As sugar beet starts to emerge, growers are being reminded to start checking crops for aphids.
Dr Simon Bowen, BBRO鈥檚 head of knowledge exchange, says crops drilled three to four weeks ago have just reached the true leaf stage, making them particularly attractive to pests, which are drawn in by the field colour contrast between green and brown.
Rothamsted鈥檚 aphid model, which triggered the Cruiser SB (thiamethoxam) neonicotinoid emergency authorisation, predicted that aphids would start to move into crops on April 19, although the colder spell of weather may have slightly delayed this, says Dr Bowen.
鈥淗owever, it is good to start looking and knowing what is coming as crops come through the ground. At this point (April 19) not a lot of aphids have been seen, both in the larger Rothamsted suction traps and in other crops, but it is about this time we would expect to see our first aphids coming. We had quite a cold spell which has probably slowed things down a little bit. Now is the time to start looking, particularly in crops where Cruiser SB has not been used as a treatment. In crops with Cruiser SB on, they will be protected for a good period of time.鈥�
Drilling
This season sugar beet drilling was fairly uninterrupted with most crops going into good conditions.
鈥淭here is bit of moisture and nice seedbeds,鈥� says Dr Bowen.
鈥淚t is drying now so I would imagine in the near future we could do with some rain. If you just dig below the surface there is moisture and the seedbeds have a good, fine tilth so they will retain the moisture as well.鈥�
Cereals
Dr Alan Dewar of Dewar Crop Protection adds that most crops will be in for an 鈥榚ntomologically active summer鈥�.
鈥淭he Rothamsted forecast for virus yellows in sugar beet is the second highest that I have experienced since the 1980s. We have had a relatively mild winter and aphids are likely to have survived quite well. They will be flying into sugar beet and other host crops like potatoes, cabbage and brassicas, earlier than last year but maybe not quite as early as 2020.
鈥淚f we have another warm spring, aphids will be up very well and spread diseases as well as increasing in number. Other overwintering species like cereal aphids will do the same. And I have seen pea and bean weevil in winter beans which are causing damage, but generally not economic damage.鈥�
