For more detailed information on management of Imperata cylindrica (cogon grass) please read: Imperata cylindrica (cogon grass) Management Information. The information in this document is summarised below.
Preventative measures: A Risk assessment of Imperata cylindrica for the Pacific region was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung 1995). The result is a score of 19 and a recommendation of: reject the plant for import (Australia) or species likely to be a pest (Pacific).
Results from a study by King and Grace (2000a) suggest that efforts to prevent I. cylindrica invasion should focus on preventing I. cylindrica propagules (seeds and rhizomes) from reaching sensitive communities.
Chemical control: Ramsey and colleagues (2003) report that herbicides may temporarily control I. cylindrica foliage up to 12 to 24 months (Willard et al. 1996 1997, in Ramsey et al. 2003). Without the re-establishment of desirable species, viable rhizomes will eventually allow cogon grass to re-infest the area (Shilling et al. 1995, in Ramsey et al. 2003). Controlling rhizomes with herbicides is a difficult task. A combination of glyphosate applied at 2.8 kg ai ha_1, followed by fertilization and reseeding with Bermuda grass (Cynodou doctylon) showed that rhizome reserves were sufficient for cogon grass to recover from both treatments (Johnson 1999, in Ramsey et al. 2003). In another study, cogon grass recovered after imazapyr was applied at 2.24 kg ai ha_1 in a 2-year-old loblolly pine plantation (Miller 2000, in Ramsey et al. 2003). Even these relatively high herbicide application rates there is still a remnant population of viable rhizomes that has the potential to re-infest the treated site. Further research is needed to integrate herbicide usage, which provides short-term control and a ‘‘window for re-establishment’’, with bio-control using desirable, yet highly productive plant species for long-term control (Ramsey et al. 2003).
Recommendations (Demers et al. 2008) to control cogon grass in the southeastern USA are to treat infestations in autumn (May through to October) with glyphosate and/or imazapyr herbicides. These recommendations are consistent with a wide range of studies conducted (Miller 2003, Faircloth et al. 2005, in Demers et al. 2008). Fluazifop is also an effective option (Demers et al. 2008). Guidelines for herbicide control are detailed by Demers and colleagues (2008).
Integrated management : Shade, repeated herbicide application, and mechanical control have all been used to control I. cylindrica (Macdicken et al. 1997, Terry et al. 1997, in Brewer & Cralle 2003). An integrated approach that combines burning, tillage (mechanical control) and chemical applications provide the best approach for cogon grass management (MacDonald et al. 2009). Cogon grass should first be burned or mowed, preferably in summer, to remove excess thatch and older leaves. Subsequent regrowth (of one to four months) will reduce rhizome biomass and allow herbicides to target actively growing leaves which maximises herbicide effectiveness. Once control of cogon grass has been achieved planting of desirable vegetation should occur as quickly as possible to prevent reinvasion (MacDonald et al. 2009).
Other: Brewer and Cralle (2003) found that short-lived, high-level pulses of phosphorus addition reduce the competitive advantage I. cylindrica has over native plants without negatively affecting native plant diversity. Additional work is needed, however, to elucidate the mechanism of inhibition of I. cylindrica by P addition (Brewer & Cralle 2003).
Location Specific Management Information
Almost all farmers (94%) surveyed in Benin applied some strategies for I. cylindrica management. These strategies are integrated control options which comprise slashing, burning, ridging and rotating cowpea with maize. A guide for improved management of speargrass at farm level was jointly developed with participating farmers. This new set of practices includes deep ridging taking into account depth where rhizomes are found; sowing of cowpea or pigeonpea cultivars at higher density to shade cogon grass shoots; deep hoe-weeding; hand pulling whenever necessary; treatment of cowpea to prevent damage by defoliating insects; and deep ridging by incorporating cowpea residues into the soil. Farmers’ evaluation of improved management showed that the effectiveness of this scheme depends on the time during which is shaded. Therefore, the set of practices should be repeated the following year, if cogon grass is not sufficiently suppressed. The bottleneck, which may constrain adoption of these integrated practices, is labour shortage. The integrated practice is three times as labour demanding as farmers’ practices. Farmers stated that despite labourers receiving a great deal of money, as well as food and drink, deep ridging was not properly done unless the farmer involved himself to set a good example. Women reported they were cheated by laborers who did not ridge and hoe weed as deeply as expected (Vissoh et al. 2008).
With less than 50 known infestations Imperata cylindrica is an emerging invasive species in Georgia. State and federal agencies, university personnel, and Georgia Exotic Pest Plant Council members have combined to form the Georgia Invasive Species Task Force. The task force has adopted a four-fold approach to managing cogon grass in Georgia: (1) management of known infestations, (2) discovery of any existing but unknown infestations, (3) reduction of pathways of spread, and (4) preparation for new infestations. United States Department of Agriculture, Animal and Plant Health Inspection Service - Plant Protection and Quarantine, or Georgia Forestry Commission personnel are currently administering control efforts on known infestations. University of Georgia faculty and staff are maintaining a database of known infestations and have created an online mapping program of their locations. Plans are underway to implement on-the-ground and remote sensing surveys to aid in discovering new infestations. Workshops, educational materials, and press releases are all being used to inform and educate the public on this new threat. To prepare for the inevitable increase in new infestations, the Georgia Invasive Species Task Force is developing protocols for handling new finds, initiating a land-owner assistance program, and training agency and Extension agents on identification, management, and control of cogon grass.
In Ghana, fifty-one percent of farmers reported of inadequate level of control of Imperata cylindrica with current control practices. Farmers relied mainly on manual methods of weed control supplied mostly by family labor. Glyphosate was applied on fields with > 50% cogon grass cover. Follow-up weed control could be required 3-6 times/season depending on initial land preparation, type of crop and/or level of infestation. Cost of weed control was 20–60% higher on cogon grass-infested field ($71/weeding/ha) than on other fields, and weeding may take 20–25 man-days/ha. The development of a comprehensive management strategy for I. cylindrica and other weeds should be a priority research because the weed threatens the livelihood of over 200 million people in West Africa. (Bolfrey-Arku et al, undated).
The use of GIS was found to be effective in mapping and detailing an herbicide control strategy for Imperata cylindrica in Camp Shelby Joint Forces Training Center Mississippi (Yager & Smith 2009).
A study of I. cylindrica management in Nigerian corn fields evaluated the following methods: tilling, glyphosate application and planting of velvetbean. The study found an integration of all three to be most effective (Chikoye et al. 2005).
Nicosulfuron was found to be an effective herbicide in controlling I. cylindrica in corn fields of Nigeria when applied at concentrations of 70 and 105 g a.i. ha-1 (Lum et al. 2004).
Riam Kiwa trial area
In 1983 the Reforestation and Natural Forest Management Project, part of the Indonesian-Finland Forestry Programme, established a trial area in Riam Kiwa in order to study methods of reforestation. Today, 60% of the 1000 hectare trial area in Riam Kiwa has been reforested. 10 to 15 species were found promising for grassland restoration and different plantation methods have been tested (Otsamo et al in press, in Jussi et al 1995). Problems of reforestation have been studied for over ten years in the area (as of 1995) and both fast-growing exotics and indigenous species have been planted and evaluated including dipterocarps such as Schorea spp., Hopea spp. and Vatica spp (Jussi et al 1995). Several exotics have shown promising results in terms of growth and suppressing I. cylindrica. Successful establishment of these species requires heavy site preparation, which turns over the rhizomes of I cylindrica and improves the rooting of tree seedlings (Otsamo et al in press, in Jussi et al 1995). The plantations create microclimate and soil conditions that improve the germination and survival rates of species unable to germinate in the open or within I. cylindrica grass cover. Most of the tree species spread naturally to the plantation and are fruit-bearing plants with animal vectors (notably birds and bats) as the principle dispersal mechanism. This suggests that plantation canopy promotes the regeneration process by providing roosting habitats for seed-dispersing animals. The majority of tree species dispersed into the plantations belong to the pioneer or secondary forest species characterised by effective means of rapid dispersal.
Royal Bardia National Park
Grasslands (or phantas) may occur as a result of anthropogenic disturbance (Pokharel 1993, in Peet et al. 1999). The I. cylindrica grassland is important for biodiversity. Cutting and fire have been promoted to prevent succession from grassland to forest or taller grassland (dominated by Erianthus, Narenga and Saccharum species (which are less favourable to ungulates). However traditional cutting and burning has been deleterious to less mobile species such as the pygmy hog and hispid hare (Oliver 1980, Bell, Oliver and Ghose 1990, in Peet et al. 1999).
A study by Peet and colleagues (1999) was designed to investigate best management practices for preserving cover-dependant species such as the hispid hare, in particular whether rotational patches of unmanaged grassland could provide refugees for these species. The experimental site was located in Baghoura Phanta, the second largest Imperata dominated grassland (covering approximately 80 hectares). A randomised block experiment (with four treatments: cutting, burning, cutting and burning, and no management) was used to examine species abundance, richness and grassland structure. In all managed plots there was in increase in species richness of forbs, a decrease in D. bipinnata and an increase in I. cylindrica. The authors concluded that rotational cutting and burning of the grassland would provide suitable habitat for the population persistence of small mammals, herpetofauna and invertebrates. In Bardia the total area of I. cylindrica grassland is small (less than 340 hectares) so the total area removed by cutting and burning should not be more than 25 to 50 hectares.
Yap Is. (Yap Islands)
I. cylindrica has been evaluated and eradication recommended (Space & Falanruw 1999).
1. Bolfrey-Arku, G.E., Onokpise, O.U., Carson, A., Shilling, D.G., Coultas, C. Undated. The Speargrass (Imperata cylindrica (L) Beauv.) Menace in Ghana: Incidence, Farmer Perceptions and Control Practices in the Forest and Forest-Savanna Transition Agro-ecological Zones of Ghana.
2. Brewer, J. Stephen and Cralle, Sean P. 2003. Phosphorus addition reduces invasion of a longleaf pine savanna (Southeastern USA) by a non-indigenous grass (Imperata cylindrica). Plant Ecology. 167(2). 2003. 237-245.
4. Chikoye, D., Manyong, V. M., Ekeleme, F. 2000. Characteristics of speargrass (Imperata cylindrica) dominated fields in West Africa: Crops, soil properties, farmer perceptions and management strategies. Crop Protection. 19(7). August, 2000. 481-487.
5. Chikoye, David, Ellis-Jones, Jim, Avav, Ter-Rumun, Kormawa, Patrick M., Udensi, E. Udensi, Tarawali, Gbassey, Nielsen, Ole K. 2007. Promoting integrated management practices for speargrass (Imperata cylindrica (L.) Raeusch.) in soybean, cassava and yam in Nigeria. Journal of Food Agriculture & Environment. 5(3-4). JUL-OCT 2007. 202-210.
6. Chikoye, David, Ellis-Jones, Jim, Kormawa, Patrick, Udensi, Udensi E., Ibana, Simon E., Avav, Ter-Rumun. 2006b. Options for cogongrass (Imperata cylindrica) control in white Guinea yam (Dioscorea rotundata) and cassava (Manihot esculenta). Weed Technology. 20(3). JUL-SEP 2006. 784-792.
7. Chikoye, David, Ellis-Jones, Jim, Tarawali, Gbassey, Kormawa, Patrick, Nielsen, Ole, Ibana, Simon, Avav, Ter-Rumun. 2006a. Farmers' perceptions of the speargrass (Imperata cylindrica) problem and its control in the lowland sub-humid savannah of Nigeria. Journal of Food Agriculture & Environment. 4(3-4). JUL-OCT 2006. 118-126.
8. Chikoye, David, Udensi, Udensi E., Ogunyemi, Shola. 2005. Integrated management of Cogongrass [Imperata cylindrica (L.) Rauesch.] in corn using tillage, glyphosate, row spacing, cultivar, and cover cropping. Agronomy Journal. 97(4). JUL-AUG 2005. 1164-1171.
9. Chikoye, David., 2003. Characteristics and management of Imperata cylindrica (L.) Raeuschel in smallholder farms in developing countries. In Weed Management for Developing Countries Addendum 1 (Ed) by R. Labrada. Food And Agriculture Organisation Of The United Nations (FAO) Rome
10. Cummings, Jason, Reid, Nick, Davies, Ian, Grant, Carl. 2005. Adaptive restoration of sand-mined areas for biological conservation. Journal of Applied Ecology. 42(1). February 2005. 160-170.
11. Daneshgar, Pedram; Shibu Jose, Alexandra Collins, and Craig Ramsey., 2008. Cogongrass (Imperata cylindrica), an Alien Invasive Grass, ReducesSurvival and Productivity of an Establishing Pine Forest. Forest Science 54(6) 2008
13. Dozier, Hallie, Gaffney, James F., McDonald, Sandra K., Johnson, Eric R. R. L., Shilling, Donn G. 1998. Cogongrass in the United States: History, ecology, impacts, and management. Weed Technology. 12(4). Oct.-Dec., 1998. 737-743.
15. Evans, Christopher W., Moorhead, David J., Bargeron, Charles T., Douce, G. Keith. 2007. Implementation of control and prevention strategies for managing cogongrass (Imperata cylindrica) by the Georgia Invasive Species Task Force. Natural Areas Journal. 27(3). JUL 2007. 226-231.
17. Holly, D. Christopher and Ervin, Gary N. 2006. Characterization and quantitative assessment of interspecific and intraspecific penetration of below-ground vegetation by cogongrass (Imperata cylindrica (L.) Beauv.) rhizomes. Weed Biology & Management. 6(2). 2006. 120-123.
18. Hutchinson, Jeffrey T., MacDonald, Gregory E., Langeland, Kenneth A. 2007. The potential for herbicide resistance in non-native plants in Florida's natural areas. Natural Areas Journal. 27(3). JUL 2007. 258-263.
20. Jussi, K., Goran, A., Yusuf, J., Antti, O., Kari, T. and Risto, V. 1995. Restoration of Natural Vegetation in Degraded Imperata cylindrica Grassland: Understorey Development in Forest Plantations, Journal of Vegetation Science 6. [Accessed 13 March 2006, from Jstor (online database)]
Summary: Paper on the restoration of I. cylindrica wastelands in an Indonesian site via secondary exotics.
21. Kaewkrom, Puangpaka, Gajaseni, Jiragorn. 2006. Effects of two combinations of multi-purpose species plantations on Imperata cylindrica in restoring site, Northern Thailand. Indian Forester. 132(5). MAY 2006. 565-574.
22. King, Sharon E. and Grace, James B. 2000a. The effects of gap size and disturbance type on invasion of wet pine savanna by cogongrass, Imperata cylindrica (Poaceae). American Journal of Botany. 87(9). July, 2000. 1279-1286.
23. King, Sharon E. and Grace, James B. 2000b. The effects of soil flooding on the establishment of cogongrass (Imperata cylindrica), a nonindigenous invader of the southeastern United States. Wetlands. 20(2). June, 2000. 300-306.
24. Langeland, K.A. 2003. Help Protect Florida's Natural Areas from Non-Native Invasive Plants. Circular 1204 University of Florida (IFAS Extension) This document is Circular 1204, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published March 1998. Revised April 2003.
25. Lippincott, Carol L. 2000. Effects of Imperata cylindrica (L.) Beauv. (cogongrass) invasion on fire regime in Florida sandhill (USA). Natural Areas Journal. 20(2). April, 2000. 140-149.
26. Lum, A. F., Chikoye, D., Adesiyan, S. O. 2004. Evaluation of nicosulfuron for control of speargrass (Imperata cylindrica (L.) Raeuschel) in Nigeria. International Journal of Pest Management. 50(4). October 2004. 327-330.
28. MacDonald, Gregory. 2004. Cogongrass (Imperata cylindrica)—Biology, Ecology, and Management. Critical Reviews in Plant Sciences, 23(5):367–380 (2004).
29. McNamara, Sean, Tinh, Duong Viet, Erskine, Peter D., Lamb, David, Yates, David, Brown, Sharon. 2006. Rehabilitating degraded forest land in central Vietnam with mixed native species plantings. Forest Ecology & Management. 233(2-3). SEP 15 2006. 358-365.
30. Nielsen, Ole K., Chikoye, David, Streibig, Jens C. 2005. Efficacy and costs of handheld sprayers in the subhumid savanna for cogongrass control. Weed Technology. 19(3). JUL-SEP 2005. 568-574.
31. Peet, N.B., Watkinson, A.R., Bell, D.J. and Sharma, U.R. 1999. The Conservation Management of Imperata cylindrica Grassland in Nepal With Fire and Cutting: An Experimental Approach, Journal of Applied Ecology 36. [Accessed 13 March 2006, from Jstor (online database)]
Summary: Rationale behind cutting and fire practises in Imperata grasslands in Nepal.
32. Peet, Nicholas B., Watkinson, Andrew R., Bell, Diana J., Sharma, Uday R. 1999. The conservation management of Imperata cylindrica grassland in Nepal with fire and cutting: An experimental approach. Journal of Applied Ecology. 36(3). June, 1999. 374-387.
33. Perkins, Reed M. & Wei-Ning Xiang ., 2006. Building a geographic info-structure for sustainable development planning on a small island developing state. Landscape and Urban Planning 78 (2006) 353–361
34. Ramsey, Craig L.; Shibu Jose, Deborah L. Miller, Joseph Cox, Kenneth M. Portier, Donald G. Shilling and Sara Merritt., 2003. Cogongrass [Imperata cylindrica (L.) Beauv.] response to herbicides and disking on a cutover site and in a mid-rotation pine plantation in southern USA. Forest Ecology and Management Volume 179, Issues 1-3, 3 July 2003, Pages 195-207
37. Swarbrick, J. T. and Hart, R. 2001. Environmental weeds of Christmas Island (Indian Ocean) and their management. Plant Protection Quarterly. 16(2). 2001. 54-57.
38. Terry, P. J.; G. Adjers, I. O. Akobundu, A. U. Anoka, M. E. Drilling, S. Tjitrosemito and M. Utomo., 1996. Herbicides and mechanical control of Imperata cylindrica as a first step in grassland rehabilitation. Agroforestry Systems Volume 36, Numbers 1-3 / December, 1996
40. Udensi, Udensi E., Akobundu, I. Okezie, Ayeni, Albert O., Chikoye, David. 1999. Management of cogongrass (Imperata cylindrica) with velvetbean (Mucuna pruriens var. utilis) and herbicides. Weed Technology. 13(2). April-June, 1999. 201-208.
41. Van Loan, A.N. Meeker, J.R. and Minno, M.C. Cogon Grass In: Van Driesche, R. et al., 2002, Biological Control of Invasive Plants in the Eastern United States, USDA Forest Service Publication FHTET-2002-04. [Accessed 13 March 2006, from http://www.invasive.org/eastern/biocontrol/28CogonGrass.html]
Summary: Overview of the biology and status of I. cylindrica in the USA.
42. Vissoh, P. V., Gbehounou, G., Ahanchede, A., Kuyper, T. W., Roling, N. G. 2004. Weeds as agricultural constraint to farmers in Benin: results of a diagnostic study. NJAS Wageningen Journal of Life Sciences. 52(3-4). DEC 04. 305-329.
43. Vissoh, Pierre V., Kuyper, Thomas W., Gbehounou, Gualbert, Hounkonnou, Dominique, Ahanchede, Adam, Roling, Niels G. 2008. Improving local technologies to manage speargrass (Imperata cylindrica) in southern Benin. International Journal of Pest Management. 54(1). 2008. 21-29.
44. Wilson, Colin, Wildlife Management Officer, Department of Infrastructure, Planning and Environment, Parks & Wildlife Service, Northern Territory, Australia.
Summary: Compilor of original GISD profile of Chromoleana odorata.
45. Yager, Lisa Y.and Matt Smith., 2009. Case Study: Use of GIS to Prioritize Cogongrass (Imperata cylindrica) Control on Camp Shelby Joint Forces Training Center, Mississippi. Invasive Plant Science and Management 2009 2:74–82
47. Yandoc, C.B. R. Charudattan and D.G. Shilling. 2004. Suppression of cogongrass (Imperata cylindrica) by a herbicidal fungus and plant competition. Weed Science 52: 649-653.
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