Article taken from the Farmers Guardian, written by Teresa Rush
Oilseed rape crops across northern England may need protection from aphids for the first time this autumn as unusually mild weather increases the risk of migration.
Other pests might also cause more damage than usual unless cold weather returns soon.
Agrovista technical manager Chris Martin says peach potato aphids – the primary vector of turnip yellows virus in oilseed rape – should be on everyone’s radar over the next few weeks.
He says; “We rarely see them from North Yorkshire northwards but we do not know how good a hob neonicotinoids have been doing. We need to be aware – keep looking for peach potato aphids on the undersides of leaves.”
High Risk
Affected crops should be treated with Plenum (pymetrozine) or Biscaya (thiacloprid), he says.
Cereal crops are at high risk from grain aphids, says Agrovista agronomist Phil Campion who looks after crops in Lancashire, Cheshire and North Wales.
He says: “Barley yellow dwarf virus [BYDV] is very much as the forefront this season, with a lot of crops drilled earlier than normal in the good conditions.”
Clothianidin (in Redigo Deter) can offer six weeks’ protection. But efficacy can fall away on wheat drilled early at low seed rates, Mr Campion says.
Unless the weather turns dramatically colder, these crops will need a pyrethroid follow-up. Those grown from single-dressed seed will need watching from the start.”
Problem
Across the Pennines, volunteer barley in oilseed rape is, Mr Martin says, ‘absolutely stuffed’ with aphids.
“They are not usually a problem but the green bridge is there. As cereal crops emerge, aphids will move into them.”
Warm weather could encourage more egg laying than usual by cabbage stem flea beetles and an early hatch/migration into plants, he adds. More than two larvae per plant warrants treatment with a pyrethroid spray, also controlling winter stem weevil, which can be significant in northern counties.
Other pests are thriving in the warm and damp, says Mr Campion. Slugs are active again and hatching, following the recent rain.
“Backward, later-drilled rape might need an application of ferric phosphate pellets and cereals will need monitoring in known trouble spots,” says Mr Campion.
High numbers of leatherjackets pose a threat to new grass leys, he says. Dursban (chlorpyrifos) will work well in moist soils and will also control frit fly, which is prevalent.
Pest alerts
Oilseed rape crops across northern England may need protection from aphids for the first time this autumn as unusually mild weather increases the risk of migration.
Other pests might also cause more damage than usual unless cold weather returns soon.
Agrovista technical manager Chris Martin says peach potato aphids – the primary vector of turnip yellows virus in oilseed rape – should be on everyone’s radar over the next few weeks.
He says; “We rarely see them from North Yorkshire northwards but we do not know how good a hob neonicotinoids have been doing. We need to be aware – keep looking for peach potato aphids on the undersides of leaves.”
High Risk
Affected crops should be treated with Plenum (pymetrozine) or Biscaya (thiacloprid), he says.
Cereal crops are at high risk from grain aphids, says Agrovista agronomist Phil Campion who looks after crops in Lancashire, Cheshire and North Wales.
He says: “Barley yellow dwarf virus [BYDV] is very much as the forefront this season, with a lot of crops drilled earlier than normal in the good conditions.”
Clothianidin (in Redigo Deter) can offer six weeks’ protection. But efficacy can fall away on wheat drilled early at low seed rates, Mr Campion says.
Unless the weather turns dramatically colder, these crops will need a pyrethroid follow-up. Those grown from single-dressed seed will need watching from the start.”
Problem
Across the Pennines, volunteer barley in oilseed rape is, Mr Martin says, ‘absolutely stuffed’ with aphids.
“They are not usually a problem but the green bridge is there. As cereal crops emerge, aphids will move into them.”
Warm weather could encourage more egg laying than usual by cabbage stem flea beetles and an early hatch/migration into plants, he adds. More than two larvae per plant warrants treatment with a pyrethroid spray, also controlling winter stem weevil, which can be significant in northern counties.
Other pests are thriving in the warm and damp, says Mr Campion. Slugs are active again and hatching, following the recent rain.
“Backward, later-drilled rape might need an application of ferric phosphate pellets and cereals will need monitoring in known trouble spots,” says Mr Campion.
High numbers of leatherjackets pose a threat to new grass leys, he says. Dursban (chlorpyrifos) will work well in moist soils and will also control frit fly, which is prevalent.
Pest alerts
OSR crops may need protection against aphids for TuYV control
Cereal crops at risk from grain aphid and BYDV control
High levels of aphids on barley volunteers in OSR acting as a green bridge
Winter stem weevil a potential pest in northern OSR crops
Slugs are active
Leatherjacket numbers high