Polygonum Pensylvanicum Research Articles

Glufosinate Efficacy on Annual Weeds Is Influenced by Rate and Growth Stage

Field experiments were conducted in 1993, 1994, and 1995 to determine the effects of glufosinate rate and application timing on giant foxtail, common lambsquarters, common cocklebur, and Pennsylvania smartweed control in absence of a crop. Glufosinate at 140 g ai/ha controlled less than 80% of the weed species evaluated. When glufosinate rate was increased to 420 g/ha and applied to 10-cm giant foxtail, control was greater than 80% all 3 yr of the study. Applications made to 10-cm plants resulted in 80% or greater control for common cocklebur all 3 yr and Pennsylvania smartweed 2 of the 3 yr with 420 and 560 g/ha, respectively. Common lambsquarters was the most tolerant species evaluated and was not consistently controlled acceptably (> 80%), even with glufosinate at rates of 560 g/ha. Control with glufosinate at 420 or 560 g/ha was most effective when applied at the 10-cm weed height compared either to the 5- or 15-cm weed height.

Broadleaf Weed Control in Hard Red Spring Wheat (Triticum aestivum) with F8426

Studies were conducted at Rosemount and Crookston, MN, in 1994 and 1995 to determine weed control efficacy and crop injury of F8426 (proposed common name carfentrazone-ethyl) in hard red spring wheat. F8426 alone and with 2,4-D or dicamba generally controlled common lambsquarters, kochia, and velvetleaf 90% or more at 0.026 and 0.035 kg/ha. F8426 alone and with 2,4-D or dicamba controlled Pennsylvania smartweed, wild buckwheat, and wild mustard 39 to 100% and was less consistent than control of the aforementioned species. Weed control varied little among the F8426 rates. Weed control was inconsistent between location, year, and species when F8426 was combined with crop oil concentrate, urea–ammonium nitrate solution, and nonionic surfactant. Control was more consistent when 0.28 kg/ha 2,4-D or 0.07 kg/ha dicamba was tank mixed with either F8426 rate. The best control with an F8426 treatment was similar to control from MCPA tank mixed with thifensulfuron plus tribenuron, bromoxynil, or dicamba. Weed control 30 and 45 days after treatment (DAT) was less for F8426-containing treatments than standard treatments, which likely was related to reduced crop competition after severe crop injury. Increasing F8426 rate from 0.026 to 0.035 kg/ha did not greatly increase wheat injury, whereas adding 0.28 kg/ha 2,4-D to either F8426 rate greatly increased crop injury. Wheat yield was reduced up to 63% by F8426 and 2,4-D combinations.

Effects of Tillage and Light Environment on Emergence of 13 Annual Weeds

Seeds of many plant species require a brief exposure to light to induce germination. Modifying the light environment during soil tillage may alter weed emergence in agricultural systems. The objective of this research was to evaluate the effect of secondary tillage conducted during daylight and at night on the emergence of 13 summer annual weed species under the same soil and environmental conditions. Annual grass and large-seeded broadleaf species showed little response to light environment during tillage. However, emergence was often less when no tillage was conducted than with any tillage by light environment combination. Emergence of small-seeded broadleaf species often was lower when tillage was conducted during darkness than with tillage during the light. Reductions varied by experiment and species and ranged from 70% for common lambsquarters to less than 30% for Pennsylvania smartweed. Large variations in response also occurred within species.

Evaluation of True Metabolizable Energy for Waterfowl

True metabolizable energy (TME) bioassays of waterfowl foods typically use birds not provided with grit, and foods are fed in an intact, natural state. To determine if the use of grit-free birds provides accurate estimates of the TME of intact foods, we fed corn (Zea mays), milo (Sorghum vulgare), wild millet (Echinochloa crusgalli), and largeseed smartweed (Polygonum pensylvanicum) to giant Canada geese (Branta canadensis maxima) supplied with grit ad libitum and denied grit for the duration of TME bioassays. In a second experiment, the 4 test foods were ground and fed to grit-free geese to determine if this procedure provides results that approximate the energy extracted from intact foods by geese having access to grit. For TME bioassays of intact foods, we detected no difference in the ability of the 2 groups of geese to digest either corn (P = 0.064) or millet (P = 0.606); however, grit-free birds digested smartweed (P < 0.001) and milo (P < 0.034) more efficiently than geese supplied with grit. We attribute the results for smartweed and milo to the retention of these food items in the gizzards of grit-free geese, because birds frequently substitute hard seeds for grit when mineral particles are unavailable. In the second experiment, grit-free geese digested smartweed (P < 0.001) and milo (P = 0.037) more efficiently than geese supplied with grit and fed these 2 foods intact. Grit-free geese also digested ground millet more efficiently than geese provided with grit and fed millet intact, however, this difference was only marginally significant (P = 0.056). Corn was digested more efficiently when fed intact to geese supplied with grit, (P = 0.027), although the difference in digestive efficiency was less than 5% between these 2 treatments. Feeding birds ground food appears to overestimate TME for some foods because grinding may eliminate the fraction of food that normally passes through the digestive tract intact. We recommend researchers provide experimental birds with grit and feed foods intact for accurate estimates of TME.

Genotypic variation in Polygonum pensylvanicum: nutrient effects on plant growth and aphid infestation

Variation in the performance of 20 genotypes of Polygonum pensylvanicum under two nutrient treatments was studied in a garden experiment. Nutrient fertilization enhanced vegetative biomass and fruit biomass production, but did not result in significant genotype–environment interactions, suggesting that nutrient variation of the range used in the experiment has little potential as a microevolutionary factor in this species. Leaf nitrogen concentration was not affected by a nutrient pulse. The degree of transient aphid infestation that occurred during the experiment had a weak positive correlation with final reproductive biomass of plants. Mean density of aphids per leaf was negatively correlated with percent leaf nitrogen and was not affected by genotypic identity of host plants. Key words: Polygonum pensylvanicum, genotype–environment interaction, phenotypic plasticity, aphids, nutrients.

Preemergence Broadleaf Weed Control and Crop Tolerance in Imidazolinone-Resistant and -Susceptible Corn (Zea mays)

Field studies were conducted in 1994 and 1995 at Dekalb and Urbana, IL, to evaluate preemergence broadleaf weed control and crop tolerance in imidazolinone resistant (IR) and susceptible (non-IR) corn using atrazine, imazethapyr, AC 263,222, CGA-152005, MON 12000 with and without MON 13900 (a safener), and flumetsulam + clopyralid. When sufficient rainfall occurred within 28 d of application to insure herbicide absorption, the IR corn variety was more tolerant than the susceptible variety to imazethapyr, AC 263,222, CGA-152005 at 40 and 80 g/ha, and MON 12000 with and without MON 13900. Overall crop tolerance of IR corn was equal to that of corn treated with atrazine for all herbicide treatments except CGA-152005, which injured IR corn. Control of velvetleaf, common lambsquarters, Pennsylvania smartweed, tall morningglory, and jimsonweed for all herbicide treatments was equal or superior to that of atrazine at 1.7 kg/ha. However, control of common cocklebur was significantly greater with atrazine compared to imazethapyr and the low rate of CGA-152005.

Timing and Measurement of Weed Seed Shed in Corn (Zea mays)

In west central Minnesota the extent and duration of weed seed shed was measured for two years in corn that received cultivation but no herbicides. Percentage of seed production represented by viable (filled) seeds was about 79% for green foxtail, 68% for wild mustard, 49% for Pennsylvania smartweed, 48% for common lambsquarters, and 35% for redroot pigweed. Percentage viable seeds varied from 11% in 1993 to 59% in 1994 for redroot pigweed, but was more stable for other species. Seed shed commenced in late August in a cool year (1993) and early August in a warm year (1994). Average growing degree days (base 10 C) from corn planting until 25% seed shed was 983 for common lambsquarters, 984 for wild mustard, 1004 for Pennsylvania smartweed, and 1034 for both green foxtail and redroot pigweed. Brief weather events, such as wind storms, dispersed large percentages of total seed production within a single day. More than one-fifth of all viable seeds of green foxtail, redroot pigweed, and common lambsquarters were retained by the seedheads and dispersed by combines at harvest. In contrast, seeds of early-maturing species, such as wild mustard, were completely dispersed before corn harvest in the warmer year, but one-third of seeds were retained by seedheads at harvest in the cooler year. Measurement of seed shed was compared using five seed trap designs. The preferred design consisted of a 10-cm-diam plastic cup, whose bottom was replaced by a brass screen, and the entire unit attached to a small wooden stake for support. This design provided, on average, the highest estimates of seed production, least among-replication variability, highest correlation with weed population density and aboveground dry-weight, lowest assembly cost, and greatest ease for sample access and seed processing.

Seed Viability and Dormancy of 17 Weed Species after 9.7 Years of Burial in Alaska

A 50-year study at Fairbanks, AK, was started in 1984 to determine soil seed longevity of 17 weed species. Seed were buried in mesh bags 2 and 15 cm deep and were exhumed 0.7, 1.7, 2.7, 3.7, 4.7, 6.7, and 9.7 yr later. Viability was determined by germination and tetrazolium tests. All common hempnettle and quackgrass seed were dead after 2.7 and 3.7 yr, respectively. Less than 1% of wild oats and foxtail barley seed were viable after 3.7 yr, but &gt; 6.7 yr were required for loss of all viability. By 9.7 yr, &lt; 1% seed viability remained for: bluejoint reedgrass, corn spurry, pineappleweed, prostrate knotweed, and wild buckwheat From 2 to 5% of seed from common chickweed, common lambsquarters, flixweed, Pennsylvania smartweed, rough cinquefoil, marsh yellow-cress and shepherd's-purse were viable, while 62% of American dragonhead seed was still alive. Seed longevity in agricultural fields is not greater under subarctic conditions than under warmer conditions.

Negative‐ion fast atom bombardment and tandem mass spectrometric investigation of phenylpropanoid glycosides isolated from Polygonum pensylvanicum L.

AbstractInvestigation of the novel phenylpropanoid sucrose esters vanicoside A, vanicoside B and hydropiperoside, derived from Polygonum pensylvanicum L., by negative‐ion fast atom bombardment and tandem mass spectrometry has elucidated collision‐induced decomposition pathways and identified common trends of fragmentation for this class of compounds. The constant neutral loss spectrum of the crude extract of P. pensylvanicum, monitoring the loss of a p‐coumaryl ketene fragment, can be used to identify homologues in the mixture for further investigation. This information can be used to characterize mixtures of this type of compound without the need for derivatization and prior to chromatographic separation, providing a method for guiding the isolation of similar compounds from crude extracts of other plants in the Polygonaceae family.

Reduced Preplant‐Incorporated Imazaquin Rates for Broadleaf Weed Control in Soybean

AbstractPublic pressure and economic distress have together provided a strong incentive for reduced chemical use in U.S. agriculture. This field study was designed to determine if preplant‐incorporated imazaquin {2‐[4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1H‐imidazol‐2‐yl]‐3‐quinoline‐carboxylic acid} rates could be reduced from the labeled rates when applied with alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide] without incurring yield penalties due to broadleaf weed infestations. Imazaquin was applied at 0, 47, 93, and 141 g ha−1 in earlyplanted soybean [Glycine max (L.) Merr.] studies in Fayette County in 1989, 1990, and 1991 and in Simpson County (1989), Hardin County (1990), and Hopkins County (1991), Kentucky. Preplant‐incorporated alachlor was followed by postemergence fluazifop‐P‐butyl {butyl(R)‐2‐[4[[5‐(triliuoromethyl)‐2‐pyridinyl]oxy]phenoxy]propanoate} (as needed) to minimize grass competition. Perennial broadleaf weeds were controlled with hand‐wicked glyphosate [isopropylamine salt of N‐(phosphonomethyl) glycine]. Acceptable broadleaf control was obtained at sub‐label imazaquin rates, except for Fayette 1991, where ivyleaf morning‐glory [Ipomoea hederacea (L.) Jacq.] and velvetleaf (Abutilon theophrasti Medic.) were planted. Two studies (Simpson 1989 and Hopkins 1991) showed minimal broadleaf weed pressure at any imazaquin rate; this may have been a result of the early planting dates used. The common lambsquarters (Chenopodium album L.) and Pennsylvania smartweed (Polygonum pennsylvanicum L.), which dominated in Fayette 1989 and 1990, were successfully controlled with 47 g ha−1 imazaquin. While alachlor provides some control for these two species, their competition with soybean was severe without the addition of imazaquin. Producers who can accumulate detailed knowledge of the broadleaf weed species present in their soybean fields could potentially use such information to select herbicides likely to control their broadleaves at sub‐label rates.

Decomposition and litter production in a northern bald cypress swamp

. Primary production as measured by annual mean litter fall in the Lower Cache near Perks, Illinois, was the lowest recorded for cypress swamps (2345.5 kg/ha/yr). This swamp is continuously flooded with a low input of phosphorus (< 0.24 mg 1). Rates of leaf litter decomposition were higher in the Lower Cache for Taxodium distichum than in swamps to the south of the region. The winter rates of leaf litter decomposition in the Lower Cache were slower than summer rates for Cephalanthus occidentalis, Echinochloa muricata, Polygonum pensylvanicum, Jussisaea repens, Taxodium distichum, and Eleocharis obtusa, but not for Typha latifolia. Because the 99% turnover rates for these species (0.69–5.10 years) often exceeds one year, undecomposed litter can be expected to accumulate or be exported from the system. Most leaves are shed in the autumn (October through December; 83.6%).

Vanicosides A and B, protein kinase C inhibitors from Polygonum pensylvanicum.

Two new protein kinase C inhibitory glycosides, vanicosides A [1] and B [2] were isolated from Polygonum pensylvanicum (Polygonaceae) by chromatographic techniques guided by bioassays for PKC inhibition. The structures of these glycosides were established primarily by analysis of 1H- and homonuclear correlated nmr and high-resolution fab mass spectra of 1 and 2 and the derived octaacetate, 3. Both glycosides were found to have p-coumaryl esters at the 1, 3, and 6 carbons of sucrose and a feruloyl ester at the 6' carbon. Vanicoside A [1] also had an acetate group at the 2' carbon.

How Neighbor Canopy Architecture Affects Target Plant Performance

Plant competition is a process that occurs through the negative effects that individual plants have on resource availability to neighboring individuals. Therefore competition experiments need to examine how different species change resource availability to their neighbors, and how different species respond to these changes–allocationally, architecturally, and physiologically–through time. In a greenhouse study we used a model system of annuals to examine how canopies of species having differing morphologies differed in their architectures and light—interception abilities, and how different species performed when grown in these canopies. Abutilon theophrasti, Datura stramonium, and Polygonum pensylvanicum were grown as "targets," surrounded by neighbors of a single species. Neighbors could be any one of the target species or Setaria faberii. Plants were grown in pots, with one target plant and four neighbor plants. Detailed measurements of neighbor canopy structure and target plant canopy architecture were made at five harvests. Species with different morphologies showed large differences in canopy structure, particularly when grass and forb specie were compared. Setaria, a grass, had a more open canopy than the other species (all forbs), and was a consistently weak competitor. Overall, however, the relative effects of different neighbors on target biomass varied with target species. Target biomass was poorly correlated with neighbor biomass and leaf area, but was highly correlated with a measure of target light—interception ability that took into account both target leaf deployment and neighbor light interception. Despite clear differences among neighbor species in canopy structure and effect on light penetration, the results suggest no broad generalizations about the effects of different species as neighbors. Knowledge of morphological, physiological, and life history characteristics of both the target and neighbor species may be necessary to explain the results of their competition.

The Genetic Component in Plant Size Hierarchies: Norms of Reaction to Density in a Polygonum Species

An important motivation for the study of variability in size and reproductive output in plant populations is its potential relation to natural selection. However, very few data are available to assess the genetic component of fitness—related traits in competing plant populations, or the differential performance of plant genotypes at different densities. To address these issues we conducted an experiment using 25 genotypes of a colonizing herbaceous annual, Polygonum pensylvanicum. These genotypes were randomly sampled from a natural population and cloned by axillary meristem enhancement. Cloned plants were grown in a glasshouse at three densities spanning the range encountered in the natural population (from individually grown to 850 individuals/m2). The growth and fate of a total of 1400 individuals were followed over the course of a 10—wk growing period. Variability in size and reproductive output (as measured by the coefficient of variation of vegetative and reproductive dry mass) increased with density. Early plant size measures were positively correlated with subsequent relative growth rates in dense populations, but not among individually grown plants. These observations indicate the likely importance of asymmetric or "one—sided" competition in the dense populations. The proportion of variance in final size and reproduction explained by genotype was generally higher for individually grown plants than for plants grown under crowded conditions. We suggest that this may result from asymmetric competitive interactions working to amplify early size differences resulting primarily from environmental and developmental "noise." The same genotypes were not superior across all densities. Qualitative ("cross—over") interactions for fitness—related characters were observed in comparing genotype performance between the individually grown vs. the low and high density treatments. Genotypes with an early size advantage were predictably favored in dense populations, but the genetic correlation between early and final performance was weaker among individually grown plants. In sum, density increased relative variation in fitness correlates such as reproductive biomass, but decreased the heritability of these traits. The response of selection is the product of these two opposing forces. Applying our results to some elementary quantitative genetic models suggests that the potential for natural selection would increase with population density, while the potential for genetic drift would decrease. Such patterns may be of particular evolutionary importance in colonizing annuals, whose life histories imply an alternate exposure of genotypes to high and low densities.

Allozyme variation in the Polygonum lapathifolium complex

The Polygonum lapathifolium complex consists of populations that are widely distributed in the Northern Hemisphere and that have been classified at different taxonomic levels. Allozyme data were used to test the current North American taxonomic status of members of the complex (including P. lapathifolium var. lapathifolium, P. lapathifolium var. salicifolium, and P. scabrum) and to verify diploidy in the P. lapathifolium complex and polyploid origins of the morphologically similar P. persicaria and P. pensylvanicum. Of the 15 enzyme systems surveyed in 50 populations of the complex, only 3 of the 23 loci (Acon, Lap, and Skdh) were polymorphic in the North American populations and a total of 6 loci in European populations. Fifteen multilocus genotypes were evident in the complex. Four genotypes (all with Lap-10.67 were exclusive to North American populations of P. lapathifolium, providing support for a North American element of the complex. Nine genotypes (all with Lap-10.63) were found in North American and European populations of P. scabrum, all European populations of the P. lapathifolium complex, and three populations of North American P. lapathifolium var. lapathifolium. Lap-10.67 was also found in the native tetraploid P. pensylvanicum, whereas Lap-10.63 was found in the introduced tetraploid P. persicaria. Genetic distances among populations did not support the current taxonomic divisions within the complex, nor did it support separate species status of P. scabrum. Allozyme data provided support for the allotetraploid origins of P. pensylvanicum and P. persicaria, with members of the P. lapathifolium complex as one of the parents of each. Key words: Polygonum lapathifolium, Polygonum scabrum, Polygonum pensylvanicum, Polygonum persicaria, allozymes.

Use of a Grower Survey for Estimating Weed Problems

A random mail survey of Ohio growers was conducted to determine the geographic distribution of weeds across Ohio and the influence of production practices on the severity of agronomic weed problems. Statewide, the ten most severe weed problems, in descending order, were Canada thistle &gt; foxtail spp. &gt; velvetleaf = common ragweed &gt; common cocklebur &gt; giant ragweed = annual morningglory spp. &gt; quackgrass = common lambsquarters = Pennsylvania smartweed. Distribution of most weeds varied geographically. Infestations of common and honeyvine milkweeds, hemp dogbane, and tree seedlings increased as tillage was reduced. Infestations of common cocklebur and common ragweed decreased as tillage was reduced. As crop rotation became more diverse, infestations of velvetleaf, common cocklebur, giant ragweed, Pennsylvania smartweed, and jimsonweed decreased. Where rotations included forage or hay crops, infestations of large crabgrass, common chickweed, wild carrot, and common dandelion increased.

The orthography of Mammillaria esperanzensis Bödeker (Cactaceae)

Brummitt & Taylor (1990) stated that they were unable to see how or why the epithet of Mammillaria esperanzaensis should be corrected (Heath 1989) to esperanzensis. They remarked that may be common practice to elide the final 'a' when forming such epithets, whereas elision is not involved. Steam (1983: 286) advised that first and each non-final component of a Latin compound consists of the stem of a word; in the case of esperanzensis the stem is esperanz-, to which is added the Latin adjectival suffix -ensis (indicates country or place of growth or origin or else habitat Steam, 1983: 308). Recommendation 73D gives three examples of this process: Ostrya virginiana (from Virginia), Eryngium amorginum (from Amorgos), Polygonum pensylvanicum (from Pennsylvania). Amorgos is Greek, but in forming a Latin compound the -os case ending (the equivalent of the -us nominative singular case ending of many Latin Second or Fourth Declension nouns) is deleted before adding the Latin adjectival suffix -inum (indicates possession or resemblance Stearn, 1983: 309). The toponym Esperanza is a Spanish feminine noun meaning hope, and has an ending that is the exact equivalent of the case ending borne by Latin nouns of the First Declension, which end in -a in the nominative singular (except for some late borrowings from Greek, with -ri transliterated as -e). Steam (1983: 206) stated Names of Latin form, whatever their origin, are treated grammatically as Latin words. Thus Africa, Alsatia, Jena, Japonia and others ending in -a are declined as feminine nouns in the First Declension. Steam gave the adjectival forms of those names as africanus, alsaticus, jenensis, and japonicus. Other well established examples are canadensis, cubensis andjamaicensis. Hence, as Esperanza ends in -a it is treated as a First Declension noun, and failure to delete the -a before adding a suffix is a correctable orthographic error. Even if, as Brummitt and Taylor argue, Article 73.1 does not itself require, but merely permits, the correction of orthographic errors, the correction of erroneously compounded adjectival epithets is nevertheless obligatory under Article 73.8, which is cited by Article 73.1 as an imposed standardization.

Mutant Weeds of Iowa:S-Triazine Resistant Pennsylvania Smartweed (Polygonum pensylvanicum)

Suspected triazine resistant Pennsylvania smartweed plants were discovered near Holy Cross, Dubuque County, IA. Subsequent variable chlorophyllafluorescence assays confirmed these selections to be triazine resistant. This is the first reported evidence ofs-triazine resistance in Pennsylvania smartweed.

Allelopathic effect of common weeds on soybean growth and soybean-Bradyrhizobium symbiosis

Water extracts of shoot of common lambsquarters (Chenopodium album), yellow nutsedge (Cyperus esculentus) and sunflower (Helianthus annuus) at 1% level significantly reduced soybean seed germination. Soybean seedlings inoculated with broth culture of nodule bacterium were grown for 25 days in N-free nutrient solution amended with cold water extracts of weed residues at 1 and 2% levels. At both levels extracts from residues of all weeds except that of lambsquarters enhanced growth of soybean. Nodulation was generally stimulated by the extracts of five weeds at 1% level except that of lambsquarters. Extracts from lambsquarters at 2% level completely suppressed and at 1% level reduced nodulation by 60%. Extracts from green foxtail (Setaria viridis), Pennsylvania smartweed (Polygonium pensylvanicum) and sunflower at 2% level reduced and at 1% level enhanced nodulation. The residues of lambsquarters shoot incorporated with soil at 0.5 and 1% levels caused 85 and 96% reduction respectively in seed germination and those of Pennsylvania smartweed and sunflower at 1% reduced seed germination by 40–70% but not at 0.5% level. The residues of foxtail and smartweed at both levels enhanced growth and nodulation. Under similar conditions nutsedge at 1% level stimulated nodulation but not growth. The residues of lambsquarters at both levels were inhibitory to nodulation but stimulated growth at 0.5% level.

Comparison of Ronstar Formulations for Efficacy and Phytotoxicity in Container Grown Landscape Plants

Three formulations of Ronstar [oxadiazon-2-tert-butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-2-1 ,3,4-oxadiazolin-5 one], were evaluated for control of 3 weed species and injury to 3 woody landscape plants over 90 days. Wettable powder (WP) 50%, 20% granular and 0.24 kg/L (2 lb/gal) emulsifiable concentrate (EC) were evaluated at 3 rates, 2.2, 4.5 and 9.0 kg/ha (2,4 and 8 lb/A). The WP formulation was generally more effective than the G formulation for control of goosegrass [Eleusine indica (L.) Gaert] and Pennsylvania smartweed (Polygonum pensylvanicum L.). Ronstar at the 4.5 kg/ha (4 lb/A) rate of WP and EC formulations provided excellent control of goosegrass and Pennsylvania smartweed. Prostrate spurge (Euphorbia humistrata Eagelm. ex gray) was controlled only by the 9.0 kg/ha (8 lb/A) rate of all 3 formulations. Pronounced injury to Compact Japanese Holly (Ilex crenata Thumb. ‘Compacta’) and ‘Hershey Red’ Azalea Rhododendron obtusum was evident at 14 and 30 days after treatment with the WP and EC formulations. Ninety days after treatment the species were marketable plants. Evergreen euonymus (Euonymus japonica) was not injured with any formulation or rate of Ronstar.