We are now in the last season of using Deter seed dressing. The main benefits of Deter are the insecticidal properties of clothianidim. These benefits include reduction in slug damage in the form of grain hollowing and up to 6 weeks aphid protection which therefore protects against Barley Yellow Dwarf Virus (BYDV).
Things to be aware of for our first season without Deter will be a higher incidence of grain hollowing by slug activity. It is therefore important to begin trapping in the stubble of the previous crop to ascertain slug pressure in the field. If you find 1 or more per trap it indicates a slug risk in the next crop therefore an application of slug pellets post drilling would be justified. To avoid issues regarding buffer zones and metaldehyde it is recommended to use products containing ferric phosphate such as Ferri Max. To provide the optimal baiting points of 40/m2 apply 7kg/ha. If damage is still being seen after most of the pellets have gone you can perform a repeat application. The maximum total dose is 28kg/ha per cropping year which equates to four 7kg/ha applications.
To protect the crop against aphids and BYDV a pyrethroid based insecticide can be applied from the two-leaf stage or when aphids are seen in the crop. Following the first application, the T-sum 170 method can be applied to predict when the next generation of winged aphids are likely to emerge. The AHDB website provides a handy tool to help with aphid risk assessment and therefore spray timing.
Life without Deter will mean an increase in insecticide use and crop monitoring. Bartholomews are currently investigating the best aphicides and the optimum time of use to protect crops against BYDV. We’re hopeful that our results will mean our agronomists can give the best technical advice for a crop without Deter. For further advice call our crop protection department on 01243 755610.