Cultural Practices

A. Propagation and Nursery Management

While kiwifruit plants can be grown from seeds, it is not commonly used for commercial propagation as plants grown from seeds may exhibit variability in traits. The most common method involves vegetative propagation, such as using cuttings or grafting. Cuttings involve taking sections of stems with several buds and rooting them in a suitable medium. Grafting involves joining a piece of stem (scion) from a desired cultivar onto a rootstock of a different kiwi plant.

Nurseries can be container-based or in-field, with soil preparation being paramount, ensuring fertility and freedom from pests and diseases. Diligent plant care involving water, nutrient provision, pest, and disease control, alongside regular monitoring for stress indicators, is pivotal. Pruning and training young plants to establish a robust framework, gradual exposure to outdoor conditions (hardening off), and subsequent transplantation to the field when well-established are integral steps. Through effective propagation methods and meticulous nursery management, healthy and uniform kiwifruit plants are readied for successful integration into commercial orchards, contributing significantly to the overall success of kiwifruit cultivation endeavours.

B. Field Preparation

Thorough field preparation establishes the groundwork for successful kiwifruit cultivation by providing an optimal environment for plant growth, essential nutrients, water supply, and effective management practices essential for healthy and productive orchards. The initial step is site selection: kiwifruit plants thrive in well-draining soils with ample sunlight exposure. Preferred sites have slightly acidic to neutral soil pH (around 5.5 to 7.0) and good air circulation while avoiding frost pockets and ensuring adequate water availability.

Soil preparation involves conducting soil tests to determine nutrient levels and pH, facilitating necessary amendments to meet plant requirements. Enhancing soil fertility through the incorporation of organic matter such as compost or well-decomposed manure improves soil structure and nutrient content. Ensuring proper drainage, possibly through contouring, terracing, or drainage system installation, is crucial to prevent waterlogging. Clearing land by removing weeds, rocks, and debris is essential, with considerations for land levelling or terracing based on terrain for erosion prevention and improved irrigation. Based on soil test results, fertilisers are applied as needed to provide essential nutrients for plant growth, either before planting or as part of ongoing soil management practices.

Trellises or support structures suitable for training and aiding vine growth must be constructed. Appropriate spacing between kiwifruit plants optimises sunlight exposure and airflow, ensuring proper depth and alignment during planting. Typically, female vine spacing should be around 5 meters apart; however, for some hardy kiwi varieties, a closer spacing of approximately 2.5 meters is acceptable. Male vines do not require immediate proximity to female vines, but they should be planted no further than 15 meters away.

C. Transplanting and Plant Spacing

Transplanting kiwifruit vines is a critical step, typically carried out during the dormant season, preferably in late winter or early spring before active growth resumes. Preparing the plants before transplantation is vital for their successful establishment. Adequate root pruning, removal of damaged roots, and ensuring proper hydration reduce transplant shock and promote healthy growth. Planting holes slightly larger than the root ball accommodate the roots comfortably, ensuring the plant is positioned at the same depth as in the nursery. Additionally, installing trellises or support structures during transplantation provides immediate stability for young vines, while thorough watering post-transplantation settles the soil around the roots and eliminates air pockets.

Determining the appropriate spacing between kiwifruit vines is essential, influenced by factors such as the cultivar, trellis system, and local growing conditions. Typically, for the Hayward cultivar, spacing ranges between 3.6 to 6 meters between rows and 3 to 4.5 meters between plants within a row. This spacing should allow sufficient room for vine growth and training on the trellis or support structure, ensuring adequate sunlight exposure and airflow between plants. Variations in spacing might be necessary for different kiwifruit varieties based on their growth habits, vigour, and expected canopy size. Varieties like Zespri SunGold might require distinct spacing due to differing growth characteristics.

Proper plant spacing facilitates effective canopy management, allowing ease of pruning, pest management, and harvesting. Adapting plant spacing to local climatic conditions, soil fertility, and site-specific factors ensures optimal plant health and maximises yield potential, emphasising the importance of tailoring spacing practices to local environments for successful kiwifruit cultivation.

D. Irrigation

Kiwifruit plants have specific water needs critical for their growth, particularly during significant developmental stages like flowering, fruit maturation, and plant establishment. Consistent and ample moisture is essential during these periods, but preventing waterlogging is equally vital to avoid root damage and diseases.

Various irrigation methods are employed in kiwifruit orchards to meet these water needs. Drip irrigation, for instance, delivers water directly to the root zone, reducing water wastage and allowing precise control over irrigation frequency and amount. Conversely, micro-sprinklers evenly distribute water across the orchard, covering a larger area than drip systems, albeit with potentially lower water efficiency. Furrow or flood irrigation, although less common in kiwifruit orchards, involves flooding specific areas between rows to direct water to the plant roots.

Effective irrigation scheduling is key and relies on factors such as soil moisture, weather conditions, growth stages, and evapotranspiration rates. Monitoring soil moisture using sensors aids in determining irrigation requirements, with adjustments necessary to accommodate seasonal variations. Kiwifruit plants typically demand more water during hot, dry spells and less during cooler, wetter periods. Mulching around kiwifruit plants proves beneficial in retaining soil moisture, curbing evaporation, weed suppression, and regulating soil temperature, promoting more efficient water use. Maintaining irrigation systems is crucial, necessitating regular checks for leaks, clogs, or malfunctions to ensure uniform water distribution.

Considering water quality is paramount, as poor-quality water can impact soil structure and plant health. Water containing high salinity or contaminants may adversely affect kiwifruit plants. During droughts, efficient water management practices, such as adjusting schedules, prioritising water use, and employing water-saving techniques, become essential to sustain plant health amidst water scarcity.

E. Pruning

Pruning of kiwi plants is predominantly conducted during the dormant season, typically in late winter or early spring before active growth commences. This timing allows plants to recover and adapt before the growing season resumes. Pruning serves multiple purposes, aiming to manage the canopy, enhance sunlight penetration and airflow, eliminate dead or diseased wood, encourage fruit production, and shape vines for better support and accessibility.

Various pruning techniques are employed in kiwifruit vine management. Cane pruning involves selectively retaining robust, healthy canes while removing weaker or older wood, often pruning canes to a specific length based on vine vigour. Spur pruning stimulates the growth of lateral shoots or spurs along the main stems, facilitating the development of flowering and fruiting wood. Additionally, thinning practices involve the removal of surplus shoots or branches to decrease vine density, allowing improved light penetration and airflow within the canopy.

Crucial aspects of pruning include the removal of dead or diseased wood to maintain plant health and prevent disease spread, managing vine growth to balance vigour, and supporting and training vines on trellises or support structures. Pruning also aids in canopy management, facilitating effective pest control, simplifying harvesting procedures, and enhancing fruit exposure to sunlight, thereby potentially improving fruit quality.

Tailoring pruning techniques to suit different kiwifruit varieties is essential, considering their distinct growth habits, vigour, and fruiting characteristics. Adapting pruning practices based on variety-specific requirements optimises fruit yield, vine health, and overall orchard management. Pruning, when executed correctly, significantly contributes to the health, productivity, and manageability of kiwifruit vines. Proper pruning practices are instrumental in achieving optimal fruit yield, maintaining vine structure, and ensuring efficient orchard management.

F. Fertilisation

Fertilisation plays a pivotal role in nurturing kiwifruit plants, providing essential nutrients crucial for robust growth and fruitful yields. Before planting and periodically thereafter, soil tests are conducted to evaluate nutrient levels and soil pH, guiding the understanding of the soil’s fertility and specific nutrient needs.

Kiwifruit plants require a range of vital nutrients, including nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and micronutrients like zinc (Zn) and boron (B). Utilising this information, growers select appropriate fertilisers and determine application rates to address deficiencies or maintain optimal nutrient levels. Fertiliser application can occur before planting or as part of ongoing soil management practices, ensuring a steady nutrient supply tailored to the plant’s growth stage. The timing and quantity of fertiliser application are contingent on the growth phase, soil nutrient content, and local environmental conditions. Dividing fertiliser applications throughout the growing season helps maintain a balanced nutrient supply without causing excesses or deficiencies.

Different types of fertilisers, including synthetic chemical options and organic choices like compost or manure, are used in kiwifruit orchards. Each type offers distinct advantages and influences soil health differently. Fertilisers can be applied through various methods, such as broadcasting, banding, or fertigation, aiming for targeted nutrient delivery near the root zone or through irrigation systems.

Ensuring a balanced nutrient supply is crucial, avoiding over-fertilisation that may lead to excessive vegetative growth, impacting fruit quality and making plants more susceptible to diseases. Conversely, under-fertilisation might limit growth and reduce yields. Growers endeavour to minimise environmental impacts by responsibly using fertilisers, reducing the risks of nutrient runoff into water bodies, and adopting sustainable practices, including organic fertilisers and amendments that improve soil health and support ecosystem vitality. Continuous monitoring and adjustments to fertiliser regimes contribute to effective and sustainable fertilisation practices in kiwifruit cultivation.

Example of how to carry out a fertilising schedule:

1. Pre-planting:

• Conduct soil tests to assess nutrient levels and pH.
• Based on soil test results, amend the soil with necessary nutrients, incorporating organic matter or specific fertilisers to meet initial requirements before planting.

2. Early Spring (Pre-bud Break):

• Apply a balanced fertiliser mix, typically higher in nitrogen (N) to support early growth and bud development.
• Aim for a fertiliser formulation suited to the specific requirements of kiwifruit plants, adjusting quantities based on soil test recommendations.

3. Late spring (after bud break):

• Apply a second round of fertilisers, incorporating a balanced blend of phosphorus (P) and potassium (K) to support flowering, fruit set, and overall plant vigour.

4. Summer (fruit development):

• As fruit begins to develop, focus on maintaining adequate potassium levels to support fruit growth and quality.
• Monitor plant health and nutrient deficiencies, adjusting fertiliser applications if necessary.

5. Early fall (post-harvest):

• After harvesting, provide a balanced fertiliser to replenish nutrients utilised during the fruiting season, preparing the plants for dormancy.
• Consider soil tests at this stage to assess nutrient levels for subsequent seasons.

6. Winter (dormant season):

• During dormancy, limit or avoid fertilisation, allowing the plants to rest. However, if soil test results indicate deficiencies, apply specific nutrients in minimal quantities.

 

Pest Management

Controlling pests in kiwifruit orchards involves integrated pest management (IPM) strategies that combine various approaches to minimise pest damage while reducing reliance on chemical pesticides. Monitoring the orchard regularly for pest populations, disease symptoms, and beneficial insects’ presence is fundamental. Employing cultural practices such as proper sanitation, pruning infected plant parts, and removing diseased or infested debris helps limit pest buildup. Additionally, using biological controls like introducing beneficial insects or organisms that prey on pests can effectively manage pest populations.

When necessary, targeted and judicious pesticide applications are employed. Selective pesticides are preferred, focusing on specific pests while minimising harm to beneficial insects and the environment. Timing pesticide applications strategically, such as during pest life cycle stages vulnerable to control measures, helps optimise their effectiveness while reducing overall use.

Managing weeds in kiwifruit orchards is essential for reducing competition for resources like water, nutrients, and sunlight, which could impede plant growth and fruit production. Mulching with organic materials such as wood chips or straw around the base of plants can effectively suppress weed growth while conserving soil moisture. Mechanical methods like mowing or cultivating between rows help control weed proliferation.

Herbicide application, when necessary, is conducted selectively and cautiously, following label instructions and considering potential impacts on soil health and adjacent vegetation. Pre-emergent herbicides are often used to prevent weed germination, while post-emergent options target established weeds. However, these chemical controls are used judiciously and in conjunction with other methods to minimise their environmental impact.

Adopting a holistic approach that integrates multiple pest management and weed control strategies tailored to the orchard’s specific needs ensures effective control while promoting a healthier and more sustainable kiwifruit cultivation environment. Regular monitoring, proactive measures, and balanced use of control methods contribute to the long-term success of pest and weed management in kiwifruit orchards. Consulting with agricultural experts or extension services can provide valuable guidance on customised pest and weed control strategies suited to local conditions and regulations.

A. Diseases

Kiwifruit orchards face various diseases that can impact plant health and fruit production. Some common diseases affecting kiwifruit plants are discussed below.

Pseudomonas syringae pv. actinidiae (PSA):

PSA is a devastating bacterial disease that causes bacterial canker. It affects vines, leading to symptoms like leaf spotting, stem cankers, and vine dieback. PSA can severely reduce fruit yield and quality.

Bacterial canker caused by PSA

 

Botrytis Cinerea (grey mold):

This fungal disease thrives in humid conditions and affects kiwifruit during flowering and fruit development. Grey mould causes fruit rot, leading to decay and loss of fruit quality.

Phytophthora root rot:

Phytophthora is a soil-borne fungal disease that attacks the roots, causing rot and decay. It often occurs in poorly drained soils or areas with excessive moisture, leading to wilting, poor growth, and vine decline.

Anthracnose:

Anthracnose is a fungal disease that causes brown lesions on leaves, stems, and fruit. It can lead to premature fruit drop and reduced fruit quality.

Armillaria root rot:

Armillaria is a root-infecting fungus that causes root rot and can lead to the decline and death of kiwifruit vines.

Viral diseases:

Several viral diseases, such as Kiwifruit Vine Decline (KVD), cucumber mosaic virus, and kiwifruit yellow ring virus, can affect kiwifruit plants, causing symptoms like leaf mottling, stunting, and decline in plant health.

B. Disease Management Strategies

• Implementing good orchard hygiene, including pruning infected plant parts and removing diseased debris, helps manage diseases.
• The application of appropriate fungicides or bactericides, following label instructions and timing, helps control fungal and bacterial diseases.
• Growing disease-resistant kiwifruit varieties can reduce susceptibility to certain diseases.
• Improving soil drainage and avoiding waterlogging can mitigate diseases like root rots caused by waterborne pathogens.
• Regular monitoring for disease symptoms helps in early detection and timely intervention, minimising disease spread.

C. Insects

Kiwifruit orchards are susceptible to various insect pests that can adversely impact plant health and fruit yield. Some common insect pests affecting kiwifruit cultivation include:

• Kiwifruit vine borer (Aristotelia rubiginosella): The kiwifruit vine borer is a significant pest that lays its eggs on the vines. The larvae bore into the vine stems, causing damage and weakening the plants, which can lead to vine dieback and reduced fruit production.
• Kiwifruit pollinating wasp (Megastigmus spermotrophus): While primarily a pollinator, when populations are high, this wasp species can become a pest by laying eggs inside kiwifruit flowers, affecting pollination and fruit set.
• Thrips: Thrips are small insects that feed on kiwifruit flowers and foliage, causing damage and affecting fruit development. They can transmit viruses and reduce fruit quality.
• Leafroller caterpillars: Caterpillars of various moth species can infest kiwifruit orchards, feeding on leaves and sometimes damaging fruit. They can reduce plant vigour and impact overall plant health.
• Passionvine hopper (Scolypopa Australis): These sap-sucking insects can affect kiwifruit plants, causing leaf yellowing, wilting, and a reduction in plant growth and vigour.
• Scale insects: Scale insects can infest kiwifruit plants, often appearing as small bumps on stems or leaves. They can weaken the plants by sucking sap and excreting honeydew, leading to sooty mould growth and reduced photosynthesis.

D. Insect Management Strategies

• Encouraging natural predators and beneficial insects that feed on pests, such as ladybugs, lacewings, or parasitic wasps, helps in controlling insect populations.
• Regularly inspecting orchards for signs of pest presence helps in early detection and intervention, preventing widespread infestations.
• Practices like proper sanitation, pruning, and removing plant debris can reduce pest habitat and breeding sites.
• In cases where pest populations exceed manageable levels, targeted and judicious use of insecticides can be considered. However, their use should be strategic, following label instructions and considering their impact on beneficial insects and the environment.

 

Harvesting and Post-Harvest Handling

Harvesting and handling practices are pivotal stages in the kiwifruit cultivation process, profoundly influencing fruit quality, longevity, and market appeal. Kiwifruit is harvested when it reaches maturity but remains firm. Evaluation of colour, firmness, and sugar content serves as key indicators for determining fruit readiness. Typically, hand harvesting is employed, utilising clippers to delicately sever the fruit from the vines to prevent damage. Given varying maturity periods, multiple harvests are conducted to ensure each fruit is picked at its peak ripeness. Leaving a small portion of the stem attached to the fruit during harvesting helps safeguard against damage and preserves freshness.

Following harvest, kiwifruit undergoes sorting and grading based on size, quality, and ripeness to align with specific market demands. Subsequently, the fruits are carefully packaged in trays, cartons, or boxes, often cushioned to prevent bruising during transit. Stored in cold storage environments with controlled humidity around 0°C, kiwifruit’s shelf life is extended, maintaining its overall quality. Exposure to ethylene gas from certain fruits like apples or bananas can expedite the ripening process. Thus, it is a common practice to regulate the fruit’s ripening in controlled environments before distribution.

Kiwi-fruit picking

Some operations utilise ripening rooms to manage temperature and humidity, facilitating optimal ripening conditions for the fruit before distribution. Additionally, applying food-grade wax coatings serves to protect kiwifruit, preserving its appearance and freshness during storage and transportation. Careful handling practices, adherence to proper storage conditions, and the use of effective transportation methods are imperative in maintaining kiwifruit quality from harvest to market. Timely harvesting, appropriate post-harvest treatments, and meticulous handling are essential in prolonging shelf life and delivering premium-quality kiwifruit to consumers.

 

Sorting and Grading

After harvest, kiwifruit undergoes a meticulous sorting process. This involves the careful examination of individual fruits to separate them according to various criteria such as colour, size, and external appearance. Automated sorting machines equipped with sensors and cameras can swiftly categorise fruits based on predetermined parameters. This process helps eliminate damaged or inferior fruits, ensuring that only high-quality produce progresses further in the handling and packaging phases. Once sorted, kiwifruits are graded based on specific standards and classifications. Grading involves assigning categories or classes to the fruits, typically defined by factors like size, appearance, firmness, and overall quality. These grades determine the market destinations for the fruits, aligning with consumer preferences and market demands. Different grades may be designated for various purposes such as export, local markets, or processing.

Parameters for grading:

• Size: Kiwifruits are often graded by size, with categories ranging from extra-large to small, ensuring uniformity within each package or shipment.
• Quality: Quality parameters encompass aspects like firmness, absence of blemishes or bruises, and overall appearance, ensuring that only fruits meeting specific quality standards progress to the market.
• Ripeness: In some cases, fruits may be graded based on their ripeness level, especially for markets where consumers seek fruits at varying stages of ripeness.

 

The following video is a good summation of kiwi fruit production.