HDC Project BOF 58. Lily: Herbicide trials. Cathy Knott, 1 Pippa Hughes 2 and Gordon R Hanks Horticultural Development Council i

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1 HDC Project BOF 58 Lily: Herbicide trials Cathy Knott, 1 Pippa Hughes 2 and Gordon R Hanks 2 1 Herbicide Consultant, 2 formerly Warwick HRI, University of Warwick i

2 Project Title Lily: Herbicide trials Project number: BOF 58 Project leader: Formerly Gordon R Hanks Warwick HRI (University of Warwick) The Kirton Research Centre Kirton Boston Lincolnshire PE20 1NN Report: BOF 58 Final Report 2007 trial year Previous report BOF 58 Annual Report 2005 and Annual Report 2006 trial years Key staff: Cathy Knott BSc (Hons) - Herbicide Consultant Gordon R Hanks BSc, MPhil, FIHort, CBiol, MIBiol Formerly Project Leader (Warwick HRI) Pippa Hughes BSc Formerly Research Officer (Warwick HRI) Location of project: Project coordinator: Warwick HRI Kirton Dr Gordon Flint, Winchester Growers Ltd Date project commenced: April 2005 Date completion due: March 2008, duration 3 years Key words: Lily, herbicide replacement, simazine, cyanazine (Fortrol), weed control, herbicides, pre-emergence, Venzar (lenacil), linuron, Stomp (pendimethalin), Sencorex (metribuzin), CIPC (chlorpropham), post-emergence, isoxaben / terbuthylazine (Skirmish), Basagran (bentazone), Goltix (metamitron), Asulox (asulam), crop safety, crop quality, vase-life ii

3 Whilst reports issued under the auspices of the HDC are prepared from the best available information, neither the authors nor the HDC can accept any responsibility for inaccuracy or liability for loss, damage or injury from the application of any concept or procedure discussed. The contents of this publication are strictly private to HDC members. No part of this publication may be copied or reproduced in any form or by any means without prior written permission of the Horticultural Development Council. iii

4 AUTHENTICATION We declare that this work was done under our supervision according to the procedures described herein and that the report represents a true and accurate record of the results obtained. [Name] [Position] [Organisation] Signature... Date... [Name] [Position] [Organisation] Signature... Date... Report authorised by: [Name] [Position] [Organisation] Signature... Date... [Name] [Position] [Organisation] Signature... Date... iv

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6 CONTENTS Page Grower Summary 1 Headline 1 Background and expected deliverables 1 Summary of the project and main conclusions 1 Financial benefits 7 Action points for growers 8 Science section 9 Introduction 9 Materials and Methods 11 Results and Discussion 15 Conclusions 27 Technology transfer 28 Appendices 30 vi

7 Grower Summary Headline The project identified safe, effective pre- and post-emergence herbicide treatments that provided season-long weed control in field grown Asiatic lilies and in Asiatic, LA hybrid, Longiflorum and Oriental lilies grown in Spanish tunnels. Background and expected deliverables There are very few on-label or off-label herbcides for flower-bulbs, thus growers have relied on off-label usage under the current Long Term Arrangements for Extension of Use and herbicides are often applied on the basis of ad hoc trials. Simazine cannot be used on lilies after December 2007 and cyanazine and terbacil can no longer be used in lilies. Others, such as lenacil, have a limited weed control spectrum. The overall aim of the project was to improve the cost-effectiveness of producing cut-flowers of lilies in UK crops by improving weed control. Specific objectives were: In the first year, 2005, to evaluate a range of candidate herbicides likely to be effective and safe to use on lilies. To select some of the best herbicides from 2005 and evaluate safety for Asiatic, LA hybrid and Longiflorum lilies grown in Spanish tunnels in To evaluate safety in Oriental lilies grown in Spanish tunnels in In order to understand the effects of weed competition and herbicide-induced yield reductions, both hand-weeded and entirely untreated control plots were included in the trials. On the handweeded plots all weeds were removed at regular intervals. 1

8 Summary of the project Conclusions in the first year 2005 In 2005 all herbicides tested appeared to be safe to use on Asiatic lily cv. Tresor there was no plant loss, no damage to flowers or leaves and no adverse effect on stem length. The greatest effect on the crop was from weeds. Weed populations were high on untreated plots and the predominant species were pale persicaria (96/m 2 ), small nettle (88/m 2 ), chickweed, groundsel and redshank. On untreated plots and where weed control with herbicides was poor, there were reductions in yield, numbers of lily buds/stem, quality, vase-life and delayed maturity. The most effective residual pre-emergence treatments were: tank-mixes Venzar Flowable + Alpha Linuron 50 ( ) L/ha, MSS 50CIPC + Alpha Linuron 50 ( ) L/ha, Stomp + Sencorex WG (3.3 L kg)/ha, Sencorex WG (1.5 kg/ha). These all gave complete, season-long control of the weed species present. The most effective post-emergence treatments were: early post-emergence tank-mix Skirmish + Basagran (0.75L kg)/ha; a programme of early (weeds at cotyledon to 1 true-leaf) post-emergence Goltix WG 2.5kg/ha followed by tank-mix Goltix WG + Asulox + 95% refined mineral oil (CropSpray) (2.5kg + 2.0L + 3.0L)/ha. Basagran SG (0.55kg/ha) controlled all weeds except a few knotgrass. Conclusions in the second year 2006 In 2006 some of the best herbicide treatments from the 2005 trial and a new one, coded 212 H, were evaluated for crop safety and weed control in Asiatic (cv. Lanzarote), LA hybrid (cv. Nomade) and Longiflorum (cv. Galloway) lilies grown in Spanish tunnels. The weed spectrum in all tunnels was predominantly shepherd s purse and small nettle, with some chickweed, black nightshade, groundsel and a few redshank and fat-hen. Herbicide treatments tested in 2006 on Asiatic, LA Hybrid and Longiflorum lilies A + denotes a tank-mix; & followed by No Herbicide active ingredient (product) Formulation Rate product L or kg/ha 1. Untreated - - 2

9 2. Hand-weeded - - Pre-emergence dormant period* 3. lenacil + linuron (Venzar Flowable + Alpha Linuron 50 SC) (standard UK treatment) 4. pendimethalin + metribuzin (Stomp + Sencorex WG) 440 g/l g/l 400 g/l + 70% w/w 5. flumioxazin 212 H 500 g/kg 50WP 60 g Early post-emergence crop & weeds 6. Flumioxazin (Sumimax) 212 H 500 g/kg 50WP 60 g 7. isoxaben / terbuthylazine (Skirmish) + bentazone (Basagran SG) Early & late post-emergence 8. metamitron (Goltix WG) early & Goltix + asulam (Asulox) + (Cropspray 11 E) Post-emergence (5 to 20 cm shoots) 9. bentazone (Basagran SG) + oil (CropSpray 11 E) 75/420 g/l + 87%w/w 70% w/w & 400 g/l + 95% refined mineral oil 87% w/w + mineral oil L 3.3 L kg kg 10. bentazone (Basagran SG) 87% w/w 1.65 kg * shoots covered by at least 2 cm soil 2.5 kg & 2.5 kg L L 1.65 kg L Effective pre-emergence herbicides that were safe to Asiatic lily, cv. Tresor in the 2005 trial, were safe to use in another variety of Asiatic lilies (cv. Lanzarote) and in LA hybrid (cv. Nomade) and Longiflorum (cv. Galloway) lilies. There was no damage to flowers or leaves and vase-life was not affected. They were: Venzar Flowable + Alpha Linuron 50 ( ) L/ha; Stomp 400 SC + Sencorex WG (3.3 L kg) /ha. The most effective, safe post-emergence treatment in 2006 (as in 2005) was a tank-mix applied early when weeds were at cotyledon to 1 true-leaf stage: Skirmish + Basagran SG (0.75 L kg) /ha In 2006 post-emergence applications of Basagran, and treatments where oil was included caused severe scorch in very hot, sunny weather (before the tunnels were covered). Damage was greatest where growth stages were advanced i.e. Asiatic lilies, where unfolded leaves caught most spray. Basagran should not be applied in temperatures over 21ºC. Longiflorum lilies (cv. Galloway) offered little competition with weeds and also matured later than the other lily types. Only the Stomp + Sencorex or Skirmish + Basagran treatments remained weed free until harvest. A herbicide programme may therefore be needed in some situations. 3

10 Weeds growing above the lilies on untreated plots delayed maturity, reduced stem weight, number of flower buds per stem, and reduced quality and vase-life compared with the best herbicide treatments or hand-weeded lilies. The trial data showed no evidence of differences in tolerance of Asiatic, LA hybrid and Longiflorum lilies to pre- or post-emergence herbicides effects from the latter were related to differences in growth stages. Pre-emergence Sumimax (flumioxazin) coded 212 H at 60 g/ha was less effective than other treatments, and the few nettles that remained was a problem for pickers. 212 H was also less effective early post-emergence until irrigation was applied to the trial and several weeds then died including nightshade, and potato shoots. Post-emergence 212 H caused scorch, followed by severe stunting, plant height was uneven and maturity was also delayed. It was not tested further. Conclusions in the third year Oriental lilies (cv. Cassandra) were grown in a Spanish tunnel in The predominant weed species were small nettle, shepherd s purse and chickweed with some scented mayweed, knotgrass and groundsel and a few fat-hen. The total number of weeds on untreated plots was 300 plants/m 2. Herbicide treatments tested in 2007 on Oriental lilies A + denotes a tank-mix; & followed by No Herbicide active ingredient (product) Formulation Rate product L or kg/ha 1. Untreated Hand-weeded - - Pre-emergence dormant period* 3. lenacil + linuron (Venzar Flowable + Alpha Linuron 50 SC) (standard UK treatment) 440 g/l g/l 2.0 L L 4. pendimethalin + metribuzin (Stomp 400 SC + Sencorex WG) 5. pendimethalin + metribuzin + metazachlor (Stomp 400 SC + Sencorex WG + Butisan S) 400 g/l + 70% w/w 3.3 L kg 400 g/l + 70% w/w + 500g/L 3.3 L kg L 4

11 6. Sencorex WG 70% w/w 1.5 kg 7. chlorpropham + linuron (Jupiter 40%CIPC + Alpha Linuron50 SC) Early post-emergence 8. isoxaben /terbuthylazine (Skirmish) + bentazone (Basagran SG) 9. pendimethalin + bentazone (Stomp 400 SC + Basagran SG) Early & late post-emergence 10. metamitron (Goltix WG) early & Goltix + asulam (Asulox) + mineral oil (Cropspray) 400 g/l g/l 6.0 L L 75/420 g/l + 87%w/w 0.75 L kg 400 g/l+ 87%w/w 2.0 L kg 70% w/w & 70% w/w g/l + 95% oil 2.5 kg & 2.5 kg L L Post-emergence (5 to 20 cm shoots) 11. bentazone (Basagran SG) 87% w/w 1.65 kg 12. Sencorex WG 0.5 kg *shoots covered by at least 2 cm soil Herbicide treatments 3-7 were applied pre-emergence of lilies and weeds. Rainfall soon after application ensured good efficacy of these soil-acting herbicides. Pre-emergence herbicides Pre-emergence herbicides did not delay or reduce emergence of the lilies and there was no visible damage or effect on maturity from Venzar Flowable + Alpha Linuron ( )L/ha and Stomp + Sencorex (3.3 L kg)/ha, Sencorex WG (1.5 kg/ha) and Jupiter 40%CIPC + Alpha Linuron 50 SC ( )L/ha (treatments 3, 4, 6 or 7) at any growth stage. All gave excellent control of all weed species. Only a few groundsel escaped control with Jupiter CIPC + Alpha Linuron. The addition of a low dose of Butisan S in the tank-mix Stomp 400 SC + Sencorex WG + Butisan SG (3.3 L kg L)/ha, treatment 5, resulted in stunting and there was a height reduction compared with hand-weeded lilies on 16 June. Damage from this tank-mix was severe and unacceptable and may have resulted from some extreme rainfall events in May before the tunnels were covered on 7 June. There was no damage from Butisan at a higher dose applied in tank-mix as Flexidor + Butisan ( ) L/ha in

12 Early post-emergence herbicides Treatments were applied on 24 May when Oriental lily shoots were 5cm tall and all leaves were folded. No damage to lilies was observed from Skirmish + Basagran (0.75 L kg)/ha, Stomp 400 SC + Basagran SG (2.0 L kg)/ha or treatment 5 with Goltix WG (2.5 kg/ha). The follow-up Goltix + Asulox + mineral oil (2.5 kg L L)/ha caused slight temporary chlorosis on 1% of the plant. Most weeds were at cotyledon stage and a few were at 2 true-leaf (TL) stage and Skirmish + Basagran (0.75 L kg)/ha, Stomp 400 SC + Basagran SG (2.0 L kg)/ha and Goltix WG (2.5 kg/ha) killed nearly all weeds in 7 days. A few groundsel remained after Stomp + Basagran. Goltix performed better on chickweed than in previous years, probably because they were at cotyledon stage when sprayed, and the small numbers remaining were controlled by the follow-up. Post-emergence herbicides Treatments were applied on 7 June, when the weather was cool (13 o C) and overcast, when 80% of lily leaves were unfolded. Under these conditions, there was negligible herbicide damage: Basagran SG (1.65 kg/ha) caused chlorosis of leaf tips until 2 July. Sencorex (0.5 kg/ha) was safe to the Oriental lilies. On 7 June, weeds were at the following growth stages: shepherd s purse 4-6 TL, small nettle, groundsel and scented mayweed were at 2-4 TL, knotgrass 2 TL, chickweed small plant stage. Basagran (1.65 kg/ha) killed all species except knotgrass, and a few of the high population of small nettle escaped control. There was a spraying error Sencorex was applied at 1.65 kg/ha instead of 0.5 kg/ha. The latter was sprayed on guard plots that had already received a pre-emergence treatment that had killed all weeds, thus only crop safety data could be assessed. (Sencorex at 1.65 kg/ha controlled all species and was also safe, causing only initial chlorosis and slight wilting). Oriental lilies, cv. Cassandra, were planted on 8 May and cropped 92 days later, on 8 August. Herbicide-treated Oriental lilies remained virtually weed-free until cropping, with the exception of Basagran SG. Nettles, which deter pickers, were completely killed by all treatments except post-emergence Basagran, which gave 97% control of the very high population. 6

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14 Main conclusions for the project A wide-spectrum pre-emergence residual herbicide treatment should be the basis for weed control in lily. Early removal of weeds avoids competition and late post-emergence applications close to flower initiation are likely to be more damaging. The high populations of nettles, which would deter pickers, were controlled by most treatments. There was no evidence of differences in tolerance of Asiatic, LA hybrid, Longiflorum and Oriental lilies (for the varieties tested) to pre- or post-emergence herbicides. The most effective pre-emergence residual herbicides were: Tank-mixes of Stomp 400 SC (pendimethalin) + Sencorex WG (metribuzin) (3.3 L + 0.5kg)/ha and Venzar Flowable (lenacil) + Alpha Linuron 50 ( ) L/ha are safe to Asiatic, LA Hybrid, Longiflorum and Oriental lilies. Jupiter 50% CIPC (chloropropham) + Alpha Linuron 50 ( ) L/ha and Sencorex WG 1.5 kg/ha were safe and effective on Asiatic lilies in 2005, on Oriental lilies in 2007 and might also be safe in other types. These all gave complete, season-long control of the weed species present. The most effective post-emergence treatments were: Early post-emergence tank-mix Skirmish (isoxaben/terbuthylazine) + Basagran (bentazone) (0.75L kg)/ha; a programme of early (weeds at cotyledon to 1 true-leaf) postemergence Goltix WG (metamitron) 2.5kg/ha followed by tank-mix Goltix WG + Asulox (asulam) + 95% refined mineral oil (CropSpray) (2.5kg + 2.0L + 3.0L)/ha. Basagran SG (0.55kg/ha) was less effective on some weed species (knotgrass, fat-hen). Basagran (see label warning for other crops) should not be applied when light intensity is high and when temperatures are above 21ºC, particularly where lily growth is advanced because it can cause scorching. It will be safer to lilies in covered tunnels. Although oil additive improved control of some waxy-leaved weed species (fat-hen), it should not be added to Basagran severe damage was seen in 2006 in hot, sunny weather. Oil added to Goltix also resulted in damage as in The amount of oil, added to improve weed control was probably too high, lower doses of 1.0 L/ha would be safer. A follow-up post-emergence herbicide would not normally be required in Asiatic or LA hybrid 8

15 lilies. Longiflorum and Oriental lilies have slower growth, offering little competition with weeds and they are also later maturing. Thus any weeds that escape control will grow vigorously and a herbicide programme may sometimes be needed. Status of the herbicides evaluated in this project (as at December 2007) All herbicides were applied before tunnels were covered. Herbicides * cannot be used under protection. NPE formulations must not be used after 31 August Jupiter is a new non- NPE formulation of CIPC. Product a.i. and formulation Marketing company EC Review UK Approval other crops Flexidor 125 isoxaben 125g/L SC Landseer Supported ornamentals Jupiter 40 EC chlorpropham 400g/L EC United Phosphorus Annex 1 ornamentals Stomp 400 SC pendimethalin 400 g/l SC BASF Annex 1 carrots etc.ltaeu Betanal Flow phenmedipham 160 g/l SE Bayer CropScience Annex 1 sugar beet LTAEU Sencorex WG * metribuzin 70% w/w WG Bayer CropScience Annex 1 potatoes LTAEU Venzar Flowable lenacil 440 g/l SC Dupont Supported ornamentals Pyramin DF chloridazon 65% w/w WDG BASF Annex 1 sugar beet LTAEU Alpha Linuron Linuron 500g/L SC Makhteshim Annex 1 carrots etc.ltaeu 50SC Skirmish * isoxaben / terbuthylazine Syngenta Supported peas LTAEU 75/420g/L SC Butisan S metazachlor 500g/L SC BASF, etc. Supported ornamentals Goltix WG metamitron 70% w/w WG Makhteshim Supported red beet LTAEU Asulox * asulam 400 g/l SL Bayer CropScience Supported amenity grass LTAEU Basagran SG bentazone 87% w/w SG BASF Annex 1 ornamentals Boxer * florasulam 50g/l SC Dow AgroSciences Annex 1 cereals LTAEU Sumimax (212H) * flumioxazin 500 g/l SC Sumitomo Annex 1 wheat LTAEU Currently all can legally be used under current LTAEU (Long Term Arrangements for Extension of Use) for non-edible crops, but this situation will change at some time in the future. Financial benefits The effect of herbicide treatments on flower cropping has been evaluated for Asiatic (two varieties), LA Hybrid, Longiflorum and Oriental lilies. Growers should benefit from this project in a number of ways: Good weed control will achieve better crop growth and ease of picking without competition and interference from weeds. Removal of weeds will minimise sources of pests and disease and optimise flower quality. 9

16 An effective herbicide will reduce the need for expensive hand weeding. Use of effective herbicides will avoid the need for unnecessary herbicide applications and possible downgrading of the crop. The cost of the most effective safe herbicide treatments ranged from around 27 (Stomp + Sencorex) to 62 for pre-emergence residual herbicides, and from 35 (Skirmish + Basagran) to 67 (Goltix programme) for post-emergence herbicides. The cost of hand weeding would be far higher. Action points for growers The indicated herbicide treatments could be tested at grower s risk, on small areas first. Early removal of weeds avoids competition, late post-emergence applications close to flower initiation are likely to be more damaging. A wide-spectrum pre-emergence residual herbicide treatment should be the basis for weed control in lily. In the trials, effective pre-emergence residual herbicides Venzar Flowable + Alpha Linuron 50 ( ) L/ha and Stomp 400 SC + Sencorex WG (3.3 L + 0.5kg)/ha are safe to Asiatic, LA Hybrid, Longiflorum and Oriental lilies. Jupiter 50% CIPC + Alpha Linuron 50 ( ) L/ha and Sencorex WG 1.5 kg/ha were safe and effective in 2005 on Asiatic lilies, in 2007 on Oriental lilies and might also be safe in other types. Growers should note that the project was on a silt loam soil. The margin of crop safety of residual herbicides (particularly Sencorex) is reduced on lighter soil types. Residual herbicides are usually ineffective on peat soils. The bulbs should be planted so they are covered by 2cm of settled soil to avoid damage from residual herbicides. Frozen lily bulbs emerge very quickly and residual herbicides should be sprayed immediately after planting. This is particularly important for Stomp because the most sensitive stage to this herbicide is just prior to emergence, when the growing shoot is just below the soil surface. A follow-up post-emergence herbicide would not normally be required in Asiatic or LA hybrid lilies. A herbicide programme may sometimes be needed in the later maturing Longiflorum and Oriental lilies. The most effective, safe post-emergence treatment was a tank mix of Skirmish Basagran SG (0.75 L kg) /ha but it should be applied early when weeds are at cotyledon 1 10

17 true-leaf stage. The first application of Goltix WG 2.5 kg/ha as part of the Goltix programme should also be applied early. Basagran (see label warning for other crops) should not be applied when light intensity is high (unlikely under cover) and when temperatures are above 21ºC, particularly where growth is advanced (i.e. where lily leaves have expanded and catch more spray) because it can cause scorching. It will be safer to lilies in covered tunnels. Although oil additive improves control of some weeds (fat-hen), it should not be added to Basagran. Oil added to Goltix also results in damage if applied under hot sunny conditions. The amount of oil, added to improve control of waxy-leaved weed species (fat-hen) was probably too high in the trials and lower doses of 1.0 L/ha would be safer. 11

18 Science Section Introduction Defra statistics for England & Wales record that some 20million lily bulbs are grown annually under protection. The wide range of colours and forms available from Dutch and US breeders has ensured the popularity of these luxurious flowers. Formerly, most lilies were planted in the glasshouse soil or in trays of peat or other compost. In recent years, with the increasing use of low-cost polythene tunnels (Spanish tunnels) for cut-flower production, lilies too are being grown in tunnels. Often the bulbs are grown in the open, the polythene covers being moved into place shortly before flower cropping, protecting the flowers from weather damage and enabling picking to take place irrespective of the weather, so giving the continuity of supply that is demanded by the multiple retail sector. Growing lilies in this situation often results in weed problems, compared with the often relatively sterile environment of the glasshouse. Good weed control is essential for the efficient production of high quality lilies. The field crop is grown on flat beds and planted at high density thus mechanical weeding is not an option. Some herbicide product labels have on-label approvals for flower bulbs or ornamentals but lilies are not specified and they may not be safe. Herbicides are often applied on the basis of ad hoc trials. There are no on-label or SOLA herbicide approvals specifically for lilies, thus growers of nonedible crops rely on off-label usage under the Long Term Arrangements for Extension of Use (LTAEU) of pesticides approved for any growing crop subject to specific restrictions and at their own risk. These Arrangements are under review and at some time in the future these uses must be replaced by SOLAs. In addition, and subject to the specific restrictions for extension of use, pesticides approved for use on any growing outdoor crop may be used on outdoor lilies and pesticides approved for use on any growing protected crop may also be used on protected lilies. Where outdoor/protected are not specified on the label for another crop then the pesticide can be used on both outdoor and protected lily. 12

19 In the 1970s and 1980s lilies were grown in the field in the UK, both for flower and bulb production, and during this time several herbicide trials were carried out at the Rosewarne and Kirton Experimental Horticulture Stations. A summary of the conclusions from these trials: Pre-planting glyphosate and paraquat were crop-safe. Successful residual herbicides for dormant-season, pre-emergence use were simazine, chlorpropham and a tank-mix of lenacil + linuron. A tank-mix simazine + lenacil at emergence was safe. For post-emergence weed control, lenacil application could be repeated, metamitron (often used as a split-dose) or cyanazine were safe to use over a wide range of crop stages. Some less safe, less effective herbicides tested included terbacil and also diphenamid and 2, 4-DES (these are not available now). Many herbicides tested have since been withdrawn, including simazine (which cannot be used in lilies after December 2007); cyanazine ( Essential Use derogation for narcissus only) and terbacil can no longer be used in lilies; paraquat has now been revoked; others, such as lenacil, have a limited weed control spectrum. For use in lily, standard herbicide treatments are: Pre-crop-emergence residual herbicides: applied before shoot emergence, Venzar (lenacil) + linuron tank-mix is the most widely used herbicide at this stage. Early-post-emergence herbicides: several available (Goltix) Post-emergence herbicides before buds visible: several available (Goltix) The overall aim of this project was to identify safe, effective herbicides for lilies to replace those active substances that have been withdrawn. Specific objectives were: In the first year to test a range of candidate herbicides likely to be effective and safe to use on lilies. In the second year to develop herbicides for a range of lily types (Asiatic, LA Hybrid and Longiflorum) grown in Spanish tunnels. In the third year to develop herbicides for Oriental lilies grown in a Spanish tunnel. 13

20 Good weed control will achieve: Better crop growth and ease of picking without competition and interference from weeds. Removal of weeds that can act as a source of pests and disease and reduce flower quality In this project a number of herbicides, as yet not formally evaluated on lily crops as far as we know, were investigated for crop safety and effective weed control. In preparation for the project, discussions have taken place with Dutch advisors and with representatives of global crop protection companies. The scientific literature has been searched, and the older annual reports of the Laboratorium voor de Bloembollenonderzoek, Lisse, consulted. Materials and Methods In year 3 (2007) the trial site, on light silt loam soil (ADAS classification) at Warwick HRI, Kirton, Boston, Lincolnshire, UK, was typical of the South Lincolnshire agricultural area where lilies can be grown. Prior to planting, the trial area in the tunnel was treated with glyphosate to eliminate perennial weeds. Calcium sulphate was applied pre-cultivation. Standard soil sampling (0-15cm depth) gave the following analysis: ph 7.6, P index 4, K index 2-, Mg index 3. Frozen lily bulbs were removed from cold store on 3 May and allowed to thaw before planting in plots on 8 May in the tunnel. Oriental lily bulbs, cv. Cassandra (white) were planted 10 cm deep so they were covered by at least 2 cm of settled soil. The tunnel was covered on 7 June, after the last herbicide sprays were applied and before flower buds were visible, to protect flowers against extreme rainfall events. Irrigation (plus fertilizer) was applied through tapes when required. The fertilizer recommended for Oriental lilies contained 50.6 kg magnesium sulphate, 7.7 kg potassium hydrogen sulphate, 97 kg potassium nitrate, 10 L soluble iron and 40.6 L nitric acid in 1000 L water, applied at 1:200 L dilution. A fungicide programme that included chlorothalonil, carbendazim and iprodione was used to control Botrytis. Insecticides were applied: pymetrozine, cypermethrin to control aphid and lambda-cyhalothrin to control lily beetle. 14

21 The tolerance of Oriental lily, cv. Cassandra, to some of the best pre-emergence and early and late post-emergence treatments was evaluated. In order to understand the effects of weed competition and herbicide damage, both hand-weeded and untreated plots (i.e. with no weed control) were included (as in 2005 and 2006). On the hand-weeded plots (treatment 2) all weeds were removed at regular intervals. 15

22 Herbicide treatments 2007 for Oriental lily A + denotes a tank-mix, & followed by No Herbicide active ingredient (product) Formulation Rate product L or kg/ha 1 Untreated Hand-weeded - - Pre-emergence dormant period 3 lenacil + linuron (Venzar Flowable + Alpha Linuron g/l g/l L SC) (standard UK treatment) 4 pendimethalin + metribuzin (Stomp 400 SC + Sencorex WG) 400 g/l + 70% w/w 3.3 L kg 5. pendimethalin + metribuzin + metazachlor (Stomp 400 SC + Sencorex WG + Butisan S) 400 g/l + 70% w/w + 500g/L 3.3 L kg L 6. Sencorex WG 70% w/w 1.5 kg 7. Jupiter 40%CIPC + Alpha Linuron 50 SC 400 g/l g/l Early post-emergence 8. isoxaben/terbuthylazine (Skirmish) + bentazone (Basagran SG) 75/420 g/l + 87%w/w kg 9. pendimethalin + bentazone (Stomp 400 SC g/l+ 87%w/w kg Basagran SG) Early & late post-emergence 10. metamitron (Goltix WG) early & Goltix + asulam (Asulox) + refined mineral oil (Cropspray) 70% w/w & 70% w/w g/l + 95% oil 2.5 kg & 2.5 kg L L Post-emergence (5 to 20 cm shoots) 11. bentazone (Basagran SG) 87% w/w 1.65 kg 12. Sencorex WG 70% w/w 0.5 kg The trial design was a randomised block with three replicates and 12 treatments (36 plots). Oriental lily bulbs were planted in 8 rows per plot at 15 cm x 15 cm spacing. There were 104 bulbs/plot. Plot size was one bed width 1.2m x 2m length, with guard areas between plots. 16

23 The following assessments were made in all years: Crop and weed stage of development at the time of treatments Crop tolerance (i.e. phytotoxic symptoms) was assessed at intervals after each herbicide application using the scores given below: Crop tolerance % Phytotoxicity score 0 Complete kill % damage % damage % damage % damage % damage % damage % damage (considered unlikely to cause reduction in yield or quality at cropping) % damage % damage 10 No damage (as untreated controls) Numbers of each weed species in random 0.33m 2 quadrats, two per plot, after each application. Common and Latin weed names are given in Appendix 1. Percentage weed cover and weed control scores on a scale of 0 to 10 (0, no control, through 7, acceptable control, to 10, complete control) at intervals after each application. Flowers were cropped at commercial cropping stage when two buds per stem showed colour, and the following were recorded: Cropping date. Weight of 10 representative stems cropped from the centre of each plot. Stem lengths, bud numbers and number of aborted buds for a sample of ten stems per plot. Quality was assessed visually and compared with hand-weeded controls - score (from 1, very poor, to 5, very good) for a sample of ten stems per plot. The presence of damaged or thin stems, or chlorotic foliage was recorded. 17

24 Vase-life under standard conditions (in plain water at 20 C and 65% Relative Humidity under 1000 lux from cold white tubular fluorescent lamps on for 12 h each day. Diary of operations and spray applications 2007 Date 2007 Operation Weather Growth stage crop Growth stage weeds (TL= true leaves) 8 May Planted 9 May Treatments 3, 4, 5, Soil moist, rain 1.4mm Shoots covered None 6, 7 pre-emergence applied by 2 cm soil May Lilies emerged 24 May Treatments 8, 9, 10 early post-emergence applied Temperature 19 o C; RH 72%; cloudy, soil dry; rain 2.8 mm on 25 May leaves folded Shepherd s purse, small nettle cotyledon a few 2 TL 7 June Treatments 10, post-emergence applied Temperature 13 o C; RH 90%; cloudy; no rain until 13 June. 80% plants with leaves unfolded Shepherd s purse 4-6 TL, small nettle 2-4 TL, groundsel 2-4 TL, mayweeds 4 TL, knotgrass 2 TL, chickweed small plant 7 June Tunnel covered 9-13 August Lilies cropped Status of the herbicides evaluated in this project (as at December 2007) All herbicides were applied before tunnels were covered. Herbicides * cannot be used under protection. Product a.i. and formulation Marketing company EC Review UK Approval other crops Flexidor 125 isoxaben 125g/L SC Landseer Supported ornamentals Jupiter 40 EC chlorpropham 400g/L EC United Phosphorus Annex 1 ornamentals Stomp 400 SC pendimethalin 400 g/l SC BASF Annex 1 carrots etc.ltaeu Betanal Flow phenmedipham 160 g/l Bayer CropScience Annex 1 sugar beet LTAEU SE Sencorex WG * metribuzin 70% w/w WG Bayer CropScience Annex 1 potatoes LTAEU Venzar Flowable lenacil 440 g/l SC Dupont Supported ornamentals Pyramin DF chloridazon 65% w/w WDG BASF Annex 1 sugar beet LTAEU 18

25 Alpha Linuron 50SC Linuron 500g/L SC Makhteshim Annex 1 carrots etc.ltaeu Skirmish * isoxaben / terbuthylazine Syngenta Supported peas LTAEU 75/420g/L SC Butisan S metazachlor 500g/L SC BASF, etc. Supported ornamentals Goltix WG metamitron 70% w/w WG Makhteshim Supported red beet LTAEU Asulox * asulam 400 g/l SL Bayer CropScience Supported amenity grass LTAEU Basagran SG bentazone 87% w/w SG BASF Annex 1 ornamentals Boxer * florasulam 50g/l SC Dow AgroSciences Annex 1 cereals LTAEU Sumimax (212H) * flumioxazin 500 g/l SC Sumitomo Annex 1 wheat LTAEU Currently all can legally be used under current LTAEU (Long Term Arrangements for Extension of Use) for non-edible crops, but this situation will change at some time in the future. Results and Discussion Results in 2005, the first year Herbicide treatments, 2005 A + denotes a tank-mix, & followed by No Herbicide active ingredient (product) Rate product L or kg /ha 1 Untreated - 2 Hand-weeded - Pre-emergence dormant period * 3 lenacil + linuron (Venzar Flowable + Alpha Linuron 50 SC) 2.0L + 1.7L 4 chlorpropham + linuron (MSS 50CIPC + Alpha Linuron 50 SC) 6.0L + 1.0L 5 metribuzin (Sencorex WG) 1.5kg 6 isoxaben + metazachlor (Flexidor +Butisan) 2.0L + 2.5L 7 isoxaben / terbuthylazine (Skirmish) 1.0L 8 Pendimethalin + metribuzin (Stomp + Sencorex WG) 3.3L + 0.5kg 9 Pendimethalin + isoxaben (Stomp + Flexidor) 3.3L + 1.0L Early post-emergence 10 lenacil (Venzar) (early post-em only, for the control of 4.0L cotyledon weeds) (standard treatment) 11 lenacil (Venzar) + metamitron (Goltix WG) 4.0L L 12 metamitron + phenmedipham (Goltix + Betanal Flow) 1.0kg + 2.5L 13 isoxaben / terbuthylazine (Skirmish) + bentazone (Basagran 0.75L + 0.6kg SG) 14 chloridazon (Pyramin DF) + metamitron (Goltix WG) (2.0kg + 2.0kg) Early & late post-emergence 15 metamitron (Goltix WG) early & Goltix + asulam (Asulox) + 2.5kg; 2.5kg + 2.0L + 19

26 refined mineral oil (CropSpray) & Goltix WG + oil (after 3.0L; 2.0L + 3.0L flower buds visible) Post-emergence (5 to 20 cm shoots) 16 bentazone (Basagran SG) 1.65kg 17 florasulam (Boxer) 100ml 18 florasulam (Boxer) 50ml * shoots covered by at least 2 cm soil) In 2005 weed populations were high and the predominant species were pale persicaria, small nettle (88/m 2 ), chickweed, groundsel and some redshank. In 2005 all herbicides tested appeared to be safe in Asiatic lily, cv. Tresor grown in the field. There was no plant loss, no damage to flowers or leaves was observed at any growth stage. There were no significant differences between the stem lengths of hand-weeded and herbicidetreated lilies, thus herbicides had no adverse effect on stem length. Herbicides did not reduce flower yield or quality and did not delay maturity. On untreated plots and where weed control with herbicides was poor, there were reductions in yield, number of lily buds/stem, quality, vase-life and delayed maturity. The best quality, longest vase-life and higher number of buds/stem were where weeds were controlled by hand-weeding or by the most effective herbicides. The following herbicide treatments (6, 10, 11, 12, 13, 7 and 18) were ineffective on the weed species on the trial area and control was unacceptable: pre-emergence tank-mix Flexidor + Butisan ( ) L/ha, post-emergence Venzar 4.0 L/ha and tank-mixes Venzar + Goltix (4.0L kg) /ha, Goltix + Betanal (1.0kg + 2.5L)/ha and Pyramin DF + Goltix ( ) kg/ha where pale persicaria, and in some cases small nettle, grew above the crop; pre-emergence Skirmish, where a few weeds grew above crop height; Boxer 50ml/ha, where removal of pale persicaria was slow. 20

27 In a commercial situation picking would probably have been uneconomic for the unacceptable treatments because of the presence of the taller weeds including a large population of nettle on plots treated with Venzar or Goltix + Betanal. In the first year 2005, it was clear that a wide-spectrum, pre-emergence residual herbicide should form the basis for weed control in lilies, removing weed competition early. The herbicide chosen would depend on the weed spectrum anticipated. Nettles, which deter pickers, were controlled with all the best treatments listed below. The most effective residual pre-emergence treatments were: Tank-mix Venzar Flowable + Alpha Linuron 50 ( ) L/ha. Tank-mix MSS 50CIPC + Alpha Linuron 50 ( ) L/ha. Sencorex WG 1.5 kg/ha. Tank-mix Stomp + Sencorex WG (3.3 L kg)/ha. These all gave complete, season-long control of the weed species present. The most effective post-emergence treatments were: Early post-emergence tank-mix Skirmish + Basagran (0.75L kg)/ha. A programme of early (weeds at cotyledon to 1 true-leaf) post-emergence Goltix WG 2.5kg/ha followed by tank-mix Goltix WG + Asulox + 95% refined mineral oil (CropSpray) (2.5kg + 2.0L + 3.0L)/ha. In this trial Goltix WG + oil (2.5kg + 3.0L)/ha appeared safe to apply at a later stage even when lily buds were exposed. Basagran SG (0.55kg/ha) completely controlled all weeds except a few knotgrass. However, it has several weaknesses (poor control of speedwell and fat-hen). Basagran + oil was therefore tested for crop safety in Boxer (100ml/ha) gave adequate control but its action on pale persicaria was slow. It would be a good option for control of mayweed, groundsel, sowthistle, shepherd s purse, etc., but it is ineffective on fat-hen. Results in 2006, the second year 21

28 In 2006 some of the best herbicide treatments from the 2005 trial and a new one, 212 H, were evaluated for crop safety and weed control in lilies: Asiatic cv. Lanzarote (red); LA hybrid cv. Nomade (deep pink) and Longiflorum cv. Galloway (white). Herbicide treatments 2006 for Asiatic, LA hybrid and Longiflorum lilies A + denotes a tank-mix, & followed by No Herbicide active ingredient (product) Rate product L or kg/ha 1. Untreated - 2. Hand-weeded - Pre-emergence dormant period, shoots covered by at least 2 cm soil 3. lenacil + linuron (Venzar Flowable + Alpha Linuron 50 SC) L (standard UK treatment) 4. pendimethalin + metribuzin (Stomp + Sencorex WG) 3.3 L kg 5. flumioxazin 212 H 50WP 60 g Early post-emergence 6. flumioxazin 212 H 50WP 60 g 7. isoxaben / terbuthylazine (Skirmish) + bentazone kg (Basagran SG) Early & late post-emergence 8. metamitron (Goltix WG) early & Goltix + asulam (Asulox) + (Cropspray 11 E) 2.5 kg & 2.5 kg L L Post-emergence (5 to 20 cm shoots) 9. bentazone (Basagran SG) + oil (CropSpray 11 E) 1.65 kg L 10. bentazone (Basagran SG) 1.65 kg The weed spectrum was predominantly shepherd s purse and small nettle, with some chickweed, black nightshade, groundsel and a few redshank and fat-hen in all tunnels. Weed numbers on untreated plots varied between tunnels: 151/m 2, 649/m 2 and 568/m 2 in Asiatic, LA hybrid and Longiflorum lilies respectively. Although all herbicides were effective (except 212 H) the few weeds remaining grew very large in the late-maturing Longiflorum and only the lilies treated with Stomp + Sencorex or Skirmish + Basagran remained weed free until harvest. The Longiflorum (cv. Galloway) plant type was the least competitive with weeds and was the latest to mature (86 days). 22

29 Weeds growing above the lilies on untreated plots: delayed maturity; reduced stem weight and the number of flower buds per stem; caused disease and abortion of buds, and reduced quality and vase-life compared with the best herbicide treatments and hand-weeded lilies. The high population of nettles, which interfere with picking, was controlled by most treatments. The trials data showed no evidence of differences in tolerance of Asiatic, LA hybrid and Longiflorum lilies to the herbicides effects were related to differences in growth stages. The most effective residual pre-emergence treatments in 2006 gave excellent control of the weed species present and were safe to Asiatic, LA hybrid and Longiflorum lilies. They were: Stomp + Sencorex WG (3.3 L kg) /ha. Venzar Flowable + Alpha Linuron 50 ( ) L/ha. In 2006 (as in 2005), the most effective, safe post-emergence treatments (applied when weeds were at cotyledon 1 true leaf stage) in Asiatic, LA hybrid and Longiflorum lilies were: Early post-emergence Skirmish + Basagran (0.75 L kg) /ha plots remained weedfree until cropping. Early post-emergence (weeds at cotyledon 1 true leaf) Goltix WG 2.5 kg/ha. In 2006 the following were effective but were applied during a period when temperatures were above 21ºC, higher than recommended for Basagran, and in conditions of high light intensity (the lilies were not yet covered). These conditions resulted in leaf scorch and reduction in marketability of flowers. The severity of damage was related to the growth stage, i.e. expanded leaves of Asiatic lilies were more exposed to herbicide spray and scorch was extremely severe, LA Hybrid and Longiflorum lilies were sprayed on the same day, but were affected less because leaves were folded. Basagran should not be applied in temperatures over 21 o C (see label). Oil increases damage in these conditions. Basagran SG 1.65 kg/ha controlled all except a few fat-hen and knotgrass. However, it has several weaknesses (speedwell, fat-hen). Basagran + oil improved control but was the most damaging treatment and will not be tested further. 23

30 The follow-up to Goltix with Goltix WG + Asulox + a 95% refined mineral oil CropSpray (2.5 kg L L) /ha also caused severe damage. Basagran alone and Goltix + Asulox + oil sprayed in cooler conditions were safe to Asiatic lilies in the 2005 trial. In 2006, 212 H pre-emergence was safe but post-emergence applications caused stunting and scorch. Weed control was inadequate pre- or post-emergence and appeared moisturedependent. It was not tested further in Results in the final year, year 3 Weed assessments for Oriental lilies in year 3 (2007) Common and Latin weed names are given in Appendix 1. The predominant weed species in the tunnel were small nettle, shepherd s purse and chickweed with some scented mayweed, knotgrass and groundsel and a few fat-hen. Numbers of each weed species are shown in Table 1. The total weed number on untreated plots was 300/m 2. Herbicide treatments 3-7 were applied on 9 May, pre-emergence of Oriental lilies (c. 50% emergence on 16 May) and pre-emergence of weeds. Rainfall soon after application ensured good efficacy of these soil-acting herbicides. All pre-emergence herbicide tank-mixes: Venzar Flowable + Alpha Linuron (2.0 L +1.7 L)/ha and Stomp + Sencorex (3.3 L kg)/ha, Stomp 400 SC + Sencorex WG + Butisan SG, Sencorex WG and Jupiter 40%CIPC + Alpha Linuron 50 SC gave excellent control of all species. Only a few groundsel escaped control with the latter. 24

31 Table 1. Oriental lilies 2007: weed species numbers/ m 2 (mean of three replicates, counts in 2 quadrats of 1/3 m 2 ) on 3 June (treatments 1, 3, 4, 5, 6, 7); treatments 8, 9, 10 on 12 June; and treatments 8, 9, 10 in italics, 11, 13 on 16 June No Herbicide Rate product L or kg/ha Chickweed Small nettle Shepherd s purse Knotgrass Groundsel Scented mayweed Fat-hen TOTAL 1. Untreated Hand-weeded Pre-emergence 9 May 3. Venzar Flowable + Alpha 2.0 L L Linuron Stomp 400 SC + Sencorex 3.3 L kg WG 5. Stomp 400 SC + Sencorex 3.3 L kg WG + Butisan SG L 6. Sencorex WG 1.5 kg Jupiter 40%CIPC + Alpha Linuron L L Early post-emergence 24 May 8. Skirmish + Basagran SG 0.75 L kg Stomp 400 SC + Basagran SG 2.0 L kg Early & late post-emergence 24 May & 7 June 10. Goltix WG early & 2.5 kg & Goltix + Asulox + mineral oil 2.5 kg L L Post-emergence 7 June 11. Basagran SG 1.65 kg Sencorex WG# 1.65 kg# # error sprayed wrong dose rate Early post-emergence treatments 8, 9 and 10 were applied on 24 May when most weeds were at cotyledon stage and a few were at 2 true-leaf (TL) stage. Skirmish + Basagran (0.75 L kg)/ha, Stomp 400 SC + Basagran SG (2.0 L kg) and Goltix WG (2.5 kg) killed nearly all weeds in 7 days. A few groundsel escaped control with Stomp + Basagran. Goltix performed better on chickweed than in previous years, probably because the weeds were at cotyledon stage when sprayed, and the small numbers remaining were controlled by the follow-up (shown in italics in Table 1). 25

32 Post-emergence treatments were sprayed on 7 June, when weeds were at the following growth stages: shepherd s purse 4-6 TL, small nettle, groundsel and scented mayweed were at 2-4 TL, knotgrass 2 TL, chickweed small plant stage. Basagran (1.65 kg/ha) achieved good control of all species except knotgrass. i There was a spraying error Sencorex was applied at 1.65 kg/ha (treatment 13) instead of 0.5 kg/ha. The latter was sprayed on guard plots that had already received a pre-emergence treatment that had killed all weeds (Stomp + Sencorex (3.3 L kg)/ha), thus only crop safety data could be assessed. Sencorex at1.65 kg/ha (treatment 13) controlled all species. Nettles, which deter pickers, were completely controlled by all treatments except post-emergence Basagran, which gave 97% control of the high population. Table 2. Oriental lilies 2007: Weed control scores (mean of three replicates) and percentage plot cover with weeds on 27 July No Herbicide active ingredient Rate product L % (product) or kg/ha May June June July July cover 27 July 1. Untreated Hand-weeded Pre-emergence 9 May 3. Venzar Flowable + Alpha Linuron 2.0 L L SC (standard UK treatment) 4. Stomp 400 SC + Sencorex WG 3.3 L kg Stomp 400 SC + Sencorex WG 3.3 L kg Butisan L 6. Sencorex WG 1.5 kg Jupiter 40%CIPC + Alpha Linuron 50 SC 6.0 L L * 1 Early post-emergence 24 May 8. Skirmish + Basagran SG 0.75 L kg Stomp 400 SC + Basagran SG 2.0 L kg * 1 Early & late post-emergence 24 May & 7 June 10. Goltix WG early & 2.5 kg & 10 Goltix + Asulox + mineral oil 2.5 kg L

33 + 3.0 L Post-emergence 7 June 11. Basagran SG 1.65 kg Sencorex WG# 1.65 kg# * groundsel remained; # spraying error All treatments gave excellent weed control with the exception of Basagran, where a few nettle and knotgrass remained. Weed cover on untreated plots was 100% by 16 June. The lily leaves were unfolded but offered little competition, with only 30% plot cover. Weeds then quickly outgrew the crop. On untreated plots on 23 June weeds were the same height as the lilies and percentage cover was 30% chickweed, 45% small nettle, 21% shepherd s purse and 4% groundsel. By 2 July untreated nettle and shepherd s purse were above crop height lilies were taller than other plots in an effort to outgrow the weeds. On 16 July weeds were above the height of lilies, and lily growth was suppressed. On plots treated with Basagran on 23 June weed cover with nettle was 0.1%. Nettle and knotgrass were above the crop, contributing to 5% cover on 27 July and weed control was only marginally acceptable. The nettles interfered with cropping but did not appear to delay maturity. On 27 July groundsel accounted for 1% weed cover on plots treated pre-emergence with Jupiter 40%CIPC + Alpha Linuron 50 SC, or early post-emergence with Stomp 400 SC + Basagran SG. Oriental lily, cv. Cassandra, were planted on 8 May and cropped 93 days later, from 9 to 13 August. Herbicide-treated plots remained virtually weed-free until cropping, with the exception of Basagran SG. Crop safety assessments for Oriental lilies in year 3 (2007) Table 3. Oriental lilies 2007: Crop tolerance to herbicides, score (0 plant death, 7 acceptable damage, 10 no damage, comparable to hand-weeded plots) assessed on several dates at growth stages of hand-weeded lilies (% leaves unfolded) 27

34 No Herbicide Rate product L or kg/ha 30 May 16 June 23 June 16 July Leaves Leaves buds buds folded unfolded enclosed emerged 1. Untreated Hand-weeded Pre-emergence 9 May 3. Venzar Flowable + Alpha 2.0 L L Linuron 50 SC 4. Stomp 400 SC + Sencorex 3.3 L kg WG 5. Stomp 400 SC + Sencorex 3.3 L kg st 4.7 st 4.3 st WG + Butisan S 1.5 L 6. Sencorex WG 1.5 kg Jupiter 40%CIPC + Alpha Linuron 50 SC 6.0 L L Early post-emergence 24 May 8. Skirmish + Basagran SG 0.75 L kg Stomp 400 SC + Basagran SG 2.0 L kg Early & late post-emergence 24 May & 7 June 10. Goltix WG early & 2.5 kg & cl 10 Goltix + Asulox + mineral oil 2.5 kg L L Post-emergence 7 June 11. Basagran SG 1.65 kg 9 cl 9 cl Sencorex WG# 0.5 kg st stunting; cl chlorosis; # followed pre-emergence Stomp + Sencorex Herbicide treatments 3-7 were applied on 9 May, a day after planting and well before full emergence of Oriental lilies on 20 May. Pre-emergence herbicides did not delay or reduce emergence of the lilies and there was no visible damage or effect on maturity from Venzar Flowable + Alpha Linuron (2.0 L +1.7 L)/ha and Stomp + Sencorex (3.3 L kg)/ha, Sencorex WG (1.5 kg) and Jupiter 40%CIPC + Alpha Linuron 50 SC (6.0 L L) (treatments 3, 4, 6 or 7) at any growth stage. The addition of a low dose of Butisan S in the tank-mix Stomp 400 SC + Sencorex WG + Butisan SG (3.3 L kg L), treatment 5, caused stunting and there was a height reduction compared with hand-weeded lilies on 16 June, leaves curled down and necrosis of 28