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Summer Weed Herbicide Research

Trial Aim:

Evaluate a range of herbicide mixes containing Glyphosate 450 or Paraquat 250 as the core product with the addition of additives or spikes and asses the level of control they offer on a range of common summer weed species.

All trials were applied at 70lts/ha water rate.

Weed species assessed on site,

. Common Sow Thistle

. Fleabane

. Heliotrope

. Paddy Melon's

In this trail the glyphosate 450 was applied at a lower rate than normal for the weed size, We were trying to evaluate the value the additives or spikes offered not so much what the glyphosate itself does eg, ester 680 vs amine 625.

The cost of the herbicide mixes in this trial ranged between $6/ha-$19.50/ha, and large variance in control was seen.

Common Sow Thistle (Milk Thistle)

Gly + Amine 14DAA $9.50/HA | Gly + Ester 14DAA $9.30HA

14DAA, as most would expect the ester doing better job with brown down after 14 days compared to the Amine. With amine summer spray jobs, be patient if you are accustomed to using ester.

Paraquat 250 14DAA $6.00/HA | Paraquat + Ester 14DAA $7.80/HA

14DAA, we tried a few different "spikes" with paraquat in these trials. We saw great burn down of the sow thistle and good coverage was important here. The spikes were targeted to hopefully help reduce regrowth with the paraquat applications especially with bigger weeds and moisture underneath them.

Gly 450 + Amine 30DAA $9.50/HA | Gly 450 + Ester 30DAA $9.30/HA

30DAA, after 30 days we were able too see that both the amine and ester brews with glyphosate achieved good control on the sow thistle. As you would all be aware its not the time it takes for plant brown down it is the end result.

Gly 450 + Pixxaro 30DAA $20/HA | Amine 625 + Sledge 30DAA $14/HA

30DAA, This was the first trial where we have been able to get a look at Corteva's, Pixxaro. It can be used in crop (cereals) or like we have here with glyphosate in fallow. Pixxaro's strength's are marshmallow, sow thistle and volunteer legumes, and if using Pixxaro be careful and watch your plantbacks, 7 months for legumes and 1 month for canola and cereals.

Paraquat 250 30DAA $6/HA | Paraquat + Terrador 30DAA $13/HA

Paraquat + Sledge $11/HA | Paraquat + Ester $7.80/HA | Paraquat + Garlon $7.50/HA

30DAA, here we have some great examples of what can happen with paraquat on larger weeds, regrowth. The paraquat alone has regrown from the centre which I was expecting as well as the tank mix with sledge. The addition of a few of the other spikes however provided good control 30DAA for a acceptable price tag too which is promising.


Gly + Amine 14DAA $9.50/HA | Gly + Amine 14DAA | Gly + Ester 14DAA $9.30/HA

14DAA, On this site we had a spread of fleabane with plants ranging from small to large. Expected levels of control for fleabane decrease as the plant sizes increase and with bigger plants you should be prepared to double knock. I have tried to showcase control on both the smaller and larger plants in these trials. So above we have our staple summer herbicides amine 625 and ester 680, with both showing effect on the fleabane after 14 days.

Gly + Pixxaro 14DAA $20/HA | Gly + Pixxaro 14DAA $20/HA | Gly + Pixxaro 14DAA $20/HA

14DAA, Pixxaro looked most promising of all products after 14 days for fleabane, especially impressive on some of the bigger plants which was an exciting surprise.

Paraquat 14DAA $6/HA | Paraquat 14DAA | Paraquat + Terrador 14DAA $13/HA

14DAA, it was interesting to see what effect paraquat type brews would have on fleabane. As you can see on the smaller plants paraquat has had good brown down however the larger plant has plenty of green leaf tissue and coverage would play its part here. The addition of Terrador (more information about Terrador in our previous blog) after 14 days seem to help increase the brown down on those bigger plants initially - Read further down for 30DAA photos

Gly + Amine 30DAA $9.50/HA | Gly + Amine 30DAA | Gly + Ester 30DAA $9.30/HA

30DAA, I would have to say after seeing what we have here if against a fleabane problem I would be changing my summer partner from ester to amine. Although the amine has not done a 100% job on the bigger plants it has given them a big headache and a double knock of paraquat would make sure of strong control. The amine mix doing a good job on smaller plants and would avoid the double knock in those cases.

As always with summer weeds size and timing are key.

Gly + Pixxaro 30DAA $20/HA | Gly + Pixxaro 30DAA $20/HA

30DAA, The pixxaro was a pleasant surprise in this trial on fleabane. It done a fantastic job on the smaller plants as well as the bigger plants we put it up against. The cost of pixxaro will most likely mean we wont be using this product on our whole program, however if fleabane is isolated to a few paddocks and you wanted to avoid the double knock this could be an option.

Gly + Sledge $11/HA | Gly + Terrador $13/HA | Amine + Sledge $14/HA

30DAA, I wanted to show these photos of what can happen if you get your product choice wrong on fleabane or any hard to kill summer weeds for that matter. These plants have been sprayed and after 30 days nearly look as good as the day I sprayed them, it is important to know what weeds you have in your paddocks and how to target them.

Paraquat 250 30DAA $6/HA | Paraquat 250 30DAA $6/HA

30DAA, As expected the fleabane has grown through our paraquat treatments, even the smaller plants that seemed to have all green leaf tissue burnt off have regrown and will push on and set seed.

Paraquat + Terrador 30 DAA $13/HA | Paraquat 250 + Ester 680 30DAA $7.80/HA

30DAA, In the 14DAA photos above we seen the terrador improve the brown down of the fleabane, but again we have seen it grow through that. The addition of ester also showed improved brown down early but has grown through also.

Heliotrope (potato weed)

Gly + Ester 680 14DAA $9.30/HA | Gly + Terrador 14DAA $13/HA

14DAA, These are great photo's to showcase the speed that a group G like terrador can work on weeds in summer conditions. Terrador was fantastic on heliotrope and shown no regrowth.

Paraquat 14DAA $6/HA | Paraquat + Ester 14DAA $7.80/HA

14DAA, For anyone that is contemplating spraying paddocks for the second or third pass and have just heliotrope paraquat is your friend and best of all it is CHEAP.

Gly + Amine 30DAA | Gly + Amine 30DAA

Gly + Ester 680 30DAA $9.30/HA | Gly + Ester 680 30DAA $9.30/HA

30DAA, This lot of photos was very interesting and 100% backs up what myself and Troy are seeing in the paddocks. Glyphosate and ester alone will often not provide strong control on heliotrope, amine is better but again on its own doesn't provide 100% control. In both treatments the larger plants are trying to push out a small flower and will set some amount of seed. A quick tip is the addition of garlon in these brews wont only increase your melon control but enhance the kill on big potato weed!!!.

Gly + Pixxaro 30DAA $20/HA | Amine + Sledge 30DAA $14/HA

30DAA, Pixxaro again provided strong control but there are cheaper options for this weed on the market. Amine and sledge providing very poor control even though it is only the label for heliotrope, higher rate would be required.

Paraquat 30DAA $6/HA | Paraquat + Terrador 30DAA $ 13/HA

30DAA, These last two photos here show that we did not seen any regrowth with any of the paraquat product mixes on heliotrope and is a great choice for this weed.

Paddy Melons

Gly + Terrador $13/HA | Paraquat + Terrador $13/HA | Gly + Pixxaro $20/HA

14DAA, Terrador with both glyphosate and paraquat here after 14 days has struggled to achieve acceptable brown down. This is a great example especially with the glyphosate where the group G product gets in and burns leaf tissue and cell membranes before the glyphosate is able to translocate through the plant efficiently. The pixxaro treatments were especially impressive and we seen no regrowth with these melons big or small.

Gly + Amine 625 30DAA $9.50/HA | Gly + Ester 680 30DAA $9.30/HA

30DAA, Both amine and ester after 30 days showed green leaf holding on and continuing to grow, the addition of stock and grazing would potentially help in this situation. Shows that when we get slightly larger melons the addition of garlon into the tank is a must.

Gly + Sledge $11/HA | Amine + Sledge $14/HA | Paraquat + Sledge $11/HA

30DAA, Sledge is an interesting product and these photos show some interesting results. All three have the same rate of sledge and show a vast difference in control. The paraquat was to be expected however the change of replacing glyphosate with amine resulted in fantastic melon control on both small and bigger plants - something interesting to note.

Gly + Terrador 30DAA $13/HA | Paraquat + Terrador 30DAA $13/HA

30DAA, As the same with the terrador treatments in the 14DAA photos, the terrador has burned too quickly for the glyphosate. Something to keep in mind is what ratio between your brown down spikes and glyphosate you have, are you burning weeds too quickly?

Paraquat 250 30DAA $6/HA | Paraquat + Ester 680 30DAA $7.80/HA

30DAA, Paraquat alone and the addition of ester did not help with melon control in this trial, these were sprayed with Kombo and myself and Troy are seeing better results in the paddock with paraquat on melons when using a product like Tribute (oil/wetter combination).

Paraquat + Garlon 30DAA $7.50/HA | Paraquat + Garlon 30DAA $7.50/HA

30DAA, Adding garlon to the paraquat did help on the smaller plants however not so much on the larger plants, our rate in this trial was most likely not high enough for control of the bigger plants. Once again stressing that you must take note and be aware of your weed size before going spraying.

Take Home Messages

. The addition of Ester, Terrador or Garlon all helped burn down and reduced regrowth on the larger Sow Thistles.

. When using paraquat, coverage is really important especially on bigger weeds.

. Summer spraying, weed size is SO IMPORTANT in achieving good control, the earlier you can spray the better.

. Don't over complicate summer weed spraying, sometimes less is best. Keep tank mixes to less products but keep your rates robust and use the right adjuvant, with glyphosate always use Soa.

. Pixxaro provided strong control on sow thistle, smaller fleabane, melons and heliotrope, however working out where this product fits because of cost is something to look into further, again we can do more of the same for less cost.

. Nufarm's soon to be released product Terrador will be very weak on fleabane but has many other great uses - was very impressive on heliotrope control.

. Spikes can work too quickly on weeds with glyphosate so when using your group G's (Striker, Hammer, Terrador, Sharpen etc) over summer make sure you have your ratios correct so you are able to let the glyphosate do what you want it to do.

. Paraquat and tank mixes with paraquat should only be used on fleabane as a double knock partner not as a first pass or one pass option.

. With Fleabane control, plant size is KEY! Small weeds with the right product and rates good control can be achieved, however once we have larger weeds a a follow up double knock will be required for acceptable control.

. Heliotrope control with our standard glyphosate and ester or amine mixes alone can and will struggle and the addition of more 2,4-D wont help, more glyphosate will and so will the addition of garlon.

. Once you start getting bigger melons in the paddock, it is a must that you start adding garlon to your tank mix for good control. When using garlon with paraquat keep your garlon rates high and look at swapping your Kombo/Li700 type products out for Tribute (Oil concentrate with >15%surfactant)

For more information on either Terrador or Pixxaro I have attached the links below and for more information on rates or any questions give myself or Troy a call.



I would like to say a big thankyou to the growers that have let us put these trials on their properties, it is much appreciated and helps us capture as much valuable in paddock information as possible.

This is something we will continue to do with more summer trials planned as well as in crop work once the season begins. We are keen to get your feedback, thoughts and suggestions on these blogs and our trial work so please get in contact with myself or Troy we would love to hear from you.

As always, please feel free to ring us to discuss any of your specific issues, questions or you are looking for more detail, In the meantime enjoy the beach.

Kevin Dart - 0474 272 577

Troy Maitland - 0499 272 544

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