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  • Author or Editor: J. P. Gilreath x
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Postemergence and preemergence herbicides were evaluated for crop phytotoxicity and weed control in seepage-irrigated ‘Bristol Fairy’ gypsophila (Gypsophila paniculata L.). DCPA, napropamide, pronamide, and oryzalin were severely injurious to gypsophila. Metolachlor, oxyfluorfen, alachlor, and oxadiazon provided varying degrees of weed control and did not reduce plant vigor or yield. Best weed control was provided by two applications of 4.48 kg·ha-1 oxadiazon. Chemical names used: dimethyl tetrachloroterephthalate (DCPA); 2-(napthoxy)-N, N-diethylpropionamide (napropamide); 3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide (pronamide); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin); 2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide (metolachlor); 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide (alachlor); 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon).

Open Access
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Abstract

Oryzalin and pronamide provided excellent control of cypressvine morningglory (Ipomoea quamoclit L.) when applied 2 or more times at rates of 2.24 kg a.i./ha. When only one application was made, pronamide was superior to oryzalin for morningglory control. Gladiolus (Gladiolus × hortulanus L.) flower spike number, length, number of florets per spike, and number of corms were not affected by either herbicide; however, spike fresh weight and weights of corms and cormels were reduced in plots treated with pronamide. Chemical names used: 4-(diproplyamino)-3, 5-dinitrobenzenesulfonamide (oryzalin); 3,5-dicloro(N-1,1-dimethyl-2-propynyl) benzamide (pronamide).

Open Access
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Abstract

A menu-driven data collection program, “Gather”, was written for a TRS-80 Model 100 (Radio Shack, a division of Tandy Corp., Fort Worth, TX 76102) portable microcomputer (3). This program creates an ASCII (American Standard Code for Information Interchange) (4) data file with each line consisting of the data entry for each observation of a single variable.

Open Access
Author:

Abstract

Data collection and analysis are time-consuming processes. Each time data are transcribed, the probability of error increases. Electronic data collection devices are commercially available; however, they are relatively expensive (more than $2000). In addition, they may require programming by the user, or purchase of program instructions in the form of read-only memory (ROM) chips. Many individuals cannot afford to invest in one of these devices. Several lightweight portable computers are now available for under $1000. Among these is one sold by Radio Shack under the trade name TRS 80 Model 100 (Radio Shack, a division of Tandy Corporation, Fort Worth, TX 76102) which can be purchased with different amounts of memory and comes with a phone modem for telecommunications, an RS-232C interface, a text editor, and resident MBASIC (Microsoft Corporation, 10700 Northrup Way, Bellevue, WA 98004) programming language. MBASIC is a relatively common version of BASIC which is available for a large selection of computers. The Model 100 could thus be used for data collection, text preparation, and programming applications in BASIC. Currently, no menu-driven data collection programs are available for the Model 100 or any other portable computer.

Open Access
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Abstract

Seventeen herbicide treatments applied pre- and posttransplant were evaluated for toxicity to statice (Limonium sinuata L.) in 2 screening experiments. From these, 6 treatments were selected for further evaluation. Two applications (one pre-transplant followed by one posttransplant over the top) of 1.7 kg/ha alachlor, 4.5 kg/ha oxadiazon, 3.4 kg/ha EPTC, 9.0 kg/ha DCPA, 2.2 kg/ha napropamide, and 2.2 kg/ha oryzalin were evaluated for toxicity to field-grown ‘Midnight Blue’ statice. Oxadiazon, EPTC, and DCPA were not injurious to statice and produced yields of marketable panicles that were comparable to those in the untreated weed-free checks. Alachlor, napropamide, and oryzalin stunted plants and resulted in low panicle yields. Chemical names used: 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide (alachlor); 3-[2,4-dichloro-5-(1-methylethoxy)phenyl]-5-(1,1-dimethylethyl)-1,3,4-oxadiazol-2(3H)-one (oxadiazon); S-ethyl dipropylthiocarbamate (EPTC); dimethyl tetrachloroterephthalate (DCPA); 2-(naphthoxy)-N,N-diethylpropionamide (napropamide); 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin).

Open Access

Abstract

Field experiments were conducted to determine the concentration of paraquat residue on black or white polyethylene mulch 0 to 144 hr after application of paraquat at 1.12 kg·ha−1. Effects of eluant from mulch on vigor of 6-week-old tomato (Lycopersicon esculentum Mill. ‘Duke’) plants were also measured. Mulch color had no effect on the rate of photodegradation or on the degree of plant injury. Substantial plant injury was observed from eluants collected from 0 through 96 hr after application of paraquat, with significant injury present until 120 hr after application. After 120 hr, plant vigor was acceptable for their survival, and injury was minimal. Concentration (in the eluant) of paraquat eluted with water from the polyethylene decreased from 275 ppm to <1 ppm from 0 to 144 hr after application, respectively. Significant plant injury was associated with recoverable concentrations >30 ppm of paraquat after 96 hr. Chemical names used: 1,1′-dimethyl-4,4′-bipyridinium salts (paraquat).

Open Access

Abstract

Eight herbicides were evaluated for phytotoxicity to field grown ‘Candidium’ caladiums (Caladium × hortulanum Birdsey) in 1983. The 4 most promising or currently used herbicides were evaluated for weed control and phytotoxicity in 1984. During 1984, 4 applications of 2.24 kg/ha alachlor, 2.24 kg/ha simazine, 1.68 kg/ha oryzalin, and 0.56 kg/ha oxyfluorfen, all in combination with 1 postemergence application of 0.28 kg/ha fluazifop-butyl, were applied to caladiums. Alachlor and oxyfluorfen provided poor weed control and reduced plant vigor, tuber weights, and tuber size in 1984. Simazine provided good weed control, but reduced plant vigor and yield. Oryazlin provided excellent weed control without crop injury. Chemical names used: 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide (alachlor); 6-chloro-N,N’-diethyl-1,3,5-triazine-2,4-diamine (simazine); 4-(dipropylamino)-3,5-dinitrobenzene sulfonamide (oryzalin); 2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene (oxyfluorfen); butyl-2-[4-[[5-(trifluoromethyl)-2-pyridinyl]oxy] phenoxy] propanoate (fluazifop-butyl).

Open Access

Abstract

One pot study and 2 field experiments were conducted to evaluate the use of ethephon, acifluorfen, endothall, dinoseb, glyphosate, oxyfluorfen, and paraquat as harvesting aids (removal of root and shoot tissue) in caladium (Caladium × hortulanum Birdsey) tuber production. Of these 7 compounds, paraquat and oxyfluorfen showed the most potential with 2 applications at 15-day intervals reducing ‘Canadium’ and ‘Freida Hemple’ caladium root weight as much as 51% and shoot weight up to 90%. No residual effects were observed for these herbicide treatments when tubers were subsequently forced in a greenhouse. Chemical names used: (2-chloroethyl)phosphonic acid (ethephon); [2-chloro-4-(trifluoromethyl)phonoxy]-2-nitrobenzoate (acifluorfen) (7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid (endothall); 2-(l-methylpropyl)-4,6-cinitrophenol (dinoseb); N-(phosphonomethyl)glycine (glyphosate); 2-chloro-l-(3-ethoxy-4-nitrophenoxy)-4-(trifluormethyl)benzene (oxyfluorfen); (1,1-dimethyl-4,4′-bipyridinium ion (paraquat).

Open Access

Drift from pesticides can kill or damage nontarget organisms. In these studies, the effects of sublethal rates of the herbicide glyphosate applied prebloom, at bloom, and postbloom of the first flower cluster were evaluated in tomato (Lycopersicon esculentum Mill.). As rates increased from 1 to 100 g·ha-1, foliar injury and flower and fruit number per plant varied with the stage of development at the time of exposure and the time of evaluation after treatment. Plants treated with 60 and 100 g·ha-1 glyphosate prebloom and at bloom had developed moderate to severe foliar injury by 14 days after treatment, but phytotoxicity to plants treated postbloom was only mild to moderate. Blooms abscised from plants treated with 60 and 100 g·ha-1 glyphosate for several weeks after application and fruit set was reduced. Greatest yield losses occurred following treatment prebloom (just prior to bloom) and at bloom. Plants treated before emergence of flower buds, and more mature plants exposed when first cluster fruit were sizing, yielded better than did those treated just prior to bloom and at bloom. Chemical name used: N-(phosphonomethyl)glycine (glyphosate).

Free access

Cucumber (Cucumis sativus L.) growth and yield in response to application of sublethal rates of 2,4-D at several developmental stages were evaluated in field studies during two seasons. In Expt. 1, prebloom applications of 2,4-D amine reduced plant vigor and increased foliar epinasty as rates increased from 0 to 112 g·ha-1. Early and total fruit yields also declined linearly as 2,4-D rates increased; 112 g·ha-1 2,4-D reduced early yield by 25% and total yield by 20%. In Expt. 2, plant vigor declined with increasing rates of 2,4-D applied at all four stages of development from first true leaf to early fruit enlargement; however, response at stage 1 differed with time after application. Epinasty increased with 2,4-D rate when applied at all developmental stages; however the severity of the response varied with time after application for stages 1, 2, and 3, but not for stage 4. Averaged over all developmental stages, vine length, fresh weight, and yield decreased linearly as rates increased. Early and total yields with 112 g·ha-1 were 22% and 19% lower than those of nontreated plants, respectively. Growth inhibition and yield decline, pooled across 2,4-D rates, were greater when exposure occurred at the earlier stages of development. Chemical name used: (2,4-dichlorophenoxy)acetic acid (2,4-D).

Free access