Donaghys looks to export grape fungicide

Overseas trials have just begun on Donaghys FoliActive a biofungicide developed in New Zealand for controlling botrytis and powdery mildew.  Last season saw its successful commercial launch in New Zealand, following two seasons of equally successful trials by a leading Crown Research Institute. 

With international markets demanding greener sustainable production of wines, onNew Zealand wine growers quickly adopted FoliActive last year with some outstanding results after focusing on the ability to properly control botrytis levels post veraison without any residue concerns.

FoliActive product manager Mick Withers recommends the product as being particularly effective in this post veraison period following on from a standard fungicide regime.  FoliActive was also found to significantly improve vine health and reduce botrytis and powdery mildew levels earlier in the season so could be alternated with chemical fertilisers to reduce the overall amount of chemical applied.

Mick emphasises that some standard fungicides need to be used until veraison in order to manage diseases to commercially acceptable levels. From that point until harvest they can be replaced by FoliActive, without any loss of disease control.

Developed and registered by Donaghys, FoliActive is based on the Bacillus subtilis KTSB strain.  It also includes microbial fermentation extracts and foliar fertiliser elements to optimise vine condition and stimulate a rapid build up of the B. subtilis population. FoliActive has a nil withholding period and can be used safely right up until harvest without contributing to fungicide residue levels.

One of the challenges that the Donaghys scientific research group overcame was the survival of the live B. subtilis bacteria, in the container, within such a mineral rich liquid environment.  Good shelf life has been established by using hardened endospores, the resting stage of the beneficial bacteria.  The endospores vary in dormancy so that at least 60000 per mL are in a relatively easily activated state. The active spores account for less than one percent of the total spores present but when suitable triggers on the grape surfaces occur, the remaining spores will be activated.

The Bacillus subtilis strain is a naturally occurring bacterium that is widespread in the environment. When applied to crops as a spray it controls the growth of a range of harmful bacteria and fungi, by competing for nutrients, growth sites on plants, and by directly attacking fungal pathogens.

The strain is approved in several countries for use on a number of food crops for the control of fungi and bacteria that cause powdery mildew, sour rot, downy mildew, and early leaf spot, early blight, late blight, bacterial spot and apple black spot diseases.

Donaghys Managing Director Jeremy Silva says, “we’ve been working with Bacillus subtilis strain KTSB for four years, with the aim of developing a treatment that gave growers high levels of disease control at a much lower cost than similar overseas products.”

“Because it has no harmful effects on beneficial organisms and because there are no chemical residues, it is ideal for the integrated pest management programmes now being adopted by the New Zealand region grape growers.  Its use in a spray programme would also help delay or manage the development of resistance to conventional fungicides, particularly the triazoles and strobilurins.”

The Crown Research Institute trials showed that when FoliActive was applied from veraison through to harvest (as a follow-on to the standard fungicide programme) botrytis was controlled to a level equivalent to a full season chemical fungicide programme, but without leaving fungicide residues.

When trial wines were produced by the Eastern Institute of Technology from the treated grapes, FoliActive was shown to have no detrimental effect on fermentation or wine quality.

While production had to work hard to keep up with demand last year, the newly expanded Donaghys facilities in Dunedin mean that the kiwi-developed technology will be readily available to local growers and export markets alike.