Pears need cold winters and dry, hot summers. They flower before apples, and are susceptible to late frost.
Nearly every cultivar needs a cross pollinator that flowers at the same time as the main scion cultivar to ensure fruit set and good production. Bees are the main pollinating agent and beehives are introduced into commercial pear orchards when the trees blossom.
In contrast to other fruit cultivars, many old pear cultivars are still commonly known and used – Bon Chrétien, for example, dates back to the 1770s.
As for most fruit trees, the number of cold units within a specific region will determine the suitability of a specific cultivar for that region. The cold unit requirement is high for pears (600 – 900 or more) and if these are not sufficient, most cultivars are prone to delayed foliation, which will lead to poor growth and inadequate production. Trees planted in such conditions will be difficult to manage in a commercial venture.
SOIL AND FERTILISER
- Pears prefer fertile, well-drained, well-prepared soils with a potential root depth of at least 600 mm.
- Don’t plant pear trees in sandy or acidic soils.
- Soils that show signs of periodic or permanent water-logging should be drained or avoided.
- Commercial cultivars are all budded onto clonal rootstocks to control tree size, enhance production efficiency and resistance to soil-borne diseases.
- The soil type and other site conditions will determine the rootstock that should be used.
- The fertilisation programme should be based on soil and leaf analysis results and the age of trees.
- Factors such as the removal of soil nutrients by the crop, soil type, effective application of fertilisers and expected production, should all be taken into account.
- Leaf samples should be taken every year in January to establish the trees’ nutritional requirements.
- Soil sampling should be done every third year after planting.
- Fertiliser mixes are expensive and some nutrients – such as nitrogen – leach readily, especially in sandy soils.
- Seek expert advice to ensure fertiliser is applied in the correct way and at the correct dosages.
A general guide for the application of nitrogen, phosphates and potassium is given in the table below. In general, phosphorous and lime requirements are addressed during soil preparation.
- During the first three years after planting, young trees must be pruned according to the set tree architecture.
- Prune when trees are dormant.
- Pruning (before and after the harvest) during summer months by removing water (wild) shoots is an effective way of improving the penetration of sunlight into the tree canopy.
- This will improve fruit colour and general production of trees, especially on the lower branches and inside the tree canopy.
- Prune on sunny days to prevent fungal infections from entering through the pruning wounds and seal large pruning cuts.
- Disinfect secateurs before moving to the next tree – this should help prevent the spreading of diseases between trees.
PESTS AND DISEASES
- The most important causes of damage and fruit loss on pears are codling moths, false codling moths and fruit flies.
- Pear scab and powdery mildew are major problems on leaves – climate is a very important factor in their development.
- There are other problems too; such as red spider mite, cutworms, aphids, scale insects, banded fruit weevil, and mealybugs.
- Get expert advice for identifying pests and diseases and the correct chemical formulations to use to treat them.
- Make sure that the dosage is right and that they are applied correctly.
Soil type, the quality and availability of water, climatic conditions, the age and size of trees, and the type of irrigation system used, will determine how much, and how often, to irrigate.
- Post-harvest irrigation is important as the next season’s fruit buds are formed during this period.
- Although the trees are dormant during the winter months, they will still need water.
- As a very general indication, young trees need about 350 mm to 400 mm a year, increasing to 600 mm to 760 mm for fully bearing trees.
- The maturity of fruit is commonly determined with the standard firmness test.
- Correct sampling is essential, as fruit on the outer branches will be riper than those on the inside of the tree.
- Pears should be picked and transported carefully as they bruise easily.
At the pack house, the fruit has to be stored in a cool room at -0,5°C before packing can start.
- The fruit is washed, sorted (according to colour and size) and packed into boxes (usually 12.5 kg, in layers, with protective layers in between).
- Most pears can be stored for one to 3 months in an ordinary cool room, but in a controlled-atmosphere cool room the fruit can be stored for up to 9 months, depending on the cultivar and maturity at picking.
DID YOU KNOW?
Archaeological evidence shows that pears were collected in the wild long before they were cultivated, and date back to the Bronze Age of Europe. Their cultivation was first mentioned in the literature of the Greeks and Romans.
A very old Saffron pear tree dating back to the days of the Dutch East India Company is still alive in the Company’s Garden in Cape Town, Western Cape.
- This article was written by Taaibos Human from the South African Agricultural Research Council Infruitec-Nietvoorbij and first appeared in Farming SA.