As conventional chemical pesticides continue to be withdrawn from the market, integrated pest management (IPM) programmes are increasingly incorporating alternative forms of control. UK researchers are also honing in on IPM to help improve the sustainable production of crops, with one novel industry-funded study focusing on the health of, and natural predation in, new orchards. Produce Business UK speaks with project research leader Dr Michelle Fountain to learn how this particular approach could help the sector to reduce production costs, alleviate concerns over pesticide residues and ultimately deliver better quality food
Speeding up orchard ecology
The three-year study, which forms part of Agriculture and Horticulture Development Board’s (AHDB) TF223 project, has chosen to focus on new orchards because they are particularly vulnerable, explains Dr Fountain at the recently merged NIAB EMR, which saw East Malling Research become part of the NIAB group in February 2016.
She says: “What often happens is new orchards get sporadic outbursts of pests because they do not yet have many natural predators. For example, ants start eating the apples because there’s nothing on the orchard floor for them to feed on. The main objective of this project is to speed up the ecology of the orchard to reach what we define as a natural balance of pests and predators.”
Dr Fountain’s work will see the creation of new habitats and food sources for natural predators – beneficial insects such as earwigs and hoverflies which eat pests that are harmful to topfruit crops. It will also create habitats for pollinating insects like bees, as Dr Fountain notes that better pollination is understood to improve the quality of fruit, including the shape and proportion of dry matter.
There are also environmental benefits to gain from increasing the biodiversity of orchards. “We hope this [project] will reduce the amount of insecticides needed to be applied to the crops because we will be boosting the population of the [natural] predators,” says Dr Fountain. “So there’s also the potential for growers to save costs.”
Cost savings made by growers will no doubt reverberate further down the supply chain as fresh produce buyers look to purchase good value products. Furthermore, by using fewer conventional pesticides the industry’s fears of exceeding maximum residue levels (MRLs) will be abated, according to Dr Fountain.
Using novel growing methods
Although many of the techniques to be deployed in this project may not come across as very ‘high-tech’, in reality they represent some of the most novel growing methods available.
For instance, rather than just planting young trees – which are very simple in structure and therefore not the most attractive option for beneficial insects looking for a place to call home – Dr Fountain hopes to install devices that clip onto the young trees to encourage natural predators to stay put. She says: “It could contain pheromones, but mostly it will provide a house for them. By adding structural complexity we are giving somewhere for predators to hide in the tree.”
Another novel technique will see the introduction into young orchards of some older branches containing the predatory mite Typhlodromus pyri – known to growers simply as “typhs”. These branches will be sourced from older, established orchards.
“Typhs are really important for controlling aphids and spider mites, which can be a problem in newly-established orchards,” explains Dr Fountain. “So we will be taking branches and hanging them in the new trees – we will be sort of inoculating the orchards with the new predator.”
Meanwhile, the new insect homes will, says Dr Fountain, include the kind of “scruffy, shrubby” areas that rodents, such as mice and shrews, like to nest in too. “Pollinators like to nest anywhere where a rodent can hide,” she says, adding that the research will look at ways to increase nectar and pollen resources by sowing wildflower mixes and grasses in the alleyways.
“We will also increase orchard complexity,” she continues. “By having a sward (an expanse of short grass), for example, you can create a three-dimensional habitat where spiders and ants can feed on aphid pests in the ground in the alleyways. We are also deliberately diverting the aphids from the trees.”
The swards would also be monitored in a more sensitive way than the current practice. “Rather than mowing them fortnightly, you mow during the flowering period – purposely pushing the bees off the wildflower mix and into the trees,” Dr Fountain reveals.
Buyers who participated in any of last year’s International Year of Soils events will recall that soil health is now a major consideration for the produce sector. In addition to looking for alternative forms of pest control, growers are striving to increase the organic matter on their lands and reverse any damage caused by years of tillage.
A large part of Dr Fountain’s orchard project will therefore focus on soil health by incorporating into the ground arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR).
“That would be the first thing to do, as the trees are going in the ground,” says Dr Fountain. “By using the AMF and PGPR whilst the trees are establishing we will better enable them to uptake nutrients, which means they are more resistant to pest and diseases.”
Previous trials at NIAB EMR have already highlighted the benefits of AMF. For instance, when it was added to the coir substrate of strawberry crops there was a 10-20% increase in class one fruit. The strawberry plants also exhibited a better tolerance to drought.
Clearly, if the introduction of this material yields similar results in topfruit trees the benefits of higher yields, more resilient trees, and less water usage will undoubtedly boost the supply chain.
Dr Fountain evidently has many techniques in the pipeline that are likely to result in wide-ranging benefits for the fresh produce industry, from growers right through to buyers. As we face the challenge of feeding a growing population sustainably, now is the obviously the time for the industry to think more carefully about the way it grows food – and if that results in hardier plants and better quality produce, then all the better. Dr Michelle Fountain is looking for UK growers to take part in her study later this year. If anyone is interested, please get in touch with [email protected]