Tannin stains are a definite “no go” for the kiwifruit market, devaluing crops and impacting growers’ bottom lines. Adding low water volume Du-Wett® Stainless delivers results and savings.
Low water volume Du-Wett® Stainless delivers results and savings
Tannin stains are a definite “no go” for the kiwifruit market, devaluing crops and impacting growers’ bottom lines. The severity of staining (caused by tannins) can vary from season to season depending on factors including rainfall, the amount of overhead irrigation, and even the amount of pruning left on top of vines.
While tannin staining doesn’t impact fruit quality it is considered a cosmetic defect and will result in fruit being rejected. That makes maximising the efficacy of stain removal products vital. Pieter Van Der Westhuizen, UPL NZ Regional Manager Upper North Island, says, it’s what contractors and growers add to the stain removal sprays that can really make a difference. He recommends the specialist, acid-tolerant, adjuvant Du-Wett Stainless to get kiwifruit stain-free and ready for picking faster. “You’ll definitely get better results.”
Kiwifruit difficult to wet
Kiwifruit, particularly green kiwifruit (Hayward), are very difficult to wet efficiently due to their distinctive dense hairs. Pieter says water and spray will just sit up on the top of the fruit. “Du-Wett Stainless works by heavily reducing the surface tension of the spray solution, so there’s a very even all over spread and contact with the stained fruit.”
While the acid in stain removal products is very effective at dissolving tannin stains, it only works well if there is good coverage of the entire fruit as well as good contact with the stain-causing tannins.
Spray deposition and coverage crucial
“Using Du-Wett Stainless will increase spray deposition and coverage compared to high water volume application without Du-Wett Stainless. It adds the surface acting properties that stain removal products need to provide superior results, without degradation or compromising efficacy.” Pieter says Du-Wett Stainless can be used with the New Zealand industry’s preferred kiwifruit stain removal sprays, including Kiwilustre®LF and Kiwi Stainoff LF.
“Du-Wett Stainless extracts every last cent of value from stain removal sprays. And that’s particularly important for the many growers facing real challenges right now. It’s about working smarter.”
Pieter says there are significant knock-on resource optimisation and cost saving benefits from Du-Wett Stainless.
“In addition to giving greater certainty of outcome for growers and contractors, Du-Wett Stainless makes life easier, and deliveries efficiencies. Using Du-Wett Stainless means growers can use around 1/3rd the water rate they otherwise would.
“Much lower water rates make spraying faster, meaning less time in the kiwifruit orchards, and reduced re-filling and travelling. That cuts diesel use, downtime, and total labour hours in the sprayer – especially if you’re covering a very large area.”
More water doesn't equal better coverage
Contrary to popular belief, spraying with more water will not necessarily improve coverage.
“Increasingly growers are looking not only to make savings, but also conserve water without compromising spray efficacy.”
Pieter says using Du-Wett Stainless also results in kiwifruit drying faster after spraying, saving time.
“Because any water on the fruit spreads evenly across the fruit in a very thin film with Du-Wett Stainless, this film tends to dry substantially quicker than large droplets trapped in the fruit hair. This means that crews can start picking earlier in the day as wet fruit no longer poses a problem. Workers aren’t left waiting around for fruit to dry. That helps maximise workable hours for the team which makes sound financial sense.”
“Conventional super-spreaders cannot withstand low pH stain removal environments (typically around pH 3). Usually, that kind of acidity will break down the surfactants and wetting properties but not Du-Wett Stainless. It really delivers.”
For more information on Du-Wett Stainless click here or contact Pieter Van Der Westhuizen at +64 21 392 740.
