IPM Pest Control in Fodder Brassicas

Understanding IPM and knowing your bugs, along with the selective insecticide Exirel®, can provide a lower cost, more sustainable Fodder brassica crop.

Luisetti Seeds agronomist Kerry Thomas uses a hand lens to monitor the crops and identify eggs of both pest and beneficial species, along with early juvenile stages, to help plan treatment application timing.

“IPM” stands for Integrated Pest Management. The combination of three pest control methods, used together in a compatible way, can provide a better outcome than any one method on its own. The three are:

1. Biological control – Make use of beneficial insects that naturally occur in the crop. Use pesticides that do not disrupt the life cycles of beneficial insects.
2. Cultural control – Cultural control involves any farm management technique that disrupts pest species and enhances the survival of beneficial species. This includes the variety of crop selected and its insect tolerance, timing of planting, weed control along fence lines, and the use of irrigation.
3. Chemical control – IPM is not about eliminating all pesticides. It’s about using them in an effective way that minimises disruption to beneficial species. It is important to understand the impact each product has on every beneficial species at each of their life stages.

The terms “IPM” and “IPM Friendly” have been used for some time in the horticulture market, and more recently in the Fodder brassica market. Despite industry-awareness of IPM, it is often misunderstood. This is particularly the case for Fodder brassicas.

The introduction of the selective insecticide Exirel® in 2014 has played an important role in developing a greater understanding of both the pest species and beneficial species of insects in New Zealand Fodder brassica crops. MPI (via the Sustainable Farming Fund) and Plant & Food Research recently completed research into “IPM strategy development and demonstration for forage and seed brassicas”. Research carried out during 2015, 2016 and 2017 seasons showed an IPM approach provided a financial benefit with a fewer insecticide applications being made, and with better crop health.

Leading Australian IPM specialists, Paul Horne and Angelica Cameron, share their knowledge with Luisetti Seeds agronomists at the FMC NZ IPM field day in Leeston.

As an extension to the work done by Plant & Food NZ, the Luisetti Seeds team were pleased to accept in-field training by FMC NZ Ltd.

Leading Australian IPM specialists, Paul Horne and Angelica Cameron, travelled to New Zealand to share their knowledge about IPM. Paul has 30 years of experience using IPM in real farming systems in all corners of the world.

The Luisetti team began with identifying pest and beneficial species in a crop near Leeston. Angelica used the various beneficial and pest species found in the crop, on the day, to demonstrate how IPM could be applied to a Fodder brassica crop.

The team and the experts discussed the insecticide options available and their impact on both the target pest and the beneficial species. Paul was able to explain IPM in a way that demonstrated logically how the insects behave and what control methods would work.

Beneficial and pest species, including different life stages from eggs to larvae to adult, in the Leeston crop.

We were able to see most of the beneficial and pest species, including different life stages from eggs to larvae to adult, in the Leeston crop. This made the training very informative and relevant, rather than theoretical, especially as Angelica and Paul were able to use real, hands on examples during the discussion. The memorable moment for the Luisetti Seeds team was seeing the effect of parasitism on caterpillars by Parasitic wasps. Wasp eggs are inserted into the caterpillar’s body when it is stung by the adult wasp, disrupting the pest caterpillars. We were able to see wasp larvae in the caterpillar.

The Luisetti Seeds team have compiled these eight tips for Integrated Pest Management in your brassica crop:

1. The key beneficial species that impact the pests in a NZ Fodder brassica crop are Parasitic wasps, Hoverfly larvae, Brown lace wing adults and Brown lacewing larvae.
2. Use a hand lens to monitor the crops and identify eggs of both pest and beneficial species, along with early juvenile stages, to help plan treatment application timing.
3. Understand the pest and beneficial species present at each crop stage, and have a plan from establishment through to late crop stages.
4. There are many selective insecticides available, however, that does not mean they are safe to all beneficial species. Gather relevant data on every product and its impact on beneficial species. We recommend Exirel® as its selective chemistry retains the key beneficial insects at all their different life stages within the crop, while negatively impacting both Caterpillars and Aphids.
5. Use broad spectrum insecticides at the early establishment stage of the crop when there are minimal beneficial species present. This allows you to best use selective insecticides (such as Exirel®) at the mid to late stages of the crop to avoid risk of resistance to other insecticides.
6. Don’t mix or use mixed insecticide active ingredients, have a plan for each crop stage, monitor the crop and apply the right single active ingredient for the pest and beneficial species present.
7. Once the crop is established apply Exirel® early at the first sign of pest pressure to minimise pest impact on yield and spread of insect transmitted disease. At the same time helping the establishment of beneficial populations.
8. Continue throughout the season to monitor the crops for signs of beneficial activity such as mummified aphids and parasitized caterpillars along with overall reduction in pest population.

Talk to your Luisetti Seeds agronomist for more information about the use of IPM in your Fodder brassica crop.