The following information is extracted in part from "Bandicoots, A disappearing part of Sydney's environment, produced as a combined effort by NSW National Parks and Wildlife Service and Pittwater Council, June 1995; NPWS 43 Bridge St Hurstville 2220 tel 02 95856333; Pittwater Council 11/5 Vuko Place, Warriewood 2102 tel 02 99707222).
A yard close to bushland can be made less attractive to tick hosts such as bandicoots. Regular garden maintenance by controlling tall grasses and weeds helps. Removing leaf litter and controlling snails and slugs should also help. Wear gloves, long sleeves, long pants and use a high grade insect repellant when performing such yard maintenance. Removing the noxious weed lantana (Lantana camara), which seems to be a favourite site for ticks and their hosts, is also useful.
It is possible to live side by side with the native wildlife that visits our gardens. The native animals that may, from time to time call your garden a sanctuary, can be accommodated in purpose-designed areas. Establish a separate area in the garden which provides shelter and food for native birds and animals while your family and pets can use a more formal, manicured area.
Your native animal animal habitat area should be located so it is not a major family or pet thoroughfare. Then, if ticks are present, they are less likely to attach themselves to passing people or pets.
An alternative is to construct bandicoot-proof fencing around the yard. Use fine galvanised wire mesh or any other material with gaps no larger than approximately 20 mm. The foot of the mesh should be buried at least 150 mm and it should rise at least 500 mm above the ground.
Please remember, it is illegal to trap or kill bandicoots unless authorised by NPWS.
The following information is extracted in part from "Bandicoots, A disappearing part of Sydney's environment, produced as a combined effort by NSW National Parks and Wildlife Service and Pittwater Council, June 1995; NPWS 43 Bridge St Hurstville 2220 tel 02 95856333; Pittwater Council 11/5 Vuko Place, Warriewood 2102 tel 02 99707222).
Whilst a yard may be sprayed with malathion or pyrethrin products the effect is usually short lived and many normal and desirable insects and arachnids will be destroyed [some of which may actually be predators of tick stages]. A "natural" alternative to chemical sprays is a mixture of chilli (cayenne powder), garlic and vinegar. After being left to brew for a few days, the mixture, sprayed around the garden , will discourage most pests.
By Bill Conroy
These notes aim to assist householders in tick-prone areas to design and manage their domestic gardens in a way that will minimise various types of tick attacks on humans. They should also serve a similar purpose for institutions with one or more buildings set in garden or natural vegetation surroundings. The information particularly applies to the Pittwater Shire and adjacent areas immediately to the north and south of the lines of road linking Pittwater with the Upper North Shore suburbs of Sydney However, the information could also prove useful in any area of warm moist climate along the East Coast of NSW.
The recommendations relate to the seasonal occurrence and behaviour of the tick species, Ixodes holocyclus, known by the common names: "grass tick" or "seed tick" for the infant, larval, or hatchling stage; "bush tick" for the juvenile, nymphal or intermediate stage; and "shellback" or "paralysis tick" for the adult. With the exception of the adult males, each phase in the tick's life cycle requires a blood feed from a mammal, bird, amphibian or reptile in order to grow and mature.
Ticks have always been present and a likely hazard for bushwalkers, clearing teams and people with similar contacts with bushy land in the Pittwater and adjacent areas. Periods of very heavy infestation have occurred in the past in association with prolonged dry spells. The current period of general atmospheric warming, accompanied by droughty weather and coinciding with the virtual abolition of in-yard burning appears to have led to a rapid build up of the tick population. In Autumn 1993, after a cool dry summer, the tick population reached plague proportions, and many people were bitten in their own gardens. At the same time there were numerous reports of attacks in the grounds of sporting venues and schools, and on footpaths with vegetative cover. Ticks also invaded houses and other buildings.
The area's tick population remained high throughout 1993, with many nymphal and adult attacks on people and domestic pets. Subsequently, there has been some drop in the intensity of infestation but the danger of tick attack during open air recreation and in domestic gardens remains high. In the current Autumn severe larval attacks with irritating rashes have been suffered by people in Avalon, who had enjoyed 20 years residence in older built-up areas without a tick-bite incident. Investigation showed these attacks had occurred in their home gardens. If the present climatic warming continues, outbreaks similar to that of 1993 can be expected to recur with some frequency and an overall high level of prevalence can be anticipated.
In the light of the situation outlined above it is desirable for householders and institution managers to give careful consideration to the layout of gardens naturally vegetated land.
Individual gardens have a very wide range of vegetation, reflecting personalities of the gardeners and it is difficult to make precise recommendations which will minimise the threat of ticks. What has attempted in the ensuing notes is to provide a broad set of principles which enable householders and institutional managers to clarify their ideas about this in the areas they control. It may still be necessary to seek expert on-the-spot assistance for particular aspects of each area.
Spatial arrangements in gardens should aim to minimise brushing against I with the head, trunk or legs and passing under vegetation from which ticks drop onto a human or animal target. Regularly used pathways to garden plots and garden sheds and other ancillary buildings, and front and back gates should be designed with this in mind. Fence lines should as far as possible be clear, so that a person can walk around them, without contact with vegetation.
Direct contact between vegetation and residential or other occupied structures should be avoided as far as possible, keeping the space around the bases of walls and pile foundations clear and trimming back branches which overhang decks, patios and roofs.
Dense multi-strand bands of twining creepers such as common Jasmine and some Pandoreas have had a wave of popularity for growing along the rails of verandas and external stairways and as overhead arches above passages and entrance ways. These, unfortunately, often carry ticks; both in these sites and on external fences and lattices.
The location of drying arrangements for laundry should receive careful attention. Clothes lines of all types should have the benefit of open-sky above the actual drying area. Even then birds will sometimes drop ticks on external drying clothing and larval ticks can drift onto it with a light breeze. If a heavy tick infestation is known to exist, it is as well to give externally dried clothing a short period in a in a clothes drier with the hot air turned on, when it is first brought into the house.
The prohibition of in-yard burning has resulted in changes in the handling of garden vegetable waste. Lawn clippings, fallen and pruned tree branches, palm and tree-fern leaves and other foliage pile-up in gardens either awaiting transport or their conversion to mulch. It is necessary to consider what should be done to avoid this leading to excessive attraction for small ground animals which can carry ticks into a garden, and the ground-level environment becoming much more favourable to ticks. It is desirable to heap garden vegetable waste in open patches, enjoying maximum access for sun and wind. It Should be turned frequently and can be given a few puffs of spray when this is done. Avoid creating such heaps along fence lines or in shaded areas of the yard, around the boles of trees, and in similar locations.
Another practice which has expanded considerably is the covering of gardens with deep layers of undigested vegetable matter as a sort of protective mulch. This again should be avoided as it makes the ground area more attractive to ticks. Where this type of mulch is piled on garden beds close to walls foundations it can lead to the invasion of the buildings by ticks. Vegetable waste should not be distributed until it is fully rotted down and it should then be dug into garden beds or raked evenly over other surfaces.
This is the aspect of gardening for which it is the most difficult to make precise recommendations which fit every individual case. It is not a case of some plants being inherently attractive to ticks and others not. The difficulties can perhaps be best understood when some extreme examples are quoted. In conditions of very heavy infestation, which were described as occurring 1993, ticks virtually treated any object giving some elevation above ground level, as a suitable site for attempts to locate a food source. They were seen on every type of annual and perennial plant and on inanimate objects such as gates and fence posts. Again, there are well known areas in Avalon where people cannot mow their lawns at certain times of the year without being attacked by ticks i.e. while generally short lawn grass is less likely to carry ticks than bushy shrubbery there is no guarantee that you will not be bitten while mowing the lawn or picnicking on the grass.
Given that these sort of extremes exist and strengthen the arguments for intelligent use of insecticides gardeners can still consider the range of plants available to them in terms of their degree of likelihood of being involved in harbouring ticks and their attractiveness for various reasons such as visual amenity, shade and windbreaks.
Ticks are most attracted by moist warm conditions. They hibernate when temperatures fall and avoid direct sunlight and drying low-humidity winds, seeking protection in dense foliage or under scaly bark Thus, among trees shrubs the smooth-barked species with large shiny well spaced leaves are less likely to harbour ticks than those with rough or papery barks and dense tightly packed or furry foliage. Among native trees and shrubs, Eucalyptus, Angophoras, Tristanias, Brachychitons, Clerodendrum and Acronychia are less likely to be harbouring ticks than species of Grevillea, Hakea, Leptospermum, Melaleuca, Casuarina and Kunzea. The latter group group tend to have tightly packed fine leaves or leaflets towards the end of their branches giving the sort of moist sheltered conditions where ticks can await opportunity to brush off on a passing human or animal.
Certain shrubs and small trees have the habit of repeated low branching the base of the trunk, and combine the heavy ground cover of a dense canopy with the above mentioned characteristic of increasingly moist dense leafage towards the ends of branches. The likelihood of these harbouring ticks is always very high. The group includes the introduced weed species lantana and privet and several of the native Leptospermums such as the coast ti-tree. The dense thickety growth which these species rapidly develop in any location is matched by that of the weed species of introduced tall grasses such as bamboo and pampas grass, also often associated with tick infestation.
Various species of natives in the genera Grevillea, Hakea, Leptospermum, Callistemon and Melaleuca have been used to form tall hedges for shade or windbreak purposes, combining an attractive appearance with this useful function. Unfortunately, these and lower growing boxed hedges provide an environment attractive to ticks and should be managed either by spraying when ticks are prevalent or by wearing treated protective clothing when working among them. The same is true of lax creepers such as the introduced Primrose Jasmine planted in dense rows to form dividing hedges in gardens, and dense masses of twiners such as common jasmine, already mentioned in the section above on spatial arrangements.
It remains to mention various types of ground cover including low-growing ferns. Soft creepers of various sorts are often employed. Gardeners in the also tend to have a constant fight with aggressive weed species in this group such as Tradescantia (Wandering Jew and its allies) and Wild Asparagus. Virtually all species in the group create a ground environment favourable to ticks and should be kept in small patches or sprayed with insecticide when tick prevalent.
People often ask if it is possible to obtain preparations which can be spray the plants in gardens and give control of ticks. Widespread concern for the environment and about toxic effects on humans, domestic and native a and plant species is shown by most of the questioners.
Potassium oleate, a natural soap, can easily be carried by dissolving in water and is effective against various pests such as thrips and aphids, interfering with their respiratory processes. It will control the larval and early nymphal ticks but not the more mature nymphs and the adults. It is a very benign substance, but should not be relied on in any situation where older nymphs and adults are a major problem, particularly from about the middle of the year to early Autumn. Most nurseries and garden service stores stock preparations of this under proprietary names.
Pyrethrum, a fully natural product, is toxic to all phases of the life-cycle of ticks. It is recommended that it be used in water dispersible forms, both because of convenience and because these are the least damaging environmentally. Pyrethrum concentrates are usually sold by nurseries or garden services in 1 litre or 2 litre quantities, suitable for 20 to 40 times dilution. During periods of heavy infestation, gardens must be resprayed every few weeks, and whenever rain has fallen.
In instances where particularly heavy infestation is occurring, usually close to a source such as a bushland area, there may be a good case for using a stronger chemical insecticide once or twice in the season of greatest prevalence followed up with the more benign sprays at a later stage. Most of the common agricultural pesticides will effectively knock out ticks. However, it is advisable to get expert advice when contemplating such a course of action.
| Update (July 2002) |
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"Potassium oleate soap is now available from some nurseries and produce stores in Sydney. It is very useful, environmentally benign, and controls aphids and scale insects without destroying wasps etc. It effectively clogs up the respiratory mechanism of soft insects, as well as larvae and newly metamorphosed nymph-stage ticks, but not older nymphs and adult ticks." We are still awaiting NRA approval for a suitable group of pyrethroids effective against ticks, for use in urban locations such as private gardens, street verges, parks and sporting venues. Those who wish to use a pyrethroid-like permethrin for control in such circumstances still need to obtain specific NRA approval for a particular use. The same is true for treatment of personal clothing. Although products are regularly used by the Australian and US military for mosquitoes and other biting insects, Australian civilian use for ticks is specifically excluded." |
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Bill Conroy BSc. (Agr) (Syd), TAGS (Tick Alert Group Support Inc., PO Box Mona Vale, NSW 1660) Newsetter July, 2002. |
Many gardeners like to maintain a section of wild land in their garden for the opportunity it gives to observe and preserve native plant species and visitors to such an area such as birds, possums, gliders etc. This is best done in blocks of normal residential size by maintaining a section two to four metres deep adjacent to the back fence. This allows observation from the outside at times when there is a high risk of tick attack and minimises difficulties about entering the area for weeding and maintenance. Such a strip can be sprayed wiith water-dispersible pyrethrum solution without having to enter the wild garden.
Island patches of wild garden are really suitable for areas much larger than normal residential blocks. In terms of the considerations outlined under Arrangements" they should have adequate clear pathways around them and in institutional grounds it may be necessary to have signs warning of the possibility of tick bites.
For the much smaller number of people who desire a complete wild garden occupying all the area not covered by structures, the earlier comments about cleared set-backs from the bases of walls and other external structures should be carefully noted and consideration given to requirements of protective clothing and the pre-spraying of areas where maintenance is to be done. Such a wild garden can be extremely rewarding in terms of visual amenity and scientific interest, but the problems for human health should not be underestimated.
Summarising the information presented in the foregoing notes the points can be itemised as follows:
1. Outbreaks of tick infestation in private and institutional gardens in the Pittwater and adjacent areas are likely to continue to occur.
2. To combat these outbreaks, so as to minimise adverse effects on health and welfare, householders and managers should carefully study the details of the local climate to develop an awareness of the type of weather leading to outbreaks of infestation, the behaviour of the birds and animals of their area which might bring ticks to their gardens, and the growth rates and space requirements of the plants in their gardens.
3. It may be necessary to carry out insecticidal spraying at certain times and suitable sprays and equipment can usually be obtained without too much difficulty.
4. A careful selection should be made of the plants to be included or preserved in private gardens. This selection should be made with a view to isolating tick-prone plants and giving them appropriate treatment when ticks are prevalent. It should also aim at the control of the growth of those which may be retained for their visual attractiveness but become unmanageable habitat for ticks when out of control. Spatial arrangements are extremely important in this respect.
Bill Conroy is a retired agricultural scientist who has had a long career in the tropics and was, on a number of occasions, co-opted to work as a medical entomologist and parasitologist, most importantly during Wo4d War II when he commanded a malaria control unit in the Australian Army. His career has given him widespread experience of tick and other arthropod-borne diseases in both human's and animals. Bill has lived in the Pittwater area for many years and been an active member of the Tick-borne Diseases Research Unit (TRDU) since 1993.
By Claire deLacey
Letter to Tick Alert Group Support (TAGS), June 2001.
Having subscribed to TAGS and read the magazine articles with great interest, I'd like to take the opportunity to contribute my observations on tick distribution to TAGS.
As a free-lance field botanist I work in a range of areas in NSW, from Jervis Bay in the south to Karuah in the north and Lithgow to the west. I have been interested in tick distribution for some time, as ticks are a considerable problem in my work. I have always been particularly susceptible to tick bites and find that I have experienced increasing levels of irritation and side-effects in more recent years.
I live in Maianbar (near Bundeena in Royal National Park), where we have been inundated with ticks over the spring and summer months, though I'm happy to report that their numbers have declined steadily with the onset of colder weather. However, I have noticed an interesting increase in ticks in this area over the last few years. The general consensus in the neighbourhood seems to be that the success of the fox baiting programme in Royal National Park has led to an increase in Bandicoot numbers turning up in people's back yards, which has contributed to increased tick numbers.
I have found the increase in tick numbers to be an interesting situation, but I'm not convinced that an increase in Bandicoot numbers is the complete picture. In areas surrounding Maianbar and Bundeena (i.e. in the Royal National Park) high numbers of ticks do not seem to be solely associated with good Bandicoot populations. I have suspected for some time that the increase in tick numbers is also associated with the fragentation of understorey vegetation in the area, with a consequent loss of habitat for small bird species. It may be that a loss of smaller bird species, which could play an important part in reducing tick numbers, would lead to an increase in tick infestation.
Maianbar and Bundeena are small villages located at the mouth of the Hacking Estuary. Although much of the tree canopy has been retained (more so in Maianbar than in neighbouring Bundeena), most of the understorey which provides suitable habitat for small bird species has been removed or replaced with ornamental native, exotic or mesic (softer rainforest-type) shrub species. Additionally, the remaining sclerophyllous (heathy) vegetation remains unburnt (as in most suburban situations), and as most of the sclerophyllous plants need fire to promote regrowth and regeneration, they become displaced by mesic plant species. In addition, mesic plants are often better adapted to altered hydrological and environmental factors which follow on from increased run-off and nutrient levels common to suburban environments. Mesic species such as Sweet Pittosporum Pittosporum undulatum, which belongs naturally to the landscape, and weed species such as Privets Ligustrum spp. generally have a greater requirement for nutrients and water and create more humid environments than do their heathy counterparts. Stands of mesic species also create a dense canopy beneath which heathy plants cannot regenerate, thereby removing habitat for small birds. These humid environments tend to make very suitable habitats for ticks.
When I spend time in my garden I am aware of the plant species which are likely to be host to ticks. They seem to turn up most commonly on exotic species such as Mulberry Morus alba, Banana Musa spp. and in unmown grass. They also occur on ornamental native species such as Lillypilly Acmena smithii, Magenta Lillypilly Syzygium paniculatum and often isolated specimens of Eucalyptus species. In a single visit to the areas of my garden where this vegetation is concentrated I can sometimes be the target of 30 or 40 tick nymphs. Conversely, I can walk through areas of the Royal National Park just 10 minutes away from my back yard and bring only one or two adult ticks home with me.
The vegetation in the villages of Bundeena and Maianbar (isolated large trees with little understorey) supports larger opportunistic native bird species such as Magpies, Currawongs, Cockatoos, Lorikeets, Ravens, Rosellas and Wattle Birds, and exotic species such as Indian Miners. These larger birds are further attracted into the area by being fed by local residents. Smaller native bird species numbers are declining, especially species like Silvereyes, Treecreepers, Gerygones and Thornbills, which normally feed on the ticks.
It seems to me that the increase in the spread of urban areas, the removal of habitat and the alteration of the cycles of natural phenomena such as fire frequency all contribute to a variety of ecosystem responses, of which increasing levels of tick infestation is one.
Unfortunately, attracting small birds into the garden might not be as straightforward as it appears; some of my own thoughts on this are as follows:-
None of the above constitutes proper scientific research; it is simply based on my own observations and hypothesising, and it is likely that research has already been done on this subject. If this is so, perhaps this information could be shared; then we might be able to do a little more to reverse biodiversity decline and rid ourselves of some tick problems at the same time.