NGN Cultural control strategies for slugs

WHY THIS PROJECT IS IMPORTANT

Slug damage to establishing crops is increasing in Victoria and NSW, both in terms of the severity of damage and the area affected. Likely causes include recent wet seasons, reduced predator activity, adoption of conservation agriculture practices (for example, stubble retention and minimal tillage), exotic species adaptation, and tighter crop rotations.

Slug damage can reduce seedling numbers, impacting yield. Where seedling damage is extreme, paddocks may need to be resown at additional cost to the farmer. Populations as low as one grey field slug per square metre can inflict severe damage on a canola crop at establishment.

In short: This project aims to give growers practical and effective non-chemical (cultural) control options to reduce slug damage in establishing canola or cereal crops. Through on-farm demonstrations, the project will evaluate practical approaches to slug control such as stubble management, rolling after sowing, pre drilling urea and soil amendments (e.g. lime and gypsum), as well as other agronomic practices that influence slug habitat and activity.

Feedback from NGN Forums has highlighted gaps in on-farm slug management knowledge and the lack of in-crop control options, which impacts establishment and crop growth.

Survey data from Riverine Plains shows that baiting is nearly universal, with farmers spending between $50–100/ha, raising concerns about long-term sustainability of this approach. Burning stubble is sometimes used, but its effectiveness is uncertain due to slugs’ underground habitat.

Given limited research on non-chemical control options, this project is helping develop practical cultural strategies that may reduce reliance on chemical baiting, with the aim of reducing production costs.

Project focus

This project focuses on supporting growers in southern NSW and Victoria who are experiencing ongoing slug pressure in their paddocks. It aims to identify and demonstrate practical cultural management strategies that can reduce slug activity and improve crop establishment outcomes.

In Year 1, two paddocks with a history of slug infestation will be monitored, and current grower management practices will be recorded to establish a baseline for measuring practice change, adoption and impact at the completion of the project.

In Years 2 and 3, a minimum of two paddock-scale demonstrations in south west Victoria and south east NSW will be established to assess how different cultural control strategies can influence slug activity and crop establishment under local farming conditions.

Management strategies to be demonstrated and monitored for slug activity include:

• Application of gypsum and lime (with shallow incorporation)
• Post-sowing rolling (to test its influence on canola emergence)
• Use of pre-drilled urea (to assess whether faster crop establishment reduces the risk window for slug damage)
• Different stubble management approaches