- Location
- S E Glos
Oh no, not the old 'reduced rates encourage resistance' fallacy
The NFU backs gene editing. Do you ?
- Thread starter delilah
- Start date
Rate has nothing to do with fungicide resistance
What’s it to do with then?Bayer and the like spend money on research but mr big knows better!!!
It’s frequency of use/exposure in fungicides, herbicide is dose rate. ‘Mr Big’ does not know best but ‘mr big’ gets excellent advice from Niab.
- Location
- Kent
This was just after a quick Google but is also one of the first things that I was taught on my PA courses always read and follow the label
4. Apply the appropriate amount.
Many people believe if a little is good, a lot is better. Nothing could be further from the truth, or more toxic to your plant. Most fungicides have gone through numerous trials to identify optimal amounts. Excessive amounts can result in phytotoxicity. This is really no different from an overdose in a human: Two aspirins can control a headache; 50 aspirins can kill you. Making up the right amount in the beginning is helpful, so you don’t feel you’re wasting fungicide -- or money.
Overdosing isn’t the only problem. A much larger problem lies in underdosing or cutting labeled rates. Less than labeled amounts usually fail to control the problem and can create fungicide-resistant pathogens.
StackPath
www.greenhousemag.com
ollie989898
Member
Lots of chemistry does not work as first intended; I can take you to fields in the South West where a lot of chemistry no longer works and I'm not talking 20 acres here and there.
ollie989898
Member
When I have ever advised reduced rates on products, it was only done so with regard to the following:
1. In line with manufacturer recommendations for scenario envisaged (i.e reduced-rate roundup).
Or
2. Product being applied in tank mix with other chemicals with known efficacy on target species (for example you would not apply full rate Epoxi if you were tank mixing with a product that already had some in as well).
Another scenario I can remember was with the application of slug pellets where pest pressure was a consideration or weather was an issue- you would hardly slap the maximum total dose on allowed in one hit as the first few storms of rain would see it all gone and your crop potentially marooned.
The use of roundup at reduced rates is specifically discussed by the manufacturer of most glyphosate products. There is absolutely no point in my attacking tiny weeds in stubbles with the same rate of product I would use to destroy permanent grassland.
I would at no time apply a product (particularly an insecticide or fungicde) at a rate drastically lower than the recommended rate because it makes the application pointless. The manufacturers do a lot of work on dose rates. A lot of products show a huge decline in control as you drop the rates.
Case in point: label from Roundup Flex, a posh 480g glyphosate product marketed by Monsanto. You will not a considerably reduced rate for some weeds and a higher rate (though nothing like the maximum) for others. Also note the stipulation that farmers should not cultivate or touch the field for at least 24 hours application.
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Of course follow the label and don’t go below recommended rates. But that is irrelevant. It’s frequency of exposure that causes resistance in fungicides. It’s dose rates the cause resistance in herbicides.
Will Blackburn
Member
- Location
- Cheshire
Label rates are max rates not recommended rates.
@Fromebridge could you explain how fungicide resistance works compared to herbicide please?
ollie989898
Member
Most fungicides you are provided with come with extensive technical backup from the manufacturer where they indicated what their recommended dose was; normally only part of the maximum label dose was mentioned and this usually gave consideration toward the expected cost vs the level of control achieved.
- Location
- S E Glos
As I understand, it depends on the type of resistance.
For herbicides, there's target site and enhanced metabolism. Target site is encouraged by selection pressure, i.e. higher doses are more effective at taking out the susceptible individuals but have no effect on the resistant ones, (since resistance is 'total'). hence high doses encourage resistance. For EM, because the resistance is more metabolic than genetic, the weed concerned is able to metabolise the chemical and survive, and higher doses would be harder for it to cope with hence these are more likely to kill it. Lower doses can be shrugged off hence control is poorer and it appears the herbicide is ineffective.
I must admit I thought the same distinction applied to fungicides: strobilurins and SDHIs being single site so resistance is of the target site kind, and higher doses again kill more of the susceptibles and don't touch the resistant ones. It was suggested at one point that triazole resistance is more EM but recently bods have spoken about it as being TS in its dose response, i.e. high doses encourage resistance.
Manufacturers are thinking this way now and accept that new fungicide product lifespan will be shortened by high doses as well as by frequent use.
- Location
- South Molton
What is your connection, if any, to landworkers alliance?
- Location
- South Molton
You post alot of links for them, that was all
- Location
- Scottish Highlands
Do you have the same attitude toward the Green Party ? Last I checked, that was a written policy of theirs, was it not?
- Location
- South Molton
Well according to the NFU Gene editing means should lower the amount of artificial inputs we HAVE to use.
Have?
Don't think so!
Have?
Don't think so!
I know GM and GE are different in terms of how they are made, but, the Americans are often using more pesticides now certainly triple stacked BT cotton because the pests get around the resistance so quick.
some are trying to paint the people doing the work on GE as some kind of British cottage industry. They will be swiped up by the big guys pretty quick I think.