Technical Information 
Malling Centenary Fruit Production Guidelines - November 2017

These fruit production guidelines for Malling Centenary are based on Jorrit de Vries’ agronomic observations and trials work for Meiosis Ltd.

 

The two main challenges for the successful production of Malling Centenary are disease control (especially Phytophthora cactorum and Pestalotiopsis clavispora) and ensuring sufficient flower truss initiation to provide economic yield.

 

Malling Centenary is known to be susceptible to Phytophthora cactorum. In commercial production Pestalotiopsis clavispora has also been identified in plant samples. This disease is not well known in the UK and northern Europe, but a useful summary of disease characteristics and potential control measures can be found here.

 

The symptoms of both diseases are similar, and it is possible that P. clavispora weakens the plant then P. cactorum lethally infects the plant.

 

Management of fruiting plants needs to minimise the conditions that enable both pathogens to infect the plants:

      • Ensure adequate nutrition to maximise plant health
      • Minimise irrigation
      • Ensure very good drainage of water away from the plants
      • Minimise physical damage to the plants so there are no points of entry for diseases
      • Control insects, especially sciarid fly, that can cause physical damage to stems

Nutrition

      • Optimum nutrition is necessary to reduce plant susceptibility to fungal disease.
      • In fruit production plants should be grown vegetatively to maximise truss expression.

Current recommendation for feeding:
Fruit recipe

        Starter feed        Harvest
Ammonium        0.0 millimoles        0.0
Potassium        4.0       5.0
Calcium        6       5.0
Magnesium        1.5       1.0
Nitrogen        11.5         11.5
Sulphate        1.5        1.5
Phosphate       1.0       1.0
Iron        30.0 micromoles       30.0
Manganese        20.0        20.0
Zinc       7.0       7.0
Boron        15.0       15.0
Copper        0.75       0.75
Molybdenum        0.5       0.5

 

NB Fruiting mix uses elements in the same ratio as for propagation.

 

 

NITROGEN:

      • High nitrogen will cause less Ca uptake, especially ammonium nitrate

 

CALCIUM

      • Malling Centenary can be affected by tip burn due to low calcium levels in the plant, and this can be severe enough to cause the loss of the first fruit truss. Therefore, measures must be taken to ensure maximum calcium levels in the plant during and especially at the completion of the propagation cycle.
      • The fruit grower can use cultural techniques to encourage the flow of calcium from the roots into the leaves.
      • Calcium chloride (for example Koppert Veni Calcium) has been shown to supply calcium in a form that is easily available to plants, helping to quickly correct localised deficiencies.
      • In fruiting apply higher Calcium until the start of harvest then apply calcium and potassium at the same levels.

 

POTASSIUM

      • Skin firmness is not an issue with Malling Centenary therefore lower Potassium levels are recommended in fruiting than used with Elsanta.
      • Potassium levels should be increased at harvest.

Irrigation

      • Malling Centenary requires less irrigation than other varieties such as Elsanta.
      • Overhead watering will encourage disease therefore irrigation needs to be managed carefully in propagation and fruiting plants.
      • More water applied at less frequent intervals, though overall water application is less than for Elsanta. The less frequent watering events minimises the fluctuations in substrate temperature. A uniformly stable temperature stresses the plant less.
      • During establishment especially after planting, irrigation should be limited but can’t be too dry in order to promote root pressure
      • Malling Centenary is sensitive to less than ideal conditions.

 

EC levels

      • Trials with EC of 3.5 in a quite dry substrate showed no negative effects.
      • In fruiting drain EC level can be 2.8 with no negative effects. Sum drip+drain EC 4.0 – 4.5

 

Growing media

      • A freely draining media is recommended such as coir.

 

Chemical use

      • Any chemical use should always comply with the regulations in the country of use, if in doubt seek professional advice.
      • Fenomenal works against both P.cactorum and P. clavispora
      • Paraat works against P.cactorum.
      • Apply Paraat onto substrate pre-planting.
      • 7 days after planting apply Fenomenal and/or Paraat.
      • The use of Folicur is not approved or recommended with Malling Centenary as it can significantly reduce the leaf petiole and truss length.

Plant Type

      • Several propagators have tried techniques to produce larger healthier plants, such as establishing tray plants or waiting bed plants from cold-stored ‘frigo’ plants rather than ‘tips’ or fresh field-grown runners.
      • Establishing ‘tips’ as misted-tip modules before potting on into trays is another possibility.
      • Double cold stored plants can show more variability in truss numbers due to later plant development and therefore initiation.
      • Tarsonemid mite control is crucial for double cold stored plants.
      • Generally, bare-root plants have shown less disease susceptibility than tray plants. Focusing on smaller ‘A’ grade plants at higher density plantings (30/m) has given good results in fruiting.

Flower Mapping

      • Variability between flower mapping and actual fruit production has been high in some instances.
      • Although no work has been funded, commercial laboratories are developing their methods to provide a more accurate assessment of the truss and flower numbers present in Malling Centenary.

 

TRIALS AND COMMERCIAL PRODUCTION OBSERVATIONS

Glasshouse early planted Planting date: 12/01/17 First harvest: 20/03/17

Waiting bed had more flowers but developed slowly Tray plants produced large fruit but had 20% plant losses No second flush

Very high picking speeds achieved – 85kg per hour Production too low for all plant types.

Glasshouse over-wintered crop Planting date: August 2016 Autumn crop taken

Over-wintered at 10°C, no chill

Reacted very well to night-break lighting Very good spring production

Flowered until the end of July

Table top early planting

Waiting bed needed one more truss

Tray plants didn’t develop as normal due to Folicur (tebuconazole) use in propagation – severely shortens leaf height and truss length.

Poly-house fruiting of ‘A’ grade bare-root plants – 60-day substrate production

Planting density: 30 per metre No plant losses

1.5 trusses per plant on average

5 berries per truss = 225 berries per metre 20-30g per berry

99% class 1 + high picking speeds

Compares favourably in production to other tray plants where plant losses can be an issue.

Glasshouse fruiting of ‘A’ grade plants – double cropping

Planting date: 28/08/17 First harvest: 21/10/17 Plant density: 30 per metre

Picked biggest yield in November – results to follow for autumn 2017 crop & spring 2018 crop

Meiosis Ltd seeks to make it clear that the information contained above is based on practical observations but not on robust replicated trials. No warranty is given or implied and, to the maximum extent permitted by law, Meiosis accepts no liability for loss, damage or injury howsoever caused (including that caused by negligence) or suffered directly or indirectly in relation to information and opinions contained in or omitted from this article.