Search Results
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.
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).
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.
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).
Abstract
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).
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).
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).
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).
Glyphosate at sublethal rates was applied prebloom, at-bloom, or postbloom relative to the first flower cluster to tomato (Lycopersicon esculentum Mill.) to determine the effect on foliar concentrations of N, P, K, Ca, and Mg. Glyphosate rates of 0, 1, 6, 10, 60, and 100 g·ha-1 were used to simulate the effects of spray drift. In three studies, plant vigor declined with increased glyphosate rates and younger plants were more sensitive than older plants. Plant height decreased as glyphosate rate increased, but the response differed with time of evaluation and with stage of development. In Expt. 1, N content decreased with increasing rate of glyphosate, regardless of stage of development, but response varied with time of evaluation with prebloom and at-bloom applications. In Expt. 2, prebloom glyphosate applications reduced N content, but applications at-bloom did not. P declined with prebloom and at-bloom glyphosate applications in Expt. 1, but only with prebloom applications in Expt. 2. In Expt. 3, P concentrations generally declined with glyphosate rates ≤10 g·ha-1, but were unchanged or increased with rates of 60 and 100 g·ha-1. Tissue K, Ca, and Mg concentrations were not consistently affected by glyphosate rate and sample times. Although significant changes in foliar concentrations of N, P, K, Ca, and Mg occurred, leaf mineral analysis was not considered to be a reliable method of quantifying sublethal effects of glyphosate in tomato. Mineral deficiency did not occur in response to glyphosate application. Chemical name used: N-(phosphonomethyl)glycine (glyphosate).
Sublethal rates of 2,4-D and dicamba were applied to pepper to evaluate the possible effects of single or multiple exposures to drift from these herbicides. Dicamba induced more foliar injury than did 2,4-D and reduced vigor more as herbicide rates increased. Postbloom applications reduced vigor less than did earlier applications. Epinastic response was affected by stage of development at application and time after treatment. Postbloom applications did not affect yield, but dicamba and 2,4-D applied at earlier stages of development resulted in linear reduction of marketable and total yields as rates increased to 112 g·ha-1. Reductions in plant vigor with increased rates were greater and foliar epinasty was more pronounced with two sequential applications of 2,4-D or dicamba than with single applications. Marketable yields were unaffected by single prebloom applications but declined linearly with two applications. Cull and total yields were not affected by the number of applications. With prebloom and bloom applications of 2,4-D, flower abscission increased and fruit set decreased as rate increased. Chemical names used: 3,6-dichloro-2-methoxybenzoic acid (dicamba); 2,4-dichlorophenoxy)acetic acid (2,4-D).