Research into weed biology and control at Massey University has covered many different areas over the past few decades. Some of the main topic areas have been:
Ground covers in orchards
Much of our recent research has centred on investigating whether ground covers can be grown under orchard trees to replace residual herbicides for weed control. The low-growing ground covers need to be competitive enough to stop new weeds from establishing yet small enough that they do not compete with the fruit trees. We have been looking for ground cover species which tolerate a number of herbicides so that any weeds that do establish can be selectively removed in winter while the trees are dormant. We have investigated about 15 different ground cover species for their suitability as weed-smothering ground covers under fruit trees. Some published papers describing this research include:
Harrington, K.C. and Grant, M.R. (1993). Herbicide tolerance of potential orchard ground covers. Proceedings Asian-Pacific Weed Conference 14: 256-260.
Harrington, K.C. (1995). Establishment of several ground covers in an orchard. Proceedings New Zealand Plant Protection Conference 48: 68-71.
Harrington, K.C. and Rahman, A. (1998). Herbicide tolerance of ground cover species for New Zealand. Plant Protection Quarterly 13: 111-116.
Harrington, K.C. and Zhang, T. (1997). Herbicides for controlling weeds in Mercury Bay weed. Proceedings New Zealand Plant Protection Conference 50: 462-466.
Hartley, M.J., Rahman, A., Harrington, K.C. and James, T.K. (2000). Assessing ground covers in a newly planted apple orchard. New Zealand Plant Protection 53: 22-27.
Harrington, K.C., Anderson, B.J. and Cameron, E.A. (2002). Establishment techniques for dichondra ground covers in orchards. New Zealand Plant Protection 55: 202-206.
Clark, P.J., Long, P.G. and Harrington, K.C. (2002). Mycorrhizal fungi in Whangarei avocado orchards. New Zealand Plant Protection 55: 440.
Harrington, K.C., Hartley, M.J., Rahman, A. and James, T.K. (2002). Strategies for controlling weeds in New Zealand apple orchards. Proceedings of 13th Australian Weeds Conference, pp 208-21.
Harrington, K.C. and Bedford, T.A. (2004). Control of weeds by paper mulch in vegetables and trees. New Zealand Plant Protection 57: 37-40.
Harrington, K.C., Hartley, M.J., Rahman, A. and James, T.K. (2005). Long term ground cover options for apple orchards. New Zealand Plant Protection 58: 164-168.
Herbicide resistance
Every year, large amounts of phenoxy herbicides such as MCPA and 2,4-D are applied to New Zealand pastures to control weeds such as thistles and ragwort. As a result of applying the same herbicide year after year, our research group have discovered biotypes of nodding thistle (Carduus nutans) and slender winged thistle (Carduus pycnocephalus) which have developed resistance to these herbicides. We have investigated how widely this phenomenon has occurred within New Zealand for nodding thistle, looked at which other herbicides are now no longer effective against these plants, tackled the physiological mechanism for the resistance and developed control recommendations. Some published work on this includes:
Harrington, K.C., Popay, A.I., Robertson, A.G. and McPherson, H.G. (1988). Resistance of nodding thistle to MCPA in Hawkes Bay. Proceedings New Zealand Weed and Pest Control Conference 41: 219-222.
Harrington, K.C. (1989). Distribution and cross-tolerance of MCPA-tolerant nodding thistle. Proceedings New Zealand Weed and Pest Control Conference 42: 39-42.
Harrington, K.C. (1992). Aspects of resistance to phenoxy herbicides in nodding thistle (Carduus nutans L.). Unpublished PhD thesis, Massey University, Palmerston North. 196 pp.
Harrington, K.C. (1996). Herbicide management and thistle control - how to avoid resistance. Plant Protection Quarterly 11: 273-275.
Harrington, K.C. (1996). Strategies for managing herbicide resistance. In G.W. Bourdot and D.M. Suckling (Eds): Pesticide Resistance - Prevention and Management (pp 91-98), New Zealand Plant Protection Society, Rotorua.
Harrington, K.C. and Hewage, N. (1997). Resistance of slender winged thistle to MCPA. Proceedings New Zealand Plant Protection Conference 50: 538.
Harrington, K.C., Ward, A.J. and Wells, D.M. (2001). Herbicide resistance in black nightshade and Onehunga weed. New Zealand Plant Protection 54: 152-156.
Harrington, K.C. (2002). Recent herbicide resistance research in New Zealand. Proceedings of 13th Australian Weeds Conference, pp 622-624.
Harrington, K.C. and Woolley, D.J. (2006). Investigations of how phenoxy-resistant Carduus nutans biotypes survive herbicide spraying. New Zealand Journal of Agricultural Research 49 : 465-474.
Martin, N.A., Beresford, R.M. and Harrington, K.C. (2005) (eds): Pesticide Resistance - Prevention and Management Strategies 2005. New Zealand Plant Protection Society, Hastings. 166 pp.
Beresford, R.M., Follas, G.B., Hagerty, G.C., Harrington, K.C. and Martin, N.A. (2009). The New Zealand Committee on Pesticide Resistance (NZCPR). New Zealand Plant Protection 62: 393-394.
Weed control in novel crops
Whenever a new crop species is grown, weeds are often a major problem as little information often exists on how to control weeds in these crops. As a result of research at Massey University by agronomy and seed technology colleagues into new crop species, we have conducted a number of trials to determine the best way to control weeds within these species. Some of these projects are included below:
Askarian, M., Hampton, J.G. and Harrington, K.C. (1993). Control of weeds, and particularly white clover (Trifolium repens), in lucerne (Medicago sativa) grown for seed production. Journal of Seed Production 11: 51-55.
Harrington, K.C. and Fakava, V.T. (1993). Herbicide tolerance of garden nasturtium (Tropaeolum majus). Proceedings New Zealand Plant Protection Conference 46: 49-52.
MacKay, T.J. and Harrington, K.C. (1994). Weed control in calla seedlings. Proceedings New Zealand Plant Protection Conference 47: 163-167.
Waugh, C.D. and Harrington, K.C. (1994). Herbicide tolerance and weed control in meadowfoam (Limnanthes alba). Proceedings New Zealand Plant Protection Conference 47: 168-172.
Harrington, K.C. and Chioco, L.R. (1995). Herbicide tolerance of Viola cornuta. Proceedings New Zealand Plant Protection Conference 48: 335-336.
Turf weed control
Due to our involvement with the New Zealand Sports Turf Institute, we have conducted a number of projects on controlling weeds in turf. Much of this work has involved working with cotula, which are Leptinella species used for lawn bowls in New Zealand. As this turf species belongs to the same family as many important weed species (Asteraceae), some of the herbicides used in these bowling greens are different to those traditionally used in grass greens. Relevant publications include:
Harrington, K.C. (1993). Weed control in turf. New Zealand Turf Management Journal 7(4): 28-29.
Harrington, K.C. (1994). Weed control in cotula. New Zealand Turf Management Journal 8(2): 19-22.
Fleming, P., Harrington, K. and Wrigley, M. (1996). Controlling Poa trivialis in racetracks. New Zealand Turf Management Journal 10(4): 22-24.
Harrington, K.C. (1997). Controlling weeds in new cotula greens: some new options. New Zealand Turf Management Journal 11(4): 24-26.
Harrington, K.C. (1998). Clover control in cotula. New Zealand Turf Management Journal 12(1): 18-19.
Harrington, K. and Williams, M. (1998). Quantifying bromacil residues in bowling greens. New Zealand Turf Management Journal 12(2): 33-35.
Harrington, K. and Williams, M. (1999).Selectivity of cotula herbicides throughout the year. New Zealand Turf Management Journal 13(3): 27-29.
Harrington, K.C., Hood, M.Z. and McKinnon, K.C. (2000). Assessment of two herbicide wiping devices. New Zealand Plant Protection 53: 273-276.
Harrington, K.C. (2000). Weeds of lawns and sports turf - identification and control. NZ Sports Turf Institute, Palmerston North. 56 pp.
Harrington, K.C. (2003). Controlling weeds within dichondra (Mercury Bay weed) lawns. New Zealand Turf Management Journal 18(2): 18-20.
Other research
Other topics covered in recent research projects have included use of goats for controlling pasture weeds; control of two environmental weeds, one called pypgrass (Ehrharta villosa) in sand-dune communities and the other was Madeira vine (Anredera cordifolia); studying the biology and control of ragwort in pastures; investigating the persistence of metsulfuron in forestry soils; and surveying weed control practices in New Zealand orchards. Present trials include looking at weed control strategies for the crop stevia, and assessing use of weed wipers. Some of this research has yet to be published, but some relevant papers include:
Beskow, W.B., Harrington, K.C., Betteridge, K. and Beskow, A.M.S. (1994). Ragwort (Senecio jacobaea) control by sheep in a hill country bull beef system. Proceedings New Zealand Plant Protection Conference 47: 49-52.
Harrington, K.C., Hodder, L.M. and Outred, H.A. (1998). Biology and control of pypgrass. Proceedings New Zealand Plant Protection Conference 51: 255-259.
Sims, R.E.H., Berry, S.B. and Harrington, K. (1994). Herbicide application equipment use in New Zealand pipfruit orchards. Journal of Agricultural Engineering Research 59: 121-131.
Harrington, K.C., Berry, S.B. and Sims, R.E.H. (1992). A survey of weed control practices in New Zealand pipfruit orchards. Proceedings New Zealand Plant Protection Conference 45: 285-288.
Armstrong, M.L., Harrington, K.C. and Seefeldt, S.S. (2002). Weed establishment in the second year after high pasture sowing rates. New Zealand Plant Protection 55: 116-120.
Armstrong, M.L., Seefeldt, S.S. and Harrington, K.C. (2001). Effect of perennial ryegrass density on ragwort emergence. New Zealand Plant Protection 54: 111-115.
Webb, H.J. and Harrington, K.C. (2005). Control strategies for Madeira vine (Anredera cordifolia). New Zealand Plant Protection 58: 169-173.
Harrington, K.C., Thatcher, A. and Kemp, P.D. (2006). Mineral composition and nutritive value of some common pasture weeds. New Zealand Plant Protection 59 : 261-265.
Moyo, C., Harrington, K.C., Kemp, P.D. and Eerens, J.P.J. (2006). Wiper application of herbicides to Californian thistles. New Zealand Plant Protection 59: 361.
Harrington, K.C. and Schmitz (2007). Initial screening of herbicides tolerated by native plants. New Zealand Plant Protection 60: 133-136.
Moyo, C., Harrington, K.C., Kemp, P.D. and Eerens, J.P.J. (2007). Effectiveness of spraying herbicides on the centre compared to the whole plant of Scotch thistle (Cirsium vulgare) rosettes. New Zealand Plant Protection 60: 321.
Harrington, K.C., Osborne, M.A. and Kemp, P.D. (2008). Weed cover unaffected after converting a dairy farm to organic production. New Zealand Plant Protection 61: 116-120.
Moyo, C., Harrington, K.C., Kemp, P.D. and Eerens, J.P.J. (2008). Herbicide deposition on weeds from weed wipers. New Zealand Plant Protection 61: 395.
Foo, C.L., Harrington, K.C., MacKay, M.B. and Wrigley, M.P. (2009). Establishment rate of 12 ornamental ground cover species for weed control. New Zealand Plant Protection 62: 415.
Harrington, K.C. and Gregory, S.J. (2009). Field assessment of herbicides to release native plants from weeds. New Zealand Plant Protection 62: 368-373.