Peaches and Nectarines (Prunus armeniaca)

How well established is this crop?

This crop has been grown commercially in the region for at least 25 years. Commercial returns, current growers and some level of regional based research is available to help those new to this industry.

Background

Until recently peaches and nectarines have been available in New Zealand only during the summer months. Now with imports coming from California in our winter they are available for a lot longer. They have been grown in New Zealand for many years for domestic consumption. Exports are a relatively new part of the business and only really began with large volumes leaving New Zealand in the 1980s. The main markets are in Australia with some product going to Asia (especially Taiwan) and the USA. Export volumes have dropped in the past 5 years mainly due to the varieties being unsuitable and no new plantings coming on stream. Export returns have fallen in recent years.

Peaches have what is traditionally known as a ‘furry’ skin and nectarines are smooth. This difference is caused by very slight genetic difference. When breeding new varieties, peaches and nectarines are crossed with each other.

Climate

Most areas of New Zealand that grow this type of summerfruit are characterized by cool winters, hot dry summers with plenty of sunshine hours and low humidity. The Hawkes Bay and Central Otago provide this environment perfectly. The recommended growing degree day figure is at least 800 GDD at a base of 10°C.

Winter Chilling and Frosts

Frosts do not directly affect the tree unless it is flowering or fruiting.

All varieties of peaches and nectarines are self fertile. Flowering usually happens in the middle to end of September, a period that is characterised by frosts. The young flowers and fruit are susceptible to this frost and can all be killed if temperatures drop below 0 degrees C. Traditional frost control methods methods such as smoke pots have been surpassed by over-head sprinkler frost fighting and now in some cases wind machines.

Rainfall and Irrigation

Rainfall by itself does not tend to harm the trees but it does raise humidity and increase the chances of fungal and bacterial diseases such as spot and blast.

During period of dry weather peaches and nectarines will benefit from irrigation especially in the period before harvest as it allows the fruit to grow. Under tree irrigation is recommended to keep both leaves and fruit dry, reducing the chances of bacterial disease.

Wind

Even though peaches and nectarines grow into large trees, they still benefit from some wind protection, especially when they are young. It reduces the chance of bruising on the fruit and reduces the drying effects of wind over the summer period.

Soil

Peaches and nectarines require sunny well drained soils if they are to do well. A gentle slope also brings benefits as it can cause the frosts to be less severe during the sensitive flowering period.

Fertility

Peaches and nectarines require reasonable levels of soil fertility as they tend to be cropped heavily, up to 20 tonnes per hectare. Regular soil and foliage tests will quickly identify any deficiencies and this can be easily corrected with the addition of fertiliser. Companies such as Hills Laboratories have a datasheet with the recommended soil and leaf nutrient levels for this crop. See the ‘Contacts’ section at the end of this datasheet.

Weed Control

Weed control in peach and nectarines blocks tends to be quite straightforward. When young trees are planted, plastic spray-guards are put around the trunks. This prevents rabbit damage and allows herbicides to be sprayed right up to the tree. Weeds growing up inside these guards are removed by hand. As the trees mature the bark on the trunk hardens and herbicides can contact them with no damage to the tree.

Varieties

A large range of peach and nectarine varieties are available to the new grower. Many of these have been developed in New Zealand and more and more are being imported from overseas based breeders. Getting varieties which suit your property is important. Talk to local growers who have a similar land form to your block before deciding what to plant. Also talk with exporters who will be selling your fruit for the latest market information.

Pests and Diseases

Peaches and nectarines suffer from a range of insect and fungal pathogens. Research work in Otago has shown that some of the diseases are going to be very difficult to manage by organic principles leaving agrichemicals the best method of control.

Insects include leafrollers, mites, thrips and scale. The disease pathogens include bacterial blast and bacterial spot, silver leaf, brown rot and a range of storage rots.

Layout

Most peach and nectarine blocks are planted on a reasonable scale and allow for tractor access between rows. This is usually 4.5 -5.0m. Within the row spacing is usually about 2m. Final tree height is anywhere from 4-5m.

General Management

Ground preparation is the key to developing a peach or nectarine block. Irrigation installation and any drainage work is completed in the period before planting. Trees are delivered from the specialist nursery ‘bare-rooted’. This means they have been dug and shipped without any soil around the roots. They usually arrive in bundles of approximately 10 trees. These are usually ‘heeled in’ meaning the roots are covered with soil or sawdust until they can be planted. Tree rows are usually ripped with a deep blade to free up the soil. Holes are dug and the trees planted, usually with the graft union pointing into the direction of the prevailing wind. This gives the tree more strength as it grows. Weed control using herbicides, mowing, spraying and irrigation are needed from this time. Some pruning and tree shaping is also done, generally in the winter. The traditional shape for a mature tree was the vase shape. However, more recently training the tree into a centre leader has become popular. It is important to seal the cuts made at pruning with a fungicide/bacterial spore killer as the trees are susceptible to infection through these wounds. Fruit is generally removed from the tree in the first two seasons to ensure the tree grows vegetatively. After flowering the fruit is generally thinned to a standard number of fruit. If this is not done the tree will produce considerable small fruit.

Harvest

Picking is done by hand with care being taken not to bruise the fruit. They are placed in large bins in the orchard before being taken to the packhouse for processing.

Equipment

Because most blocks of peaches and nectarines are planted on a reasonable scale, a tractor is required along with spray units, mowers, forks for transporting bins and maybe a truck to get fruit to a packhouse.

Returns

Returns are usually quoted on a per kilogram basis in the export and domestic markets. Howver it does depend on variety and the value of the $NZ at the time of sale.

In general a fully developed block should produce between 10-15/t/ha with prices ranging between $2-2.50/kg is normal.

Contacts

If you are thinking of growing peaches and or nectarines, talk to some local growers and look at the following website.

For fertility information contact for Hills Laboratories.

Industry based grower organisation www.summerfruitnz.co.nz