Growing a turnip rape border around oilseed rape crops could significantly reduce the number of both pollen beetle and cabbage stem flea beetle, studies at Rothamsted Research found.
Discussing how plant diversification strategies can give oilseed rape a chance at survival, Dr Sam Cook of Rothamsted Research told the Cereals Live non-chemical controls webinar: “Our data indicates trap cropping can be effective at reducing populations and damage of both pollen beetle and CSFB.”
Trials in 2005, which only tested larvae found plots of OSR with turnip rape had significantly fewer larvae per plant than plots without trap crops.
The work was repeated in 2015/16 but this time also looked at looked at feeding damage and plant establishment.
“These were both improved in plots with turnip rape compared to control plots,” said Dr Cook.
“We also looked at companion planting for pest control - undersowing crops with different mixtures to try and confuse the beetle. Of four different mixtures, brassica mixtures showed great promise.”
Rothamsted is looking to scale-up the studies next year as part of the EU project, EcoStack. Dr Cook is asking for any farmers who are trialling undersowing, or would like to, to get in touch.
Plants that are a more attractive species or at a more attractive growth stage, planted in proximity to the main crop to lure pests away from colonising it.