Sophie Williamson Beta Guard

  • Tauira / Student
    Sophie Williamson
  • Kaiako / Lecturer
    Bahareh Shahri
  • Client
    Bragato Research Institute
  • School
    University of Canterbury

Although a seemingly small issue, in recent years, a wētā pest has caused crop losses worth thousands of dollars for winegrowers in the Awatere valley of Marlborough. The Beta Guard is a well thought out, simple solution to the wētā issue. The brief was to design a form of non-lethal wētā pest control for Awatere valley winegrowers. The wētā are nocturnal, venturing out at night to feed on new vine buds, and have proven capable of causing significant damage to crop yield, ultimately resulting in significant profit loss. Conventional pest control/pesticides are forbidden for use on these wētā as they are protected due to their threatened conservation status, and how little is known about them and their populations. A better wētā guard was required to improve on cost, sustainability, durability, or a combination of these.

Similar to the existing solution, the smooth, extruded outer surface is too slippery for wētā to climb. The Beta Guard aims to improve the end user experience by simplifying the process of application. Existing wētā guards require time costly application, involving wrapping the plastic sheet around the vine and applying two rows of staples. The BETA Guard is applied in a single swift movement. The hinge is bent, bringing the two ends together to simply clip into place using an inbuilt snap fit. Operation of this device also requires minimal thought or concentration, contributing to a greatly reduced application time, and ultimately lower associated labour costs.

Increased durability was a key requirement of the Beta Guard, with a solid outer shell of recycled ABS plastic. This piece is stabilised with Biochar for UV resistance and carbon storage. Similarly, the inner filter foam layer is also Biochar reinforced. The foam inner is made from open-cell, low-density polyurethane foam to ensure drainage, avoiding rotting of vines. It has the flexibility to compress into itself with vine growth and has a surface texture which provides grip to the vine. Both foam inserts are identical for streamlined manufacturing and minimising costs. During application, the guards will be transported using a tractor-trailer which are commonly already in use on vineyards for various other tasks. No specialised equipment or unnecessary application tools are required.

With wētā capable of causing anywhere from 10-100% bud damage and crop loss, the cost of these guards is justified. During research it was estimated that even 30% crop loss would incur potential losses of approximately $8000. The overall material and manufacturing cost is $0.29 NZD per unit, or as little as $0.26 depending on material sources. This includes material and manufacturing costs of $825 - $900 per hectare (2500 vines). When combined with the expected lifespan of a minimum 10 years, this is a cost of $82.5 - $90 per ha, per year. The existing solution costs approximately $155 NZD per ha, per year. For the minimum expected life-span, this is an estimated saving of up to $72.5 NZD per ha. For the approximate overall area, this is a total projected saving of $181250 NZD annually.