It won’t come as a shock to many to hear that the year thus far has been incredibly warm and dry, particularly in the south and east of the UK. Back in September, Gravesend in Kent faced temperatures of 34.4 degrees celsius, the hottest September day in more than 100 years. Other areas have suffered from thundery downpours that have caused chaos. This hot, dry weather has been bad news for growers of oil seed rape who have struggled to establish their crop. The drought has combined with the seemingly continual attack of Cabbage Stem Flea Beetle (CSFB) to make this an awful year for establishment. Social media has been riddled with messages of farmers ploughing up land previously sown with OSR, having failed in their efforts to establish the crop:
The Association of Independent Crop Consultants have reported that, across 8 counties in the east of the country, from Northumberland southwards, 9% of the crop has been written off by drought and 7% by flea beetle damage. Hertforshire, Bedfordshire, Essex, Suffolk and Northamptonshire have been the worst hit. Indeed, in both Hertfordshire and Essex, 45% of OSR has been lost due to arid conditions. It is still significant in Bedfordshire (26%) and Northamptonshire (19%). Herts is also the worst hit when it comes to flea beetle damage with 33% of the crop affected. Overall, across all counties, the figure is something like 30,000 acres of OSR lost to CSFB.
What’s the problem with Flea Beetle?
Cabbage stem flea beetle (Psylliodes chrysocephala) is widespread across Europe and the UK and are renowned as probably the biggest pest threat to the oil seed rape crop. Their life cycle is driven by temperature. It is when a crop emerges that they are most vulnerable as the beetles feed on the seedling and destroy it before it can get away. The beetles will chew holes in the cotyledons and early leaves leaving a ‘shot hole’ effect. Larvae will hatch in OSR fields and attack the base of plants from October to April. They bore into the leaf and later into the main stem which can affect plant vigour by itself. Near the end of spring the larvae will leave the plant and pupate in the soil. The adults will emerge in June or July and feed on the plants. The main damage is done in those early stages however.
A dry autumn means that crops will develop more slowly and the risk factor for failing increases. Air temperatures above about 16 degrees celsius are good news for CSFB. This favours high success rates of egg laying and the earlier hatching of larvae, meaning that OSR seedlings have less chance to get away.
The defences that farmers have are becoming more and more limited, principally due to the growing scientific proof of a causal link between the application of certain insecticides, namely the neonicotinoid family and the decline in the bee population. Further, older chemistry, such as the pyrethroids now suffer from resistance by adult beetles in many places across the UK.
Does Oil Seed Rape have a future?
OSR might be suffering from low prices, CSFB damage and droughty conditions but there are still many reasons to grow the crop. In an article in South East farmer earlier this year, technical director for grainseed, Neil Groom, made sure that farmers don’t forget the positive sides of growing this break crop.
Firstly, it is still the best option available in terms of a profitable break crop between other cereals. Wheat follows on very well after growing OSR and you can use the same harvesting machinery as you can with cereals. It’s also good for pollinators and works to break the cycle of many weeds. It’s also good for pollinators, providing a high level of pollen in the spring as it floods the countryside with its bright yellow colour. So, there’s a lot to be positive about OSR.
Until a much better alternative is presented to growers it is highly unlikely that many will desert this crop. It is becoming more and more difficult to grow, but that is the case with many other crops. CSFB and further drought is a worry for farmers though, and it is quite understandable why they are so concerned by the near continual attacks on available chemistry. Some are turning to winter linseed and another alternative could ptentially be winter oats.
To finish, here is a good video from farmer Andrew Ward (@wheat_daddy on twitter) explaining the drilling process of his OSR (filmed in Sept 2015):