Palmleaf Morningglory Research Articles

Use of propanil and quinclorac tank mixtures for broadleaf weed control on rice ( Oryza sativa) levees

Broadleaf weed control on rice levees is an emerging problem faced by growers and consultants in Arkansas, USA. Field experiments were conducted at Lonoke and Stuttgart, Arkansas, in 2007 and 2008 to evaluate the effectiveness of various postemergence herbicides applied alone or in tank mixture with propanil or quinclorac for large-sized broadleaf weed control on rice levees. Rice injury was minimal (≤5%) from all herbicides at 2 weeks after treatment (WAT), and no injury was observed at 4 WAT. Sida spinosa (prickly sida) and Amaranthus palmeri (Palmer amaranth) were the most difficult-to-control weeds on levees. Of the herbicides applied alone, 2,4-D generally supplied the highest and most consistent weed control across the six species evaluated. Quinclorac was generally a better tank-mix partner than propanil for control of the weed spectrum evaluated. Propanil at 4.48 kg/ha lowered the activity of several systemic herbicides on S. spinosa, Polygonum pensylvanicum (Pennsylvania smartweed), and Ipomoea wrightii (palmleaf morningglory). Quinclorac plus 2,4-D was the most consistent tank mixture, providing more than 80% control of all weeds at 2 and 4 WAT, except A. palmeri.

Utility of Hyperspectral Reflectance for Differentiating Soybean (Glycine max) and Six Weed Species

Reflectance data were subjected to a variety of analysis methods to determine the utility of hyperspectral reflectance for differentiating soybean, soil, and six weed species commonly found in Mississippi agricultural fields. Weed species evaluated were hemp sesbania, palmleaf morningglory, pitted morningglory, prickly sida, sicklepod, and smallflower morningglory. Hyperspectral reflectance data were collected from mature plant leaves three times in 2002 and two times in 2003. Vegetation indices were calculated and subjected to principal component analysis (PCA) and linear discriminant analysis (LDA). The PCA, using vegetation indices, produced the poorest classification accuracies for the plant species studied, generally less than 50%, whereas LDA resulted in classification accuracies greater than those from PCA. Best spectral band combination (BSBC) provided the greatest classification accuracies, with all better than 80% for all data sets. The BSBC indicated three wavelength bands of interest for species discrimination in the short wavelength infrared portion of the electromagnetic spectrum, which are not commonly used in current vegetation indices for species differentiation. These areas of interest were located from 1,445 to 1,475 nm, 2,030 to 2,090 nm, and 2,115 to 2,135 nm. The top 10 wavelengths determined by BSBC were then added to the vegetation indices and reanalyzed using PCA and LDA. Classification accuracies increased for all species when these wavelengths were added rather than using vegetation indices alone, suggesting greater crop and weed species differentiation can be obtained when using sensors that include these wavelength regions of the short wavelength infrared portion of the electromagnetic spectrum.

Utility of Multispectral Imagery for Soybean and Weed Species Differentiation

An experiment was conducted to determine the utility of multispectral imagery for identifying soybean, bare soil, and six weed species commonly found in Mississippi. Weed species evaluated were hemp sesbania, palmleaf morningglory, pitted morningglory, prickly sida, sicklepod, and smallflower morningglory. Multispectral imagery was analyzed using supervised classification techniques based upon 2-class, 3-class, and 8-class systems. The 2-class system was designed to differentiate bare soil and vegetation. The 3-class system was used to differentiate bare soil, soybean, and weed species. Finally, the 8-class system was designed to differentiate bare soil, soybean, and all weed species independently. Soybean classification accuracies classified as vegetation for the 2-class system were greater than 95%, and bare soil classification accuracies were greater than 90%. In the 3-class system, soybean classification accuracies were 70% or greater. Classification of soybean decreased slightly in the 3-class system when compared to the 2-class system because of the 3-class system separating soybean plots from the weed plots, which was not done in the 2-class system. Weed classification accuracies increased as weed density or weeks after emergence (WAE) increased. The greatest weed classification accuracies were obtained once weed species were allowed to grow for 10 wk. Palmleaf morningglory and pitted morningglory classification accuracies were greater than 90% for 10 WAE using the 3-class system. Palmleaf morningglory and pitted morningglory at the highest densities of 6 plants/m2produced the highest classification accuracies for the 8-class system once allowed to grow for 10 wk. All other weed species generally produced classification accuracies less than 50%, regardless of planting density. Thus, multispectral imagery has the potential for weed detection, especially when being used in a management system when individual weed species differentiation is not essential, as in the 2-class or 3-class system. However, weed detection was not obtained until 8 to 10 WAE, which is unacceptable in production agriculture. Therefore, more refined imagery acquisition with higher spatial and/or spectral resolution and more sophisticated analyses need to be further explored for this technology to be used early-season when it would be most valuable.

Herbicide efficacy, leaf structure, and spray droplet contact angle amongIpomoeaspecies and smallflower morningglory

Abstract Greenhouse and laboratory studies were conducted to evaluate responses of ivyleaf morningglory, pitted morningglory, palmleaf morningglory, and smallflower morningglory to several herbicides in relation to leaf structure, epicuticular wax, and spray droplet behavior. Two- to four-leaf stage plants of each species were highly susceptible to acifluorfen, bentazon, bromoxynil, glufosinate, and glyphosate. However, at the five- to eight-leaf stage, these species were less susceptible, and control was herbicide specific. Spray droplets of these five herbicides had a higher contact angle on ivyleaf morningglory than the other three species with a few exceptions. Stomata and glands were present on both adaxial and abaxial leaf surfaces of all species, and palmleaf morningglory and smallflower morningglory had more of these than did the other two species. Trichomes were present on all species except palmleaf morningglory. Epicuticular wax mass was highest in ivyleaf morningglory (57 μg cm−2) and lowest i...

Differential response of palmleaf morningglory (Ipomoea wrightii) and pitted morningglory (Ipomoea lacunosa) to flooding

Palmleaf morningglory (IPOWR) and pitted morningglory (IPOLA) were compared in field and greenhouse tests under simulated rice field conditions to quantify flood tolerance characteristics of the two species. IPOWR survived a 13-cm flood in the field if the flood was applied 12 days after planting (DAP) or later. In contrast, IPOLA did not survive floods applied before 19 DAP. Only IPOWR survived a 5-cm flood applied 5 DAP in the field. In the greenhouse, both species were unable to emerge from under 1 cm of soil when flooded greater than 1 cm deep. Although both species emerged from water-saturated soil, IPOWR emerged earlier and produced more dry weight than did IPOLA. Emergence from the water surface of 2-cm-tall IPOWR was better than that of IPOLA when submerged in water up to 7 cm deep, and total dry weight (as a percent of a nonflooded control) was two to four times greater for IPOWR. Even a 5-cm flood reduced leaf area, height, dry weight, and photosynthesis of IPOLA more than that of IPOWR. At 20 C and low oxygen (1%), germination percentage of IPOWR was about four times higher than IPOLA. Germination, growth, and certain physiological processes of IPOWR are more tolerant than those of IPOLA to moderately deep floods (and low soil oxygen levels). Thus, IPOWR is potentially a greater weed problem than IPOLA in rice fields. The fact that neither species was capable of emerging from soil under even shallow flood depths helps explain why morningglories are prevalent only in shallow or water-saturated areas on rice field levees.

Influence of Application Variables on Efficacy of Glyphosate

Field experiments were conducted from 1993 to 1995 to compare weed control by the isopropylamine salt of glyphosate at 0.21, 0.42, 0.63, and 0.84 kg ae/ha applied at three stages of weed growth. Weed control by glyphosate applied at these rates alone or with ammonium sulfate at 2.8 kg/ha was also evaluated. In other experiments, potential interactions between glyphosate and acifluorfen, chlorimuron, and 2,4-DB were evaluated. Velvetleaf, prickly sida, sicklepod, pitted morningglory, entireleaf morningglory, palmleaf morningglory, and hemp sesbania were controlled more easily when weeds had one to three leaves compared with control when weeds had four or more leaves. Glyphosate controlled redroot pigweed, velvetleaf, prickly sida, sicklepod, and barnyardgrass more effectively than pitted morningglory, entireleaf morningglory, palmleaf morningglory, or hemp sesbania. Increasing the rate of glyphosate increased control, especially when glyphosate was applied to larger weeds. Greater variation in control was noted for pitted morningglory, palmleaf morningglory, prickly sida, and velvetleaf than for redroot pigweed, sicklepod, entireleaf morningglory, or hemp sesbania. Ammonium sulfate increased prickly sida and entireleaf morningglory control but did not influence sicklepod, hemp sesbania, or barnyardgrass control. Acifluorfen applied 3 d before glyphosate or in a mixture with glyphosate reduced barnyardgrass control compared with glyphosate applied alone. Chlorimuron did not reduce efficacy. Mixtures of glyphosate and 2,4-DB controlled sicklepod, entireleaf morningglory, and barnyardgrass similar to glyphosate alone.

Interaction of Glyphosate and 2,4-DB for the Control of Selected Morningglory (Ipomoeaspp.) Species

Interaction of glyphosate and 2,4-DB was evaluated in greenhouse and laboratory studies with respect to control of four species of annual morningglory. The greenhouse study included smallflower, pitted, palmleaf, and ivyleaf morningglory at three growth stages: seedling, juvenile, and vining. A series of glyphosate rates (0.28 to 1.26 kg ae/ha) and 2,4-DB (0.022 and 0.045 kg ae/ha) were applied alone, and in all possible two-way tank mixtures. Morningglory response to both glyphosate and 2,4-DB applied alone was species- and growth stage-dependent. All combinations were either additive or synergistic for control of pitted, palmleaf, and ivyleaf morningglory. Response of smallflower morningglory ranged from antagonistic to synergistic. Absorption and translocation of14C-2,4-DB was independent of the addition of glyphosate in all four species. By contrast, absorption of foliar-applied14C-glyphosate and translocation of14C from treated leaves to other plant parts were enhanced by the addition of 2,4-DB in all species except palmleaf morningglory. In palmleaf morningglory,14C-glyphosate absorption and translocation were independent of the addition of 2,4-DB. Absorption and translocation data were in agreement with greenhouse studies.

Interaction between timings and doses of quindorac in rice

SummaryQuinclorac (3,7‐dichloro‐8‐quinolinecarboxylic acid) is a new herbicide in United States rice production. Field studies were conducted in 1990 and 1991 in Mississippi to determine the influence of application timings and rates on weed control efficacy and rice yield. Control of Echinochloa crus‐galli (L.) Beauv. (barnyard‐grass), Sesbania exaltata (Raf.) Rydb. ex A. W. Hill (hemp sesbania) and Ipomoea wrightii Gray (palmleaf morning glory) were greatest with early post‐emergence application. Efficacy of pre‐emergence application depends strongly on soil moisture, with significantly reduced weed control resulting when applied to dry soil. Weed control with pre‐emergence application to moist soil was comparable with early post‐emergence application at higher rates of quinclorac. Pre‐plant and incorporated quinclorac controlled weeds effectively. Control of E. crus‐galli, S. exaltata and I. wrightii ranged from 73 to 99%, 75 to 99%, and 92 to 99% at 28 days after treatment, respectively. Rice yield generally reflected weed control. No rice injury was observed for any treatment. Results indicate that early post‐emergence application of quinclorac is the best time for using reduced rates and field conditions at application should be considered with these rates pre‐emergence.

Influence of Application Rate and Timing on Efficacy of DPX-PE350 Applied Postemergence

Broadleaf weed control with DPX-PE350 at 56, 84, 110, 140, and 170 g ae ha−1applied postemergence was evaluated. DPX-PE350 was less effective and higher rates were required when applied to three- to six-leaf weeds compared to one- to two-leaf weeds. Listed in order of increasing susceptibility are sicklepod, tall morningglory, pitted morningglory = palmleaf morningglory, and entireleaf morningglory = hemp sesbania = velvetleaf.

Seed ergot alkaloid contents of Ipomoea hederifolia, I. quamoclit, I. coccinea and I. wrightii

AbstractErgot alkaloides were extracted from seed of native, wild‐type morning glories (i.e. Texas red morning glory (Ipomoea hederifoliaL.), cypress vine morning glory (I. quamoclit L.), red morning glory (I. coccinea L.) and palmleaf morning glory (I. wrightii Gray) and quantified by spectrophotometry as ergonovine maleate equivalents. A horticultural variety (I. tricolor Cav. cv. Heavenly Blue) was utilized for comparison and contained 0.052% total alkaloids in the seed. Total ergot alkaloids in these four native, wild‐type morning glories ranged from 0.003 to 0.005% (i.e. 5.97 to 9.77% of the alkaloids found in Heavenly Blue seed) and were not present in sufficient quantity to induce any psychotomimetic hazard. Major alkaloids found in these wild‐type morning glory species were separated and identified by two‐dimensional thin‐layer chromatography and co‐chromatography with authenticated standards. Alkaloids identified included chanoclavine, elymoclavine, penniclavine, ergonovinine, agroclavine, ergonovine, ergosine and ergosinine. Alkaloids varied between morning glory species.

Variations in Seed Production and the Response to Pests of Morningglory (Ipomoea) Species and Smallflower Morningglory (Jacquemontia tamnifolia)

Flowering dates, seed production, and disease and insect susceptibility of sevenIpomoeaspp. and smallflower morningglory [Jacquemontia tamnifolia(L.) Griseb.] were determined under field conditions in 1973 and 1974. Seed produced per plant were as follows: ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.], 6000; entireleaf morningglory [I. hederacea(L.) Jacq. var.integriusculaGray], 5000; pitted morningglory [I. lacunosaL.], 10000; wild tall morningglory [I. purpurea(L.) Roth.], 26000; commercial tall morningglory [I. purpurea(L.) Roth ‘Crimson Rambler′], 15 000; cypressvine morningglory (I. quamoclitL.), 9000; cotton morningglory [I. trichocarpaEll. var.torreyana(Gray) Shinners], 9000; palmleaf morningglory (I. wrightiiGray), 7000; and smallflower morningglory, 11000. Seed weights were about 29, 26, 22, 21, 19, 13, 19, 37, and 5 mg/seed, respectively. Pitted morningglory appeared to have a qualitative short day-length requirement for flower initiation and the other species appeared less day-length sensitive. Ivyleaf morningglory and entireleaf morningglory were highly susceptible to orange rust [Coleosporium ipomoeae(Schw.) Burrill] and white rust [Albugo ipomoea panduratae(Schw.) Swingle], but the otherIpomoeaspecies were only slightly susceptible and smallflower morningglory was resistant. Cotton bollworms (Heliothis zeaBoddie) and cabbage loopers (Trichoplusia niHubner) fed preferentially on ivyleaf morningglory and entireleaf morningglory.