Too much Blackberry Jam?

With blackberry infesting roughly 8.8 million hectares of temperate Australia, biological control remains the only viable management option for many infestations (CSIRO, 2011). In South Gippsland there is a great deal of community interest in leaf rust-fungus as a tool for controlling blackberry. Below are some of the frequent questions I'm asked about the biological control agent.

 

What is blackberry leaf rust-fungus?

A defoliating disease host specific to European blackberries approved for use in Australia.  The rust-fungus has fruiting bodies (spores) that damage leaves occasionally green stems, stalks, sepals and unripened fruit and is capable of causing severe defoliation in susceptible species given the right conditions.

 

What are the right/suitable conditions for the leaf rust-fungus to establish?

Light is one of the more important requirements, generally sites that have full sun and or very little shade are suitable.  Sites in open woodland, open creek lines and fence lines etc are preferable.  Shaded sites are typically not suitable.  Rainfall and temperature are the other important factors. Sites receiving an annual rainfall of 800mm or greater with an average maximum daily temperature of about 20°C for the month of January are more likely to be successful (Weeds CRC 2005).   

 

Is the blackberry leaf rust-fungus safe?

Rust spores are not toxic to humans and animals but may cause irritation to people sensitive to pollens and dusts. In such cases, it is recommended to wear safety equipment such as goggles, a respiratory mask and gloves when handling rust spores or infected foliage (CSIRO 2011). Strains of the blackberry leaf-rust fungus (Phragmidium violaceum) were thoroughly tested by the CSIRO before approval was obtained to release it in the environment. They were shown in host-specificity tests to be highly specific towards weedy European blackberries.

 

 

Sounds like a cheap & easy way to solve my blackberry problem! Where can I get some?

You may already have the leaf-rust on your property it's widely established in Australia including in South Gippsland; spores of the blackberry leaf-rust are spread by wind and can travel long distances in relatively short periods of time. Although it can be effective, the leaf-rust will not completely kill a blackberry plant. The leaf-rust relies upon its host to survive, its not going to eat itself out of house and home now is it? Also keep in mind that Biological control will not be effective across the range where blackberry infestations occur and therefore an integrated weed management approach will be necessary if effective control is what you're after.  If effective control is not viable given the size and location of the infestation and costs associated with control etc then the leaf-rust is particularly useful.

 

What if effective/thorough control is viable for me and my situation?

Then don't rely solely on the leaf-rust fungus, use a combination of control measures, (termed integrated control) at an on-going and landscape scale i.e. talk to your neighbours; have a year by year action plan based on resources at your disposal and, (to quote USA sports brand, Nike) Just Do It! True recovery of large areas of land for the production of pasture and the establishment of seedlings in plantation forests should only be expected following this. In areas reserved for conservation of native flora and fauna, control of blackberry infestations is a first step towards achieving an increase in species diversity. Reinvasion by weeds is a recurrent challenge therefore revegetation or pasture improvement strategies should be considered in tandem with any weed control program (CSIRO, 2011).

 

Kate Williams

South Gippsland Landcare Network

Run Rabbit Run!

A visible increase in rabbit (Oryctolagus cuniculus) numbers across south east Victoria has prompted Landcare groups along with the South Gippsland Community Weeds Taskforce to raise the issue.  As were all well aware, rabbits are nothing new to mainland Australia.  Since the late 18^th century they have hopped about the landscape digging warrens, decimating native vegetation, devouring pastures, sustaining fox populations and so on. Rabbits are that common these days that one doesn't bat an eyelid at the sight of bug's bunny peacefully nibbling grass on the roadside edge.

 Is it rabbits 'commonness' that has management efforts falling by the way side? Or is the effort to control rabbits by land managers undermined by the sheer magnitude of the problem? Or rather are we stepping back from the problem and depending on the release of a new biological control agent to save the day? The likely answer is yes to all of these factors.

It's a given that control programs cost money, as a result land managers often rely on once a year poisoning programs. Typically only on their own properties and when rabbit populations are high with no integration/follow up with other control methods. To achieve effective rabbit control effort must be continuous. Therefore it's not the effort that is undermining the result but rather the ineffective methods that are generally used. One needs to be able to; adopt and use integrated rabbit control, kill rabbits at a faster rate than they can replace themselves at all densities, ensure rabbit immigration into your control site is zero, monitor rabbits at low densities and take immediate action if the population increases and maintain a social environment with your neighbours and community that supports the goal of aiming for rabbit free.

The success of the myxomatosis virus released in 1952 was poignant, reportedly wiping out 99.8% of rabbits. However by the 1990's rabbits showed resistance to the virus and their numbers once again climbed back into the millions.  From 1996-1998 the Rabbit Calicivirus Disease (RCD) reduced rabbits by >50% in arid areas however once again, as with the myxo virus, numbers have bounced back.  If the history of biological control agents is anything to go by then we shouldn't depend on it to keep rabbit numbers under control, at least not in the long run.

If we stop tolerating the 'commonness' of rabbits and start to adequately control numbers we stand to win big time. A dairy farmer in Colac, Victoria (similar growing conditions to parts of South Gippsland) increased his milk production by 300% and doubled his fodder harvest over 5 years simply by tackling his rabbit problem. A sheep farmer in Colac, who also managed his rabbits effectively, increased his dry sheep equivalent from 1.75 to 7.75 over a 5 year period.

Whilst researching the topic of the impact on native vegetation from rabbits I came across this insightful quote; 'What's the difference between chainsaws, bulldozers and rabbits? Not much really. Though chainsaws and bulldozers are the preferred tool for clearing land, rabbits are just as effective. They eat tree seedlings so that when the mature trees die there are no young ones to replace them. The net effect is identical, only the time scale differs' (Pickard 1995, Managing Vertebrate Pests; Bureau of Resource Sciences and CSIRO).  Adequate control would give native vegetation a chance to regenerate and ultimately lend itself to providing habitat and food for native wildlife that was previously displaced by rabbits.

It's important to recognise that rabbits do impact us economically, socially and environmentally. We must not wait for the next biological control agent but rather act now to control their numbers using a variety of techniques, continuously and in coordination with our neighbours, (including public land managers) and local community. For further information on rabbit control visit the Department of Primary Industries (DPI) website at www.dpi.vic.gov.au or contact the South Gippsland Landcare Network Project Officer Kate Williams on 5662 5759 or email katew@wgcma.vic.gov.au. To record rabbit sightings in your area visit www.feralscan.org.au. Feral Scan is a citizen science website where you help map feral animals and the damage they cause.

Reference

Bloomfield, T., Paroz, G. Rabbits and Their Impact October 2010, LC0298 Department of Primary Industries, Attwood.

Photo caption: A single pair of rabbits (Oryctolagus cuniculus) can produce 30-40 young a year.

 

 Kate Williams, South Gippsland Landcare Network Project Officer

Wandering jew or trad (Tradescantia fluminensis, syn. T. albiflora) Environmental foe or Chicken delight?

The waterways in South Gippsland are well aquatinted with this weed from South America.  It loves nothing better than shady spot down by the river where it thrives on silty alluvial soils.  It's not a huge fan of being submerged in water but it does tolerate the occasional flood and will put up with being waterlogged ever now and again.

Wandering trad has hairless leaves which are glossy, slightly fleshy and dark green in colour. A distinctive feature of the plant is its stem-clasping leaves at the base. Flowers are white, about 1cm across displayed during spring and summer. Fruit is not formed on the plant in Australia therefore it does not spread by seed but rather by broken off sections of stem taking root.

As the name suggests, it wanders about and forms dense mats that smothers all native groundcover vegetation in its path. Subsequently preventing natural regeneration of trees and shrubs. Over time, (in a stream bank situation) this process causes eventual loss of native tree and shrub cover which can lead to erosion.  This makes wandering trad an unpopular addition to the natural environment in Australia. 

In terms of its control, there are several options (see below). Using a combination of these, (based on site specifics and resources at hand) is the best method.

Manual removal: small infestations can be dug out ensuring that all stem fragments are removed, (if not they will regrow) and disposed of appropriately. 

Solarisation: covering the plants with plastic sheeting for 6 weeks in the warmer months will weaken the plant (sunny situations only, this will not be effective in full shade). After removing the plastic any regrowth can be dug out or sprayed.

Herbicide: spraying with selective or non-selective herbicides, (using a surfactant) will work eventually but repeat treatments will be required. Herbicides registered in Victoria for use on wandering trad can be found on the APVMA website; www.apvma.gov.au.  

Alternative uses: Julie Cave, Blue Mountains City Council Bush Regeneration Team member has made some suggestions for the use of trad which include; turning the plant into liquid fertiliser or compost. Read more on this by visiting http://www.weedsbluemountains.org.au/index.php.

Whilst researching control methods for wandering trad I came across findings that suggest ducks and chickens love the stuff. Apparently Muscovies and chickens consume wandering trad readily with no ill effects (given that the plants have not been sprayed with herbicide). If someone works out how to drive a flock of ducks down to an infested gully for some crash grazing we might have another viable management tool. In a domestic situation, those with chooks (and wondering trad) may have themselves a cheap and useful solution to the problem.

For further information on the identification of wandering trad visit www.southgippslandweeds.com.au or contact Kate Williams, South Gippsland Landcare Project Officer on (03) 5662 5759 or email katew@wgcma.vic.gov.au. Information from this article taken from Wandering jew (Tradescantia fluminensis, sny. T. albiflora)  http://www.esc.nsw.gov.au/site/Weeds/Sheets/herbs/H%20Wandering%20jew.htm, Eurobodella Shire Council, NSW.

Kate

African lovegrass

No love for African Lovegrass (Erogrostis curvula)

 

African lovegrass, or 'ALG' as it's referred to by those who know it,  is a major weed of grazing land throughout mainland Australia. South Gippsland's not immune to invasion by African lovegrass. There has been a recent report of isolated plants as close as 10km from the South Gippsland Shire boundary; it may very well be within the Shire boundary.  Being a tussock grass, its presence is often overlooked; (unlike weeds with bright purple flowers that are easy to spot) it can also be confused with some other native or introduced grasses. Early detection allows early control. What to look for;

·        Perennial tussock grass (forms as a clump)

·        Grows from 30-70cm high with a diameter of 25-35cm at ground level

·        Begins flowering in spring or early summer with erect, open or compact seed heads that are a lead-grey or grey green colour  (see photo below showing the seed heads)

·        Leaves are blue-green, long and narrow with curly tips

·        Has a ring of hairs below the base of the leaf blade

Whilst is can be confused with some native and introduced species, it is clearly distinct from them;

·        Spear and corkscrew grass (Austrostipa sp.) look similar to African lovegrass in the early vegetative growth but have awns on the seed.

·        Other native and introduced lovegrasses often look similar but have different seed heads.

African lovegrass is a problem in an agricultural situation as readily establishes in overgrazed pastures and only produces a limited quantity of green feed during the spring and summer months. Overall carrying capacity is reduced where infestations are dense. Forage quality declines as the plants mature and also with the commencement of frosts. The amount of green leaf dry matter utilised by the animal is at best 65% in early spring and 50% in early summer. Come winter, the amount utilised by the dead material is only 38%. Crude protein of the dead leaf in winter is only 3.6%.  Minimise the risk of seed entry and establishment on your property by paying attention to likely sources of seed import. The movement of fodder is a main cause of weed seed spread in agriculture. If you're looking to purchase hay or livestock from a known African lovegrass area (check with Bob Wilson, DPI Gippsland Coordinator Pest Management to find out general distribution on T: (03) 56 629 930). Supplementary feeding in a smaller 'sacrifice' paddock is a good precautionary measure followed by monitoring.  Be conscious of livestock movements, seeds take up to 7-10 days to pass through livestock and can still be viable for 10 days, as with the fodder keep livestock in a smaller paddock and monitor.

For further information on the identification of African lovegrass contact Kate Williams, South Gippsland Landcare Project Officer on (03) 5662 5759 or email katew@wgcma.vic.gov.au. To find out the general distribution of African lovegrass in Gippsland contact Bob Wilson, DPI Gippsland Coordinator Pest Management on T: (03) 56 629 930). Information from this article taken from Primefacts, February 2010 Edition via www.industry.nsw.gov.au and African lovegrass, May 2009. 3D weed management, Meat & Livestock Australia, Sydney.

Photos of African lovegrass courtesy of Peter Kershaw, VicRoads Eastern Region 2011.