Watch for pest outbreaks in forage brassica

Insect pests cause damage which may significantly reduce the potential of your forage brassica crop.

These pests can impact yield by reducing plant population or damaging leaf tissue and growing points, which restricts plant development and provides infection sites for disease or transmission of virus. Forage quality and palatability may also be impacted. Forage brassicas are most vulnerable during the establishment phase, but continue to be at risk throughout the growing season. Pest populations and subsequent damage can develop rapidly in forage brassicas and in some unfortunate cases the decline from having a great crop to a replant scenario can be just 3–4 days. Crops should be walked regularly during establishment to ensure issues are identified as soon as possible. Start walking each crop every three days from planting then push out to weekly from canopy closure. Key things to observe in your brassica crop include any damage to seedlings and the presence of both insect pests and their natural enemies i.e. beneficial predators and parasitoids. The key insect pests of brassicas in New Zealand are springtail, diamondback moth, white butterfly and aphids. Other notables include leaf miner, Nysius and cutworm. The AgPest website (www.agpest. co.nz) is a great resource for familiarising yourself with these pests and their impact. Ideally your crop will host a population of beneficial insects such as ladybirds, hoverfly, lacewings and parasitic wasps. These are worth protecting by adopting an integrated pest management (IPM) approach and using insecticides with minimal impact on beneficial insects such as SpartaTM and TransformTM from Corteva Agriscience SpartaTM and TransformTM are ideal tools for control of key insect pests in forage brassicas. Both products have excellent environmental and toxicology profiles, providing a high level of safety for both ground and aerial based applicators. Only minimal protective equipment is required when mixing and applying Sparta or Transform—overalls, chemical resistant work boots, gloves and a washable hat. Use of a face shield or goggles is recommended when measuring and mixing. The use of a respirator is not required. Sparta works by contact and ingestion to provide ‘best in class’ control of key pests in forage brassicas including springtail, leaf miner, diamondback moth, white butterfly and looper caterpillars. Translaminar activity ensures good control of insects feeding on the underside of leaves. Transform is a systemic insecticide that provides fast knockdown and residual control of both green peach aphid and cabbage grey aphid. Transform can be applied as a standalone product if aphids are the only pest needing treatment, or included as a tank partner with Sparta if leaf miner and caterpillar pests are also present. Always read the product label before using agricultural chemicals to ensure suitability for your situation and understand directions for use. For more guidance talk to your Ruralco Representative or the team in store.

ABOVE: Sparta works by contact and ingestion to provide ‘best in class’ control of key pests such as white butterfly. Image by Paul Russell

THIS PROMOTIONAL FEATURE WAS PROVIDED BY CORTEVA AGRISCIENCE.