Hall Hunter embraces IPM
Technical Review magazine December 2004
Producing quality soft fruit while minimizing pesticide usage, the Hall Hunter Partnership is committed to IPM (Integrated Pest Management) . Indeed, having recently carried out successful trials of two new nematode controls – the company is very much at the forefront of IPM developments in soft fruit. In addition, having introduced initiatives aimed at boosting levels of natural beneficials at their organic site, Hall Hunter is now adopting these at its conventional production sites.
Heathlands Farm, at Wokingham, is one of three Hall Hunter sites producing conventional soft fruit crops in Berkshire and Surrey. Organic fruit is produced at an additional 20ha site in Guildford.
At Heathlands 24ha of strawberries, 12ha of raspberries and 4ha of blackberries and blueberries are marketed through Berryworld to Waitrose, Sainsbury's and Tesco.
While 2.5 acres of strawberries are grown on tabletops, the remaining crop is field grown with Spanish tunnels providing protection and improving fruit quality during harvesting.
Four years ago Hall Hunter began using biological control to control spider mite using the predatory mite Phytoseiulus persimilis.
According to the Heathlands production manager, Slavey Slavchev, the available chemicals were not very effective and often required repeat application. “There were also resistance issues and we were losing crop yield,” he says.
“We initially introduced Phytoseiulus at the first sign of the pest. However, this was a little too late.”
Working with Chris O’nions of Avoncrop – specialist suppliers to commercial horticulture and one of two BCP distributors in soft fruit - Slavey has now adopted a new strategy.
“We now use Phytoseiulus at a low rate at the beginning of the season, as soon as it is warm enough and there is sufficient crop canopy. We get very good control, even in 2003 – when the hot summer created high spider mite pressure. In fact it was so successfull that in some fields we didn’t see the pest at all the following year.”
“If hotspots are found, further introductions of Phytoseiulus are made,” says Avoncrop’s director Chris O’nions, one of the company’s specialist soft fruit team. “Hall Hunter view spraying very much as a last resort. Next year, in a bid to eliminate the need for chemical intervention, Slavey plans to trial Majestik – the IPM-compatible soft pesticide.”
At all Hall Hunter sites, thrips are controlled using BCP Ambsure, containing Amblyseius cucumeris. Up till now these predators have been introduced as soon as the pest is found, with up to a further two applications depending on the pest pressure. The strategy generally works well. In 2004 the team had to resort to a single chemical treatment in early June, in some of the everbearer crop.
The Amblyseius also play another role helping control tarsonimid mite, a problem pest with no chemical solution.
In 2004, in a bid to boost thrips control in the organic strawberry crops, Hall Hunter trialled Nemasys F – containing Steinernema feltiae nematodes.
“Applied as a high volume spray to the crop foliage, the nematodes attack the adult, pre-pupae and larval stages,” says Slavey. “It is important to keep the leaf surface wet for at least two hours after application. The fixed set sprinkler system makes this relatively easy.”
Impressed by the level of control, Hall Hunter now plan to use Nemasys F as part of their thrips IPM strategy at their conventional production sites.
Vine weevil
At Heathlands vine weevil is a particular problem. Keen to find a biological solution – which can be used during cropping – Slavey put Nemasys L to the test in the tabletop strawberry crop.
Unlike previous nematode vine weevil controls, this new product contains Steinernema kraussei nematodes, which remain active at temperatures as low as 5°C. Having produced good results, Nemasys L is now routinely applied to the compost bags in September.
Slavey is now trialling the product in the field grown crops. With a double row of T-tapes per row, application was relatively straightforward. With grub damage to the roots noticeable from mid-August, the first application was made late-August, with a second half rate application in mid-September. “With the new low temperature tolerance, we have the option to apply again in February,” he says.
“Raspberry canes are generally better able to stand up to vine weevil damage,” says Slavey. “However, in established plantations the pest has weakened some plants and we intend to trial Nemasys L here too.”
Organic principles
According to Chris O’nions, as a result of the wet summer of 2004, slugs were a major problem for many soft fruit growers.
However at Hall Hunter’s organic site, the pest was effectively controlled using Nemaslug, the nematode slug control which is applied through the sprinkler system.
To help boost levels of natural beneficials including ground beetles – a natural predator of vine weevil and slugs - field margins and beetle banks have been created at the site. Following their success, some of these principles are now being adopted on Hall Hunter’s conventional production sites. For example at the Heathlands site over a kilometre of native hedgerows have been laid containing five native species including hornbeam and beech.
Propagation
Biological control also plays a central role in pest control at Hall Hunter’s propagation site.
Unable to always locate sufficient quality plants, the company started propagating their own. Two years on, and working closely with Edward Vinson, the company uses micropropagation techniques to produce 80% of its plant needs including 600,000 long cane raspberries.
While VapoGro compost, containing biofungus, provides instant microbial and fungal resistance, Phytosure and Ambsure are routinely used to control spider mite and thrips.
Disease control
“Due to the wet summer in 2004, we saw high levels of botrytis and powdery mildew in soft fruit crops,” says Chris O’nions. “Unlike many growers, rather than adopt a routine spraying programme, Hall Hunter carry out weekly crop walks to access disease levels before spraying.”
To minimise any resistance issues, the crop team alternate between several fungicides including Frupica, Rovral and Aliette.
“With the demise of methyl bromide, Slavey has tested the granular soil sterilant Basamid in seven acres of raspberries,” says Chris O’nions. “Impressed with the level of weed, disease and pest control, he is now using Basamid to treat all 12ha of raspberries and has extended the trials programme to strawberries.”
Pollination
In 2004 Hall Hunter used Beesure triple hives for crop pollination. “The pollination has been problem free,” says Slavey. “ While we use 2.5 hives per ha of strawberries or raspberries, later on we rely on natural honeybees.”
