (v) Broad-leaved, annual crop plauts, as a type target, may be treated as a single species since thay are uniformly killed by the high dosages of ORANGE obtained in Vietnam, I > ** 1 VIII. EMPLOYMENT OF VEGETATIONCONTROL 5Y5TEHS j A. BLANKET COVERAGE - CROP CONTROL j Prior Co the iniclacion of the defoliation p r a g m a in Vietnam (1961), I a large body of research data on ehe dissemination of chemical vegetation[ control agents vas developed by Crops Division, Fort Decrick, in cooperation | with USAF and USN. Several experimental, prototype, and developmental j spray devices were tested with a variety of aircraft (C-47, F-3D, F-7U, j B-17, C-119, B-29). With, but few minor exceptions^ the test programs had as their objective the ultimate development of blanket-coverage capabilities for large-scale attacks on crop plants.. The chemical sprays were released as elevated line .sources normal to the prevailing winds; delivery altitudes were varied from 100 to 2,000 feet, and results showed the optimal spray altitude to be 1,000 to 1,500 feet. Further, in recognition that a given mass of material produces the greatest effect when applied as small drop lets (<100 }i). considerable effort was devoted to studies on means of t producing high-volume sprays of droplets having an HMD of approximately 175 p. \ and ground deposits*, of what now is loxown a s ORANGE, at 0.1 lb./acre and greater.3 The final spray tests with low-speed, propdllor-driven aircraft were accomplished during the spring of 1953 at Egiin AK3, Florida. The studies were on the Hourglass unit in B-29 and C-119 aircraft with crosswind 3 pray releases at 3,500- and 5,000-foot intervals at altitudes of 1,000 and 2.000 feet and agent flow rate at 100 gal/ain. Tito mean deposit in the 3,500-foot swaths was 0.39 lb./acre; in the 5,000-fooe swaths it was 0.36 lb. /acre. The results of these and other* tests show that the system was capable of blanketlng approximately 48 .square miles of target with 1.000 gsl of chemical.7 9 Further investigations involved small-capacity spray systems on USN high-performance fighter aircraft. B. CONTROLLED APPLICATION - DEFOLIATION The nature of the conflict in Vietnam and the spray mission demanded that new employment concepts, techniques, and equipment be developed. Careful control o f chemical sprays was required in order to prevent or minimize damage to economic crops not belonging to the.VC. In order to satisfy fully this requirement, the following guidelines were evolved: (1) the missions will be accomplished under inversion or neutral temperature conditions with calm (0 to 5 mph) winds; (ii) the spray will be delivered at 150 feet altitude or lower; (Hi) Che spray flight will be lnwind if direction of flow can be determined; (lv) the HKD of the spray will be coarse (300 n), an attempt to reduce the number of small droplets available to drift off-target; and (v) delivery aircraft speed will be slow (130 knots) to minimize droplet breakup from impingement of the airstream on rl Ii * (i ; t - r j i <i l i C3J CD C55 ^1 GO : ir 55 I Ch* spray ac the-nozzle and Co maincain a capability Co stay on target . , T with changes In direction. An objective of che early tests waa Co obtain . 1 \ ground deposits of 1 gal (approximately 10 lb.) chemical per acre. The fIIr ; first C-123/MC-1 spray configuracin satisfied the spray requirements initially; however, the OSD/ARPA evaluation team determined that deposits j of 3 gal (30 lb.) of agent per acre were required to Insure significant defoliation of upland forest vegetation. Numerous modifications and extensive \ evaluations were accomplished in efforts to achieve the 3 gal/acre deposits. \ Ultimately, the a /AA5Y-1 spray system was`developed and supplanted the earlier models. However. It was not calibrated and performance characteristics were not evaluated prior to 1968 at which time Che system was included in studies directed by the Chief of Staff of the Air Force. Concurrent with the calibration studies on the C-123B and A/A45Y-1 spray system, it was being modified. Two gasoline-burning jet engines were added to the air craft that now Is designated the UC-123K, and wing booms 22 feat long have replaced the 17-foot booms that had been shortened previously by the field units. Performance of the UC-123K and A/AA5Y-1 system also was evaluated by'AFGC, Eglin AFB, Florida, in the 1968 test and evaluation program. The system in operation is portrayed in Figure 7. i t ! r t i . i! t CD It co 60 JT b ti V i nCUBE 7 . D e fo lia tio n with Cha UC-IZSC and A /M ST-l S y ita a la wm, 1969. i f i i Iti i CO ;-cr (CD i IX. REVIEtf A. EVALUATIONS It is of Interest to note that, among all the controversial subjects that- are parts of the ccnfliet in Vietnam, the use of vegetation-control agents, "defoliation," continues to receive an undue amount of publicity that Is generally critical. Protest groups have objected to the use of defoliants but appear to be most concerned with the war itself, that people are being, killed with che unique methods chac tend Co Incite1strong asociaos, such s s Che use o napalm. A ouch smaller group, predominantly scientists, has chosen to criticize Che use. of herbicides on "scientific,1* economic,- and/or political bases since ehe defoliants do not kill or maim as conven* Clonal weapons. The U.S Government has not been insensitive to their pronouncements and justification for continuation of the RANCH HAND pro* gram has been reviewed periodically,-with the last evaluation (among others) completed lace in 1963. The conclusions of each evaluation recognize that defoliation has reduced the incidence of ambushes, has saved lives, and has disrupted VC/NVA tactics; the crop-denial efforts have made subsistence of the enemy in the field more difficult have adversely affected his operations. Each evaluation group, in turn, . approved or recommended continued use of the vegetation-control system. 3. SCOPS OF OPERATIONS 'IN VIETNAM * The number of acres sprayed yearly from 1962 through 1968 for defolia tion and crop destruction are given in the following tabulation based on furnished in MACV reports: Tear Aeres Scraved Crop Defoliation Destruction Total 1962 1963 1964 1965 1966 1967 1968 * 4,940 24,700 83,468 155,610 741,247 1,486,446 1,267,110 741 247 10,374 65,949 101,517 221,312 63,726 5,681 24,947 93,842 221,559 842,764 1,707,758 1,330,836 This Information serves to indicate the magnitude of the overall effort and the increasing intensity of spray operations with time. Further, since most requests for spray operations are submitted by field canaaanders, the information is indicative of thalr recognition of the importance of the program to the fighting troops. 03 968 V * X. APPRAISAL X . VIETNAM The Introducelcn of a vegetatlon-cnnerol capability Into the armed conflict la Vietnam la unique In modern warfare, in that the method doea - not kill, malo, or othervlaa harm people nor deatroy their buildings. In fulfillment of a defensive role, defoliation In critical areas taken the initiative from the enemy for a favorite tactic, a. g. launching a eloaa-in, demoralising, surprise attack, Chen withdrawing before a eountarattack can be launched by the defenders. When the screening foliage required for successfully mounting such an operation Is reduced or eliminated, the enemy is faeed with the prospect of exposure. Defolia tion of enemy lines of conamication (roads, trails, waterways, ate.), staging areas, and camps has exposed enemy, activities and revealed other wise unseen targets. The enemy abandons1treated areas. Offensive strikes against food crops have denied the enemy large quantities of food. VC/NVA defectors report food shortages, hunger, discon tent, and the requirement for more and more foraging parties to obtain food supplies. Ho question has been raised on the effectiveness of available systems to destroy crop productivity. However, there have been serious questions regarding the sociological and political impacts of ant1 food operations. Efforts have been made to weigh the effects of crop destruc tion on the enemy against the attitudes of the Vietnamese, whose produce is taken by the VC/NVA troops, and the influence of public opinion at home and abroad is considered. Ho conclusive study has been accomplished, and while the subject Is still open for debate, aneicrop operations have continued in Vietnam where many commanders are convinced of the military worth of .the effort. B. SYSTEM LIMITATIONS It has been shown that the vegetation-control systems in Vietnam are capable of producing militarily significant effects and that these systems have earned a permanent place In military operations. It is recognized, however, that the systems currently in use have limitations that may be eliminated only by improvement of performance of the various components. * 1. Delivery Aircraft The DC-123 aircraft currently in use has developed a remarkable ' record of reliability in Vietabs. During the period starting with the Jest 3 months in 1965 through the first 8 months of 1968 the DC-123' flew almost 11,000 sorties and received nearly 2,000 hits from ground fire, and only four of the aircraft were lost to enemy fire. In the Vietnam conflict, che only opposition has bean from ground flra, whereas in a high-intensity war, fighter aircraft and more sophistleated antiaircraft missiles could be expected to effectively counter slow, cargo-type air craft such as the UC-123. More versatile delivery Systems and support technologies must necessarily be developed to provide for unrestricted captoyment of vegetation-control agents. 2 Vegetation-Control Agents r The agent components of the current systernsj on crop-control missions, have produced results as predicted because they were developed initially for that purpose. In the defoliation role, the agents have satisfied the objectives visualized at the time of their Introduction into Vietnam. PURFIE and ORANGE disrupt the normal physiologic processes of the sensitive plant system and defoliation results even though the affected plane may recover partially or completely. An extensive array of broad-leaved plants Is killed by dosages adequate to cause defoliation. Intensive use of these compounds in Vietnam demonstrates that some few species appear to be immune from the effects of the growth-regulator chemicals, thus complete defoliation of mixed forest targets has not been accomplished. Another limitation of these compounds is that maximum defoliation is achieved slowly; peak In effects from use of ORANGE is about 3 months, from use of WHITE, 5 months. A chemical defoliant agent that will produce effects much more rapidly on all treated vegetation is desired. Agent BLUE functions as a contact or desiceant chemical and produces local effeces (browning, shriveling, and necrosis). Since translo cation of the. chemical from the point of contact is not a requirement, the effects develop store rapidly than with ORANGE and WHITE. However, with some plant species regrovrh soon follows defoliation (30 to 60 days). Frequent retreatunt is required where BLUE is used and long-term effects are desired. C. RDT&E Development'of chemical vegetation-control agents is the responsibility of the Army and the work is accomplished in the Plant Sciences Laboratories, Fore Detriek, Frederick,.Maryland. The work leading to development of improved chemical agents was-initiated in 1961 and represents a modest level of effort in the exploratory development category. The general objectives to be satisfied include: (1) develop a nonselectlve agent, capable of causing rapid defoliation without destruction of valuable forest species; (ii) develop a nonselectlve chemical agent capable of causing defoliation and persistence of effects for 1 year (or more); and (ill) develop a nonselectlve agent capable of causing rapid defoliation with effeces persisting for at least 6 to 9 months. Work on delivery systems is the responsibility of the individual services to fulfill assigned missions. LIt EkATURE CITED 1. Contribution from Special Projects Division, Chemical Warfare Service, Coop Detrick, Maryland. 1946. Bot. Gas. 107:475-632. 2. Minerlk, C.E.; Latterell, Prances H. August 1958. Anclcrop agents (U), (Technical Study 11). Crops Division, Fort Detrick, Frederick, Maryland. SECRET (58-FDS-666). AD 322 512.- Acc Ho. 30623 3- Smith, H.H.; Norman,. A.G. April 1945. Crop destruction by aerial sprays: Preliminary trials, Bushness Army Air Field, February to April 1945 (U), (Special Report 12). Special Projects Division, Camp Detrick, Frederick, Maryland. CONFIDENTIAL. 4. Swanson, C.; Mlnarlk, C . ; Acker, R.M. October 2945. Crop destruc tion by aerial sprays:' Field trials, 1945; Vigo plant CUS, Terre Haute, Indiana, and Beaumont, Texas, April to October 1945, (Special Report 25).' C Division, Camp Detrick, Frederick, Maryland. 5. Acker, R.M,; Hartmeyer, R.W.; Wolf, W.R. May 1951. Low-volume anticrop aerial spray trials (U), -(Special Report 149). C Division, Camp Detrick, Frederick, Maryland. CONFIDENTIAL. 6. Acker.. R.M. Hartreyer, R.W.; Teatran, J.N.; Wolf, W.R.; Wares, H.A. December 1951. Low volume anticrop aerial sprey trials,. Phase II (U). (Special Report 151). Crops Division, Comp Detrick, Frederick, Maryland. CONFIDENTIAL- 7. Acker. R.M.;, Hartmeyer, R.W.; Heather ly, J.E.; Bullard, W.E. February 1953. Anclcrop aerial spray trials, Phase III (U), (Special Report 1S4). C Division, Camp Detrick, Frederick, Maryland. CONFIDENTIAL. .8 Air*Force Armament Center. August 1953. Evaluation of production modal of large capacity spray system for B-29 and C-113 aircraft, (AFAC Technical Report 53-33). Air Force Armament Center, Eglin Air Force Base, Florida. Acc No. 23438. 9. Brown. J.W.~ 8 Kerch 1962. Preliminary report of vegetntlonal spray tests, (First Quarter Technical Status Report). Crops Division, Fort Detrick, Frederick, Maryland. Acc No. 40029. .10 Brown, J.V. April 1962. Vegetational spray tests in South Vietnam. Crops Division, Fort Detrlck, Frederick, Maryland. AD 476 99XL. Acc No. 38371. 11. Brown, James W. April 1962. Vegetational spray tests in South Vietnam, supplement (U). Crops Division, Fort Detrlck, Frederick, Maryland. SECRET (62-FDS-834). AD 368 997L. Acc Mo. 38372. IB B S S I PAS K M | i' ) t ( I | [ i !. j 12. Delaona, F.J.; Shaw, W.C. S Burcham, L.T.; Mindrifc, C.2.; Whittain, 0. Kay- 1962. Review and evaluacin of ARFA/OSD "Defoliation" program In South Vietnam (U), (Report of Evaluation Team). Army Chemical Corps Research and Development Comsaad, Washington, D.C. CONFIDENTIAL. Acc No. 45646. 13. Warren, William F. August 1968, A review of the herbicide program in South Vietnam (fa), (CINCPAC Scientific Advisory Group Working Paper No. 10-68). CXNCFAC Scientific Advisory Grouo, FPO San Francisco, California, 96610. SECRET (68-FDS-1544). 14. Darrov, RoLert A . ; Truchelut, George B . ; Bartlett, Charles H. July 1966. 0C0NUS defoliation test program, (Technical Report 79). , Crops Division, Fart Detrick, Frederick, Maryland. 15. Bess, Charles E. April 1958. The potentialities of cacodylic a d d as an anticrop agent (U), (Technical Report 6). Crops Division, Fort Detrick, Frederick, Maryland. CONFIDENTIAL. I 16. Bess, Charles E. August 1959. *Caeodylic a d d : An agent of choice (TJ), ' (Technical Report 17). Crops Division, Fort Detrick, Frederick, Maryland. CONFIDENTIAL. AS 322 291. Acc No. 32198. 17. Bouse, W . B . G o o d s on, L.H.; Gadberry, H.H.; Dockter, K.W. November t 1967. Assessment of ecological effects of extensive or repeated use * of herbicides, (Final Report, 15 August - 1 December 1967). Project No. 3103-3 on Contract .3AHC15-63-C-0119, Midwest Research Institute. AD 824 314. Acc No. 47229. 18. Ring, J.Z.; Penfound, W.T. 1946. Effects of two of the now formagenlc herbicides on bream and iargemouch bass. Ecology 27:372-374. j 19. Elingman, G.C. 1961. Weed control as a science, p. 330-331. John Vi ley A Sons, Inc., New York. I ! 20. Weed Society of America.* 1967. Herbicide handbook of the Weed j Society of America! W.F. Humphrey Press, Inc., Geneve, New York. I 2S3 p. i 1 21.' Watson, A. J , ; Hanson, R.G.; et ai. January 1965. Evaluation of the [ sensitivity of some eoamon food crops to the herbicide 4-malno-3,5,6- trlchiorcpleolinie acid, (Final Report, 1 April 1963 31 August 1964). i Contract DA-18-064-AMC-119(A) Dow Chemical Company, Midland, Michigan. Ace No. 42174. I 22. T0RD0N Information manual. Dow Chemical Company1, Midland, Michigan. I ii i ii i i i ft I i 03 I 9685 *7 &V' * *"' 67 V 23* Tschirley, F.H. 1968 Response of tropical and subtropical woody plants to chemical treatments, (CR 13-67) Contract Report on ARFA Order 424. Agricultural Research Service, U.S. Department of Agriculture, Washington, D.C. 24. Brown, J.tf. ; Whit tarn, Donald July 1962. Modification and calibration of defoliation equipment, (unnumbered ARPA report). O.S. Department of Agriculture, U.S Air Force, and U.S. Array Chemical Corps. AD 478 189, Acc Vo. 39045. Supplement, AD 478 190 25. Boyer, taster U. ; Brown, James W. June 1964. Calibration of spray systems: C-123/MC-1 H-34/HH1AL, A-1H/FIDAL, (Technical Report 46). Crops Division, Fort Detrlck, Frederick, Maryland. AD 442 477. Acc Vo. 38996. i F CD f C O l V CO 5 CO CD CO \