MIMOSA, BANANA FRECKLE, CITRUS CANKER and BOGGED on the FLOODPLAIN

Hello again

We recently had a biosecurity person from the Commonwealth Department of Agriculture, Water and the Environment at Croker Island for the best part of a week. We conducted three surveys - The photo below shows us checking bananas for the disease called Banana Freckle - it is serious threat to the banana industry. We were also looking for Citrus Canker amongst other diseases - thankfully nothing nasty was found. 

We also did an aquatic biosecurity survey at low tide looking for aquatic creatures that we don't want in Australia - like the Asian Green Mussel. They can easily hitch a ride on vessels, marine litter or ghost nets.

Ranger 'PK' accompanies us when it is convenient. Here she is watching a traditional owner who accompanied us on a recent boat trip and wanted to take a couple of fish home. 

One of the Class A (highest priority) weeds we are seeking to eradicate is mimosa pigra. It is a floodplain weed which, if left untreated will form a mono-culture. The photo below shows that the leaf is made up of many small sections.

The leaves are touch and even light sensitive. If you touch the leaves they close up - see below. The adult plants also have rather nasty thorns. 

Mimosa pigra is a prickly shrub from Latin America rated one of the nation’s worst weeds. There are suspicions it was brought into Australia in the 19thcentury as a curiosity because of its mildly sensitive leaves. If so, that was a very big mistake, because it spread from the Darwin botanic gardens to the Adelaide River floodplains and has now infested 80,000 hectares in northern Australia.

Below is a photo taken around the Daly River showing how mimosa can take over large areas if left untreated - that is all mimosa in the foreground.

Again in the Daly River area - an area that has been recently treated. At Croker Island we are not to this stage - and hopefully will never be.

Below is an exclusion zone on the floodplain at Croker Island. This seeks to monitor the impacts of the feral horses. On the other side of the fence the horses are excluded. After the recent fire, the grasses inside the exclusion zone have responded quickly where as outside the exclusion zone there is no sign of any new growth yet.

There have been estimates of around 3,000 horses on Croker Island - left over from the cattle operation during the mission days.

We use this 200 litre spray unit on our Can Am Defender buggy to access areas where a conventional 4WD can't. It handles sand dunes and the floodplain very well - mostly anyway.

 Recently Clayton got the buggy completely bogged in a part of the floodplain that is very wet - under the dry crust. The Can Am buggy will float over most surfaces but not this time. It was sitting firmly on its 'belly'.

The 4WD winch saved a lot of time and sweat!!

We just had a surprise visit from one of Bryan's flying instructors from 1989, who now works with the RFDS - but that is a story for the next blog.

Take care

Nancy and Bryan (and PK)