​Hello fellow Foxies,
About three years ago during a very dry spring I noticed that parrotbush (Banksia sessilis) plants on Banksia Walk shallow ironstone soil east of the water tank were severely infested with a scale insect. The damage has progressed each year to the extent that most plants there are dead or unthrifty. Accompanying golden dryandra (Banksia nobilis) plants are much less affected

​After much investigation I discovered that symptom severity is linked to soil water holding capacity, with far less damage on deeper and sandier soils. Another finding was that two organisms are involved. The first was identified as whitefly, but a new species rather than the common Aleurotrachelus dryandrae
Adult whiteflies look like tiny white powdery moths, but I am yet to see any. The mains signs are small powdery spots (early larvae), yellowish to brown scale-like mid-stage larvae and pupal cases that look like miniscule white crystal coffins. Whitefly are supposed to only be on the leaf underside, but this species is often on the upper side. Infested leaves often have a powdery or waxy looking coating and black spots that may be associated with honeydew exuded by the larva. The spots look like insect poo to me!

​While the leaves are being sucked dry, the growing points are also being killed by an evil caterpillar. From an egg laid on shoot or flower, the caterpillar hollows out the stem to the first node. It returns to the dead growing point to pupate and exit.

​Moisture stressed plants are more susceptible to diseases and pests, and increased temperatures also increase temperatures worsen pest damage by speeding up their life cycle.
The Banksia walk was named after a small group of Bull Banksia (Banksia grandis) plants that occur on this soil. They have been struggling in recent years, and some are dying this summer. Interestingly they are not greatly infested with whiteflies or borers. This area is a photo-reference site that I have been monitoring. Images changes since the 2009 fire.

​This is another biodiversity loss in Foxes Lair in addition to flooded gum death, marri decline, and wandoo crown decline that I have observed in the last 20 years.  I still remember being surprised when I arrived in Narrogin in 1986 and a farmer told me how much his farm’s rainfall had fallen. We now have even less and more variable winter rainfall. 

The balga Xanthorrhoea preissii, a grass tree, is a striking part of our bush that was use by Noongars for medicine, tools and sustenance. Grass trees are monocotyledons but neither grasses nor trees.
 Carbon dating has found grass tree ages of up to 1,000 years. Also, they have special contractile roots that pull seedlings underground so that plants on sandy soils may not develop an above ground stem for 10 to 30 years. I reckon that the five-metre plant I found in Candy Block must be ancient. Unfortunately, twenty-eight parrots are now attacking its new growth.
 
The grass tree at Foxes Lair is the smaller Xanthorrhoea brevistyla that lacks an above ground trunk. It is an insect magnet when flowering in November.
 
I regularly see severe insect attack on balga flowering spikes and brought one home for examination. The green stem had frequent reddish- brown sunken lesions with gum exuding from small holes. The split stem revealed tunnels containing bardi grubs, surrounded by reddish brown fungal infection. Once again, a canker fungus that affects eucalypts and other shrubs

Interestingly, a previous investigation on wandoo crown decline in Foxes Lair  found a similar combination of insects and fungus. The fungus causes severe damage to trees and shrubs. Fungus doesn’t seem to affect the balga trunk, presumably because flowering spikes naturally die before it can spread further.
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​The bardi grubs are larvae of longicorn and cockchafer beetles. They have tunnelled up through the entire flowering stem.
The flowers and seeds were attacked by a brownish caterpillar that eats them under a protective cover it makes from its frass (poo) and silk.

​Last year I received a shock when one of two apparently healthy balgas that I had photographed earlier snapped off at mid stem

​The centre of a normal trunk is filled with living fibrous material above a woody cone-shaped base that remains long after a plant has died. The living centre is surrounded by old leaf bases held together by natural resin, which provides support and excellent fire protection.
The fibrous centre of the dead balga was completely replaced by a soil-like material containing wireworms, which were attacking the interior of the surrounding leaf bases

​As Noongars ate bardi grubs that were in the centre of dead balgas, I suspect that they had chewed out the living material before wireworms moved in.
This balga had been surviving with a decayed centre for some time until the weakened stem snapped. It is a natural process and dead remnants can be attractive in their own right.
 
Unfortunately, increased in Australian ringneck parrot (twenty eight) numbers are causing premature balga death from them continuously chewing the new growth.

​ Greetings fellow Foxies,
 
There have been many comments recently about widespread shrub death in Foxes Lair due to the exceptionally dry spring and summer.
Certainly, there is more death than usual, but this doesn't explain the scattered pattern in Foxes Lair with dead plants next to healthy ones.
Luckily my esteemed colleague Detective Doug volunteered to investigate this problem.
 
The great man randomly selected two each of dead and healthy Dilwynnia laxiflora (pea flower) plants for examination

​Dead plants.
The roots were very bent and thickened, particularly the tap root that snaps easily. Borer channels were on both the outside and inside, including one that contained a jewel beetle emerging from its pupal case.

 Problem solved?
No, being a true scientist, Detective Doug insisted on also examining the healthy specimens
Roots of both live plants had also  been attacked, although to a lesser extent than dead plants.
The first plant had a few minor lesions but otherwise appeared normal. However when split in half lengthwise the root was hollowed out and contained a hibernating? jewell beetle. These beetles are common on pea flowers in October so presumably they hibernate until spring.

The second healthy plant showed evidence of insect attack that appeared to be confined to the surface. However, when cut in half it was obvious that insects had entered and tunnelled up the centre of the root. While doing this they brought in spores of a canker fungus, shown by the blackened areas. This fungus invades healthy tissue, blocks water and nutrient transport and kills the plant. 
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Conclusion
These plants are routinely attacked by borers and may survive for more than a year until invading canker fungus kills them or they snap off. Increased water stress from extended dry weather hastens plant death.
Case closed
​
Interestingly, a previous investigation on wandoo crown decline in Foxes Lair  found a similar combination of factors.

Greetings Fellow Foxies,
​​Yesterday I noticed honeybees clustering around cracks in a single Marri tree. My first thought was that the bees must be pretty desperate to drink the astringent reddish kino that oozes out of marri trunks and branches (kino was used by Noongars as an antiseptic and for treating stomach disorders).
 
It then dawned on me that I was surrounded by marris covered in kino deposits but the bees were only on one tree trunk. The following images reveal my discoveries as I peeled away about a centimeter of layers with a pen knife.
​​After shooing off bees and removing an outer layer of loose dead bark, I discovered droplets of honey-coloured sweet nectar oozing out with surrounding bark stained black and bright blue in one case, by a skin fungus growing on nectar-rich bark.

A bit further in was a tiny (3mm long) cigar shaped object at the top of the flow. This is an insect pupa (note the head and remnants of legs on the pupa case), that was still in the soup stage prior to reforming as an adult. Judging by the copious nectar flow, it is likely that the pupa had drowned.

​Further in was a defined oval hole of a burrow that opened out into a frass (poo) filled chamber right on the boundary between the bark and sapwood. This cambium layer contains the tree’s plumbing system where water (going up) and sugar solution (going down) is situated.
 (Random comment: this is why trees die when they are ringbarked).
 
When I mistakenly penetrated the sapwood, red kino immediately welled out and started to become gummy.

The conclusion is damage by a beetle or moth larva  borer that specifically targets the marri cambium layer causing sugars produced by the tree to flow out as nectar.
 
Large deposits of red kino on marris comes from damage to the underlying sapwood as described in this blog
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