Article taken from the Horiculture Week
New developments in the treatment of several established and emerging fruit pests were the focus of Agrovista’s Kent fruit technical seminar last month.
East Malling Research entomologist Professor Jerry Cross warned growers to start monitoring for the apple fruit Rhynchites weevil, becoming more prevalent in English orchards.
This can cause crop losses of one-to-five per cent and he advised growers to inspect orchards for adults from pink bud to early fruitlet stages, when they begin feeding remain on the tree until harvest, but those in which the female has laid eggs will wither and drop, he said.
“Everyone knows the damage but not that many people have seen the weevil,” said Cross. “Many varieties are susceptible to it, particularly slightly later-flowering varieties. Braeburn and Gala seem to suffer badly.”
He advised: “Spray Calypso (thiacloprid) as soon as possible if adults are seen in damaging numbers or if you had bad damage last year. The second half of bloom is probably the best time to do it. After flowering is probably too late.”
For the sake of beneficial earwigs, he added: “We should look to see whether Gazelle does the job.”
Cross also warned cherry growers not to rely on traps when monitoring for spotted wing drosophila (SWD) because these become less effective once the fruit arrives on the tree.
“Too much effort is given to adult monitoring and it’s giving growers a false sense of security as monitoring traps become less efficient when they start to compete with a crop. What you need to be doing is monitoring the orchard every week for SWD larvae using the ‘crush test’.”
Cross explained how this involves putting the fruit into a polythene bag and then adding a sugar solution to see whether any larvae crawl out of the fruit. He said “There’s going to be a Horticultural Development Company video coming out soon showing growers how to do this.”
Agrovista fruit agronomist Alex Cooke said Tracer and Hallmark are the best available products for treating SWD, but they can harm beneficial insects. Tracer currently has a 365-day harvest interval, but the industry is hoping to acquire an emergency 120-day authorisation from the Chemical Regulation Directorate, he added.
Cooke also appealed to growers to communicate with one another this year to help tackle the pest, given how quickly it spread in cherry orchards last year.
Meanwhile, a new integrated pest management programme for the treatment of codling moths and leafrollers (tortrix moth larvae) could soon be available following trials last year by BASF and Agrovista of two BASF products, the beneficial nematode Nemasys C and new synthetic mating disruption pheromones due for UK approval next year.
BASF agronomist Simon Townsend explained to the seminar how dispensers containing pheromones for both codling and tortrix moths “cover the whole orchard with a big cloud of pheromone, so the males are confused and give up.”
The nematode solution was then applied as a bark drench later in the early autumn, leading to a reduction in numbers of each species of 90 per cent or more.
Canker Copper foliar feed treatment
A copper foliar feed introduced by Agrovista last year is proving an effective treatment for canker in orchards, its fruit specialist Paul Bennett told the seminar.
“Canker is difficult to control because growers do not have many fungicides that can be used during the season, but the 42PHI Cu is a good canker treatment.
All of the growers that we advise are using it and we have seen a massive improvement in the levels of canker and a reduction in the amount of new canker.”
The product can now be used with Agrovista’s new canker model, the latest addition to its top-fruit pest and disease forecasting service, Growers Choice Interactive. A fireblight model will be included this year.
New developments in the treatment of several established and emerging fruit pests were the focus of Agrovista’s Kent fruit technical seminar last month.
East Malling Research entomologist Professor Jerry Cross warned growers to start monitoring for the apple fruit Rhynchites weevil, becoming more prevalent in English orchards.
This can cause crop losses of one-to-five per cent and he advised growers to inspect orchards for adults from pink bud to early fruitlet stages, when they begin feeding remain on the tree until harvest, but those in which the female has laid eggs will wither and drop, he said.
“Everyone knows the damage but not that many people have seen the weevil,” said Cross. “Many varieties are susceptible to it, particularly slightly later-flowering varieties. Braeburn and Gala seem to suffer badly.”
He advised: “Spray Calypso (thiacloprid) as soon as possible if adults are seen in damaging numbers or if you had bad damage last year. The second half of bloom is probably the best time to do it. After flowering is probably too late.”
For the sake of beneficial earwigs, he added: “We should look to see whether Gazelle does the job.”
Cross also warned cherry growers not to rely on traps when monitoring for spotted wing drosophila (SWD) because these become less effective once the fruit arrives on the tree.
“Too much effort is given to adult monitoring and it’s giving growers a false sense of security as monitoring traps become less efficient when they start to compete with a crop. What you need to be doing is monitoring the orchard every week for SWD larvae using the ‘crush test’.”
Cross explained how this involves putting the fruit into a polythene bag and then adding a sugar solution to see whether any larvae crawl out of the fruit. He said “There’s going to be a Horticultural Development Company video coming out soon showing growers how to do this.”
Agrovista fruit agronomist Alex Cooke said Tracer and Hallmark are the best available products for treating SWD, but they can harm beneficial insects. Tracer currently has a 365-day harvest interval, but the industry is hoping to acquire an emergency 120-day authorisation from the Chemical Regulation Directorate, he added.
Cooke also appealed to growers to communicate with one another this year to help tackle the pest, given how quickly it spread in cherry orchards last year.
Meanwhile, a new integrated pest management programme for the treatment of codling moths and leafrollers (tortrix moth larvae) could soon be available following trials last year by BASF and Agrovista of two BASF products, the beneficial nematode Nemasys C and new synthetic mating disruption pheromones due for UK approval next year.
BASF agronomist Simon Townsend explained to the seminar how dispensers containing pheromones for both codling and tortrix moths “cover the whole orchard with a big cloud of pheromone, so the males are confused and give up.”
The nematode solution was then applied as a bark drench later in the early autumn, leading to a reduction in numbers of each species of 90 per cent or more.
Canker Copper foliar feed treatment
A copper foliar feed introduced by Agrovista last year is proving an effective treatment for canker in orchards, its fruit specialist Paul Bennett told the seminar.
“Canker is difficult to control because growers do not have many fungicides that can be used during the season, but the 42PHI Cu is a good canker treatment.
All of the growers that we advise are using it and we have seen a massive improvement in the levels of canker and a reduction in the amount of new canker.”
The product can now be used with Agrovista’s new canker model, the latest addition to its top-fruit pest and disease forecasting service, Growers Choice Interactive. A fireblight model will be included this year.