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The bard, sorghum disease and all that rot

WHAT does Shakespeare say about troubles coming not as single spies but battalions?

The latest issue to hit our poor suffering sorghum crops is charcoal rot and probably also around is fusarium stalk rot.

Charcoal rot has the blackish appearance appearing just above ground level and fusarium stalk rot will have a distinct reddish-brown discolouration in the stem and around the nodes.

The end result of either disease is lodging.

Charcoal rot is also suspected of early entry into an actively growing sorghum plant and the onset of moisture stress - or even glyphosate desiccation - sees both diseases rapidly escalate up into the stem.

The result is lodging or, in layman's terms, it develops some soft spongy tissue and, with strong winds, the plant falls over.

What to do about it is a bit of a mystery.

Research work has found we are fairly exposed to these two separate soil-borne diseases.

Rotation and stay green varieties are our best defence for tolerance against both these stalk-weakening diseases.

Losses in these lodging situations can be high but what is not so obvious is the possible reduction in yield from plants affected by these diseases.

Some varietal differences have been discovered but if one causal agent of a stalk rot does not infect your plants, another will (the "battalion"). Even the usual desiccation by glyphosate herbicide can increase these disease lodging problems.

So, this year we have to worry about root lodging, with many sorghum crops having few secondary or prop roots, and charcoal and fusarium stalk rot.

The simple method of tolerance or avoidance to these diseases is to keep stress to a minimum during sorghum's growing season.

Easier said than done. But plant population, row spacing, strict grass weed control and fallow moisture conservation can provide major beneficial conditions to your crop, so it won't be adversely affected by these two diseases.

Get the header out and get it off the paddock!

Due to the dry conditions, there certainly was no need to desiccate the paddock and while the moisture was at 23% with the howling easterly wind on the weekend, it came down to a respectable 17% to enable harvesting to occur.

But there's no good news for our struggling sorghum crops.

With high grain prices around, it is worthwhile keeping a close eye on your sorghum crop for all the usual issues.

Like mice, midge, helicoverpa, Rutherglen bugs and stalk rots.

Topics:  grains paul mcintosh plant health sorghum