1. Why Leucaena?
2. Is my location suitable?
3. Is my soil suitable?
4. Which variety?
5. Land preparation & planting
6. Companion grasses
7. Leucaena control
8. There is always a pest
9. Where to now?
Welcome to our step by step guide to Leucaena
1. why leucaena?
The Leucaena-grass pasture is a productive and sustainable grazing system that will increase animal liveweight gain (250-300 kg/hd/yr), increase beef production per hectare (125-150kg/ha), maximise business returns and provides flexibility to meet the carcass requirements of beef markets compared to grass-only pastures.
But wait…there’s more! Read our fact sheet 1.
fact sheet 1. Leucaena (Leucaena leucocephala subspecies glabrata)Leucaena (Leucaena leucocephala subspecies glabrata) is a palatable and nutritious perennial legume shrub/tree that is ideal for cattle production in the sub-tropics and tropics of Australia. A Brief HistoryThe distribution of the genus Leucaena ranges from southern Texas in north America through Mexico and into central and south America. Wild or common leucaena arrived incoastal Northern Queensland in the late 1800s.Whilst cultivated Leucaena (Leucaena leucocephala subspecies glabrata) is better known in Australia as high quality livestock (predominately cattle) fodder, a range of species have been used for human food, timber and other uses for several thousand years. In the 1600s, leucaena was utilised in the Philippines and South East Asia for use as a shade plant in tea and coffee plantations, a use that is still predominant today. In the Philippines and Indonesia, leucaena has many purposes – timber, wood fuel, furniture, agroforestry as well as forage for ruminant livestock. In Australia, the CSIRO released the first forage variety of leucaena in the 1960s. The first commercial plantings occurred in the 1970s and since the mid-1980s, leucaena has been used extensively as a commercial cattle feed system in Australia. Approximately 150,000 hectares of leucaena is planted in Australia, predominately in the ideal growing conditions of central Queensland. Benefits of LeucaenaLeucaena is suited to deep, fertile soils in sub-humid environments where annual rainfall averages 600–800 mm. With its tap root , leucaena is able to exploit deep soil moisture beyond the reach of grasses and so can remain productive well into the dry season. A significant benefit of leucaena as a forage crop is the ability to efficiently fix nitrogen. Nitrogen fixation is caused by a symbiotic relationship between the plant and an introduced rhizobium bacteria (CB3060) which is applied to the seed prior to planting. Successfully nodulated leucaena will produce sufficient nitrogen for its own needs. However, incorporating a vigorous companion grass maximises pasture production where the grass utilizes excess nitrogen to improve soil fertility, organic matter, soil health and structure. The Leucaena-grass pasture is a productive and sustainable grazing system that will increase animal liveweight gain (250-300 kg/hd/yr), increase beef production per hectare (125-150kg/ha), maximise business returns and provides flexibility to meet the carcass requirements of beef markets compared to grass-only pastures. Once established, well managed leucaena-grass pastures can remain productive for over 40 years. MimosineLeucaena contains a mimosine, a toxin that can directly cause weight loss, hair loss and potential eventual death in cattle. However mimosine is quickly converted to dihydroxypyridine (DHP) in the rumen but this compound is also toxic to grazing animals. To overcome DHP toxicity, 10% of animals grazing leucaena should be inoculated with the anaerobic bacteria Synergistes jonesii or the ‘leucaena bug”. Over a number of weeks this bacteria spreads to the non-inoculated animals to eventually protect the whole herd from the reduction in productivity this toxin can cause over time. The Leucaena bug is available for purchase through the Queensland Department of Agriculture and Fisheries (QDAF) Tick Fever centre at Wacol, Brisbane. MaintenanceGiven the tree-like nature of leucaena, under light grazing pressure and favourable growing conditions (deep, fertile soils and warm and wet weather conditions) Leucaena can grow beyond the reach of cattle. Periodic intense grazing pressure can assist to minimise the growth of branches beyond cattle reach, keeping the plant more branched and leafy as well as reducing the opportunity for reproductive growth (flowering and pod production). However under certain circumstances mechanical trimming will be required to re-set plants back to a height to allow full grazing utilisation. Code of PracticeLeucaena produces viable seed that can cause weed problems in un-grazed areas such as gullies, banks of watercourses and road verges. The 'common' leucaena that arrived in Australia over 120 years ago has shown the colonisation potential in un-grazed situations. Cultivated leucaena will also colonise un-grazed areas if allowed to escape from grazed plantations, and precautions should be taken to prevent this. The Leucaena Network recognised this risk and developed the Code of Practice. The Code is consistent with the Queensland Government’s policy to reduce the weed threat of leucaena. Principles of the Best Management Code of Practice. The Principle of the Best Management Code of Practice is to plant leucaena ONLY if you intend to manage it and are prepared to accept responsibility to control leucaena that establishes outside the planted area on your property, including watercourses. Practices to comply with the Code are documented in The Leucaena Network’s Fact Sheet 8 DOWNLOAD FACT SHEET 1
2. IS MY LOCATION SUITABLE?
Leucaena is a very hardy plant once established, however it does need average rainfall above 600mm. It does not like frost and will tolerate cold weather but needs warm temperatures for growth.
Would you like to know more about suitable locations? Read fact sheet 3.
fact sheet 3. LocationClimateAlthough established leucaena can tolerate extended dry spells and droughts, the plant performs best in tropical climates (hot wet summers and mild winters with an average rainfall above 600mm). The majority of plant growth occurs in the warmer months with growth slowing when daily maximum temperatures fall below 25°C. Growth stops entirely when minimum temperatures fall below 10°C . The optimum growing environment is in a sub-humid area with 700 – 800mm annual average rainfall which not only provides the plant with the necessary climate but reduces psyllid insect pressure associated with the more humid areas. The new ‘Redlands’ psyllid-tolerant variety is now enabling plantings in coastal areas with rainfall above 800mm. LocationLeucaena grows best on deep, fertile, well-drained neutral to alkaline soils. Leucaena is well suited to Brigalow and scrub soils, black basalt soils, red volcanic soil and deep, fertile alluvial soils. Leucaena is difficult to establish or provides limited production in heavy grey clays (Brigalow melon-hole country) and infertile sandy or sandy-loam soils (Cypress pine, light box country). Leucaena is unproductive in shallow infertile soils (Narrow-leaf ironbark forest country) or soils where prolonged waterlogging can occur (heavy clay flood plains). Soil temperature needs to be above 18°C for leucaena seed to germinate rapidly. Plant leucaena in a deep fertile soil but avoid cold hollows or flats that regularly frost. Frost can kill seedlings and can severely reduce the productivity of established plants. Mild frosts (0°C to -3°C) result in leaf drop whilst severe frosts (below -3°C) will kill above-ground stems to ground level although established plants can grow vigorously from the root crown in spring with adequate soil moisture. If your paddock has frost-prone and frost-free areas, consider fencing to allow for management of each area. Alternatively, if areas of your paddock are prone to frost, graze the entire paddock evenly prior to the first frost and then rest to allow regeneration in the warmer spring season. Ensure planting is undertaken in accordance with the Leucaena Code of Practice and avoid planting near watercourses such as creeks, rivers and flood ways. Keep Leucaena some distance away from boundary fences and never plant leucaena in areas where livestock will be excluded. DOWNLOAD FACT SHEET 3
3. Is my soil SUITABLE?
Leucaena is an investment in your property and like any investment you should first determine if it is right for you. It is advisable to have a comprehensive soil test taken at your desired leucaena site. This will tell you if your soil is suitable for successful leucaena establishment before you invest in leucaena.
Your agronomist should be able to assist you with soil testing – we suggest three depths – 10cm; 10-30cm; and 30-90cm.
Once you have your results back, ensure your agronomist provides you with a comprehensive analysis of the results and compares these results with the necessary elements for successful leucaena establishment.
More information? Read fact sheet 4.
fact sheet 4. SoilsClimateLeucaena will grow in a wide range of soils but is most productive in fertile (high phosphorus and alkaline pH), deep (>1 m), well-drained soils (intolerant to waterlogging).Leucaena performs best in soils with high phosphorus and sulfur, and good levels of trace elements particularly potassium and zinc.It’s imperative to soil test paddocks selected for leucaena production prior to sowing to ensure adequate soil nutrient supply and soil depth. Soil testing can determine the suitability of a paddock for leucaena and so assist with paddock selection. Why Soil TestSoil testing enables an assessment of the chemical, physical and biological aspects of your soil.This can provide insight into the capacity of your soil to support the successful establishment and long-term sustainability of leucaena, and deliver productive yields, high fertiliser and water efficiencies, livestock performance and profit. Soil testing can answer the following questions:• What is the nutritional status of my soil? Do plant nutrient deficiencies or toxicities occur?• What is the effective root depth of my soil?• What chemical or physical properties are causing underperformance or affecting yield and limiting my production?• What physical or chemical soil imbalances are present, and what are the relationships between each component? How to Soil TestIt’s advisable to seek advisor assistance as this makes collecting multiple, representative, soil cores over a paddock to a depth of about 1 metre much easier. Collect at least 10-15 soil core samples (depending on paddock size and number of soil types) and break into increments of 0-10cm, 10-30cm, 30-90cm. Bulk each increment from each core together, break-up and thoroughly mix, then subsample about 500g of soil into a labelled bag. Whilst undertaking your soil testing, it is imperative that the condition of the soil, the depth ofusable soil and the structure of the subsoil s is noted. This may indicate physical impediments to root depth or soil degradation such as soil compaction, which potentially could require mechanical intervention to solve. Interpreting your Soil TestYour agronomy advisor will be able to assist you with a complete interpretation of the soil test. However the most important aspects are: pHSoil pHis measured on a scale from 0 (strongly acidic) to 14 (strongly alkaline), with 7 being neutral. Leucaena prefers soil with neutral to alkaline pH, and pH of 5.5 is the lower tolerance limit. It’s also important to measure the subsoil pH as this will influence root depth and hence nutrient and waterextraction. PhosphorusPhosphorus is an important soil nutrient for legumes. Leucaena has a higher requirement forphosphorus compared to other legumes, with a critical value (Bicarb or Colwell) in the 0-10cm soillayer of greater than 20mg/kg. Phosphorus is largely immobile in most soils, and is concentrated inthe top (0-30cm) part of the soil profile. SulfurSulfur is another soil nutrient important for legume production. Sulfur is a mobile nutrient so can befound in the deeper part of the subsoil. This means testing in the top and subsoil is required to fullymeasure the plant availability of sulfur. Leucaena has a moderate requirement for sulfur. Cation exchange capacity (CEC)Cation exchange capacity is a measure of the ability of the soil to hold the cations calcium,magnesium, potassium and sodium. While these are important plant nutrients, they also have a largeinfluence on the structure of the soil. High sodium and magnesium levels in the top soil can causedispersion and soil crusting reducing seedling establishment, whereas high levels in the subsoilrestricts root depth. DOWNLOAD FACT SHEET 4
4. Which variety?
There are five varieties you might consider when determining which variety of leucaena is best for your property. Some varieties are available only from a limited number of seed producers who have the Plant Breeders Rights. Other varieties are available from a range of seed producers or other leucaena producers. Either way, ensure your seed has had a germination and purity test and it has been stored appropriately.
Find out more about which variety in fact sheet 2.
fact sheet 2. Which varietyFive cultivars of Leucaena are now available for sowing by graziers. These include Peru, Cunningham, Tarramba, Wondergraze and Redlands. Each cultivar has specific attributes that provide benefits for individual locations (climate) which impacts on establishment, grazing, height, and insect management requirements. PeruPeru, named after its originating country, was first released as a cultivar by CSIRO in 1962. Peru has shrubby growth with good basal branching. Peru is very susceptible to psyllid damage and produces large amounts of seed. Peru has been superseded by newer varieties although seed is still available for sale typically from graziers with older stands of leucaena who take the opportunity to harvest and sell seed when seasonal conditions are favourable. CunninghamCunningham was developed by CSIRO who crossed the Peru cultivar with another variety from Guatemala. It was released in Australian in 1976. Cunningham is a highly productive variety with a shrubby growth habit. Like Peru, Cunningham is a prolific seeder and is very susceptible to psyllids and frost which can cause significantproductivity losses in certain environments. Despite being released more than 40 years ago, Cunningham is still widely sown today. Like Peru, seed is commonly harvested by graziers who take the opportunity to harvest and sell seed during favourable seasonal conditions. TarrambaTarramba was bred by the University of Hawaii and released in Australia in 1994. It has a taller, more tree-like (arboreal) growth habit. Specific grazing management is required to promote basal branching during establishment. Once established, Tarramba requires careful grazing management to minimise the need for mechanical trimming. Tarramba typically produces less seed than the older varieties, and while forage yield can be high stem yield can make up the majority of the total biomass. Other advantages include early seedlingvigour and some psyllid and cold tolerance, which can provide production advantages under certain environmental conditions. Tarramba is under Plant Breeders Rights (PBR) and can be only sourced from one seed supplier. WondergrazeWondergraze is an intraspecific hybrid and was released to the market in 2011. Wondergraze has similar seedling vigour and psyllid and cold tolerance to Tarramba however is a bushier plant, putting its growth into foliage and branches rather than woody stems, increasing its attractiveness for grazing and crop maintenance.Wondergraze seed is under Plant Breeder Rights (PBR) until 2035 and can be only sourced from one seed supplier. RedlandsThe Redlands variety is named after the Queensland Department of Agriculture and Fisheries (QDAF) research station where the University of Queensland variety development site is located in Brisbane. Redlands is an inter-specific hybrid between Lecuaena pallida and Leucaena Leucocephala subsp. glabrata. Redlands was released in 2017 for commercial plantings howeveron-farm trials investigating palatability and cattle weight gains are still being conducted (as at2018). The primary benefit of this variety is it’s very high tolerance to psyllids, making it highly suitable for planting in coastal areas or other locations prone to high psyllid incidence. While forage production in in-land districts without regular psyllid incidence is relatively unknown, the limited plantings to date (2018) indicate this variety can be highly productive in these environments. Redlands seed is also governed by plant-breeders rights (PBR) and is available from two seed suppliers. Seed QualityIrrespective of the cultivar and the seed provider, it is essential to ensure your seed is of high quality. All seed sold should have a germination and purity test which will determine if further scarification is needed (to reduce the percentage of hard (dormant) seed), or if weed seeds are present (eg parthenium). Other aspects to consider include how long the seed has been stored for and the storage conditions, and whether there is any bruchid beetle damage (small holes in the seed). The uniformity of seed size is an important aspect that might impact seed flow through a planter, the uniformity of placement in the planted row and the planting rate. Grading the seed might be required to alleviate these issues. DOWNLOAD FACT SHEET 2
5. Land preparation & planting
Adequate site preparation is a critical factor in successful leucaena establishment. Ensuring a fine seed bed and removing competition from grass and weeds through repeated cultivation is essential. The application of herbicide may also be suitable.
Distance between rows is one of the most asked questions for new producers. Initial research indicated that closer rows were suitable however we are now finding that as leucaena grows vigorously once established, closer rows can impact on sunlight and the ability for the companion grasses to flourish. Your soil tests will assist you in deciding what row space may be suitable for your needs. Some producers find 12 metre rows successful, others 16 metres, others 20 metres and some up to 40 metres.
Research has indicated that cattle eat leucaena and grass in a 27:73 ratio (MLA Project BCCH 6510 Final Report - Impacts of Leucaena plantations on greenhouse gas emissions in northern Australian cattle production systems) – this may assist you to calculate how much grass you need to have in relation to your leucaena. Every situation is different! (** with link to this report in Research area)
The right machinery makes the process much easier and equipment that provides accuracy with location and depth greatly assists the success rate. If you would like to speak to experienced producers about land preparation and planting and what machinery may be suitable, please contact The Leucaena Network at email@example.com and we can organize someone to give you a call.
Read our fact sheet 5 for more about land preparation & planting.
fact sheet 5. Land preparation & plantingLand PreparationThe key to reliable and successful Leucaena establishment is adequate planning and paddock preparation. Ensuring high levels of soil moisture before planting from fallowing is one of the most critical success factors. Ensure a fine seed bed and competition from grass and weeds is removed through repeated cultivation (or herbicide application), allowing the soil to store moisture prior to planting. Deep ripping (50cm+) along the rows at the start of the fallow period may be beneficial in non-cracking or tight soils. Producers may consider total removal of existing grass with subsequent re-planting of companion grasses; or retaining grass strips to allow some grazing during the fallowing period and reduce preparation costs, reduce the potential of soil erosion, and enable grass re-establishment without planting grass seed. However, if the existing grass pasture is either rundown or contains undesirable species, it is highly recommended to totally remove the existing pasture across the whole paddock. Young leucaena seedlings concentrate developing a strong root system, rather than above ground shoot growth. This slow shoot growth increases susceptibility to weed and grass competition, therefore post planting weed control (either mechanical or herbicide) is essential to ensure vigorous early growth. TimingThe right planting time and adequate soil moisture are critical for reliable leucaena establishment. Plant as early as possible between September and March (depending on winter temperatures and frost potential), but only when there is at least 60-90cm (preferably 1 metre minimum) of sub-soil moisture and soil temperature is rising above 18°C. Young seedlings can struggle if they emerge in extremely hot conditions in January and February in lighter textured soils, but can survive if roots are growing into a good soil moisture profile. Inoculate the planting seedThe productivity of the leucaena stand and the companion grass depends upon efficient nitrogen fixation. Nitrogen fixation is caused by a symbiotic relationship between the plant and an introduced rhizobium bacteria (as of 2018 the new strain is CB3060). Native rhizobium present in the soil do not form effective nodules, so the seed must be treated with the commercial rhizobium inoculum. Seed should be inoculated immediately before planting. Store the rhizobium in a refrigerator before use and observe the expiry date. Rhizobium is sensitive to drying out, heat, sunlight, fertilisers and chemicals. Consider the further step of water injecting the inoculum in the seed trench to maximise plant nodulation. Seed quality and planting ratePlanting quality seed with high germination percentage (scarified seed) and high viability (low percentage of dead seed) is another critical success factor. Ensure seed germination percentage is known prior to planting by either obtaining a commercial test certificate or testing the germination yourself. Aim to place each seed 5cm apart in the row (20 seeds / metre row), which equates to a planting rate of approximately 1 – 2kg/ha depending on row spacing and seed size. Row SpacingSuggested row spacings are between 6 and 12m depending on soil type, rainfall (or irrigation), and the grass:leucaena forage balance required. These spacings allow maintenance of a strong grass sward between rows, machinery access for leucaena maintenance and optimal grazing pressure. Planting twin rows (as opposed to single) can ensure a continuous hedge if one row doesn’t come up. If sowing Leucaena into fallowed strips, ensure the strips are at least 5m wide (if planting twin rows on 1m centres) to allow about 2m of weed free conditions either side of the rows until Leucaena is at least 1.5m high to minimise moisture competition from grass. Seed planting depthEnsure a uniform planting depth of 3 – 5 cm to ensure the seed is in wet soil for 5-7 days for reliable germination. Shallower seed placement will provide quicker emergence as long as soil moisture isn’t quickly depleted which might be risky in marginal moisture conditions or on lighter soil types. Germination and early emergenceGermination and emergence should occur within 7 days but this time is influenced by a range of factors including soil moisture, temperature, seed quality and scarification level, uniformity of planting depth, and seed-soil contact. Using presswheels to ensure seed-soil contact is very important for reliable establishment, however too much pressure can be detrimental. Presswheels ideally need to run beside the planted row, not over the top. In the early stages of establishment the seedling is very susceptible to predation from soil insects,native animals and weed competition. Ensure weeds are controlled after planting (as previously mentioned), assess the need for soil insect control, and plant a large enough area (at least 40ha) to allow for native animal predation. Weed Control after plantingEffective weed control for the first 3-6 months is important to minimise the time to establishment and first grazing. Weeds can be chemically or mechanically controlled. Mechanical options include over-the row (scufflers) or inter-row (tined or off-set disc) implements which need precision placement to minimise damage to Leucaena and effective weed control. Chemical options include herbicides (for example Spinnaker and Fusilade Forte) applied either over the entire area or in a band along the planting rows prior to planting, at planting or after planting depending on the situation and weed control needed. DOWNLOAD FACT SHEET 5
6. What About The GrassES in a leucaena grazing system?
You know your land best so you know what grasses suit your land best! However your soil test results can assist you to chose the right grass as your leucaena companion grass. We have provided an overview of some of the most popular choices.
Read fact sheet 6 for more about the grass in a Leucaena-grass grazing system.
fact sheet 6. Companion grassesA productive and persistent companion grass is required for sustainable leucaena-pasture systems in tropical Australia. Combining grasses with leucaena provides forage all year round to maximize weight gain. Grasses promote nitrogen fixation by leucaena which improves overall pasture and soil health, and ground cover. This reduces the opportunity for weeds and stray leucaena seedlings to establish, and minimises runoff and erosion.Consider your location, soil type and rainfall when choosing your companion grass. Bambatsi panicBambatsi panic is a palatable and perennial summer-growing grass that is well adapted to medium to heavy-cracking clay soils in Queensland where the average yearly rainfall is greater than 600mm. Bambatsi can tolerate waterlogging, drought, frost and saline soil. It performs well on melonhole (gilgai) soils in Brigalow lands; is unsuited to sandy and loamy soils of low fertility. Bambatsi can be difficult to establish and is slow to develop in its first year. But once established it is tolerant of drought and will grow into the cooler months. Green and Gatton panicGreen and Gatton Panic are very productive and palatable grasses that are well suited to high fertility soils. Green Panic is better suited to higher rainfall regions or under irrigation, whereas Gatton Panic is regarded as being more vigorous and drought tolerant. Both are shade tolerant and thrive on high nitrogen supply so can grow vigorously beside leucaena rows. Buffel grassBuffel grass is the most common improved species planted into fertile soils across southern and central Queensland. It is a deep rooted, drought resistant, palatable and very productive grass that responds quickly to moisture and fertility. Buffel prefers higher fertility scrub soil but will grow on a range of soil types, but not low fertility sands or very heavy clay soils. Three cultivars are commonly sown; American (USA), Gayndah and Biloela, with Biloela typically sown on heavier soils. Buffel is commonly sown with Leucaena in new pasture situations, or naturally colonises in paddocks where it has already been planted. Buffel is extremely competitive for moisture and will limit the productivity of established leucaena indry years. To ensure successful establishment of leucaena into existing buffel grass paddocks, it’s critical to cultivate or spray out buffel grass for at least 6mths prior to planting, and control any buffel seedlings for 3-6mths after planting. Rhodes grassesRhodes grasses can be productive and persistent on a range of soil types, however are not as hardy as other improved grasses (eg buffel). Rhodes grasses are quick to establish and provide high biomass production and require greater than 700mm annual rainfall and high soil fertility to persist. A large range of cultivars are available and the more palatable types are late flowering with high leaf to stem ratio. Rhodes grass is commonly sown with other grasses in new Leucaena pastures due to its quick establishment and good biomass production during the initial years of pasture establishment. Signal grassSignal grass is a low-growing creeping perennial, with trailing stems that root at the nodes. It forms a dense soil cover, with a canopy usually shorter than 40 cm when grazed. Signal grass is well adapted to a wide range of soils in the (more than 1000 mm annual rainfall) tropics, but also grows well in the coastal subtropics with lower rainfall due to moderate tolerance to dry periods and cold temperatures. Signal grass has not been commonly used in Leucaena pasture systems due to its main applicability to coastal environments, however this might change with the release of the psyllid resistant variety ‘Redlands’. The released cultivar is Basilisk. Pangola grassPangola is a very productive and palatable creeping grass on a range of soil types. Pangola can withstand heavy grazing and high rainfall conditions however needs to be planted from runners as it does not produce fertile seed. Pangola is highly suitable for tropical and subtropical coastal locations with annual rainfall greater than 800mm and mild winter temperatures, therefore will be a suitable companion grass for leucaena pasture systems in coastal environments. HumidicolaHumidicola is a very productive and aggressive creeping grass that is highly suited to high rainfall (greater than 1000mm) or irrigated conditions in the tropics. Like Signal grass, Humidicola has not been commonly used in Leucaena pasture systems, but this could change with the release of the variety ‘Redlands’. The released cultivar is Tully. Digit and Finger grassesDigit and Finger grasses are well adapted to the lighter soils (sands to loams) across a range of climatic conditions in Queensland. These grasses are related to pangola however have a more tufted growth habit, are taller, and produce viable seeds. A number of cultivars have been released (Premier, Strickland, Jarra), however seed supply has been variable in recent years. All are palatable and tolerant of low soil fertility, however are highly responsive to high nutrient supply eg from fertiliser. Digit and Finger grasses have not commonly being planted in Leucaena pasture systems, but would be highly suited on deep and fertile loam soils where a productive, persistent and palatable grass is required. Creeping bluegrassCreeping bluegrass is suitable for a range of soil types from low fertility forest soils to self-mulchingclays. It is a strong creeper and whilst slow to establish, it can withstand heavy grazing once fully established. It flowers late in the growing season so maintains leaf quality for longer compared to other grasses. Creeping blue grass provides very high ground cover due to its strong creeping habit, and so is suitable to sloping country that might be prone to erosion. The main cultivar available is Bisset, which is a harder variety than the superseded Hatch. DOWNLOAD FACT SHEET 6
7. Cattle Love Leucaena - Make It Stay In Their Paddocks!
There are so many benefits to leucaena however, like any plant that is hardy and grows well, it can have the propensity to become a weed is permitted to stray or is not managed well.
The Leucaena Code of Practice was developed by industry pioneers to ensure that leucaena remains a productive option for graziers. Please take the time to read the Code of Practice and ensure that your leucaena stays where you want it to be - within your own paddocks!
Read our fact sheet for more about the code of practice...
fact sheet 8. The code of practicePrinciples of the Best Management Code of PracticePlant leucaena ONLY if you intend to manage it and are prepared to accept responsibility to control leucaena that establishes outside the planted area on your property, including watercourses. This can be achieved by adopting the following practices: 1. Do not plant leucaena in areas where rivers, creeks and flood channels can disperse seed pods/seed. If leucaena becomes a restricted or regulated plant under a Wild Rivers declaration, growers must comply with the relevant Wild Rivers Code. 2. Keep leucaena at least 20m away from external fence lines. 3. Maintain a buffer strip of strong grass pasture between leucaena plantings and creeks or boundary fences. 4. Fully fence leucaena paddocks to avoid the unlikely risk of stock spreading ripe seed. 5. Graze or cut leucaena to keep it within the reach of animals and minimise seed set. 6. Chemically manage leucaena escapes. There are a range of chemical control options for example Tordon®(picloram) granules, Access®, Vigilant II (picloram + aminopyralid.) For more information on control measures please seek the Biosecurity Qld Fact-Sheet on Leucaena (NoPP85). 7. Establish and manage vigorous grass in the inter-rows to:a. provide competition to minimise establishment of volunteer leucaena seedlings.b. minimize the risk of seed being transported during heavy rain.c. productively utilize fixed nitrogen the system produces.d. maintain ground cover and prevent soil erosion. 8. Maintain the practice of:a. regularly monitoring creeks and major watercourses to detect any escaped leucaenaseedlings and plants.b. controlling all plants detected adjacent to property boundaries.• on creek banks and other adjoining areas where cattle do not normally have access.• on public roadsides (after first obtaining a permit from Main Roads or Shire Council). 9. Comply with local laws (weed declarations etc) and assist Local Government agencies to identify any escaped leucaena so that action can be taken to control it. 10. Promote the responsible management of leucaena in accordance with this Code. 11. Keep abreast of best practice developments in the management of leucaena. DOWNLOAD FACT SHEET 8
8. There is always a pest!
Like any plant, leucaena can be affected by pests -rabbits, kangaroos and even rats can be a threat to the young seedlings.
However once leucaena is established it can usually fend for itself. However leucaena in areas of high humidity and mild temperatures of around 20°C to 35°C can be highly susceptible to psyllid infestations.
Read our fact sheet for more about Heteropsylla cubana…
fact sheet 7. PsyllidsWhat Are Leucaena Psyllids?The psyllid, Heteropsylla cubana, is native to Cuba and is found only on Leucaena species and hybrids. Psyllid was first noted in Bowen Qld in 1986, and can now be found wherever Leucaena is grown across northern Australia. Eggs of the leucaena psyllid are laid on or in unopened leaves. The adult psyllids are aphid-like, 2mm in length, winged, and light green in colour. The infant pysllids or nymphs, are similar to adults, but smaller. All growth stages of the insect affect the plant by sucking the sap of terminal leaves, buds and flowers. A black sooty mold may be seen where psyllid infestations are in large numbers. This mold grows on the psyllid’s sugary excretions, preventing light from reaching the leaf surface and decreasing photosynthesis and plant growth. Where is Leucaena Most at Risk of Psyllids?Psyllids prefer high humidity and mild temperatures (20⁰C to 35⁰C)therefore Leucaena plantings in coastal areas are highly susceptible to psyllid infestation. Psyllids are sensitive to changes in temperature and humidity so areas of less than 800 mm rainfall and lower humidity are not usually subject to psyllid infestations. Yield loss in research trials in psyllid-prone areas averaged 28%, ranging from 8% to 49%, withlosses as high as 75% in conditions ideal for psyllid activity. What Varieties are Best to Plant in Psyllid Prone Areas?‘Redlands’ is a psyllid tolerant leucaena variety, which is vigorous, high yielding and has excellentforage quality, longevity and tolerance to grazing. ‘Redlands’ was developed as a joint initiative of the Meat and Livestock Association (MLA) and the University of Queensland and was named after the research facility where it originated. The variety is approximately 90% Leucaena leucocephala subsp. glabrata (the standard grazing leucaena) and 10% Leucaena pallida, which provides the psyllid tolerance. What to do about psyllids in established paddocks?It is difficult to provide a definitive answer due to the uncertainties of weather conditions, but thereare a couple of options. 1. Assess psyllid numbers and damage first2. Graze available leaf – this will maximise the utilisation of remaining leucaena while removing the food source for the psyllid. Cattle moving through the plants will also disturb feeding and encourage the psyllid to move to another location.3. Assess whether spraying will be economical. Psyllids can be effectively controlled with diomethoate at 340ml/ha, and will provide about 3-4 weeks residual control. However it is commonly more economical to graze established paddocks unless conditions are such that prolonged psyllid attack occurs. Spraying establishing leucaena (<1.5m tall) with high psyllid pressure is recommended.4. Do nothing. In inland districts weather conditions for psyllids activity is relatively uncommon as temperatures are high and humidity low. Also, by the time psyllids are noticed (defoliated an area of leucaena), the weather conditions could have changed. In locations closer to the coast where weather conditions conducive to psyllid activity are more common, or occur for longer, immediately grazing or spraying the paddock are more than likely better options. How to use the psyllid damage rating scale – what to look for: Symptoms No damage observedSlight curling of leavesTips and leaves curling and yellowTips and leaves badly curled, yellowish and covered with sapLoss of up to 25% young leavesLoss of 25 – 50% young leavesLoss of 50 – 75% young leaves100% loss of leaves and blackening of lower leavesBlackened stems with total leaf lossRating 123456789 DOWNLOAD FACT SHEET 7
9. where to now?
We hope you have found the step-by-step brief introduction to leucaena of assistance. More information can be found from the MLA publication “Leucaena – A Guide to Management and Establishment” (link to the book to be in the Research section). Please note that an updated version of this publication is due for release in 2019 which will include the most current research and information on establishing and maintaining leucaena.