Industry-driving research findings revealed at technical webinar

Microclimate management, yield prediction, and pest and disease research were the main focus points of the 2022 NIAB Soft Fruit Day technical webinar. It revealed the latest ndings from a wide range of NIAB projects led by scientists at the forefront of soft fruit research. Staff writer Henrietta Szathmary reports

Running as a virtual event in late 2022, online attendees of NIAB’s annual Soft Fruit Day could join from the comfort of their own home and learn about the latest developments in the soft fruit industry.

Divided into four sessions, the event covered the latest ndings from NIAB’s Water E cient Technologies (WET) Centre projects, updates on the performance of new strawberry and raspberry varieties, advances in crop protection research, and some interesting ndings from three CTP studentship projects.

The event was coordinated by NIAB’s knowledge exchange manager Scott Ra e. There was also an opportunity for the audience to ask questions and engage with speakers via webchat.

Soft fruit research highlights at the WET Centre

The rst session took delegates on a behindthe-scenes tour of the work that goes on at the WET Centre Consortium at NIAB East Malling, starting with tunnel microclimate and rainwater harvesting (RWH) research presented by NIAB operations manager Trevor Wignall.

According to Mr Wignall, work at the WET Centre revolves around the e cient use of resources such as water, nutrients, fertiliser, and labour, with the primary focus being on plant physiology, pest and pathogen ecology, and plant breeding.

The Centre features strawberry and raspberry departments with highly controlled microclimates that are monitored and regulated using a range of sensors. Some units also employ precision irrigation and nutrigation systems that aim to match the plant’s exact needs with supply and ultimately increase yield.

Mr Wignall said precision irrigation provides various bene ts to growers, retailers and consumers, such as consistent yields and quality, improved time management, reduced wastage, and more nutritious, avourful fruit.

Not to mention, it can lead to signi cant cost savings, as indicated by a survey showing the system can produce the same quality fruit with half the amount of water used by traditional systems.

Speaking of RWH research, Mr Wignall revealed the Centre achieved self-su ciency of up to 88% using its RWH system and determined that a full 400m3 storage tank would be needed to satisfy all water needs year-round.

Another exciting WET Centre project has been the development of BerryPredictor, led by Dr Mark Else, head of crop science and production systems at NIAB East Malling. BerryPredictor is a science-based forecasting tool that aims to tackle the challenges of accurately predicting yield in strawberry crops.

Dr Else explained the tool works by monitoring and optimising zonal phytoclimates in strawberry polytunnels. He then gave a list of some of the factors that must be accounted for when determining cropping potential, such as:

• Air temperature

• Relative humidity

• Inter- and intra-seasonal weather variations

• Polytunnel design

• Coir water and nutrient availability

• Pollination

• Film properties and age

• Plant quality

• Truss kinking

• Pest and disease outbreaks

• Zonal phytoclimates in the polytunnel.

So far, the tool has provided variety-speci c forecasts and predicted times to harvest within one day for many varieties. Following further testing and development, Dr Else and his team are aiming to launch the product on the market by 2024.

The rst session of the webinar closed with an update on recycled coir media in soft fruit.

Dr Matevz Papp-Rupar, plant pathologist and project leader at NIAB, investigated the risks and challenges of recycling coir in soft fruit production.

From comparing di erent coir types, he concluded that using recycled coir causes minimal reduction in yield and could o er substantial cost savings to growers, although the process of coir recycling needs improvement.

Progress towards improved crop protection

Session two of the event unveiled new advances in pest and disease research within the soft fruit industry and delved into how Growing Kent & Medway (GKM) can help food and drink businesses become more sustainable.

Firstly, delegates had the pleasure of listening to PhD student Eithne Browne’s talk presenting her research on Phytophthora root rot in raspberry. Sparing no detail, Ms Browne explored the various pathogen species that are present in plants exhibiting signs of the disease.

In her concluding remarks, Ms Brown established there is more to raspberry root rot than , which is commonly believed to be the primary causative agent of the disease.

Meanwhile, the research project of Dr Andrew Gladman, plant scientist and entomologist at ADAS, challenged the common grower practice of monitoring thrips with below tabletop sticky traps in soft fruit.

Dr Gladman explained that western ower thrips (WFT) have been the primary thrip species a ecting strawberry crops, but some UK native species (e.g. rubus thrips, rose thrips, onion thrips) are also problematic.

Since trapping is a key element of a good integrated pest management (IPM) system, his research explored whether the di erent placement of traps and the use of lures can improve the e ciency and sensitivity of traps and thus pest control in polytunnels.

Comparing the performance of above and below tabletop sticky traps produced very stark results, Dr Gladman said, with above tabletop traps capturing over eight times more total thrips and a higher number of pest species.

Moreover, adding lures signi cantly increased thrips catch on above tabletop traps and could be a worthwhile investment for growers depending on the site’s pest history, Dr Gladman concluded.

Alongside thrips, aphids are another major pest problem in the soft fruit industry. Celine Silva, entomological assistant at NIAB, is currently looking at ways to improve the e ciency of biocontrol parasitoids for better aphid control.

In a trial involving sites in Kent and Scotland, Ms Silva and her team monitored the impact of commercially reared parasitoids on aphid populations. While preliminary results show no signi cant decline in aphid numbers, a closer look at the correlations between aphid and parasitoid species will provide further insights.

Paving the way in spotted wing drosophila control

Considerable research has been dedicated at NIAB to the control of spotted wing drosophila (SWD), one of the most economically damaging pests in soft fruit.

According to webinar speaker Clare Sampson, technical director at Russel IMP, SWD management can cost growers in excess of £300 per ha and still relies on pesticide applications that may impact predator establishment. Improved control methods are therefore required that are more cost-e ective and kinder to bene cial insects.

With that in mind, Ms Sampson introduced ProBandz, a new food bait adjuvant that has recently been validated to be as e ective in reducing SWD numbers as full foliar sprays. This has been achieved using an insecticide rate of only 4% in the spray tank, which equates to as much as 60% reduction in cost to growers.

Delegates gained further insight into the bene ts of bait sprays from Dr Bethan Shaw, research leader in entomology at NIAB, whose presentation looked at the impact of SWD bait sprays on non-target insects. Of the two research projects conducted on the subject, neither has found an increase in mortality rates in bene cial species following application.

Another e ective and nature-friendly method for controlling SWD populations is the sterile insect technique (SIT), which involves producing sterile males of the target pest to be released into the eld and mate with females, resulting in no o spring.

Glen Slade, founder and CEO of BigSis, has been working on making the technique commercially available to achieve season-long control of target pest species on a farm scale.

Mr Slade went on to highlight the substantial cost-saving opportunity in using SIT, which beats chemicals in e ciency and duration and is fully sustainable. Other than being non-toxic and nonGMO, SIT provides a species-speci c solution with no impact on bene cial insects.

So far, BigSis has been able to demonstrate suppression of SWD at each site where sterile insects were released. The company is currently in the process of scaling up its automated rearing units to be able to o er season-long SWD control as a service in 2023.

Next up, Dr Trisna Tungadi, lecturer in plant health at Keele university, shared her research on oviposition deterrents which could form another piece of the puzzle in the ght against SWD.

Ms Tungadi and her team observed that SWD laid fewer eggs on agar media that was pre-exposed to the common fruit y (Drosophila melanogaster), but the compounds responsible for this e ect are yet to be identi ed.

Last but not least, Adam Whitehouse, project leader in strawberry breeding at NIAB, spoke of the progress achieved in research towards developing SWD-resistant strawberry and raspberry varieties. He said the results so far are really encouraging and will hopefully add to the armoury of SWD control methods available to growers.

Crop manipulation and Malling varieties update

The nal session of the webinar featured PhD student Winnie Swann’s research on optimising light recipes for strawberry crops. Amongst others, she identi ed that additional light has a dramatic e ect on yield and canopy size and causes earlier owering, but no e ect has been observed on ripening times.

Delivering the update on new Malling Fruits varieties, Alin Borleanu, technical o cer at NIAB, discussed aspects such as resistance, picking speed, yield, and performance on light and heavy mini trays for several June and everbearing varieties.

All presentations from the NIAB Soft Fruit Day technical webinar can be viewed at: www.niab. com/niab-soft-fruit-technical-webinar-30-nov-22