GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 The effects of reducing herbicides in New Zealand vineyards

The effects of reducing herbicides in New Zealand vineyards

Abstract

Context and purpose of the study – Herbicides are commonly sprayed in the vine row to prevent competition with vines for water and minerals and to keep weeds from growing into the bunch zone. Sprays are applied before budbreak and reapplied multiple times during the season to keep the undervine bare. There is growing concern about the negative effects of herbicides on humans and the environment, and weeds in New Zealand have developed resistance to herbicides. Therefore, it is imperative that we reduce our reliance on herbicides in viticulture and incorporate methods that do not engender resistance.

Material and methods – This trial was conducted in the 2016-17, 2017-18 and 2018-19 seasons in three Merlot and three Sauvignon blanc vineyards in New Zealand. The trial was a split plot, with half the vineyard receiving multiple sprays (the industry standard). The other half received a single spray around budburst, and any subsequent undervine weeding was done using nonchemical methods (mowing or cultivation). In each vineyard half, five sampling locations were established for vine, fruit, and undervine measurements. Vines were assessed for canopy gaps by image analysis, yield, and rot severity. Fruit was sampled during ripening and at harvest to assess differences in chemical composition. The undervine area was surveyed at budburst, flowering, veraison, and harvest to assess differences in bare area and presence/abundance of various plant species.

Results – Reducing herbicide had a dramatic effect on the percent bare area under vines, as well as the species of undervine vegetation from flowering onwards. In most vineyards, canopy growth was similar for both the control (C) and reduced herbicide (RH) treatments, though a few differences were found, generally with the RH treatment having more gaps. A few differences were found in midday water potential, with the RH treatment generally having more negative SWP. Despite differences in canopy gaps and SWP, there were few effects on berry size or soluble solids. There were few other fruit compositional differences, though the RH fruit tended to have lower yeast assimilable nitrogen (YAN) than the C fruit. Yield was generally not affected by reducing herbicide, and rot severity tended to be similar between treatments, indicating no negative effects on fruit quantity or health from allowing more vegetation to become established under vines. These data show that herbicide use can be reduced by 50-75% with little negative effect on grapevines or their fruit. It is anticipated that adopting this technique will reduce herbicide residues in/on fruit and slow or stop the spread of herbicide resistant weeds.

DOI:

Publication date: September 26, 2023

Issue: GiESCO 2019

Type: Poster

Authors

Tingting ZHANG1, Allison HAYWOOD2, Mark KRASNOW2*

1 Thoughtful Viticulture, Napier, Hawke’s Bay, New Zealand
2 Thoughtful Viticulture, PO Box 312, Blenheim, 7240, New Zealand

Contact the author

Keywords

herbicide, resistance, grapevine, weeds, sustainability

Tags

GiESCO | GiESCO 2019 | IVES Conference Series

Citation

Related articles…

The temperature‐based grapevine sugar ripeness (GSR) model for adapting a wide range of Vitis vinifera L. cultivars in a changing climate

 Temperatures are increasing due to climate change leading to advances in grapevine phenology and sugar accumulation in grape berries.

Grape phylloxera leaf-feeding populations in commercial vineyards – a new biotype ?

Grape Phylloxera (Daktulosphaira vitifoliae Fitch) ordinarily has great difficulty establishing leaf galls on the European Grapevine (VitisviniferaL.). Yet populations of leaf-feeding Phylloxera are increasingly being observed throughout commercial vineyards world-wide. Effective plant protection strategies including quarantine actions are currently missing to fight, grape phylloxera populations in affected vineyards and combat linked negative effects on vines and yield. Contrary to the otherwise mandatory continuous infestation pressure from externally established populations (e.g. from populations developed on rootstock foliage or other interspecific hybrids, these leaf-feeding populations seem to establish themselves annually.

Managing Grapevine Powdery Mildew with Ultraviolet-C Light in Washington State

Germicidal ultraviolet-C (UV-C) light has shown promising results for suppression of several plant-pathogenic microorganims, including Erysiphe necator, which attacks grapevine. In Washington State the majority of winegrape production is in a semi-arid steppe environment, with historically low powdery mildew disease pressure, making it a promising area to deploy UV-C as a disease management tool. Trials focusing on UVC application timing and frequency will assist in developing regionally-appropriate application recommendations for eastern Washington State.

Development of a new commercial phenolic analysis method for red grapes

Grape phenolic content is an important quality factor that influences the appearance and mouthfeel of premium red wines.

Combined high-resolution chromatography techniques and sensory analysis as a support decision system tool for the oenologist

One of the main challenges in the wine industry is to understand how different wine processing techniques and practices can influence the overall quality of the final product.