Injury to navy bean (Phaseolus vulgaris L.) from EPTC (S-ethyl dipropylthiocarbamate) was investigated as a function of soil moisture, planting depth, soil compaction, temperature, available nitrogen, and seed quality. Experiments in the greenhouse and growth chamber showed that both high and low moisture stress increased injury. Deep planting increased the injury from high rates of EPTC. Soil compaction alone reduced plant growth. In combination with EPTC at 4.5 kg/ha, further growth reduction was observed. Ambient temperature did not alter susceptibility to EPTC. Stimulation of growth by nitrogen as measured by increased fresh weight was inhibited by EPTC. Field and greenhouse studies showed that EPTC injury was greater to mechanically damaged seed than non-damaged seed.

Navy bean (Phaseolus vulgaris L.) treated with the combination of EPTC (S-ethyl dipropylthiocarbamate) and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] developed more chlorosis of the leaves than beans treated with atrazine alone. Navy bean yields in field studies in 1972, were reduced 39% when grown in the presence of 0.55 kg/ha of atrazine and 3.4 kg/ha of EPTC, whereas the single application of either herbicide reduced yields 0 to 14%, respectively. In 1973, atrazine at 0.28 kg/ha did not significantly reduce yields, but combinations of 0.28 kg/ha of atrazine plus 2.2, 3.4, and 4.5 kg/ha of EPTC, reduced yields 40, 30, and 62% respectively. The combination of atrazine and EPTC also reduced plant weight and delayed flower and pod development. EPTC was found to increase wind blast damage under conditions of low relative humidity, high winds, and limited soil moisture. EPTC at 2.2, 3.4, and 4.5 kg/ha reduced the chloroform-soluble leaf extract from the surface of leaves and scanning electron micrographs confirmed that EPTC at 10-6 M altered leaf surface waxes. EPTC at 10-5 and 10-6 M increased the transpiration rate of plants. Increased uptake of 14C-atrazine from solution was associated with increased transpiration.

Application of EPTC (S-ethyl dipropylthiocarbamate) at 3.4 and 4.5 kg/ha in 1972 increased root rot severity and reduced navy bean (Phaseolus vulgaris L.) yields in soil with an artificial root rot [Fusarium solani (Mart.) Appel and Wr. f. Phaseoli (Burk.) Snyd. and Hans.] inoculum level. EPTC at 3.4 kg/ha and chloroamben (3-amino-2,5-dichlorobenzoic acid) at 3.4 kg/ha in 1973 caused the greatest root rot severity and greatest decrease in yield. Dinoseb (2-sec-butyl-4,6-dinitrophenol) and fluorodifen (p-nitrophenyl α,α,α-trifluoro-2-nitro-p-tolyl ether) at 5 kg/ha interacted with root rot less than the other herbicides assayed. In the growth chamber at 23 C, EPTC at 3.4 kg/ha and alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide] at 2.8 kg/ha applied to navy bean grown in soil infested with F. solani reduced plant growth. Root rot injury was most severe in plants treated with EPTC at 20 C ambient temperature. Navy bean growth was reduced as the level of F. solani chlamydospore inoculum increased in the presence of EPTC.

Navy bean (Phaseolus vulgaris L.) seedlings grown in soil treated with EPTC (S-ethyl dipropylthiocarbamate) were more susceptible to root rot caused by Fusarium solani (Mart.) Appel and Wr. f. phaseoli (Burk.) Snyd. and Hans. than were control seedlings. The navy bean line ‘RRR041,’ which is moderately resistant to root rot, did not show reduced growth when grown in soil infested with F. solani and treated with EPTC. None of the several herbicides tested increased F. solani chlamydospore virulence when grown on potato dextrose agar supplemented with herbicides. No herbicide tested increased F. solani hyphal development in liquid culture or soil. Dinoseb (2-sec-butyl-4,6-dinitrophenol) reduced hyphal development by the greatest amount. Scanning electron micrographs indicated that navy bean plants grown in EPTC had altered hypocotyl surfaces. EPTC and dinoseb increased the exudation of electrolytes, amino acids, and sugars from root and hypocotyl tissue.

Phytotoxicity of glyphosate (N-(phosphonomethyl) glycine), applied at 0, 0.56, 1.12, 1.68, 2.24 and 4.49 kg ai/ha to uniform, naturally growing quackgrass, [Agropyron repens (L.) Beauv.] plants, was studied with the electron microscope. Visible damage (yellowing of the leaves) to the plants was observed at the 2.24 and 4.49 kg ai/ha dosage rates within 72 hr. Similar damage became evident 120 hr after treatment at the 0.56 to 1.68 dosages. Leaf discs (1 mm in diameter) were harvested at 24, 48, 96, and 192 hr and prepared for electron microscopy by standard techniques. Cellular damage could be detected at all dosage rates as early as 24 hr after treatment. The type of damage observed was partial to complete disruption of the chloroplast envelope, and swelling of the rough endoplasmic reticulum (RER) with a subsequent formation of vesicles. With loss of integrity of the envelope, the chloroplast became completely disrupted with increased time. Other organelles within the cell were also destroyed.

The relative volatilities of various technical and formulated ester and amine salts of 2,4-D [(2,4-dichlorophenoxy)acetic acid] were determined in a closed air-flow system consisting of a volatilization chamber and an ethylene glycol trap. The system was operated at a flow rate of 28.8 L/hr and a temperature of 30 C. Trapped herbicide vapor was analyzed by gas chromatography. The relative volatilities of technical grade iso-propyl, butyl, propylene glycol butyl ether, and iso-octyl esters, were 56, 25 to 38, 4, and 1, respectively. The relative volatilities of various formulated esters and amines were of the magnitude of 440:33:1 for the high volatile, low volatile, and amine salts, respectively.

When peanuts (Arachis hypogaea L.) were not kept weed-free, a single cultivation 4 weeks after emergence increased yields substantially over those of non-cultivated peanuts. Cultivation had no effect, however, when peanuts were maintained weed-free for 4 or 8 weeks. The length of the weed-free periods, cultivation, and the presence or absence of peanuts all strongly influenced the density of the sicklepod (Cassia obtusifolia L.) plants which grew above the canopy of peanut foliage. Peanut foliage, which was released from weed-free maintenance at 8 weeks but then competed with sicklepod until harvest, reduced the green weight of sicklepod 95 to 98% thus illustrating the competitive capacity of the peanut plant. Moderate stands of Florida beggarweed [Desmodium tortuosum (Sw.) DC] did not markedly affect yield of peanuts. Application of a growth regulator, succinic acid, 2,2-dimethylhydrazide (SADH), did not influence weed competition or yield of in-shell peanuts consistently at any of the three locations. Quality analyses showed that treatment variables did not modify the taste of peanuts; however, in some experiments, components of the market grade of in-shell peanuts were changed by SADH, cultivation, length of the weed-free period, and cultivation X length of the weed-free period.

Cotton (Gossypium hirsutum L. ‘Stoneville 7A’) grown for 3 yr in competition with various weed densities and nitrogen levels showed annual weeds could reduce cotton heights as much as 75% and cotton yields as much as 88%. Cotton yields were increased by 18 to 30% by adding nitrogen to plots with no weeds. In 1973, cotton supplied with 224 kg/ha of nitrogen could tolerate up to 50% weeds without loss of yield. Weeds left to grow and reseed with no control resulted in increasingly greater competition with each succeeding year.

Field experiments were conducted on clay and clay loam soils at the International Rice Research Institute to investigate the effects of competition between upland rice (Oryza sativa L.) and varying populations of purple nutsedge (Cyperus rotundus L.) for nitrogen, moisture, and light on the grain yield of upland rice. ‘IR5’ was used in 1972, while the experimental line ‘IR442-2-58’ was used in 1973. Grain yields of ‘IR5’ and ‘IR442-2-58’ increased with 60 kg/ha of nitrogen, and decreased with increased purple nutsedge population. The application of nitrogen to weedy upland rice fields benefited the purple nutsedge more than the rice. Purple nutsedge and upland rice competed extensively for moisture and the competition was much more serious with increased nitrogen fertilization. Purple nutsedge competition reduced the light transmission ratio (LTR). The reduction was proportional to the increase in purple nutsedge population density. Reductions in the LTR were greater at higher nitrogen levels during the three seasons.

Neither glyphosate [N-(phosphonomethyl)glycine] nor the soil metabolite aminomethylphosphonic acid were detected in the first flow of water through two canals following application of glyphosate at 5.6 kg/ha to ditchbanks when the canals were dry. Soil samples collected the day before canals were filled (about 23 weeks after treatment) contained about 0.35 ppm glyphosate and 0.78 ppm aminomethylphosphonic acid in the 0 to 10-cm layer. When glyphosate was metered into the water at a rate calculated to provide 150 ppb in the canal water at a single site on two flowing canals, about 70% of the glyphosate was accounted for 1.6 km downstream from the application site. Thereafter, the rate of disappearance diminished, and about 58% of the applied glyphosate was present at the end of the canals 8 or 14.4 km downstream from the introduction sites.

Two incorporation methods were used in applying eight dinitroaniline herbicides before planting cotton (Gossypium hirsutum L.) for 3 yr. Penoxalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] gave the best stands of cotton. Nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylaniline] and dinitramine (N4,N4-diethyl-a,a,a-trifluoro-3,5-dinitrotoluene-2,4-diamine) resulted in the poorest stands. In 2 of 3 yr, cotton stands were better where herbicides were incorporated by listing only rather than by disking before listing. The eight herbicides were equally effective in annual grass control when followed by postemergence applications of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea]. An-56477 [N,N-bis(2-chloroethyl)-4-methyl-2,6-dinitrobenzenamine] was least effective in controlling annual broadleaf weeds. In 1972, cotton yield was reduced when An-56477 was incorporated by disking. In the average cotton yields for six tests, An-56477 produced significantly lower yields than any other herbicide except butralin [4-(1,1-dimethylethyl-N-(1-methylpropyl)-2,6-dinitrobenzenamine]. No differences in cotton fiber properties or boll components were due to herbicides or method of application.

In greenhouse studies, Cyperus esculentus L. var. esculentus was less susceptible than C. esculentus L. var. leptostachyus Boeck. to preplant applications of 1.77 kg/ha of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] or 0.5 kg/ha of metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5-(4H)one]. C. var. esculentus was more susceptible than C. var. leptostachyus to postemergence applications of 2,4-D [(2,4-dichlorophenoxy)acetic acid] oil-soluble amine. C. var. esculentus had longer, slightly narrower, and more upright leaves; generally fewer but larger tubers; fewer rhizomes; and a lower frequency of flowers with less seeds per inflorescence than C. var. leptostachyus. Publications on C. esculentus should specify which variety was used.

A weevil [Rhinocyllus conicus (Froelich)] host specific to Carduus, Cirsium, Silybum, and Onopordum, was introduced into Gallatin County, Montana, for biocontrol of musk thistle (Carduus nutans L.). Releases were made in 1969, 1971, 1972, and 1973 on local musk thistle infestations. The insects became established and overwintered successfully. In 1974, R. conicus was found over a 1,280-km2 area of the county in seed heads of musk thistle. Weevil larvae severely infected the primary flowers, but only a few secondary and later flowers were attacked. Seed production from infected primary flowers was greatly reduced, and other factors influenced reduction of seeds from secondary and later flowers.

Several methods were used to overcome herbicide phytotoxicity to upland rice (Oryza sativa L., ‘IR8′). Seed pelleting with activated carbon and band application of activated carbon slurry over the rice seed were ineffective in reducing the toxicity of chloramben (3-amino-2,5-dichlorobenzoic acid) and atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] to upland rice. In contrast, a 2.5-cm layer of activated carbon and vermiculite mixture (1:1) placed over the rice seed was effective in overcoming the toxicity of these herbicides. Deep sowing (3.0 to 4.5 cm) of rice seed was adequate in protecting upland rice from herbicides which are toxic to direct seeded, flooded rice but are not toxic to transplanted rice. The degree of protection from deep sowing, however, was determined by site of uptake, herbicide adsorption by soil, leaching, and inherent toxicity of the herbicides to rice seedlings.

Differences were shown to exist in photosynthetic rate, transpiration rate, and carbon dioxide leaf diffusive resistance between atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] susceptible (S) and resistant (R) plants of redroot pigweed (Amaranthus retroflexus L.). Chlorbromuron [3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea] and diruon [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were the only herbicides tested that controlled both biotypes, but all of the herbicides except norea [3-(hexahydro-4,7-methanoindan-5-yl)-1,1-dimethylurea] controlled the S biotype. Although photosynthetic activity and transpiration were reduced in both biotypes by atrazine at 50 and 70 ppm, the decline was much greater in the S biotype than in the R biotype and persisted a longer time in the S biotype. Leaf CO2 diffusive resistances of the biotypes were increased by atrazine applications. Mesophyll resistance was increased to a greater extent than stomatal resistance suggesting that reduction of photosynthesis is due to a greater effect of atrazine on the mesophyll tissue than on the guard cells.

Pelleting rice (Oryza sativa L., ‘IR8′) seeds with activated carbon was developed as a means of overcoming herbicide phytotoxicity to direct-seeded, flooded rice. Field and greenhouse experiments showed that pregerminated rice seeds coated three times with activated carbon with 50% polyvinyl acetate as an adhesive, were adequately protected from the injurious effects of chloramben (3-amino-2,5-dichlorobenzoic acid), butachlor [N-(butoxymethyl)-2-chloro-2′,6′-diethylacetanilide] and oxadiazon [2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one]. The performance of carbon-coated rice seeds in flooded soil, however, was dependent on time of flooding, method and rate of sowing, rate and time of herbicide application, and quality of activated carbon.

Propham (Isopropyl carbanilate) at 10-5 M concentration does not inhibit DNA synthesis nor does it reduce the number of dividing cells. It does, however, induce a number of abnormal mitotic figures. At higher concentrations (10-3 M) propham inhibits DNA, RNA, and protein synthesis as well as stopping entry of cells into mitosis and causing those which divide to be aberrant. DNA and RNA synthesis are not inhibited for approximately 3 hr, while protein synthesis is reduced within 1 hr. The metabolic inhibitory effect of propham is reversible at least in roots treated for 8 hr. The most likely mode of action of propham is the inhibition of certain mitotic specific proteins, or possibly some kind of protein binding function as has been suggested in the literature.

Johnsongrass [Sorghum halepense (L.) Pers.] was grown for 4, 8, and 12 weeks at 24, 32, and 40 C at 9, 13, and 19 klux illumination. Maximum growth and development after 12 weeks were obtained at 32 C and 19 klux. Maximum leaf growth and development were obtained at 32 C and 9 klux. Primary culm height and weight were greater at 24 C than at 40 C, regardless of the illumination, whereas secondary culm height and weight were greater at 40 C than at 24 C. Secondary culm production increased at 40 C and decreased at 24 C. Root and rhizome development increased with increasing light intensity. Growth of roots and rhizomes was maximum at 32 C and minimum at 40 C.

A ‘tifgreen’ bermudagrass [Cynodon dactylon (L.) Pers.] golf-type green was treated with seven preemergence and one postemergence type herbicides at two rates each for three consecutive years to assess their phytotoxicity. A few herbicides were applied on a second, third, and fourth treatment date during the year with applications made in separate plots. Severe foliage injury occurred the first year with siduron [1-(2-methylcyclohexyl)-3-phenylurea] while moderate injury occurred with bromacil (5-bromo-3-sec-butyl-6-methyluracil) and DCPA (dimethyl tetrachloroterephthalate); and slight injury occurred with benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), bensulide [0,0-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide], and terbutol (2,6-di-tert-butyl-p-tolyl methylcarbamate). No injury was observed with bandane (polychlorodicyclopentadiene isomers) and tri-calcium arsenate. Injury to the bermudagrass in the second year following renewal treatments was severe with siduron and bromacil; moderate with benefin, bandane, DCPA, and terbutol; and slight with bensulide and tri-calcium arsenate. Injury in the third year following repeat applications was severe with siduron, terbutol, bandane, bromacil, benefin, and DCPA; slight to moderate with bensulide, and slight with tri-calcium arsenate. Injury observed the fourth year resulting from residues was moderate with bandane; slight with terbutol, benefin, bensulide, and DCPA; and none with siduron, bromacil, and tri-calcium arsenate.

A great deal of energy in recent months has been expended in worrying about energy. The procurement, allocation, utilization, and conservation of energy sources have been probed countless times and viewed from almost every possible vantage point. The word “energy” now shares the stage with the word “environment.”