BYDV prevention still key part of autumn workload
BYDV is still a threat to cereal crops and, if growers are able to travel and spray, a pyrethroid insecticide should be included as a key part of the autumn workload agenda.
BYDV symptoms in the spring
Dr. David Stormonth, Technical Manager for Interfarm UK Ltd., says that for the very limited cost of a BYDV insecticide spray, cereal crops which have been hard work to establish this year will benefit from protection against aphids, particularly in crops that haven’t received a seed treatment. “BYDV may appear to be down the list of priorities after such a challenging autumn, but the risk is still well and truly there and is easily dealt with. When you are going through with your herbicide treatment, it makes absolute sense to add in an effective pyrethroid such as Sumi-Alpha with quick knockdown and long persistence. It adds little to the overall cost but could protect your crop from significant and costly yield loss.”
He explains that in spite of the awful weather this autumn, aphids are still migrating, are being trapped in significant numbers by the Rothamsted Insect Survey in most areas and are still potentially a major threat. “Aphids are still flying into crops and have a remarkable ability to survive poor weather. Stubbles are also acting as a widespread source of aphid pests. It is worthwhile monitoring crops. If aphids are found and in order to prevent them from transmitting BYDV, an insecticide with rapid initial activity, good repellancy and long-lasting effects will give the necessary protection. Sumi-Alpha, which contains esfenvalerate, offers the best persistence of all pyrethroids as well as having strong repellency activity against aphids. It has flexible dose rates according to the persistence required. The full rate of 165 mls per hectare is used in high risk situations where up to 6 weeks protection can be obtained. High risk crops include early drilled crops, crops grown after grass or grassy stubbles, crops in the South and West, crops in sheltered fields close to hedges and coastal areas, fields with green bridges of weeds and volunteers and crops that received no seed treatment,” explains Dr. Stormonth.
Developed by Sumitomo Chemical Company, Sumi-Alpha contains 25 gm ai/litre esfenvalerate as an emulsifiable concentrate and packed in a 1 litre pack. Recommended on all varieties of winter wheat, winter barley and spring wheat, it is recommended for the prevention of BYDV by controlling aphids at a maximum dose rate of 165 ml/ha, with a maximum of 2 applications per crop. It can be applied up until the 31st March of the year of harvest. It is also recommended on potatoes, vining peas, edible podded peas, combining peas, field beans, cabbages, Chinese cabbage, kale, Brussels Sprouts, cauliflower, broccoli/calabrese, Kohlrabi, ornamental plants, permanent grassland, rotational grassland and managed amenity turf for the control of aphids, caterpillars, weevils, thrips, midges, leaf rollers, leaf miners, whitefly and bibionid larvae and preventing viruses. Esfenvalerate is also available as Sven.