Weeds In Cotton Research Articles

A Survey of Weeds in Various Crops in Georgia1

A survey of county extension agents was conducted in 1998 to determine the most troublesome weeds in corn, cotton, forages and pastures, peanut, small grains, soybean, tobacco, and vegetables in Georgia. The most troublesome weed statewide averaged over all crops was sicklepod. It was the most troublesome weed in cotton and soybean and among the four most troublesome weeds in corn, peanut, tobacco, and vegetables. Sicklepod was found in each of the nine climatological districts and in all the crops surveyed. Perennial nutsedge species were the second most troublesome weeds in Georgia. They ranked as the most troublesome weeds in tobacco and vegetables and were among the top five most troublesome weeds in corn, cotton, peanut, and soybean. Pigweed species were ranked third averaged over all the crops surveyed and were the second most troublesome weeds in cotton and vegetables and among the top five most troublesome species in corn, soybean, and tobacco. Morningglory species were listed as troublesome in six of the eight crops surveyed and ranked fourth overall. Similarly, Texas panicum was found in all districts and was the fifth most troublesome weed species. Texas panicum was the most troublesome weed in corn and among the top five most troublesome weeds in peanut, soybean, and tobacco. Florida beggarweed was the most troublesome weed in peanut, the second most troublesome weed in tobacco, and a top-10 weed species in corn, cotton, soybean, and vegetables, resulting in a ranking of sixth overall. Wild radish, large crabgrass, and tropic croton were the seventh through the ninth most troublesome weeds. Wild radish was the most troublesome weed of small grains and the sixth most troublesome weed of vegetables. Large crabgrass was the second most troublesome weed of forages and pastures and was reported in six other crops. Tropic croton was a troublesome weed in seven of the eight crops surveyed and was among the top five most troublesome weeds of cotton and peanut. The 10th most troublesome weed overall was bahiagrass, the most troublesome weed of forages and pastures.Nomenclature: Bahiagrass, Paspalum notatum Fluegge #3 PASNO; Florida beggarweed, Desmodium tortuosum (Sw.) DC. # DEDTO; large crabgrass, Digitaria sanguinalis L. # DIGSA; morningglory species, Ipomoea spp.; nutsedge species, Cyperus spp.; pigweed species, Amaranthus spp.; sicklepod, Senna obtusifolia (L.) Irwin and Barnaby # CASOB; Texas panicum, Panicum texanum Buckl. # PANTE; tropic croton, Croton glandulosus var. septentrionalis Muell.-Arg. # CVNGS; wild radish, Raphanus raphanistrum L. # RAPSN; corn, Zea mays L.; cotton, Gossypium hirsutum L.; peanut, Arachis hypogaea L.; soybean, Glycine max (L.) Merr.; tobacco, Nicotiana tabacum L.Additional index words: Economically important weeds, weed distributions, weed population shifts, weed survey.Abbreviations: C, Central district; EC, East-Central district; NC, North-Central district; NE, Northeastern district; NW, Northwestern district; SC, South-Central district; SE, Southeastern district; SW, Southwestern district; SWSS, Southern Weed Science Society; WC, West-Central district.

Liquid culture production of microsclerotia of Colletotrichum truncatum for use as bioherbicidal propagules

Colletotrichum truncatum NRRL 18434 is a host-specific pathogen of hemp sesbania (Sesbania exaltata), a weed in cotton, soybeans and rice. The bioherbicidal potential of C. truncatum microsclerotia (MS) was assessed based on the feasibility of producing and storing microsclerotia and the efficacy of microsclerotia in controlling hemp sesbania. Microsclerotia were produced in highly aerated liquid cultures grown at 28 °C in a basal salts medium with 80 g glucose and 13·2 g Casamino acids l−1. Hyphal aggregation to form microsclerotial initials began on day 4 with maximum concentrations (6 × 106 MS l−1) being attained by day 6. Melanization started on day 6 and was completed by day 10. After air-drying at 22°, microsclerotia: diatomaceous earth preparations were stored at 4°. After storage for 7 months 90% of the dried C. truncatum MS germinated. Efficacy studies showed that the incorporation of either fresh or 1-month-old microsclerotia into potting soil (156 microsclerotia cm−3 soil) killed more than 95% of hemp sesbania seedlings after emergence. Microsclerotia-infested potting mix incited disease of a similar magnitude in a second crop of hemp sesbania seedlings planted 28 d after the first. These studies demonstrate that C. truncatum microsclerotia may have potential for use as an alternative to conidia for biocontrol since they can be produced in submerged culture, remain viable as a dry formulation and effectively control hemp sesbania seedlings when incorporated into potting medium prior to seeding.

311 GENETIC AND MOLECULAR STUDIES OF DINITROANILINE HERBICIDE-RESISTANT GOOSEGRASS [Eleusine indica (L.) Gaertn.

Goosegrass (Poaceae) is a member of a small but economically important genus, containing approximately 10 species. Goosegrass is a noxious weed in cotton, soybean and turf production, but was effectively controlled by the application of dinitroaniline herbicides (DNH). However, in the early 1970's two DNH tolerant biotypes were discovered. The highly resistant (R-) biotype is now found in many areas in the southeastern US, while the intermediately resistant (I-) biotype is known only from SC. We have investigated the inheritance and expression of resistance, using radicle/root growth bioassays, in F2 progeny derived from F1 hybrids (created by outcrossing this autogamous weed). The hybrid nature of presumptive F1 seedlings was confirmed by isoenzyme analysis. The DNH's effect their herbicidal action by disrupting the assembly of tubulin dimers into microtubules (MTs). The R-biotype has been shown to possess MTs that are hyperstable in the presence of the herbicide. Mutation(s) in a tubulin protein would be manifested in the gene and might be detectable at the nucleic acid level. We found that the alpha-, beta- and gamma-tubulins are encoded by multigene families (∼ 5.7 and 8 members, respectively). DNA polymorphisms were detected, but were not strictly correlated with biotype. Therefore, the differences in herbicide response phenotype cannot be attributed to large deletions and/or insertions in a tubulin gene(s).

Effects of DPX PE350 on Cotton (Gossypium Hirsutum) Growth, Yield, and Fiber Quality

DPX PE350, an experimental herbicide, has shown excellent potential for controlling a wide range of problem broadleaf weeds in cotton. PPI, PRE, and POST applications of DPX PE350 at 0.1 and 0.2 kg ai/ha were evaluated under weedfree conditions in 1991 and 1992 for effects on ‘Paymaster HS26’ cotton growth, yield, and fiber quality. In 1991, DPX PE350 applied PPI, PRE, or POST did not affect cotton population, height, yield, or fiber quality. In 1992, DPX PE350 applied PPI at 0.1 or 0.2 kg/ha or PRE at 0.2 kg/ha injured the cotton and reduced yield and micronaire value.

Growth and Interaction of Bermudagrass (Cynodon dactylon) by Cotton (Gossypium hirsutum)

Several weed-free and bermudagrass competition periods were established and maintained in cotton to evaluate their influence on cotton yields and reproduction of bermudagrass. Cotton sprayed with fluazifop for bermudagrass control 4 or 8 weeks after emergence yielded 93 and 90% as much as weed-free cotton. This compared to losses of 16 and 26% when bermudagrass was permitted to compete with cotton for 12 and 25 weeks, respectively. Cotton handweeded for 8 to 12 weeks yielded the same as weed-free cotton and 9% more than cotton weed free for only 4 weeks. Bermudagrass seed production was prevented and rhizome production was negligible when weed competition did not exceed 8 weeks and weed-free periods exceeded 4 weeks. Bermudagrass produced significant amounts of seeds (45 to 88% of weedy checks) and rhizomes (9 to 31% of weedy checks) in plots weed free for 4 weeks and in plots where control was delayed for 12 weeks. Cotton grades were reduced because the cotton lint was contaminated with grass in plots weed free for only 4 weeks, and in plots where bermudagrass competed for 25 weeks.

A grower survey of weeds and herbicide use in the New South Wales cotton industry

In 1989, 52 cotton growers from the 7 major cotton areas of New South Wales were surveyed regarding their weed-control costs, major weed problems and herbicide use. This paper presents and discusses the major results from this survey. On average, weed control costs the cotton grower $A187/ha annually, the major components being $76/ha for cotton herbicides and $67/ha for hand chipping. The major cotton weeds are Xanthium occidentale, X. spinosum, Cyperus spp., Physalis spp. and Ipomoea lonchophylla. Although these weeds affect a large proportion of the cotton-growing area, their incidence is generally stable or declining under the current management systems. However, Cyperus spp., which presently affect 15% of the cotton area, are escaping the weed management practices and rapidly becoming the major weed problem in many fields. Diplachne fusca is a major weed on irrigation channels and is not controlled by the registered herbicides. Trifluralin, diuron and fluometuron herbicides are used in cotton by over 60% of cotton growers. Glyphosate is used by 59% of growers in fallows prior to cotton, and atrazine, diuron and glyphosate are used on irrigation channels by over 60% of growers. Generally, cotton growers are dissatisfied with t h e high cost of weed control and the ineffectiveness of control of some problem weeds such as Cyperus spp.

Aplicação pre-emergente de misturas de alachlor com diuron e cyanazine para o controle de plantas daninhas em algodão "IAC-17"

Para se conhecer a ação de misturas de alachlor com diuron ou com cyanazine para o controle de monotiledôneas e de dicotiledôneas em cultura de algodão 'IAC-17', foi conduzido um experimento de campo, em 1981/82, em Mogi-Mirim, SP, em solo com textura areno-argilosa, onde alachlor a 2,15 kg, 2,58 kg e 3,01 kg/ha foi aplicado em mistura de tanque com diuron, a 1,00 kg/ha ou com cyanazine a 1,00 kg/ha. Os herbicidas que compuseram as misturas foram empregados isoladamente, naquelas mesmas doses. Constaram do experimento ainda, duas testemunhas mantidas sem mato por meio de capinas e uma testemunha sem capina. Os 14 tratamentos foram distribuídos em blocos ao acaso, com quatro repetições. Foram realizadas observações visuais de infestação de mato aos 14, 31, 45, 75, 82, 94 e 100 dias após a aplicação dos herbicidas. Quando, pelo menos, uma parcela do tratamento atingia 25% de reinfestação, todo o tratamento era capinado e mantido no limpo até a colheita. Foram consideradas também a altura das plantas, sua população e a produção do algodão em caroço. Os resultados obtidos mostram que alachlor a 3,01 kg/ha + diuron a 1,00 kg/ha conseguiram bons resultados de controle das plantas daninhas por período de 100 dias enquanto que alachlor a 2,58 kg/ha + diuron a 1,00 kg/ha, e alachlor a 2,58 kg/ha e a 3,01 kg/ha + cyanazine a 1,00 kg/ha persistiram com sua ação de controle por 94 dias. Os tratamentos com alachlor a 3,01 kg/ha, diuron a 1,00 kg/ha, alachlor a 2,15 kg, 2,58 kg e 3,01 kg/ha em mistura com diuron a 1,00 kg/ha, e ainda alachlor a 3,01 kg/ha + cyanazine a 1,00 kg/ha, apresentaram tendências a reduzir a altura das plantas, segundo resultados de suas análises pelo teste de Tukey a 5%, sendo que a testemunha sem capina apresentou altura significativamente inferior aos demais tratamentos. A população e a produção não foram influenciadas pelos tratamentos com herbicidas, sendo semelhantes à testemunha capinada e superiores à testemunha sem capina.

Field Evaluations of the Herbicidal Effects of Fluridone on Two Soils1

AbstractThe selective control of perennial weeds in cotton (Gossypium hirsutum L.) with soil applied herbicides has been difficult to achieve with currently available chemicals. Also, the long‐term use of the dinitroaniline herbicides in cotton has resulted in a shifting of the weed spectrum to species which are resistant to these herbicides. New herbicides are needed to control these weed problems. The purpose of this study was to evaluate fluridone {l‐methyl‐3‐phenyl‐5‐[3‐trifluoromethyl)phenyl] ‐4(lH)‐pyridinone}, a newly developed soil applied herbicide, for effectiveness in the control of various annual and perennial weeds found in cotton. Fluridone, at several rates, was applied preplant incorporated or preemergence to Miller clay, a fine, mixed thermic vertic Haplustolls, and Lufkin fine sandy loam, a fine montmorillonitic, thermic vertic Albaqualfs, in the springs of 1976, 1977, and 1978 and in the fall of 1977. Weed control evaluations in cotton were made periodically after application. Spring applications of 0.45 kg/ha or higher effectively controlled broadleaf weeds for the growing season. Fluridone at 0.45 and 0.90 kg/ha effectively controlled rhizome johnsongrass [Sorghum halepense (L.) Pers.] 2 of 3 years evaluated. Season‐long control of yellow nutsedge (Cyperus esculentus L.) in a sandy loam soil was observed with preplant incorporated and preemergence rates of 0.90 kg/ha. Phytotoxic effects of fluridone residue were noted in a sandy loam soil one year after treatment but these effects were not as evident in the clay soil. Fluridone applied in the fall provided variable weed control the following spring depending upon soil type, weed density, and weed species present. Incorporation of the fall treatments increased the effectiveness of fluridone on annual grasses in the sandy loam soil. These experiments determined that fluridone could effectively control yellow nutsedge, rhizome johnsongrass, and many annual weeds in cotton at rates above 0.45 kg/ha but the residue of this treatment may limit the use of rotational crops the following year.

Effect of the herbicides trifluralin, dinitramine and fluometuron on rhizoctonia disease in cotton

The effect of three different concentrations (half, equal and twice of the recommended dose) of three herbicides (trifluralin, dinitramine and fluometuron) usually used to control cotton weeds on the development of Rhizoctonia disease in cotton was studied. Trifluralin and dinitramine at the lower concentrations increased pre- and/or post-emergence damping off. Both herbicides at these concentrations increased the saprophytic activity of the fungus, while they did not affect the susceptibility of the cotton plants. Fluometuron at the highest concentration used was highly phytotoxic and increased the post-emergence damping off. This chemical at the recommended dose caused a drastic reduction in the pre- and post-emergence damping off caused byR. solani. Fluometuron at this concentration decreased both the susceptibility of the host plants and the saprophytic activity of the fungus.

Effects of Some Herbicides on Cotton Weeds in the Sudan Gezira

SUMMARYPre-emergence application of the herbicides fluometuron, oxadiazon, oxadiazon + diuron and norflurazon gave satisfactory weed control, particularly during the early stages of cotton growth, but supplementary hand-weeding 6 weeks after sowing was necessary for control of resistant weed species. The number of man-hours required for supplementary weeding was considerably less than on the untreated control (6–52%). The economic implications of supportive hand-weeding is briefly discussed. No herbicides had any adverse effect on cotton except fluometuron at 0.95 kg/ha and norflurazon at 1.59 kg/ha.

Dinitroaniline Herbicides in Soils

AbstractThe behavior and fate of dinitroaniline herbicides in the soil environment is reviewed. This rapidly expanding class of herbicides is used particularly for pre‐emergence control of annual grasses and small‐seeded broadleaf weeds in cotton (Gossvpium hirsutum L.), soybeans [Glycine max (L.) Merr.], and peanuts (Arachis hypogaea L.). All dinitroaniline herbicides in use are 4‐alkyl (or ‐sulfonyl)‐2,6‐dinitro‐N,N‐(mono‐ or disubstituted) anilines, characterized by very low water solubility and basicity. Volatilization from surface applications to moist soil is substantial for trifluralin, benefin, and profluralin, but is low for nitralin and oryzalin. In water and on dry soil, dinitroanilines exposed to sunlight degrade to photoproducts that are often polar and include dealkylated and cyclic intermediates. Such photodecomposition greatly reduces bioaccumulation of dinitroanilines by aquatic organisms.Physico‐chemical behavior of dinitroanilines in soils or sediments is influenced by volatilization and by strong soil adsorption. Nitralin and oryzalin may leach slightly, but dinitroanilines are essentially immobile. Short range diffusion may be important for herbicide efficacy or loss from the soil surface. Both solution and vapor phase transport components affect trifluralin diffusion; the extent and balance of diffusion are strongly affected by soil temperature, moisture, and bulk density. Phytotoxicity apparently cannot be correlated with adsorption strength, but may be related to volatility. Physical loss from soil, unless incorporated, is by sediment runoff and by volatilization.Dinitroaniline herbicides degrade more rapidly in anaerobic, than aerobic soil. Metabolites are numerous and often resemble those produced by the photolytic mechanisms of dealkylation and cyclization. A gradually increasing quantity of residue becomes associated with soil organic matter, as bound residue. For normal use rates, persistence in soils ranges from about 2–3 months, for oryzalin and dinitramine, to 5–6 months for benefin and trifluralin. Persistence increases with decreasing soil temperature and moisture content; seasonal carryover sometimes occurs. Limited evidence suggests that dinitroanilines produce no lasting effect on soil microbial processes.

Response of Cotton and Weeds to Herbicides by Phytobland Oil or Surfactant

In field studies, surfactant and phytobland oil were compared as additives to herbicides and herbicide combinations for postemergence weed control in cotton (Gossypium hirsutumL. ‘Stoneville 7A’). Addition of phytobland oil to MSMA (monosodium methanearsonate) and MSMA + fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea], dinoseb (2-sec-butyl-4,6-dinitrophenol), or norea [3-(hexadydro-4,7-methanoindan-5-yl)-1,1-dimethyl-urea] had no significant effect on weed control when applied as directed treatments to weeds in cotton 7 to 15 cm tall. In cotton 15 to 23 cm tall, addition of phytobland oil to MSMA + linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] and MSMA + linuron + prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] increased weed control when compared to the same treatments with surfactant. MSMA + linuron + phytobland oil decreased cotton yields. Addition of phytobland oil to DSMA (disodium methanearsonate) and DSMA combinations had no effect on weed control when compared to the same treatments with surfactant. There were no differences in several paraffinic phytobland oils or surfactant when used as additives to MSMA + fluometuron for weed control in cotton 7 to 15 cm tall.

Species nova iranica generisHeliotropium

A new species,Heliotropim gossypiiPonert, is described from N.E. Iran. Observations made in the type locality suggest that this new species may be a facultative cotton weed. The following diagnostic characters separateH. gossypii fromH. noeanumBoiss.,H. sultanenseBunge andH. chorassanicumBunge: branching of inflorescence, calyx persistent, up to 3.5 mm long corolla less than 2 mm in diameter, anthers 0.85 mm long, superstigmatic part of style erecto-pilose throughout, nutlets 2 mm long, shortly pilose.

Chemical Control of Weeds in Cotton in the Sudan Gezira

Abstract Early work on chemical weed control in the fallow towards the end of the Second World War is reviewed briefly. Attempts to use contact residual herbicides as pre-emergence applications in the early 1950s are also described. Pre-sowing applications of residual herbicides were found more phytotoxic to cotton than pre-emergence applications. The closer the time of pre-sowing application to cotton sowing, the more effective was suppression of weeds competing with cotton. Mechanical cultivations and particularly disc ploughing and rotovation to a depth of more than 15 cm were found more effective in the control of Cynodon dactylon than pre-sowing herbicide applications. Fluometuron, noruron and prometryne were found very effective as pre-emergence herbicides. Optimum rates of application were found to be only 25-50% of rates recommended for the USA and other countries. Resistant weeds included Cyperus rotundus, Cynodon dactylon, and Rhyncosia memnonia. A large-scale trial with fluometuron, covering 12...

Weed Control in Cotton over a Ten-Year Period by Use of the More Promising Materials and Techniques

JN 1950 an experiment was initiated at Mississippi State University to evaluate the comparative efficiency of certain promising herbicides in controlling weeds in cotton. The use of herbicides for weed control in cotton was beginning to be accepted as an agricultural practice. Results from a long-time experiment involving the use of herbicides for weed control in cotton were needed. The objectives of the study were (1) to control weeds in cotton by means other than the hoe and thereby complete the mechanization of the production of cotton; (2) to test under field conditions certain weed control procedures in cotton and to evaluate weed-control costs and production; and to (3) field evaluate some selected herbicides alone and in combination, applied as pre-emergence and postemergence treatments, for the control of weeds in cotton, with emphasis on economic aspects. The experimental results for 1950-53 have been reported.3

RESPONSE OF THE COTTON PLANT TO MALEIC HYDRAZIDE

SINCE MALEIC HYDRAZIDE (1,2-dihydropyridazine-3,6-dione) has been reported to inhibit the growth of numerous plants while having no apparent effect on others (Crafts, 1949; Currier and Crafts, 1950; Naylor and Davis, 1949; Schoene and Hoffman, 1949; U. S. Rubber Company, 1949), the feasibility of its use as a selective herbicide becomes evident. In that the hormone type weed-killers such as 2,4-dichlorophenoxyacetic acid and its derivatives are extremely injurious to cotton (Ergle and Dunlap, 1949), any new selective herbicides are of particular interest in the Cotton Belt. Crafts (1949) has stated that very promising results have been obtained in preliminary greenhouse experiments using maleic hydrazide for the control of weeds in cotton, particularly the control of numerous grasses. There are also some data in the literature indicating that cotton is not as susceptible to injury by maleic hydrazide as are some plants that may appear as weeds in the cotton field (Currier and Crafts, 1950; U. S. Rubber Company, 1949). This experiment, therefore, was designed to determine the effect of relatively high concentrations of maleic hydrazide on the growth and chemical composition of young cotton plants. The maleic hydrazide used in this experiment was supplied as the diethanolamine salt by the Naugatuck Chemical Division, U. S. Rubber Company, Naugatuck, Connecticut. METHODS.-Cotton, variety Stoneville 2B TPSA, was planted outside on June 18, in 2-gal. glazed jars filled with Lufkin fine sandy loam. The jars were thinned to a uniform stand of one plant per jar after 15 days. When the plants were 35 days old and had produced seven to eight true leaves, segregation was made into three groups. One lot was sprayed with 5 ml. per plant of an aqueous solution containing an equivalent of 2400 p. p. m. of maleic hydrazide, the second with 5 ml. per plant of 4800 p. p. m. of maleic hydrazide and the third remained untreated. These series will be hereafter designated as 2400, 4800, and control, respectively. Each of the maleic hydrazide solutions contained 2 ml. of Grasselli spreader per liter. Care was taken in each of the spray treatments that all parts of the plants were covered and that none of the solution was lost by run-off. At noon of the twenty-sixth day after application of the maleic hydrazide, the sixth and seventh leaves of all the above series were harvested for histological examination and chemical analysis. Histological material was taken from corresponding areas on