This may sound like a silly question but I have noticed that Simazine is registered in the US for control of fall panicum as a pre em.

We have a grass problem every year in our corn that I cant control with Metolachlor, Pendemethalin or Atrazine and we have no post emergent herbicides available in Aus.

Our grass seems to be a panicum type species that grows rapidly has fine hairs on its leaves and puts out a seed head that when matures, rolls away with the wind and spreads more seed, oh, and it seems to laugh at Atrazine as a post em.

No one over here can tell me why Simazine isn't registered or if it will damage my corn. Do you think it will control this grass? and can it damage the corn?

Also can any one think of other options I may have in conventional corn. think old school, say 30yrs ago! Linuron, Bladex etc.

I can use droppers if I have to.

Thanks for your help,

Jim

As Matt said, simazine is very safe on corn when applied as a pre-emergence product.

Simazine has a longer residual that atrazine.  So, depending on what your rotational crop is, you may or may not see a problem in the subsequent crop.  If you are in a relatively dry environment, I would think that residual carryover would be enhanced. 

Do you grow corn several seasons in a row?  or do you grow 1 crop of corn, then rotate to another crop?  and, if rotating, which crop(s) do you tend to rotate to?

Thanks everyone for your advice.

Firstly Simazine is readilly available and we use it on TT Canola, Chickpeas, Vetch etc.

I would be looking to use it as a post plant pre em with Atrazine and Metolachlor on corn.

Matt, unfortunatley, we can't get Nicosulfuron, Foramsulfuron or the like. Mesatrione(Callisto) I think originated in Australia but I don't think it is available to Australians! Would Cyanazine (Bladex) be better than Simazine? or safer? I was looking at using 2kg/ha (2lb/ac) of Simazine ( loam soil).

Martin, I will be looking to plant chickpeas after the Corn, or if it is too wet (like this year) it will go back to corn. Our average ranfall for spring/summer is 7".

Cheers

Jim

I would be very concerned about simazine carryover into the chickpeas, esp at the 2 lb/ac rate, and especially with only 7" annual rainfall.

For rotational concerns (with chickpeas), I would try the Cyanazine/Bladex first - see if that gives you the extra grass control you need. 

Sometimes, I use a post-emergence grass product called Option (From Bayer). It can rotate to any crop in 60 days (if my memory is correct).  However, I suspect you don't have access to it, if you don't have access to all those other products.

Another product that comes to mind is Basis.  However, again, I suspect you don't have access to it either.  Is that correct?

While I am thinking, maybe you want to try some simazine on fields which will be corn this year, AND next year.  Then drop the simazine in the last year of corn before you rotate out.  I don't know if you have this kind of flexibility, but I thought I would suggest it.

Jim,

Simazine is safer on corn than Bladex (cyanazine), although cyanazine has been banned in USA for over a decade, so my memory may not be perfect on this (we sometimes worried about Bladex dinking up the corn, but we've never worried about simazine -- always looks just fine, even on high-pH).  Both chemistries have good activity on broadleaf weeds, but weaker on summer grasses.  I wouldn't consider either of them very solid on summer annual grasses, but in a dry climate they might be adequate to good.  For instance, Bladex was almost always tankmixed with atrazine to gain the synergy and improve control.     

2 lbs/a of simazine (Princep) sounds like a lot. Remember that it has more soil activity than atrazine, so you can't compare rates of the two.  Three-quarters of a pound of simazine probably provides more soil activity than a full lb of atrazine (although the simazine has less burndown capability).   

Martin,

Chickpeas are very tolerant of pre-plant simazine.

best regards,

"Chickpeas are very tolerant of pre-plant simazine"

I stand corrected. 

Thanks.

As far as I know Bladex is still available. It was used for years for pre em broadleaf weed control in lentils.

I have never used it.

 Matt, the 2kg/ha rate I quoted was off the US Princep 90 label. I just want to throw all guns at this grass, it is a brute.

We have used Simazine pre plant pre em on chickpeas for years.

I did read that Bladex + crop oil applied early post em did a bang up job on fall panicum, with little damage to the corn.

As far as residual goes the more the better in this rotation!.

I'll let you know how it pans out.

Thanks everyone.

Jim.

Thanks for the info -- I always learn something on this forum!  (Now that I think about simazine's lesser foliar activity vs atrazine, that does make sense that it would be well-tolerated by corn . . . .)  Thanks again.

I guess we cant really afford crop damage as we are marginal to say the least as far as corn growing goes, but I will certainly try some different options that have been bought up and see how they go. The other issue is how effective pre em chemicals are working sprayed on to large amounts of wheat residue and zero tilled. I will try both Simazine and Bladex this year and maybe a little Bladex as post em if i have a problem.

Jim

Jim, since you already use simazine on chickpeas, I have a question:  do you see this grass problem in your chickpeas?  where you are already using simazine?  If you don't have a problem, that might really clue you in that simazine will control this grass problem. 

how are you using simazine in your weed control program on chickpeas? alone? in combination with other products?

timing?  do you have issues in getting the simazine to work well in your arid climate?  or you using any management strategies to help you get it to work better?  These kinds of questions might help you to decide how to use it on corn.

I would not use simazine alone, but would use it in combination with other products, to broaden weed spectrum control. But what you use will depend on what other weeds you deal with.    Just my thoughts.

Why pre-emerge instead of early pre-plant (or early post-emerge)?  Soil residual chemistries won't do any good lying on top of the soil.  For corn, in a climate such as yours, I'd think it best to get the residual products out there soon enough to up the odds of getting them rained into the soil.*  Either that, or hold onto them for post-emerge and try not to apply just after a rain (lest some weeds be germinated but not yet emerged enough to catch spray droplets). As far as triazines killing grasses, you're more likely to accomplish the job w/ foliar application (with oil) when the grasses are small, as opposed to purely as soil residuals.

*I'm guessing that your climate history has decreased odds of rain during corn planting as opposed to earlier, such as during chickpea planting.  Note the word 'guessing.'  But most of Oz cropland is in a Mediterranean climate, is it not?

The grass generally germinates about two weeks after the corn goes in. I gathered that post-em Simazine would have little effect on germinated grass. Timing of application with follow up rains can be an issue, so early pre plant could be a good strategy Matt. Early post emergent atrazine with oil doesn't seem to work on this grass, although I am keen to try the cyanazine +oil post em.

Martin, as far as chickpeas go, they are grown over winter, so we sometimes see the grass late in the crop, but we only use 0.5lb/a of simazine pre em with Balance so the residual probably isn't there 6months later.

Jim