Matt Cadd, of Whitlees Farms at Agery, 20 minutes south of Kadina on the Yorke Peninsula of South Australia has welcomed a switch from liquid to a granular formulation of Overwatch® Herbicide.
The Cadd family run a continuous cropping operation rotating wheat, barley, canola and lentils. As part of that, they utilise a wide range of herbicide options including Overwatch® Herbicide. "Our number one weed, probably like anyone on the Peninsula, is annual ryegrass,”Mr Cadd said. "Overwatch® Herbicide has doing a fantastic job and it's probably the best product we've now got on the market." He said they used Overwatch® Herbicide to target annual ryegrass and a wide range of other weeds including wireweed, bifora, sow thistle and wild radish. "Overwatch® is so versatile. It's just the number of weeds it can do."
In the initial year of release, Overwatch® Herbicide was used under barley and has since been used in both wheat and canola. The liquid formulation has been applied commercially and Mr Cadd trialled the Overwatch® granular formulation two seasons ago. "It was very easy to handle with the 20-kilogram bags," he said. That's the one advantage the granules have over the liquid is you're not lugging around 110 litre drums. You don't have to have a forklift out in the middle of a paddock to shift a drum." Mr Cadd said the enterprise was one of the first in the state and on the Peninsula to have a crop sprayer and in modern days they are using a self-propelled Goldacres G6 Crop Cruiser Series 2 with a 6200-litre tank and a 48-and a-half metre boom. A 1200 litre Sprayshop batching unit allows them to combine the chemicals accurately and in enough volume of water to minimise any issues.
This season Overwatch® Herbicide was used under canola and included some of the Overwatch® granule formulated product branded as Overwatch® eXL Granules as a comparison. Overwatch® eXL Granules is a 750 g/kg water dispersible granule (WG) available in 20 kg bags and applied at the single application rate of 670 grams per hectare to all registered crops. "We've had a fairly dry start to the season and as there was just no greenery in the paddock, we put Overwatch® out by itself," Mr Cadd said. "For a granular product, Overwatch® eXL Granules is probably the best I've seen in terms of low foaming. We usually have to add a bit of anti-foam to any granular product we mix. There was an agitation pocket about the size of a dinner plate and once we put the product into the sprayer there was minimal foaming. No bubbles came out of the overflow which is always nice when you're doing a full tank." The filters on the spray rig are 50 mesh and were checked after the initial 60 hectares of product was applied. "It was virtually spotless," Mr Cadd said.“Historically with granules a few don't fully disperse and can block filters. There are some granules on the market that can be a bit of a pain to mix and put through a filter. Overwatch® eXL Granules was very clean. It was an exceptional result. It also delivered a very consistent spray pattern. There was no change in spray pressure across the whole area further confirming the granules do disperse well under good agitation to not block 50 mesh filters. They are a well-performing granule."
The self-propelled applicator, combined with the truck and batch unit trailer, allows the enterprise to do more than 400 hectares per day. Mr Cadd said challenges with weather conditions and inversions meant they were restricted in when they could spray, so the larger machine allowed them to maximise that time. "There's a number of things we do in terms of machine setup,” he said. "We've got our own weather station on the farm, so we monitor straight through an app on the phone. We've got quick jet nozzle adaptors on the sprayer, so we've got options to fit up to five different nozzles." They are currently running a medium spray quality for post emergence grass sprays, a coarse spray quality for fungicides and some in-season sprays and a very coarse spray quality for other products such as Overwatch® Herbicide. "The boom has Raven auto height control on it so we can set it at half a metre above the false target the whole time," Mr Cadd said. "We're minimising drift as much as we can and averaging out at speeds of 18 to 20 kilometres per hour.”
A large part of the crop rotation is being able to utilise different herbicide groups to try to avoid resistance. "Unfortunately, we were one of the first people to develop 2,4-D resistance in wild radish, but it's probably put us on the front foot of rotating herbicides," Mr Cadd said. This includes adding Overwatch® to the mix as a rotational option in a range of crop types. "We continuously do resistance tests to check where things are at and are usually sitting pretty good," he said. "In wheat, we've usually been using pyroxasulfone and then in recent years have looked at Overwatch® Herbicide and Luximax*. Barley is tricky, but Overwatch® gives us another option to use and we can also have it in canola as well. If we want good herbicide pre-emergent products here to stay for a long time, we've really got to look after them, rotate them and do our due diligence to check that they're still working with resistance tests," he said.