Field experiments were conducted from 2017 to 2019 to determine the tolerance of carinata to several preemergence and postemergence herbicides. Preliminary screenings identified herbicides that caused large variation on carinata injury, indicating the potential for selectivity. Dose-response field studies were conducted to quantify the tolerance of carinata to select herbicides. Diuron applied preemergence at rates of 280 g ai ha−1 or higher reduced carinata population density 54% to 84% compared to the nontreated control. In certain locations, clomazone applied preemergence caused minor injury with an acceptable level of carinata tolerance and only doses above 105 g ai ha−1 caused yield reductions. Napropamide doses of 2,856 g ai ha−1 or higher applied preemergence caused at least 25% injury to carinata; however, the damage was not severe enough to reduce yields. Simazine applied postemergence at rates above 1,594 g ai ha−1 caused 50% or more injury, resulting in yield losses ranging from 0% to 95% depending on location. Clopyralid applied postemergence at 2,512 g ai ha−1 caused 25% injury with relative yield reductions, which varied across locations. The present study identified clomazone and napropamide applied preemergence, and clopyralid applied postemergence as potential herbicides for weed control in carinata. In contrast, diuron, simazine, metribuzin, imazethapyr, and chlorimuron caused high levels of carinata mortality and can be used to control volunteer carinata plants in rotational crops.

The ability to use the protoporphyrinogen oxidase (PPO)-inhibiting herbicides fomesafen, flumioxazin, and sulfentrazone in potato is limited regionally or by soil texture, largely because of crop injury noted in research in the 1990s. With that in mind, we evaluated whether reducing the herbicide rates could maintain weed control while providing more consistent crop safety. Studies were conducted on a silt loam and a coarse-textured loamy sand soil. Soil texture played a greater than anticipated role in PPO-inhibitor herbicide injury risk as it relates to high-precipitation events. For example, in 2020 at the silt loam location, there were five precipitation events across the season that exceeded 2.5 cm, including one 6 d after treatment (DAT), and a seasonal total precipitation that was over 10 cm greater than the previous year. Despite excessive moisture and initial potato injury as high as 27% where flumioxazin was applied at the high rate with S-metolachlor, by 29 DAT injury was less than 10% in all treatments, and marketable tuber yield was similar among treatments. In contrast, in 2020 at the loamy sand location, there were four precipitation events across the season that exceeded 2.5 cm, and potato injury was as much as 60%. In 2020 the high amount of injury from flumioxazin was hypothesized to be caused by precipitation before herbicide application and not after, suggesting a need for more research in this area. This work documents the fine line between yield reduction presumably caused by reduced weed control and yield reduction assumed to be related to herbicide injury. This delineation between adequate weed control and consistent crop safety may differ by soil texture and environmental conditions, supporting the notion that custom-tailored weed management may become more necessary as high-precipitation events become more common in upper midwestern U.S. agricultural systems.

Safeners have been widely used to reduce phytotoxicity to crops, thus serving as an alternative weed control strategy. Benoxacor and fenclorim safeners have the potential to protect plants from herbicide phytotoxicity by increasing glutathione S-transferase (GST) activity within the plant. The study aimed to evaluate the safening effect of benoxacor and fenclorim on tomato against selected herbicides applied POST. The experiment was conducted in a greenhouse in a completely randomized designed with four replications in a 9 × 3 factorial scheme, where Factor A consisted of eight herbicides including a nontreated control, and Factor B consisted of two safeners including a nontreated control. The herbicide treatments were sulfentrazone (0.220 kg ai ha−1), fomesafen (0.280 kg ai ha−1), flumioxazin (0.070 kg ai ha−1), linuron (1.200 kg ai ha−1), metribuzin (0.840 kg ai ha−1), pyroxasulfone (0.220 kg ai ha−1), and bicyclopyrone (0.040 kg ai ha−1). Safener treatments consisted of benoxacor (0.67 g L−1) and fenclorim (10 µM). Tomato seeds were immersed in safener solution before sowing and herbicides were applied when tomato plants were at the 3-leaf stage, or 25 days after sowing. Visible injury was scored at 3, 7, 14, and 21 d after application (DAA), and shoot biomass was recorded 21 DAA. Seed treatment with fenclorim reduced injury caused by imazamox and bicyclopyrone by 5.5 and 1.3 times, respectively, whereas benoxacor reduced the injury from bicyclopyrone 1.3 times. In addition, tomato plants pretreated with fenclorim showed a lesser reduction in biomass after application of imazamox, fomesafen, and metribuzin, whereas plants pretreated with benoxacor showed lesser biomass reduction after metribuzin application. Thus, the use of safeners promotes greater crop selectivity, allowing the application of herbicides with different mechanisms of action on the crop.

Weed and cucumber (Cucumis sativus L. ‘Poinsett’) growth was studied where herbicides were soil-applied or applied to emerged weeds in the established crop. Cucumber yields were decreased at least 36% in 2 of 5 yr when weeds interfered for 4 weeks after emergence. Sequential applications of bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide] applied preplant and incorporated (PPI) + trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) applied postemergence and incorporated (POI) were outstanding and controlled Japanese millet (Echinochloa crus-galli Link. var. frumentacea), Texas panicum (Panicum texanum Buckl.), Palmer amaranth (Amaranthus palmeri S. Wats.), and common purslane (Portulaca oleracea L.) without affecting the growth or yield of cucumber. Compared with bensulide, the selectivity of soil-incorporated butralin [4-(1,1-dimethylethyl)-N-(1-methylpropyl)-2,6-dinitrobenzenamine] with cucumber was limited. Laboratory bioassays showed that under warm field soil conditions, PPI applications of 1.7 kg/ha of butralin persisted more than 2 months, but were dissipated after 4 months. Ethalfluralin [N-ethyl-N-(2-methyl-2-propenyl)-2,6-dinitro-4-(trifluoromethyl)benzenamine] reduced cucumber yields only when it was soil-incorporated to the crop-seed depth at planting. Applications to soil of bensulide + DCPA (dimethyl tetrachloroterephthalate) stunted cucumber plants, reduced leaf area, increased leaf thickness, and caused higher near-infrared (0.75 to 1.34 μm) leaf reflectance.

14C-labeled 4-amino-6-(1,1-dimethylethyl)-3-(ethylthio)-1,2,4-triazin-5(4H)-one (ethiozin)3 was metabolized more rapidly in tolerant than in sensitive wheat, Triticum aestivum L., cultivars. After a 6-h herbicidal pulse, the main metabolites were conjugates at all incubation times up to 48 h. The levels of deaminated and dethioethylated metabolites never exceeded 4% of the extractable radioactivity and also did not differ between tolerant and sensitive plants. On the contrary, 92% of the extractable radioactivity was in conjugates after 24 h in the leaves of tolerant plants compared to 25% in the leaves of sensitive plants. The differently sensitive wheat cultivars conjugated metribuzin, 4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one, at about half the rate that was observed with ethiozin. This finding may explain the fact that most wheat cultivars are more sensitive to metribuzin compared with ethiozin.

Absorption of 14C-imazaquin by leaves of field-grown flue-cured tobacco was similar when applied to young seedlings immediately after transplanting or to plants 3 wk after transplanting. The distribution of 14C in treated leaves indicated that 40% was absorbed, 54% remained in water extracts of leaf surfaces, and 6% was found in the epicuticular wax layer 8 d after treatment. Translocation of the herbicide from treated leaves to roots was very low (4 to 5%). In contrast, soil applications of imazaquin and subsequent uptake by roots resulted in retention of 40 to 53% in roots and translocation of 47 to 60% to shoots after 8 d. Analyses of methanol-soluble extracts of 14C indicated that more than 77% of the foliar-applied herbicide was metabolized in roots and upper shoots after 2 d. Similarly, 64% or more of the imazaquin was degraded in roots and shoots 2 d after root absorption.

Concentrations of clomazone in nutrient solution causing 50% reduction in shoot fresh weights were 325 and 2 μM for soybean and velvetleaf, respectively. Root uptake of 14C–clomazone from nutrient solution and translocation to shoots were similar for the two species. Soybean and velvetleaf contained similar amounts of 14C per plant; however, because velvetleaf had lower tissue weights, concentration of 14C was higher in velvetleaf. Clomazone did not accumulate in roots but was rapidly translocated to shoots of both species. No more than 30% of absorbed clomazone remained in roots at any time in the experiment. Soybean and velvetleaf leaves contained 4.2 and 1.7 nmol clomazone g−1 fresh weight, respectively, and 3.7 and 6.1 nmol clomazone metabolites g−1 fresh weight, respectively. Thus, velvetleaf metabolized clomazone more rapidly than soybean did. Treatment of clomazone metabolites with β-glucosidase demonstrated that metabolism occurred by oxidative cleavage and conjugation of the benzyl moiety in both plant species. One aglycone cochromatographed with 2–chlorobenzylalcohol. The results suggest that reduced absorption or translocation or increased detoxication of clomazone by soybean seedlings is probably not responsible for their tolerance to this herbicide.

Greenhouse and field experiments were conducted to evaluate the control of eastern black nightshade and velvetleaf in tomato with bentazon, metribuzin, pyridate, and acifluorfen. Metribuzin controlled velvetleaf but not eastern black nightshade, whereas pyridate controlled eastern black nightshade but not velvetleaf. A combination of metribuzin + pyridate controlled both weeds, but caused tomato injury 4 wk after application. Bentazon neither controlled the weeds nor injured the crop. Acifluorfen controlled both eastern black nightshade and velvetleaf. Diammonium phosphate and oxysorbic (5 POE) improved bentazon and acifluorfen activity against velvetleaf. Although initial crop injury from some treatments applied prior to fruit initiation was severe, the crop recovered and there were no reductions in fruit weight compared with the control. However applying acifluorfen with oxysorbic (5 POE) during fruit development reduced yield 50%.

The absorption and translocation of the isopropylamine salts of 14C-glyphosate and 14C-imazapyr were compared in established terrestrial alligatorweed. Results indicated that more than twice as much imazapyr as glyphosate was absorbed by treated leaves of alligatorweed. In addition, more imazapyr was translocated to the underground storage tissues in alligatorweed than was glyphosate. This difference in translocation to roots and subterranean storage tissues is proposed as a mechanism for tolerance of alligatorweed to glyphosate and susceptibility to imazapyr.

Penetration, translocation, and metabolism of acifluorfen {5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid} in soybean [Glycine max (L.) Merr. ‘Ransom’], common ragweed (Ambrosia artemisiifolia L.), and common cocklebur (Xanthium pensylvanicum Wallr.) were studied. Using liquid scintillation spectrometry and autoradiography, little movement of 14C-acifluorfen from the leaf surfaces of the two weed species could be detected in 24 h. After 48 h, less 14C was recovered from the leaf surface and more was found within the leaves of the two weed species. Autoradiographs of the weed showed limited acropetal movement of 14C from leaves 24 and 48 h after treatment. For soybean, most of the 14C still remained on the leaf surface after 48 h. Autoradiographs of soybean plants showed no movement from the treated leaflet. Studies using thin layer chromatography suggested that acifluorfen was metabolized within the plants. Rate of metabolism was inversely related to plant susceptibility (common ragweed and common cocklebur>soybean). The more rapid penetration and translocation, coupled with slower metabolism of acifluorfen by the weed species in comparison to soybean, may account for the difference in susceptibility of the weeds and soybean to acifluorfen.

Translocation and metabolism of 14C-2,4-D [(2,4-dichlorophenoxy)acetic acid] and effects of 2,4-D on protein synthesis were compared in ‘T–68’ (2,4-D tolerant) and ‘Viking’ (susceptible) birdsfoot trefoil (Lotus corniculatus L.) in an attempt to elucidate some tolerance mechanisms. After 14C-2,4-D was applied to upper trifoliate leaves, significantly less 2,4-D was found in stems, in leaves below the treated leaves, and in roots of T–68 compared to Viking. More 2,4-D was bound to alcohol-insoluble cellular constituents of T–68 leaves, stems, and roots. When alcohol-soluble components were fractionated, slightly more 14C water-soluble compounds were found in T–68, indicating further inactivation by glycosylation. No amino acid-2,4-D conjugates were found. The rate of 14CO2 evolution from 14C-2,4-D treated seedlings in T–68 was five times that in Viking. Protein synthesis appeared to be more rapid in T–68 but the relationship to 2,4-D was not clear. In part, 2,4-D resistance in T–68 may result from its ability to inactivate 2,4-D by differential binding and conjugation and by side chain breakdown as indicated by 14CO2 release.

Field experiments established that tetraploid soybean [Glycine max (L.) Merr.] plants were relatively tolerant while diploid plants were highly susceptible to metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] applied both preemergence and postemergence. Sensitivity of diploids and tolerance of tetraploids was also found in growth chamber experiments. Autoradiographs prepared 4 days after 14C-metribuzin application showed a high level of 14C-translocation to all parts of diploid plants including meristems. In contrast, only low levels of 14C were translocated in tetraploid plants, with no 14C-movement into meristems. Tetraploid plants rapidly transformed absorbed metribuzin to nontoxic products. Diploids were incapable of inactivating absorbed metribuzin at a rate sufficient to prevent injury. Differences in absorption, translocation, and metabolism of metribuzin appeared to be the main factors in the diploid and tetraploid differential response in field and growth chamber experiments. Differences in the rate of metribuzin metabolism appeared to be the factor responsible for the differential response in diploid and tetraploid cell suspension cultures. The primary polar metabolites were conjugates of metribuzin and deaminated metribuzin [6-tert-butyl-3-(methylthio)-1,2,4-triazin-5(4H)-one] with a ratio of 8:1, respectively.

Sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one} is used to control weedy grasses in red fescue (Festuca rubra L. # FESRU and F. rubra ssp. commutata), an important seed crop in Oregon. The sethoxydim rate required to reduce growth rate of 11 cultivars of red fescue and four cultivars of bentgrass (Agrostis tenuis Sibth. # AGSTE and A. stolonifera L. var. palustris # AGSST), a common contaminant in red fescue fields, by 50% (GR50) was determined in greenhouse and laboratory experiments. Field experiments compared only red fescue cv. ‘Pennlawn’ and bentgrass cv. ‘Penncross'. The GR50 values for Pennlawn red fescue in the field, the greenhouse, and the laboratory were 30 kg ai/ha, 15 kg/ha, and 5300 μM, respectively. Penncross bentgrass was approximately 400, 1400, and 12 900 times more susceptible than Pennlawn red fescue in the field, in the greenhouse, and in laboratory experiments, respectively. Plants were at different growth stages in the different experiments. The xylene and surfactant used as a solvent for the technical grade sethoxydim was as toxic to red fescue without sethoxydim as when sethoxydim was included. Cultivars of red fescue differed in their response to sethoxydim, but cultivars of bentgrass did not. The GR50's of other species tested in the greenhouse were >4 kg/ha for annual bluegrass (Poa annua L. # POAAN), 0.22 kg/ha for tall fescue (F. arundinacea Schreb. # FESAR), 0.37 kg/ha for downy brome (Bromus tectorum L. # BROTE), and 0.017 kg/ha for Italian ryegrass (Lolium multiflorum Lam. # LOLMU).

Greenhouse and laboratory experiments were conducted to determine the basis of imazethapyr tolerance in cowpea. Cowpea required more than 700 g ha−1 imazethapyr to reduce shoot growth 50% while corn required 70 g ha−1 to reduce growth 50% in greenhouse experiments. Extractable acetohydroxy acid synthase activity from cowpea 24 h after foliar imazethapyr treatment was only 20% of that of untreated cowpea but increased to control levels 72 h after treatment (HAT). The unifoliate leaves of cowpea absorbed 25% of the 14C-imazethapyr applied 72 HAT. Movement of 14C-imazethapyr out of the treated zone increased gradually to approximately 47% of the absorbed 14C 168 HAT. Parent imazethapyr decreased from 41 to 27% of the recovered 14C between 4 and 24 HAT, and continued to decrease to 14% by 168 HAT. Polar metabolites increased from 27 to 55% of the recovered 14C from 24 to 168 HAT. The polar metabolites of imazethapyr included hydroxyimazethapyr and conjugates of hydroxyimazethapyr. Tolerance of cowpea to imazethapyr is based on the plants ability to metabolize the herbicide to nontoxic metabolites.

Bell pepper is an economically important vegetable crop that is often impaired by weeds. Management of weeds in bell pepper is required to minimize yield loss because this crop does not tolerate weed competition. Several herbicides have been reported as selective for bell pepper, but research supporting their use for weed control in this crop is limited. Several herbicides were screened in a greenhouse to assess effects on plant biomass, and eight were selected that appeared to be safe for bell pepper. These herbicides, in addition to oxadiargyl, were then evaluated at two different Chilean locations, using different application timings. We measured the effects on plant injury, fruit yield, and the need for additional hand weeding on transplanted bell peppers. The herbicides clomazone, napropamide, pendimethalin, and S-metolachlor caused minimal foliar chlorosis and necrosis but did not affect fruit yield at either location. Pretransplant-incorporated application (PTI) caused no effect on fruit yield from the herbicides evaluated, whereas applications 2 wk (POST2) and 8 wk (POST8) after transplanting reduced fruit yield significantly. For weed management, the best combination was PTI + POST2 + POST8, which reduced the hand-weeding time by 30% compared to the control, at both locations. Based on our results, clomazone, pendimethalin, and S-metolachlor were the most effective treatments applied after transplanting, whereas all herbicides tested were selective for bell pepper when applied and incorporated before transplanting. Results presented here provide new insight into herbicides that can be used to manage weeds in bell pepper and shows that timing of herbicide application is critical to prevent injury to this crop.

Lake Pend Oreille is the largest (36,000 ha or 91,000 ac) freshwater lake in Idaho. Approximately 27% or 10,000 ha of the lake is littoral zone habitat supporting aquatic macrophyte growth. Eurasian watermilfoil has invaded large areas of this littoral zone habitat, with early estimates suggesting approximately 2,000 ha by the mid 2000s. Idaho State Department of Agriculture developed a state-wide eradication program in response to the threats posed by Eurasian watermilfoil, which attempts to quantify Eurasian watermilfoil infestations and its effects on the native plant community. Littoral zone point intercept surveys were conducted in 2007 and 2008 to monitor the trends in aquatic macrophyte community structure and assess management strategies against Eurasian watermilfoil. Lake Pend Oreille has a species-rich aquatic macrophyte community of more than 50 species. Lake-wide, the presence of Eurasian watermilfoil significantly decreased from 2007 (12.5%) to 2008 (7.9%). The native plant community has remained stable from 2007 to 2008 despite lake-wide management activities. In managed areas, the frequency of Eurasian watermilfoil during the 2008 assessment was 23.6% after herbicide applications. This represents a 63% reduction in Eurasian watermilfoil presence from the 2007 (64.5%) survey. When 2,4-D was combined with endothall, the presence of Eurasian watermilfoil declined from 63% (2007) to 36.5% in 2008. Eurasian watermilfoil treated with triclopyr also declined significantly, 64% to 18.2%. When all treatment methods were pooled and compared with areas that were not treated, the presence of Eurasian watermilfoil was significantly greater (52.5%) in untreated areas as opposed to treated areas (23%). The removal of Eurasian watermilfoil resulted in an increase in native species in most areas. Currently, there is as little as 200 ha of Eurasian watermilfoil remaining, which represents an overall reduction of 90% in approximately 7 yr of management.

Alfalfa–orchardgrass hay is popular in the Western United States because of an expanding horse-hay market. However, weed control in mixed alfalfa–orchardgrass stands is problematic, as herbicides must be safe for both species. Most growers rely solely on the competitiveness of the crop for weed control, which is often insufficient, especially in older stands. Field experiments were established in northern California to determine the efficacy and crop safety of several herbicides for winter annual weed control in established alfalfa–orchardgrass. Metribuzin at 560 or 840 g/ha and hexazinone at 420 g/ha applied in late fall provided at least 95% control of shepherd's purse and at least 80% control of downy brome without crop injury. Imazethapyr at 70 g/ha applied shortly after crop green-up provided more than 85% control of emerged mustards without crop injury. Paraquat at 560 g/ha applied shortly after crop green-up gave 50 to 82% weed control and caused significant injury to orchardgrass, which was still noticeable at first cutting.

Tembotrione inhibits 4-hydroxyphenyl-pyruvate-dioxygenase (HPPD) and was recently registered for use in all types of corn. Some sweet corn hybrids are killed by tembotrione, yet a mechanistic understanding of sensitivity has not been reported. Sensitivity of mesotrione, another HPPD-inhibitor, is conditioned by a single allele. Two hypotheses were tested: (1) response to tembotrione and mesotrione are conditioned by alleles at the same or closely linked loci and (2) the extent of early-season injury from tembotrione and mesotrione is similar on hybrids. The first hypothesis was tested by comparing responses to tembotrione and mesotrione in 136 F3:5 families derived from a cross of mesotrione-sensitive and mesotrione-tolerant sweet corn inbreds. F3 families cosegregated for responses to tembotrione and mesotrione: 94% of the families had the same response to both herbicides. Thus, the same gene or very closely linked genes condition response to both herbicides. On the basis of chi-square goodness of fit tests, responses of families to tembotrione fit a 3 : 2 : 3 sensitive : segregating : tolerant ratio (P = 0.24), which would be expected if sensitivity to tembotrione was conditioned by a single recessive allele. The second hypothesis was tested in six field experiments by quantifying the extent of early-season injury to 249 sweet corn hybrids 1 wk after treatment (WAT) of tembotrione (184 g ha−1) or mesotrione (210 g ha−1). One hundred ninety-three hybrids were tolerant to both herbicides. Seven sensitive hybrids that were severely injured by both herbicides 1 WAT differed in their response 3 to 4 WAT; sensitive hybrids treated with mesotrione had apparently resumed normal growth, whereas those treated with tembotrione died. Conversely, hybrids with intermediate levels of injury (> 10 to 50%) 1 WAT with mesotrione had no visual symptoms of injury from applications of tembotrione. Despite the common genetic basis for response to mesotrione and tembotrione, hybrids with sensitive or intermediate responses to mesotrione did not have identical responses to tembotrione.

Nicosulfuron, mesotrione, dicamba plus diflufenzopyr, and carfentrazone are postemergence herbicides from different chemical families with different modes of action. An association between the sensitivity of sweet corn to these herbicides was observed when 143 F3 : 4 families (F4 plants) derived from of a cross between Cr1 (sensitive inbred) and Cr2 (tolerant inbred) were evaluated in greenhouse trials. The ratio of tolerant : segregating : sensitive families was not significantly different from a 3 : 2 : 3 ratio, which would be expected if a single gene conditioned herbicide response. Families cosegregated for responses to these herbicides. In field studies with 60 F3 : 5 families in 2005 and 120 F3 : 5 families in 2007, responses to these herbicides and foramsulfuron and primisulfuron were associated. Responses to bentazon in field trials were similar to the aforementioned herbicides for tolerant families, but differences were noted for families that were sensitive or segregated for responses to nicosulfuron, foramsulfuron, primisulfuron, mesotrione, dicamba plus diflufenzopyr, and carfentrazone. The gene(s) affecting herbicide sensitivity in Cr1 maps to the same region of chromosome 5S as a previously sequenced cytochrome P450 gene, where alleles previously designated nsf1 and ben1 were associated with sensitivity to nicosulfuron and bentazon and appear to be the result of a 392–base-pair insertion mutation. This work supports the hypothesis that a single recessive gene or closely linked genes in the sweet corn inbred Cr1 condition sensitivity to multiple cytochrome P450 enzyme-metabolized herbicides.

Spot treatments with hexazinone (0.03, 0.046, and 0.06% ai [v/v]) were evaluated for their effects on thistle density, seed production, and crown vetch vigor from 1991 to 1994 to determine if long-term usage of hexazinone caused damage to the vetch and exacerbated the thistle problem. Thistle densities were reduced within a year at any concentration of hexazinone and seed production was reduced or eliminated. Environment had a large impact because initial thistle densities varied widely among years. The amount of precipitation during July of the previous year accounted for 89% of the variation in initial thistle densities in the subsequent year. Vetch injury from hexazinone was also best explained by the amount of precipitation during July. Vigorously growing crown vetch in wet years may have suppressed the thistles enough to reduce density the following year while drought years reduced the competitiveness of the crown vetch, resulting in higher initial densities of thistles in the following year.