Septoria

From that description, it could be several things.

Septoria, nitrogen deficiency, sulphur deficiency, water logging, natural leaf senescence, or something else entirely.

Show me the plant.

I couldn't show ChatGPT the plants, but I could show it some photos.

I'm finishing up my PhD with Chris Smart in the plant pathology department here.

Jocelyn Schwartz works on septoria leaf spot.

Septoria leaf spot is a really common disease of field-grown hemp here in New York.

It's caused by the fungus Septoria cannabis.

Lesions start like these brown lesions here, surrounded by yellow halos.

Primarily, the lower leaves and the inner canopies are most severely affected by this disease.

And management is quite challenging.

We did a couple of fungicide trials over the course of three years and found that the products labeled for use on hemp in New York were not efficacious against Septoria cannabis.

Okay.

Septoria, how early in the planting life of the tomato does it appear? How soon does it appear?

It seems to come on reasonably late, actually.

So not... young, sort of mid-range I'd say.

And your

pruning techniques? Okay, Septoria, a number of reasons.

Look, it can be present in the soil, no matter where you are.

It can appear from over-watering, wetting the foliage too often.

A time capsule sealed 50 years ago at South Australia's then Roseworthy Agricultural College is about to provide a unique insight into how cereal crop diseases mutate.

The capsule holds the first samples of the then-emerging Septoria tritici blotch, a now common wheat disease.

Plant pathologist Dr Tara Gerrard is from the South Australian Research and Development Institute.

She told Country Today's Gabrielle Hodson it's a rare chance to compare historical and modern isolates.

So if it's been stored like that, there's a good chance.

What we'll do is it's a little piece of leaf tissue and we'll put it on an agar plate in a petri dish.

And so the agar is a medium that's specialised for the growth of Septoria.

Give it the right temperature and moisture conditions and hopefully after about a week, the spores should emerge and we'll get the fungus growing in a plate culture.

But first of all, I guess everyone wants to know what was actually in the time capsule?

Stuff from Roseworthy itself, principally books, soil samples, samples of superphosphate, a biological sample, which was Septoria tricticus.

Yeah, I trip on the name, but it's a fungus disease that causes leaf blotch in wheat.

And that was put in 50 years ago by a researcher, a wheat breeder at the... at Roseworthy at the time in the hope that in 50 years' time it could be retrieved and its viability tested, which is what's going to happen.

We are going through the discussion process and, um, at the end of the day, we will ultimately negotiate a position that benefits all parties, and we'll be very happy to share that news with you when we do.

When we reflect a little bit upon what we're seeing on cereal crops, in particular wheat, which is, uh, one of the top three crops being grown globally, when we are targeting Septoria, one of three major diseases that affect wheat.

Here what we see is that we have very, very good efficacy when compared to the biological and conventional references across not just the one, but four different disease targets.

Here what we see is that the product that we are developing for this category is not only effective against Septoria, but also we have good efficacy against brown rust, yellow rust, and ultimately powdery mildew as well.

The point, again, is that we are providing not conventional, but biological control, um, approaches to control these major diseases to be used in conjunction with conventional pesticides.

So to put this into a, a nice summary table and to give you an opportunity to look at both the size of the opportunity, but also where we stand, I, I think this lays it out nicely.