A newly developed beneficials applicator has lived up to its promise this season at one of the UK’s largest strawberry producers.
The New Forest Fruit Company is a major player in the production of strawberries for the UK market. Supplying the main supermarket chains, wholesalers, restaurants and local outlets, it has over 75ha dedicated to the crop across three sites between the Solent and the New Forest national park, producing around 4000t of fruit every year.
Most of the crop is produced under polytunnels. Biological pest control is employed across 45ha of everbearers, equally split across three sites three miles apart. Table-top systems are used across the enterprise, using Botanicoir Precision Plus Ultra growbags.
Yield and quality are critical, and NFFCo’s high standards are reflected in its progressive approach, being keen to trial new varieties, different crops and novel systems, working closely with Agrovista’s fruit team.
Nowhere is this illustrated better than in the company’s approach to pest control, particularly of red spider mite and thrips. Farm manager Vova Karavan says:
“Both insects are the big enemies of the strawberry crop and can be difficult to control especially during the harvest period. Few conventional spray programs are successful.”
Chemical control is still employed in the early part of the season to ensure the biological programme gets the cleanest possible start. A further chemical application is made after the last fruit is picked to minimise overwintering pests.
The biocontrol programme is based on Spidex, which contains the predatory mite Phytoseiulus persimilis, and Thripex, which contains Neoseiulus cucumeris. The programme typically runs through to the end of July. Being away from the main fruit-growing areas pest pressure is lower, allowing for an earlier finish, as beneficial levels remain adequate right through to the end of September.
Each 15ha block of everbearers is treated every third week, to fit in with the farm’s fungicide programme. Historically, the programme has relied on hand application. However, optimum control relies on even dispersal of beneficials throughout the crop, which is difficult to do manually, even using experienced staff.
“Hand application wasn’t a complete success due to uneven distribution across the top of the crop canopy, and there is also the risk that patches, and even complete rows, could be missed,” says Mr Karavan.
“With our table top system, the top of the canopy is about 1.6m above the ground, so you have to keep your hand above shoulder height to apply the products. This is not ergonomic and is very time consuming.”
Koppert Biological Systems, the manufacturer of Spidex and Thripex, had developed an applicator called the Rotabug-W to help improve application accuracy and establishment of beneficial populations. This hand-operated machine has aluminium booms fitted with 3-litre capacity revolving dosing drums and is pushed like a wheelbarrow through the crop.
However, this applicator is only suited to ground-level crops up to 4ha. Recognising the potential, Tony Girard, director of Koppert UK linked up in 2014 with Jonathan Sibun of Protechnic (Chichester) Limited to develop a mechanised version, the Rotabug-R.
“The first time we heard about Rotabug-R was at the Fruit Focus event in 2014, when we saw the prototype on the Koppert stand and saw a demonstration,” says Mr Karavan. ‘We had no doubt this was the way forward.”
After going through the details with Koppert and Agrovista, who work closely together on the development and implementation of biological systems for crop protection across the UK soft fruit sector, Mr Karavan started using a rear tractor-mounted version attached to the three-point linkage in 2016. This consisted of Koppert’s applicator drums attached to a home-built frame.
“It was the quickest solution to move away from hand application for us. However, initial results were average as we found this machine with its fixed booms tricky to use on uneven ground, making it difficult to achieve even dispersal throughout the crop and risking hitting the crop. This, and the fixed drum speed, meant we had to travel very slowly, typically 1.4kph but as low as 0.8kph in places.”
Despite this, the potential was obvious. In April this year, NFFCo took delivery of the latest version of Koppert’s latest Rotabug-S (straddle version). This is towed behind the tractor, attached to a carriage which carries the boom and applicators, explains Koppert’s Tony Girard.
Rather than being driven by individual motors, the 3-litre dosing drums on this machine are attached to a central rotating axle within the boom, which is driven by a single, variable-speed hydraulic motor, improving reliability and performance and allowing higher rates to be applied without compromising speed.
“Machines are built to individual specifications, taking into account row width and tunnel design. Machines can also be easily altered to suit specific situations and conditions if needed, including adjustments for the distance between the drums and drum height above the crop,” says Mr Girard.
At 7.5m wide the machine is one of the largest made so far, built to fit the farm’s five-row table-top system. “The trailed design is a key success to stability, therefore greater travelling speed can be achieved,” says Mr Karavan. “We now typically travel at 3-3.5kph.”
The machine is paired with a cabless John Deere 3033R fitted with cruise control. According to Mr Karavan, this results in a very user-friendly system, as it frees up the operator to concentrate mainly on the position of the applicators, ensuring coverage is directly above a centre of the crop canopy. This has been further improved by fitting long cable ties underneath the rotating drums, helping the operator judge the correct position.
Good distribution of product is the key benefit of switching to the Rotabug, says Mr Karavan. “We are seeing better establishment of beneficials, resulting in less damage to crop and higher yield and quality. I would say we have picked and sold around 8-10% additional Class 1 product as a result.”
Cost benefits are hard to pin down. Although the Rotabug is much faster than hand application, two staff are usually used, one to operate the machine, the other to open and close tunnel doors and help refill.
“Based on one season’s work, I’d estimate we are saving up to 50% on labour alone, but you have to factor in machinery running costs and depreciation plus the hire of the machine. I reckon we are seeing up to 15% cost benefit overall.”
This is lower than Koppert’s figures; “Other growers using one person and/or wider systems might achieve more,” Mr Karavan acknowledges.
“That said, we have ended up with a system that overcomes the shortage of available labour at the times when application needed to be applied, with the added benefit of simplifying planning and budgeting aspects of the business.
“We are covering a lot more ground while delivering a very even distribution of products, thereby increasing the efficiency of integrated pest management.”
Pioneering crop protection
The application of biological control agents is an area where attention to detail pays dividends, says Mark Davies, Agrovista’s commercial head of fruit.
“The Agrovista Fruit team, together with Koppert UK, works closely with our growers to ensure that we are maximising the effectiveness of these products. The soft fruit Industry has been one of the pioneers of this method of crop protection, reducing reliance on conventional chemistry.
“However, work continues to further improve. Timeliness and accuracy of application rates make a huge difference to the effectiveness of biological control programmes.”
Mr Davies maintains that a plan of attack produced in advance of the season, coupled with rigorous crop monitoring thereafter, produce the best results. However, the accuracy of application has been more difficult to police, with products typically being applied by hand until now.
“The introduction of the Rotabug guarantees that every plant receives the treatment prescribed, eliminating the inevitable under and/or over dosing associated with hand application.
“In our mind this is the primary benefit of using the Rotabug. However, this season in particular, given the problems we have seen with recruiting staff, the labour-saving benefits have also come to the fore.People that would have otherwise have been applying predators by hand are being freed upto do other tasks that can only be done by hand, such as picking.”
Rotabug key benefits
Evenness and accuracy of distribution exceeds hand application
Higher application speeds
Aids planning and budgeting
Application can be managed, supervised and executed by one person
Labour savings (by calculation)
4-row 75%Financial benefit (including tractor use and Rotabug hire)
32-38% (6-row)
5-row 80%
6-row 83%