Organic production methods in orchards – something for everyone?

Cool and humid conditions in the UK, as well as increasingly frequent dry summers, have a significant effect on organic apple and pear production as they favour the development of fungal diseases and increase pest pressure on farms.

Curative control options are limited in organic systems, so growers should take a preventative approach and follow an integrated strategy, with timely use of approved organic inputs only when necessary.

Good organic orchard management starts with site selection. It is best to avoid frost pockets, or at least mitigate risk by choosing less susceptible varieties and introducing frost protection. Poor drainage and sheltered sites with limited airflow and prolonged leaf wetness increase disease pressure significantly, particularly for scab and canker. Orchards should be established on free-draining soils, or suitable drainage measures need to be adopted, together with good airflow.

Winter and summer pruning should aim to maintain an open canopy that allows rapid drying of leaves and fruit after rainfall. Excessive vegetative growth can be driven by vigorous rootstocks and high nitrogen availability, increasing susceptibility to canker, scab, powdery mildew, and fire blight, as well as aphids and pear sucker infestations. 

Nutrient inputs should be carefully matched to tree demand, using soil and leaf analysis to avoid over-fertilisation. This will also support overall good tree health. Well-timed applications of biostimulants, such as Organomex/Kelpomex, will support fruit set and improve the tree’s resistance to biotic and abiotic stress by priming plants and boosting self-defence mechanisms. 

Organic disease control

Apple scab overwinters in leaf litter, releasing ascospores during wet spring periods that coincide with green tip through early crop development. Variety choice is very important for sustainable organic production. Scab-tolerant apple varieties such as Topaz, Natyra, Santana and newer resistant selections perform better in organic systems than traditional high-value varieties that are more susceptible.

During spring, protectant sprays with sulphur remain the backbone of organic scab control in the UK. Potassium bicarbonate-based products provide curative activity and are used to target high-risk infection events.

Powdery mildew is favoured by warm weather conditions and dense canopies with limited airflow. Infected shoots act as a primary source of inoculum, making winter pruning a key control measure.

Sulphur applications from green tip through early shoot growth provide effective protection against powdery mildew. Where infection levels are significant, growers can benefit from regular applications of potassium bicarbonate that dries the mycelium. 

Organic pest control

Among insect pests, codling moth is the primary concern for both apples and pears. Monitoring male population thresholds with pheromone traps alongside female activity with Agrovista’s Fruit Insight model can help growers intervene if required and optimise treatment timings.

Where thresholds are exceeded, applications of granulovirus products such as Carpovirusine EVO2 starting at egg hatch are effective, but accurate timing is critical. Tracer can be applied when codling egg hatch risk is at its peak.

In orchards where codling presence was high and crop damage was noted, autumn and spring applications of Koppert’s Capirel nematodes will reduce population carryover by 60–80% for the following season. Again, timing and conditions are very important and growers need to consult their Agrovista agronomist to ensure optimum results.

Hard-body insects like apple blossom weevil and Rhynchites weevil need to be monitored from bud burst stage using a beating tray. When threshold is reached, grower and agronomist should discuss the best application to control these pests, typically based on natural pyrethrins. 

Soft-body insects like aphids (rosy apple aphid, woolly aphid, pear bedstraw aphid), pear sucker and others can become a problem in orchards if left untreated, particularly in springs following mild winters. Efficient monitoring is important to avoid an outbreak and ensure whether an application is necessary.

Aphid control in organic systems relies on maintaining natural predator populations, such as ladybirds, lacewings, hoverflies, anthocorids and parasitic wasps. Where necessary, the targeted use of fatty acid oils, plant-derived carbohydrates like maltodextrin or silicon-based products can contain insect populations.

 For pear sucker, the introduction of Koppert Anthocoris during white bud stage can boost natural anthocorid populations. If nymph presence is high, applying Flipper (a fatty acid) or EpsoTop (foliar fertiliser) together with Logic Oil can help contain the negative effects of honeydew. To achieve the best results with such contact products, good coverage is necessary. In addition, pruning out heavily infested shoots and removal of infested fruitlets can prevent colony establishment.

While yields may be more variable than in conventional systems, organic orchards can achieve consistent production and high fruit quality in the long term. With the steady loss of effective synthetic actives, conventional growers have started to adopt some of the practices that are well established in the organic sector. 

For more detailed advice on organic production, as well as conventional, consult your agronomist. 

ABOUT OUR EXPERT

Fokion Chatziavgerinos joined Agrovista’s highly regarded team of fruit specialists in 2021, advising on tree fruit and vines across England and Wales.

Key interests include integrated pest management, plant pathology, fruit tree nutrition and fruit crop physiology.

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