NovaChem > Industry News > 2020 > Optimising IPM in forage brassica

Optimising IPM in forage brassica

Published on 08/12/2020

Exirel Insecticide, from FMC New Zealand, controls a wide range of pests including diamond back moth, leaf miner, cabbage white butterfly and aphids (suppression). 

Importantly, says FMC NZ southern area business manager Stan McKay, it leaves key beneficial insects in the crop to continue to work for a long time after the initial insecticide application. These species include parasitic wasps, hoverfly larvae, brown lacewing adults and brown lacewing larvae. 

By incorporating Exirel into their insect pest management plan at the mid to late stage of brassica maturity, McKay says farmers can make the most of natural predators in their crops. “Understanding IPM and knowing your insect species, along with appropriate use of Exirel as required, can provide your clients a lower cost, more sustainable fodder brassica crop.” 

As well as being safe for beneficials, Exirel has an innovative mode of action that ensures pests stop feeding rapidly after application for excellent crop protection.

“Translaminar activity and local translocation allow the insecticide to reach further into the crop canopy and control insect pest species that were not the immediate target of the spray application.”

IPM refers to the use of three pest control 
methods in a compatible way. The three methods are:

1. Biological control - the use of beneficial insects that naturally occur in the crop and making sure they are not disrupted by using pesticides that may impact the beneficial species various life cycles. Parasitic wasps and Hoverfly larvae are two important examples.

2. Cultural control - any farm management technique that disrupts the pests and enhances the beneficial population. Examples may be the variety of crop selected and its insect tolerance, timing of planting, weed control along fence lines or the use of irrigation.

3. Chemical control - IPM is not about eliminating all pesticides but rather 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. In the example of the Hoverfly, it is the larvae, not the adult, that preys on aphids. The mixing of insecticide active ingredients can also have a negative impact on the beneficial species through the mixture causing greater disruption than either of the ingredients used on their own. For the target pests a mixture can increase the risk of pesticide resistance.

Stan McKay says to avoid disruption to beneficial species in clients’ crops, it’s essential to understand the pest and beneficial species present at each crop stage, and to plan pest management accordingly. Broad spectrum insecticides, for example,still have their place at early establishment of the crop when beneficial insects are minimal. “This allows the best use of selective Group 28 insecticides (Exirel) at mid/late stages of the crop to avoid risking the creation of Group 28 resistance.” 

While many selective insecticides are available, that does not mean they are safe to all beneficial species, he says, so he also recommends gathering data on each product used and its impact on beneficials.

Using a hand lens to monitor the crops and identify the eggs of both pests and beneficial species, along with early juvenile stages, will help plan treatment application timing. 

“Once the crop is established, apply Exirel early at the first sign of pest pressure to minimize impact on yield and spread of insect transmitted disease, at the same time establishing beneficial populations. Continue to monitor the crop for signs of beneficial activity such as mummified aphids and parasitized caterpillars along with overall reduction in pest population. Retained biological control continues after Exirel control has subsided.”

For more detail phone your FMC NZ area business manager.

This page is best viewed in an up-to-date web browser with stylesheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so. The latest version of Firefox, Safari, Google Chrome or Internet Explorer will work best if you're after a new browser.