I/EC
ANNUAL
REVIEWS . : : • ;
: : : : . : ; - ;
Fertilizers and Pesticides 1957
Table I. Nutrients
Supply o f Primary for United States Possessions"
N , P 2 Os, or K2O, 1000 Tons 1956-7 6 1955-6 Nitrogen U. S. production Synthetic ammonia By-product ammonia Natural organics
1,945 201 30
Total production Import-export a d justment
2,231
2,176
34
75
Total supply
2,265
2,251
1,585
1,604
736 200
775 120
Total production Import-export adjust ment
2,521
2,499
-169
-97
Total supply
2,352
2,402
Potash U. S. production Muriates Sulfates Manure salts Other
Fertilizers OTAL DOMESTIC s u p p l y of n i t r o gen, p h o s p h a t e , a n d p o t a s h for t h e y e a r e n d e d J u n e 30, 1957, was esti m a t e d by t h e U . S. D e p a r t m e n t of A g r i c u l t u r e as slighdy less t h a n for t h e previous year, based on p r o d u c tion r a t h e r t h a n p l a n t capacity. S u p p l y of n i t r o g e n a n d potash was slightly higher, whereas that of p h o s p h a t e was lower. The consumption of fertilizers in t h e U n i t e d States a n d Territories
Table II.
for t h e y e a r e n d e d J u n e 30, 1956, t h e last y e a r for w h i c h d a t a a r e available, was 22,193,070 tons, w h i c h was a decrease of 533,392 tons ( 2 . 3 4 % ) from t h e p r e c e d i n g year. T h e 1 9 5 5 - 6 c o n s u m p t i o n of p r i m a r y n u t r i e n t s (N, available P2O5, K 2 0 ) was 6,054,741 tons, or 64,398 tons ( 1 . 0 5 % ) less t h a n in t h e p r e c e d i n g year. T h i s was t h e first t i m e in 17 years t h a t t h e total c o n s u m p t i o n of p r i m a r y n u t r i e n t s failed to increase.
Consumption o f Fertilizers and Primary Plant Nutrients in United States and Possessions" Tons 1955-6
1,800 111 3 26
1,739 106 2 26
Total production Import-export a d justment
1,940
1,873
-66
-10
Total supply
1,874
1,863
" C o m m o d i t y Stabilization Service, U. S. Department of Agriculture. 6 Estimated.
48 A
W . R. G r a c e & Co., Washington Research Center, Clarksville, M d .
Τ 2,023 178 30
Phosphate U. S. production Normal and enriched superphosphate Concentrated super phosphate AU other
G . L. BRIDGER
Plant and
1954-5
Fertilizers Mixtures Materials
14,775,653 7,417,417
15,347,850 7,378,612
Total
22,193,070
22,726,462
1,932,603 2,247,420 1,874,718
1,960,536 2,283,660 1,874,943
6,054,741
6,119,139
Primary plant nutrients Nitrogen Available P 2 Ot
κ2ο Total
INDUSTRIAL AND ENGINEERING CHEMISTRY
* Agricultural Research Service, U. S. Department of Agriculture.
I n 1955-6 use of nitrogen decreased by 1.42%, available P 2 0 6 by 1.59%, a n d K 2 0 by 0 . 0 1 % . For fertilizer consumed as mixtures and materials, and primary plant nutrients, direct application use ac counted for 5 8 . 8 % of the nitrogen, 2 0 . 6 % of the available P 2 0 6 , a n d 1 1 . 7 % of the K 2 0 used in 1955-6. T h e concentration of p r i m a r y plant nutrients in fertilizers con tinued to rise (see chart below). Nitrogen Nitrogen capacity continued to increase despite the slight decrease in consumption. A t the end of 1957, synthetic a m m o n i a capacity was approaching 5,000,000 tons of N H 3 per year. Approximately 55 a m m o n i a plants were either in opera tion or scheduled for operation in the near future. T h e principal forms in which nitrogen was consumed for fertilizer purposes were a m m o n i u m nitrate and a m m o n i u m nitrate-limestone mixtures, anhydrous a m m o n i a , so dium nitrate, a m m o n i u m sulfate, nitrogen solutions (including a q u a a m m o n i a ) , urea, calcium cyanamide, calcium nitrate, a n d natural organic materials. T h e proportion of nitro gen supplied to the soil directly rather t h a n in mixed fertilizers has increased steadily over the past 10 years. I n 1946, less t h a n half was applied directly, whereas in 1956, the proportion had risen to 5 8 . 8 % . I n 1955-6, there were significant
changes from the preceding year in the distribution of nitrogen m a terials used for direct application, despite the small change in total direct application nitrogen. For ex ample, there were marked increases in usage of urea ( 3 5 % ) , a q u a am monia ( 3 4 % ) , a n d anhydrous am monia ( 1 8 % ) , and marked decreases in a m m o n i u m sulfate ( 2 0 % ) , a m m o n i u m nitrate ( 1 6 % ) , a m m o n i u m nitrate-limestone mixtures ( 1 2 % ) , and sodium nitrate ( 1 2 % ) . Of particular interest is t h e rapid increase in urea capacity. United States production has been estimated at 230,000 tons in 1954, 419,000 tons in 1956, and 545,000 tons are projected for 1958. T h e principal use of urea is for fertilizers, although significant quantities are also used for animal feeds, synthetic resins, and other industrial applications. A n u m b e r of new nitrogen solu tions appeared on the m a r k e t for use in mixed fertilizer formulation. I n m a n y granulation processes use of nitrogen solutions having different composition a n d properties t h a n those previously developed is ad vantageous. T h e result is t h a t there are now over 50 different nitrogen solutions on the market for use either in mixed fertilizer formulation or direct application. Phosphates T h e proportion of total phosphates produced as concentrated or triple superphosphate has been increasing
Concentration of Nitrogen, Phosphate, and Potash Mixtures
1955-1956
1954-1955
1953-1954
Materials
A l l Fertilizers
28.67%
27.43%
28.29%
27.90%
27.88%
27.90%
26.87%
25.99%
26.61%
over the past several years a n d is now about 3 0 % of the total. Pro duction has more t h a n doubled during the past five years a n d will increase from about 1,700,000 tons in 1956 to an estimated 3,000,000 tons in 1965. However, in certain areas a competitor for triple super phosphate is marketed in the form of wet-process phosphoric acid. This product, formerly used entirely for making triple superphosphate and industrial phosphates at the site of production, appeared on the m a r k e t during the past year and is being used in mixed fertilizers of high con centration. Electric-furnace proc ess phosphoric acid is also used to some extent in both liquid a n d solid mixed fertilizers. Considerable interest was shown in various processes for making wet process phosphoric acid. A new method called the "clinker" process, disclosed by Davison Chemical Co., is based on heating a mixture of phosphate rock a n d strong sulfuric acid to form a clinker, and separation of phosphoric acid by leaching. For removing gypsum, several of the new phosphoric acid plants use the Bird Prayon filter or the DorrOliver (Giorgini) travelling p a n filter; other filters used are the Mercer-Robinson b a n d filter, the Dorr-Oliver horizontal rotary filter, a n d the Eimco horizontal rotary tilting-tray filter. A new phosphatic fertilizer raw material, superphosphoric acid, has been developed by the Tennessee Valley Authority and is available in experimental quantities. This product, which is a eutectic mixture of ortho- and pyrophosphoric acids, contains 7 6 % Ρ 2 Οβ, and has been used experimentally in both liquid and solid mixed fertilizers. New developments in superphos phate production include processes for m a k i n g quick-cured normal superphosphate a n d granular triple superphosphate. A method, de scribed by T V A for making a quick-cured normal superphosphate suitable for immediate use in pro duction of mixed fertilizers, depends on use of finely ground phosphate rock and an excess of sulfuric acid of lower concentration t h a n usually employed. T V A also disclosed a process for making granular triple superphosphate by acidulating phos phate rock with phosphoric acid in their rotary ammoniator-granulator VOL. 50, NO. 1
·
JANUARY 1958
49 A
n o r m a l l y u s e d for g r a n u l a t i n g m i x e d fertilizer. P l a n s for m a k i n g c a l c i u m m e t a p h o s p h a t e from western p h o s p h a t e rock w e r e a n n o u n c e d by Central Farmers Fertilizer. Go-operative. T h i s will b e t h e first c o m m e r c i a l production of calcium metap h o s p h a t e in t h e U n i t e d States, previous production having been carried out only by T V A .
REDUCE OPERATING COST of VACUUM SYSTEMS with this "AERO" (air-cooled) VAPOR CONDENSER W i t h free air the c o o l i n g m e d i u m , you use the least water, evaporated in the a i r s t r e a m . Y o u save t h e c o s t a n d p u m p i n g of large volumes of cond e n s i n g water. Air-vapor s u b c o o l i n g reduces mixture evacuated from the system, saving in the operation of steam ejector or vacuum p u m p . T h i s air-cooled condenser gives y o u m o r e capacity than o t h e r types at a substantial saving of steam a n d p o w e r . W a t e r supply, scaling t r e a t m e n t and disposal p r o b l e m s are eliminated. Y o u g e t p u r e c o n d e n s a t e , an imp r o v e d p r o d u c t ; often profit by recovery of residues n o w wasted. T h e r e can be n o contamination of y o u r p r o d u c t at any t i m e ; it never touches raw water. C o n d e n s i n g , of water, of solvents or of your p r o d u c t , is simplified; you have one, compact, easily maintained unit replacing b o t h cooling t o w e r a n d barometric or surface type condenser. Write for full information.
Potash Niagara Aero Vapor Condenser Panel Casing Construction gives access to all parts, saves first costs in shipping and installation.
Maintenance expense is low. N i a g ara Aero V a p o r Condenser Panel Casing construction gives access t o all parts, saves first costs in s h i p p i n g and installation. Summer-winter dampers and Balanced W e t Bulb C o n t r o l provide precise, year ' r o u n d adjustment of capacity to load. Constant temperature, uniform products and m a x i m u m p r o d u c t i o n 12 m o n t h s a year are assured. Capacities u p t o 15 million B T U / h r . Ask for Bulletin
129R
N I A G A R A BLOWER C O M P A N Y Dept. B C - 1 , 4 0 5 L e x i n g t o n A v e . , N e w Y o r k 1 7 , N . Y . Niagara
District Engineers in Principal
Cities of U. S. and
Canada
TO COOL A FLUID... and have a problem of water supply or disposal... use NIAGARA "AERO" HEAT EXCHANGER vapors, cool water, oils, solutions, intermediates, coolants for mechanical, electrical or thermal processes. Y o u have a closed system free from dirt. Y o u h a v e s o l v e d all p r o b l e m s of water availability, quality o r disposal, m a i n t e n a n c e expense is low. Y o u may apply this to solvent recovery, vacuum systems controlling reactions, c o n d e n s i n g distillates, cooling reflux p r o d u c t s .
For more information, write for Bulletins 120, 124, 135. Address
Dept.
N I A G A R A BLOWER COMPANY Dept. E C - 1 , 4 0 5 Lexington Ave., N e w York 1 7 , N . Y . Niagara 50 A
Mixed Fertilizers T h e m i x e d fertilizer i n d u s t r y w a s characterized by continued growth of g r a n u l a t e d p r o d u c t s a n d l i q u i d fertilizers. T V A r e c e n t l y e s t i m a t e d t h e n u m b e r of g r a n u l a t i o n p l a n t s in t h e U n i t e d States as 1 7 1 , a n d t h e p r o p o r t i o n of all m i x e d fertilizer in g r a n u l a t e d f o r m a s 2 0 t o 2 5 % . I n the year ending J u n e 30, 1955, o n l y a b o u t 9 % of all m i x e d fertilizer was granulated. This trend toward i n c r e a s e d g r a n u l a t i o n is c o n t i n u i n g i n a l l a r e a s of t h e c o u n t r y e x c e p t the South.
WHEREVER YOU NEED
• Evaporating a very small amount of water in an air stream you can cool liquids, gases or vapors with atmospheric air, removing heat at the rate of input, controlling temperature precisely. Save 9 5 % of the cost of cooling water; save piping, pumping and power. Y o u quickly recover your equipment cost. Y o u can cool and hold accurately the temperature of all fluids, condense
C a p a c i t y of t h e d o m e s t i c p o t a s h i n d u s t r y is i n c r e a s i n g a n d also m a j o r potash deposits in C a n a d a are being developed. T h e r e appears to be a n a m p l e s u p p l y of p o t a s h for m a n y years to c o m e a n d competition a m o n g producers seems to be increasing. I n 1955-6, although total potash consumption decreased slightly ( 0 . 0 1 % ) , u s e of d i r e c t a p p l i c a t i o n potash increased by 1.24%. Most of t h i s i n c r e a s e w a s i n 58 t o 6 2 % potassium chloride. M a t e r i a l s of v a r i o u s p a r t i c l e size r a n g e s w e r e offered b y p r o d u c e r s t o m e e t r e q u i r e m e n t s of g r a n u l a t e d mixed fertilizer p r o d u c e r s .
District Engineers in Principal Cities of U. S. and
INDUSTRIAL AND ENGINEERING CHEMISTRY
Canada
R e c e n t figures o n p r o d u c t i o n of liquid mixed fertilizers a r e n o t available, b u t in c o m p a r i s o n with solid m i x e d fertilizers, t h e p r o p o r t i o n is still s m a l l i n s p i t e of a r a p i d i n c r e a s e i n t h e n u m b e r of p l a n t s . L i q u i d mixed-fertilizer plants a r e usually small a n d their production is l i m i t e d b y t h e s u p p l y of e l e c t r i c furnace phosphoric acid. Wet-process p h o s p h o r i c a c i d h a s n o t b e e n used t o a n y significant e x t e n t b e c a u s e of difficulties w i t h its i m p u r i t i e s . G r a n u l a t i o n of solid m i x e d fertilizers is d o n e p r i n c i p a l l y i n t w o t y p e s of p r o c e s s e s — n a m e l y , t h e T V A rotary ammoniator-granulator or the paddle mixer ammoniator - gran-
ulator. These plants generally must have substantial capacity a n d require substantial capital investment. T h e principal advantages of granulation are ease of handling, storage, and distribution, a n d usually granulated fertilizers can be produced in higher concentrations t h a n nongranulated products. For example, granulated 15-15-15 and 6-24-24 are now on the m a r k e t in m a n y areas, a n d granulated 17-17-17 a n d 7-28-28 have been m a d e experimentally. T h e T V A rotary ammoniationgranulation system has been used on a pilot-plant scale for making nitro-
phosphates, alkaline grades, amm o n i u m phosphate-nitrate products, a m m o n i u m phosphate-urea products, a n d g r a n u l a r triple superphosphate. The nitrophosphate process involves mixing phosphate rock with nitric acid and feeding the resultant slurry into the a m moniator-granulator where it is mixed with the other ingredients a n d reacted with a m m o n i a . This process is said to overcome one of the principal disadvantages of other nitrophosphate processes—namely, high capital investment. M u c h attention has been given
in the past few years to the question of water solubility of the phosphate content of mixed fertilizers. For most applications on acid soils where water is not a limiting factor, water soluble phosphate does not a p p e a r necessary. For certain other a p plications, water solubility of at least 5 0 % appears desirable—e.g., starter fertilizers and use on alkaline soils. For still other applications, water-soluble phosphate could be disadvantageous—e.g., on sandy soils of low anion exchange capacity where the phosphate might be lost by leaching.
L. S. HITCHNER National Agricultural Chemicals Association, Washington, D. C.
Pesticides
E,
XPORTS
OF
CHEMICAL
PESTICIDES
continued to rise during 1957 but production a n d domestic sales leveled off" near the peak reached in 1956. For example, government figures show that production of D D T for the first 11 months of the crop year (Oct. 1, 1956, to Sept. 30, 1957) was 5,000,000 p o u n d s less t h a n for the same period in 1956. However, exports for the first 10 m o n t h s were higher by 6,000,000 pounds. Actual domestic sales, however, were probably higher t h a n decreased production figures show, because inventories held by producers a n d formulators a t the end of the 1957 season were higher t h a n those of the previous year. O n e reason for the 1957 sales leveling off near the 1956 peak is that in m a n y areas, boll weevil a n d corn borer infestation were less severe t h a n during the previous crop year. Also, the 1956 control p r o g r a m s against the M e d i t e r r a n e a n fruit fly a n d the K h a p r a beetle were successfully completed. Although threats from grasshoppers, M o r m o n crickets, a n d spotted alfalfa aphid were greater in 1957, domestic sales seemed to d r a w their m a i n strength from two basic trends —farmers are realizing t h a t investm e n t in crop protection pays off in increased net income. Also, m o r e pesticides are used in nonagricul-
tural areas such as in highway roadside maintenance, forest a n d park m a n a g e m e n t , home gardening, a n d industrial applications. Park m a n agers for the first time are showing real interest in improving recreational areas by chemical control to tormenting insects a n d poisonous
plants. Highway-landscape engineers are beginning to cut costs of roadside-weed control and h o m e gardeners are using more pesticides as new homes are built and suburb a n areas are extended. T h e present status of the pesticide industry is best demonstrated by the
Pesticide Production" (11 months) Lb.
Oct. 1, 1956Aug. 31, 1957 9,100,000 120,536,000 Z9,310,000 5,085,000 131,936,000 20,357,000'' 11,620,000 6
Oct. 1, 1955Aug. 31, 1956
Materials BHC, gamma basis 12,495,000 DDT 125,836,000 2,4-D, acid equiv. 26,706,000 2,4,5-T, acid equiv. 4,091,000 136,472,000 Copper sulfate Calcium arsenate 23,744,000 6 Lead arsenate 13,088,000 6 * From U. S. Dept. of Agriculture and U. S. Dept. of Commerce. 6 Estimated. Pesticide Exports-
Lb.
Materials Copper sulfate DDT, 25% or more BHC, gamma basis Weed killers Agricultural insecticides and fungicides, not elsewhere classified Household industrial insecticides Agricultural sulfur, not elsewhere classified Calcium arsenate Lead arsenate " From U. S. Bureau of the Census.
Oct. 1, 1955July 31, 1956 57,730,933 48,751,881 2,587,121 16,586,748 81,200,474
Oct. 1, 1956July 31, 1957
14,719,204 5,777,964
13,947,629 10,096,598
1,020,282 1,027,960
1,839,390 1,361,311
VOL. 50, NO. 1
·
52,192,594 54,774,736 1,890,352 16,607,638 85,727,867
JANUARY 1958
51 A
ANNUAL REVIEW
PHYSICAL PROPERTIES OF
QO FURFURAL GENERAL Boiling point ( a t 7 4 4 mm), (Todd Still) C Freezing point, C
1 60(98)% —36.5
Refractive index (n 2 0 / D )
1.524-7
Specific g r a v i t y , 2 0 / 2 0
1.161-3
Solubility in w a t e r ( w t . % a t 20°C.) alcohol; e t h e r
8.3 co
FLUID PROPERTIES Viscosity, cps. a t 2 5 ° C at 3 8 ° C
1.49 1.35
Surface tension, d y n e s / c m . at 30.0° C
41.1 2
V a p o r diffusion coefficient, cm /sec. at 2 5 ° C
0.087
THERMODYNAMIC PROPERTIES H e a t of v a p o r i z a t i o n , Δ Η „ , „ kcal./mole Thermal conductivity, B.T.U./(hr.) (sq.ft.) (°F. p e r f t . ) a t 1 0 0 ° F
10.22
0.1 525
For complete details on the physical properties of Q O Furfural, write for Bulletin 203-A
The Quaker Qats Company CHEMICALS DEPARTMENT 337P The Merchandise Mart, Chicago 5 4 , Illinois
The Quaker Oats Company
Room 537P, 120 Wall Street, N e w York 5, N e w York Room 437P, 48 S.E. Hawthorne Blvd., Portland 1 4 , Oregon In the United Kingdom: Imperial Chemical Industries, Ltd., Billingham, England In Europe: Quaker Oats-Graanproducten N. V., Rotterdam, The Netherlands; Quaker Oats (France) S. Α., 3, Rue Pillet-Will, Paris IX, France; A / S " O t a , " Copenhagen, S. Denmark In Australia: Swift & Company, Ltd., Sydney In Japan: F. Kanematsu & Company, Ltd., Tokyo
52 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
production record. Although total o u t p u t for the first 11 months of 1957 crop year was down from t h a t of 1956, 2,4-D acid a n d 2,4,5-T acid increased. I n 1956, the opposite was true—except for these two acids, production of all products was m u c h higher. O u t p u t of benzene hexachloride ( g a m m a basis) in 1957 was down 2 7 % ; D D T , 4 % , calcium arsenate, 13%; lead arsenate, 1 1 % ; a n d copper sulfate, 9 % . O n the other h a n d 2,4-D a n d 2,4,5-T acid was u p 9 a n d 2 5 % , respectively. A realistic estimate of the over-all status of t h e pesticide chemicals industry is difficult because statistics are lacking on production a n d sale of organic phosphate pesticides. Sales for these items seem to be growing, particularly in agricultural a n d h o m e gardening uses. Exports, of course, are independ ent of fluctuations in domestic m a r kets. These have been supported by the need to increase foreign crop yields a n d the continued programs to stamp out malaria. Significantly, the large increases in exports during the first 6 months of 1957 went to food hungry, underdeveloped areas. N o r t h America remained the larg est export market, b u t sales actually dropped 5 % as compared with 4 % for South America. Exports to Eu rope were 1 1 % higher, b u t the big increases were for countries in Asia a n d Oceania ( 3 3 % ) a n d Africa ( 5 0 % ) . T h u s , except for the slight drop in exports to South America, the general p a t t e r n of increasing ex ports continues. O t h e r t h a n shifts in production a n d sales, the major development in 1957 was a marked shift in emphasis by manufacturers. Following intro duction of chlorinated hydrocarbon a n d organic phosphate pesticides after World W a r I I , the industry was primarily concerned with pro duction to meet a rapidly growing d e m a n d . Afterward, the later period from 1952 into 1956 was character ized by readjustment a n d internal progress. T h e Miller Pesticide Resi d u e A m e n d m e n t to the Federal Food, Drug, and Cosmetic Act was passed and implemented during this time. Now, as this period of readjust m e n t comes to a close, manufacturers are shifting emphasis from problems
ANNUAL REVIEW
DISC-ROLL MILL
PRODUCT OUTLET
"GYROTOR" AIR CLASSIFIER
PNEUMATIC PRESSURE CONTROL
GRINDING ROLLS
FEED INLET GRINDING DISC OR TABLE
T h e H a r d i n g e Disc-Roll Mill is a roller-type m i l l w i t h t w o a d j u s t a b l e , p n e u m a t i c a l l y loaded rolls for g r i n d i n g m a t e r i a l o n a h o r i z o n t a l r o t a t i n g disc o r t a b l e (Loesche t y p e ) . T h e H a r d i n g e " G y r o t o r " A i r Classifier, i n c o m b i n a t i o n w i t h t h e m i l l , provides a c o m p l e t e g r i n d i n g , classifying, a n d d r y i n g system. A full description is given i n B u l l e t i n 52-12.
HARDINGE COMPANY,
INCORPORATED
YORK, PENNSYLVANIA · 240 Arch St. · Main Oifice a n d Works New York · Toronto · Chicago · Hibbing · Houston · Salt Lake City · San Francisco 54 A
INDUSTRIAL AND ENGINEERING CHEMISTRY
of production a n d legislation to marketing. I t is significant that papers on research a n d panels on legislation which were featured at most recent annual meetings of t h e National Agricultural Chemicals Association were n o t o n t h e program in 1957. Instead, t h e discussions concerned improving communications between manufacturers a n d customers a n d improving methods for a c quainting potential users with benefits of using pesticides. Improvements in this area c a n be expected to affect favorably future production and sales. Meanwhile, there has been n o lag in research. I n 1957, t h e industry spent a n estimated $15,000,000 to find better pesticides compared with $8,000,000 as recently as 1950. T h e U . S . D e p a r t m e n t of Agriculture and other federal governm e n t agencies a r e spending a n additional $4,500,000 to $5,000,000 a year which brings t h e total to a b o u t $20,000,000. This excludes research d o n e by t h e states. Along with this increased expenditure for research, cost of bringing a single new pesticide to t h e market has increased also. Recent estimates indicate that it n o w costs $1,500,000 to $1,750,000 to develop a n d thoroughly test a n e w pesticide to meet both competition a n d t h e high standards set forth by the U . S . D e p a r t m e n t of Agriculture a n d t h e Federal Food a n d D r u g Administration. Need for more scientifically trained personnel has accompanied this expansion in research, '.not only t o carry out research b u t also to handle administrative a n d sales work. Recognizing that both future expansion and current progress depend largely on research, t h e industry h a s launched a program to encourage talented young people to select careers in t h e biological sciences— entomology, plant pathology a n d physiology, a n d agronomy—as well as in chemistry a n d chemical engineering. This program of career recruiting has been well received. I t is hoped t h a t it will attract m e n a n d women needed to spur progress in controlling insects, plant diseases, weeds, a n d rodents which n o w rank high a m o n g the most hostile elements in m a n ' s environment.
