Visiting Maroochy Research Station – 2002

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Bob – you’ll see some netting where we’ve planted some new breeding lines of stone fruit so we don’t lose any of the fruit to birds, bats etc. We also have fruit fly exclusion netting about 2mm diameter which is a clear monofilament type to allow adequate light penetration and no fruit fly to go through the net.

Q.  How do you go with humidity under the fruit fly netting?

Bob – It’s increased

Q.  Do you get any fungal problems?

Bob – No, not as yet but we’re just trialing it to see what problems we are going to have.

To show you what happens when you don’t net, 2 weeks ago we had fruit here on these trees then we had a flock of parrot and there’s not a single Persimmon left.  The only way to be environmentally friendly is to put up netting. My way of thinking is that if we want to have a clean/green system of growing fruit and vegetables then everyone should be paying – not just the growers or the industries.

We have high chill pears but they haven’t fruited.  We tried a whole range of low chill pears a few years ago grafted on Pyrus callarina rootstock and they fruited but we removed them from the Research Station due to money to work on pears. These have come in from our plant breeder who transferred to Maroochy from Stanthorpe, Dr. Bruce Topp. He’s now working on Stone Fruit – we have some Apricots but they have not fruited or flowered heavily because we’re too low-chill and they need high-chill environment. We also have a Strawberry breeding block.

Sheryl – what’s the new PVR type we’ve been hearing about?

A. I think it’s the Camerosa type.

Bob – we can’t get KJ Pink Custard Apple because they think we will use it to cross with other varieties.That is up to the people who have taken out a plant patent on that variety.

Part of the exclusion netting work I’ve been doing with other people – Geoff Wade is our Entomologist, Dr. Ennis Lloyd, & Dr. Alan George. We have a net for bird/bat/fruit-piercing moth.  Sometimes growers will put on fairly heavy insecticide spray which will destroy the predators and sometimes there’s a commercial decision made to eliminate one pest which takes out the predators for another pest. They then re-introduce the predator later so there are many systems that have to be managed in running a commercial enterprise.

We have a monofilament net over the lychees.

Collection Block

Carob –– they have male and female trees for the types used to produce beans – the main use for this hermaphidite type is for feeding cattle and that’s the reason why many of the hermaphodite types were bred.  They can feed cattle with this foliage – particularly in very dry, arid conditions as these varieties will grow well.

Sheryl – there are big plantings in S.A.

Bob – we get fruit on this tree but lose a lot due to too high a level of moisture.

Sweet Tamarind – we do have a tamarind here but due to the cool conditions it does not produce good quality pods

Sheryl – you’re better off to buy it in a packet at the Chinese shop already prepared!

Bob – Abiu fruits very well here, Wampi – Tem Pay & Gay Sham, both good varieties, Star Apple doesn’t get much dieback – we have the purple type, a green one as well as a yellow type. Wax Jambu, Water Apple has had quite a few fruit on it, Mammy Americana took about 7 years to fruit

Robert P – I got my Mamy A as a root graft from Cairns.

Bob – the Mammy Sapote in California in 1987 was worth $5 million making them into sherbets and drinks in the restaurant trade.

Robert P – are these prone to phythophera as they can get dieback

Bob – heavy soils seem to affect them – they like a lot of organic matter

Robert P –  I’ve heard that if you have trouble with these you can put it on as a foliar spray

Bob – you can spray or drench the ground with a phosphoric acid but it is not registered to be used with this tree fruit.

Bob Feijoa – if it won’t fruit, graft a few varieties onto the one tree so this allows for cross pollination.

Patrick – another alternative to grafting onto Feijoas is to plant 2 trees into the same hole.

Bob White Sapote need pollinators as well

Robert – my Pike seems to set by itself, Vernon, Bluemthel are pollinators.  Will Pike and Lemon Gold be OK with each other?

George Lemon Gold is a partial pollinator

Bob – Yellow Gold needs a pollinator.  Denzler is an ever-bearing variety – all Casimoria fruit is thin-skinned and won’t last so it’s very difficult to get it to a consumer

George – Miracle fruit likes a bit of shade

Bob – Mulberry – Morus alba – Morus nigra is the European mulberry (black) but it doesn’t grow very well here.

Fruit Fly Exclusion Netting Trial

Netting – we have black netting and white netting – that’s the fruit fly netting.  The normal black netting is used for bird/bat and the white is the special fruit fly netting from NetPro with the logs being donated by Coppers Logs.  NetPro erected the netting for us and the net was manufactured by Gale Pacific in Melbourne.  The black net is cooler by 3 degrees and the white net is hotter by 5 degrees compared to ambient air temperature.

Sheryl – black absorbs heat – how is this?

Bob – black netting intercepts more light whereas the white netting with the translucent fibres lets more light go inside.  The light bounced around inside and with the restricted air flow the heat is trapped inside due to the smaller diameter of the net.

George – so we can use black and get a slightly lower chill factor

Bob – yes, but you’ve got problems with fruit fly exclusion. With the netting last year we didn’t spray the block at all for fruit fly, we had 100% infestation of fruit fly under the black net if we did not spray – it’s approximately 10ml mesh.

With the fruit fly netting on we’ve had 4 male fruit fly trapped – they’re runts and we don’t know whether they incubated in the ground over last season or because they are so small they got through the net – the other thing with the male is that he won’t sting the fruit.  We have attractants to pull the fruit fly inside the net to test its effectiveness.

George – do you have male and female traps inside or are you using the yeast bait to see if there are any female?

Bob – no we just have the pheromones – we don’t use any chemical sprays.

George – With Grumichamas they never use to get stung but now they do and the grubs are a lot smaller than the grubs in normal fruit – I think you’ll find that the fruit fly will eventually mutate to be able to get through there and I think you’ll selectively breed small fruit fly!!!

George – nature has its way of getting around things unfortunately!

Sheryl – getting back to this black & white netting – you can’t compare two different colours if they’re not the same density.

Bob – no that’s a normal (control) – that’s normally the type of netting that growers have been putting up.  What we’re doing is applying a different regime with 2 different management strategies to each block. One looking at the effects of normal commercial practices carried out on this site (block) compared to our modified practices out on the other site (modified is the white netting).

Bob – we have both the yellow and the red Pitaya but the cacto-blastus gives it a real flogging. They do best in a hotter climate. They’re growing approximately 10,000 acres of Dragon Fruit in Vietnam. There’s also the spineless type.

Robert P – the yellow tastes the best.

George – Gordon Vallance used to crop them very successfully down in Mullumbimby – basically the red flesh one.

Article compiled by Sheryl Backhouse