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1 Final Research Report for Bowls New Zealand Control of Starwe eed using III 2015/ 16

2 Prepared By: Dr Andrew Mitchell New Zealand Sports Turf Ititute DDI: Mobile: Job Reference: Prepared For: Final Research Report Control of Starweed Using II Bowls New Zealand Disclaimer This report has been prepared by the New Zealand Sports Turf Ititute (NZSTI) specifically for use by the client for the identified project or location. No respoibility will be accepted by NZSTI for the use of the information by other parties or for other purposes. Conditio of Copyright The contents of this report are copyright of the New Zealand Sports Turf Ititute (NZSTI). The information shall not be copied or reproduced in any form or by any mea without the written approval of NZSTI. New Zealand Sports Turf Ititute Ltd Acknowledgement NZ Sports Turf Ititute would like to acknowledge Bowls NZ for their support and funding of this trial.

3 Table of Contents 1. Trial Objectives Materials and Methods Trial details... 1 Variety details Trial itallation and maintenance... 1 Treatments... 2 Assessments... 3 Statistical analysiss Results Conclusion... 5 Appendix 1: Photographs of treatment damage... 7 i

4 1. Trial Objectives The aim of this second trial was to: 1. Determine the efficacy of sequential applicatio of herbicide (375 g/l a.i.) applied at 4 to 6 week intervals at two rates of application 1.05 and a 2.1 L/haa (140.7ml and 281.4ml per 1340m 2 bowling green) in controlling starweed 2. To test the tolerance of cotula dioica and cotula maniototo to repeated applicatio of Materials and Methods Trial details Location: Dates established: Soil type: Pot size: Trial design: NZSTI, 163 Old Westt Road, Palmerston North Week of 1 September mm Ruamahanga River sand amended with w 30% byy volume Hauraki Gold peat moss. Cotula and starweed plants weree grown in PB3 P size planter bags (120mm dia. x 120mm H.) filled with approximately 1.8L 1 of sand/ peat moss mix. Treatments were allocated randomly to established planter bags with four replicates used for the each application of. M 2.2 Variety details Species grown: Cotula dioica (Leptinella dioica) Cotula maniototo (Leptinella maniototo) Starweed (Plantago triandra) 2.3 Trial itallation and maintenanc ce Establishment method: Fertiliser: Cotula dioica andd maniototo was established fromm three 20mm plugs of established plantss per bag; starweed was w established from 5-6 cores of small starweed plants per bag. The cotula and starweed plants were fertilised threee times over the course of the trial t (15/9/2015, 17/11/2015 and 12/2/2016) ), with the equivalent of 2.2g N/m 2 applied as ammonium sulphate, 2.2g K/m 2 as potassium sulphate and 0.8g Mg/m 2 as magnesium sulphate. The fertiliser was dissolved in water, applied with a watering can and then watered in to avoid any burning. 1

5 Weed control: Iect pests: Disease control: Irrigation: Cutting: Pots were hand weeded prior to each M application and prior to any assessments of plant quality/ damage. A severe outbreak of mealy bug (Pseudococcuss spp.) in late summer caused coiderable damage to both thee cotula species, particularly to the cotula maniototo and since the end of the trial has caused the complete loss of both the treated and mostt of the untreated cotula maniototo pots. No disease control required. Applied as required. Both the starweedd and cotula has been allowed a to grow naturally. 2.4 Treatments The treatments applied in the trial includedd the following: Treatment 1: 1.05L/ha (375 g/l 1340m 2 green a.i.), equivalent to 140.7ml 1 (375 g/l a.i.) per Treatment 2: Treatment 3: 2.1L/ /ha (375( g/l a.i.), equivalent to 281.4ml (375 g/l a.i.) ) per 1340m green Control (untreated) m 2 The was sprayed on using a calibrated 5L hand held pressure sprayer using the equivalent of 350L/ha of water (46.9L of water per 1340m 2 green). Treatments were applied on following dates: 8 December 2015, 14 January and 26 February 2016 (Figure 1) ). Figure 1: Replicates ready for spraying 2

6 2.5 Assessments Plants within each PB3 were scored for damage using a scale ranging from 1 to 9 where 1 represents all plants completely dead and 9 represents no sign of o herbicide damage or checking of growth. Assessments of damage occurred as stated in Table 1. Table 1: Date Dates on which assessment ts of plant damage were undertaken Description 8 December December January February April 2016 Before 1st application 1 week after first application of Before 2nd application Before 3rd application of 6 weeks after last application 2.6 Statistical analysis Results were statistically analysed usingg multiple sample comparison function of Statgraphics Centurionn XV version with the least significant difference (LSD) used to determine differences in the degree of damage with each species and overall mean treatment damage at the 5% probability level. Mea were groupedd using Duncan s Multiple Rangee Test. Mea with the same letter in each column for f each species are not significantly different. Note: = not significant. 3. Results Sig of damage in both the cotula plants were similar to those recorded in the t previous trial. In cotula dioica, the applicatio, particularly at thee high rate (2.1L/ha or 281.4ml per 1340m 2 green) causedd yellowing of the foliage, a slowing of growth, followed by some browning off of the leaves and thinning of growth. In cotula maniototo the applicatio caused a browning and/or silvering off of the foliage with some minor loss of foliage. This wass most notable at the higher ratee of (2.1L/ha or 281.4ml per 1340m 2 green). However, generally, A damage on the cotula maniototo plants didd not appear to be as severe as was observed on the cotula dioica until mealy bug started to attack the plants during March In the starweed plants, both rates of caused significant damage d to the plants as indicated by yellowing followed by death of the older foliage. As recorded in the previous trial, a single application of did not kill the growing point of the starweed. However, subsequent applicatio have reduced the growing points vigour ultimately, leading too a complete kill of the starweed after 3 applicatio of at either rate used in the trial. t The first application of (8 December 2015) resulted in some significant (P<0.05) damage to the starweed at the first assessment, (1 week after application on o 16 December) but no significant 3

7 damage to either cotula species (Table 2, Appendix 1). However, by about six weeks (14 January) after the first application, significant damage was recorded to both cotula species and the starweed. Subsequent applicatio of have not caused any further damage to the cotulas, the four to six week period between applicatio giving sufficient time for some recovery to occur (Table 2, Appendix 1). However, after the final application (26 February), at the high rate plus damage caused by a major infestation of mealy bug (Figure 2) has resulted in almost total loss of cotula maniototo by the assessment on 7 April. Mealy bug damage has also resulted in coiderable loss of cotula maniototo in the control and low rate of treatments. At the final assessment all the starweed plants treated with at either rate of application were dead. Figure 2: Mealy bug caused coiderable damage to both cotulas between mid-march and April assessment 4

8 Table 2: Mean treatment scores Species Treatment Assessment dates 8 December* 16 December 14 January 266 February 7 April C. dioica Control a a 1.05L/ha b a 2.1L/ha c b P value Lsd Cv% C. maniototo Control a 9 3.5a 1.05L/ha a a 2.1L/ha b 9 1.5b P value Lsd Cv% Starweed Control 9.0 9a 9a 9a 7.5a 1.05L/ha b 5.8b 3.3b 1.0b 2.1L/ha b 3.5c 1.8c 1.0b P value Lsd Cv% * applied on 8 December 2015, 14 January 2016 and 26 February F Conclusionn This second trial has shown that repeat applicatio of (375 g/l a..i.) at 1.05 and 2.1L/ha (140.7ml and 281.4ml per 1340m 2 respectively) will eventually kill starweed. As observed in the previous trial, a single application at either rate will not kill the starweed, a further two additional applicatio were required to give a complete kill. The results also show that C. dioica and C. maniototo are reasonablyy tolerant of the three applicatio of used in the trail when applied approximately four to six weeks apart. However, applied particularly, at thee higher rate of 2.1L/haa (281.4ml per 1340m 2 green) may cause unacceptable damage to cotula plants that are already under stress from some other factor such as an iect attack. In common with other herbicides, should only be applied to plants that are actively growing and not suffering any other form of growth stress. Note: According to the New Zealand Novachem Agrichemical Manual website straight formulatio of containing 375 g/l a.i. are no longer available, so will disappear from supplier s shelves. The now available in New Zealand contai higher concentratio of off 750 g/l a..i. Therefore, it will need to be applied at rates half of those discussed in thiss article (i.e and 1.05L/ha or and 140.7ml per 1340m 2 green). There are also a other herbicides available that 5

9 contain as a mixture with other active ingredients. So always check the label of the spray you are planning on using to check the concentration of active ingredient (a.i.) and whether the spray contai other actives that may damage desirable species. 6

10 Appendix 1: C. dioica Photographs of treatment damage 16 December 14 January 26 February 7 March 15 March Trt. 1 Trt. 2 Trt. 3 7

11 C. maniototo 16 December 14 January 26 February 7 March 15 March Trt. 1 Trt. 2 Trt. 3 8

12 Starweed 16 December 14 January 26 February 7 March 15 March Trt. 1 Trt. 2 Trt. 3 9

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