Strawberries - Varieties and Culture for Commercial Production

1. Introduction
2. Varieties
3. Soils and Site
4. Plants
5. Harvesting
6. Pests and Diseases

Introduction

Strawberries can be grown in most parts of New Zealand, but the main districts of commercial production are Auckland, Waikato, Hawke's Bay, Horowhenua and Canterbury. The Auckland region produces over 40% of the commercial crop.

Strawberries are usually grown as an annual crop, as the largest proportion of large fruit, suitable for fresh export is produced in the first growing season after planting.

Strawberries may be grown for two, three and even four years, with cropping life longer in cooler southerly areas and shorter in warmer northerly areas. However, this practice is in decline because of the poor quality of fruit produced in second and subsequent growing seasons.

Close planting is a feature of annual cropping with 50,000 - 75,000 plants/ha in single rows and up to 150,000 plants/ha in double rows, or four row beds.

Production varies with the variety grown, district, system of growing and the efficiency of the grower. The average yield over the life of the crop from well managed strawberry gardens is about 35t/ha in the Auckland district. Yields are normally expressed in g/plant. Yields up to 1000g/plant are possible with 350g considered minimum over the four month cropping season.

Varieties

Strawberry varieties are classified as short day, day neutral or intermediate. For short day varieties, flower initiation is triggered by short day lengths. Fruiting is normally confined to October - December, although some short day varieties will continue later fruiting, depending on climate and crop loading factors.

Day neutral varieties are not affected by day length. Flower initiation and fruiting will occur when temperatures are high enough to maintain growth.

Intermediate varieties usually produce an October - December crop, and a smaller February - May crop.

Pajaro is the main variety grown in New Zealand. Fruit is consistently large and firm, with good flavour when fully ripe. Yield is average rather than high, but very good fruit quality results in a high proportion of saleable fresh market fruit.

A wide range of other varieties are grown. Variety selection should be determined by climate and growing conditions, and end uses or market opportunities for strawberries.

Soils and Site

Strawberries can be grown successfully on a wide range of soils. Free draining soil types, which dry out more rapidly, will require irrigation. The plants respond to warm, moist but not wet soil conditions in early spring. Avoid frost pockets.

A northerly aspect and good shelter from prevailing and cool southerly winds are advantages. Avoid planting where shelter will heavily shade the strawberry plants. A site which has an easy contour to aid machinery use is an advantage.

Drainage
Drainage problems must be overcome before starting soil preparation. Strawberry plants can only tolerate temporary poor drainage, so to obtain maximum performance, measures must be taken to control high water tables, and improve drainage on soils where drainage is very slow.

On heavy soils, permanent drainage installation coupled with deep subsoiling or mole draining are necessary.

Subsoiling is best carried out before preparation for planting when the soil is at its driest in late summer. The subsoil cuts are made at 1m centres in both directions and to 1m in depth. Adequate outfall for the drainage water is essential.

Light contouring to encourage surface water run-off is also helpful.

Soil Testing
Strawberries will grow in soils with a wide range of pH, but grow best in pH range of 5.5 - 6.5. The lower end of this range is preferred on heavier soils and the higher end is preferred on light soils..

A soil test to find pH, Calcium, Potassium, Magnesium, Phosphorus and organic matter levels should be taken before working up the soil in preparation for planting.

Soil Preparation
The area should be cleared of perennial weeds such as couch, thistles, kikuyu and paspalum before planting.

Ideally, cultivation begins about 6 to 8 weeks before planting. Old pasture land is often used for strawberry crops. Use paraquat or glyphosate to kill the turf. Break up the pasture by cultivation. For heavy soils where machinery working will not be possible in winter, soil preparation is normally completed by the end of March.

Plough or disc to a depth of 150mm to 200mm and finally use a rotary hoe to get a fine tilth, as near as possible to seedbed condition.

Replanting
When replanting old beds, mow the plant tops off as low as possible, without causing damage to the plastic. The plastic mulch can be removed by hand or pulled off with tined implements. Plastic mulch is best removed in cool weather, as plastic stretches and breaks in hot weather, making the removal job much more difficult. Pick up all small plastic pieces, bundle and burn or dump the plastic, off the strawberry block. Do not cultivate the block until all plastic mulch is removed.

Soil Sterilising
Soils are sterilised to reduce the level of soil-borne diseases, weeds and pests. Sterilisation by annual fumigation has become common practice. Soil direct from pasture will not normally require sterilisation.

The most common fumigant is a mix of methyl bromide (66%) and chloropicrin (34%). The fumigant is applied to moist soil of fine tilth. Methyl bromide helps move chloropicrin through the soil, but both materials together have excellent activity against a wide range of soil-borne pests, diseases and weed seeds.

Overall fumigation relies on correct soil preparation, fumigant gas injection, covering with polythene film, then film removal once fumigation is complete.

Ridge-only fumigation is carried out similarly, except that the process fumigates only the soil in the already-formed ridges, using the polythene film through which the strawberries are to be planted, as the film for scaling the fumigant gas in.

The soil must be checked for freedom from choropicrin residues before strawberry planting. Chloropicrin not dissipated from the soil can cause severe plant and foliage damage.

To check for chloropicrin, dig to 18cm depth to smell for chloropicrin residues. Damp spots are the best places to check. Do not plant until the smell of chloropicrin has disappeared.

Take soil samples from 12cm to 18cm depth, from sterilised and unsterilised soil. Place in glass preserving jars. Sow cress seed on the soil surface, then seal the jars. If cress growth is equal between the two jars after three to four days, there is no significant chloropicrin residue. If germination is delayed or reduced, or growth is less on the sterilised soil than the unsterilised soil, delay planting. Check again in another week.

Fumigating with a mix of methyl bromide and chloropicrin has provided a single effective treatment for soil borne diseases, pests and weeds, including old strawberry plants. Methyl bromide use for sterilisation is being phased out, in line with the Montreal Convention to reduce or eliminate the use of materials which destroy ozone, including methyl bromide. Separate treatments are likely to be effective for single problems, as reliance on methyl bromide for fumigation, is reduced.

Alternative chemical fumigation treatments include Metam, Basamid and Chloropicrin. Solarisation which uses the heat of the sun to sterilise soil, may be a suitable alternative in some places. Rotation, fallowing, or leasing ‘clean’ land for strawberry growing are possible management alternatives.

Disease resistance breeding offers a longer term option, but at present, no varieties are available with acceptable commercial characteristics and root disease resistance.

Biological control agents against the root disease Phytophthora fragariae are offering promise. Other biological control agents are under development. The use of biological control agents is likely to involve pre-treatment survey or analysis to determine which agents are required.

Nutrition
Soil fertility, soil structure and water application are management factors which need to be considered for each site and strawberry variety grown. Plant nutrition involves managing all of these factors, rather than using arbitrary formulae or fertiliser mixes.

For annual replanting, nutrients are required to establish and grow the strawberry plants, before cropping commences.

Annual planting involves more frequent cultivation compared with plants cropped over a number of years, on the same site. Frequent cultivation results in a more rapid loss of soil structure, breakdown of organic matter and worm population decline.

As strawberries are planted through plastic mulch, most fertiliser is applied in a base dressing before the mulch is laid. Unless fertigation is to be carried out, all fertiliser is applied before planting, whether the strawberries are to be cropped for one or more seasons for multi year cropping. There is no advantage in making higher than normal fertiliser applications before planting or applying more fertiliser in subsequent cropping years.

Where strawberries are planted in land previously in alternative uses such as pasture, soil testing is used as a guide to determine soil nutritional status for major elements except nitrogen.

Where strawberries are planted in land previously growing strawberries, soil tests, leaf analyses, sap nitrogen testing and crop nutrient removal information should be used to estimate fertiliser requirements relevant to the cropping system.

Where strawberries are planted and cropped over a number of years, annual nutrient removal data can be used to estimate fertiliser requirements. The nutrient removal figures below are the minimum amounts which need to be replaced from soil reserves or fertiliser applications each year. Estimated nutrient removal figures are Nitrogen 2kg/tonne of crop removed, Phosphorus 0.3kg/tonne, Potassium 2kg/tonne, Magnesium 0.3kg/tonne and Calcium 1kg/tonne.

Table 1: Estimated Nutrient Requirements Due to Crop Removal

Soil pH in the range 5.5 - 6.5 is favourable for plant nutrient uptake and earthworm activity, providing soil is moist and well aerated. Soil pH can be improved by agricultural lime application.

Strawberries require macronutrients including nitrogen, phosphorus, potassium, magnesium and calcium. As the main demand for nutrients is associated with berry development, fertiliser nutrients should be plant-available in the soil before berry development.

In practice, base fertiliser is incorporated into the soil before final cultivation, ridging and mulch laying, since it is not easy or cost effective to apply base fertiliser after polythene laying. For annual replanting, a combination of fertilisers providing readily available nutrients to be used in plant development and cropping is appropriate.

While cost influences fertiliser choice, proneness to leaching and volatilisation, potential acidifying effects, rate of nutrient release, fertiliser rating, plant and site requirements all need consideration.

Generally, day-neutral varieties have higher potassium requirements than short-day or intermediate varieties. Each variety differs somewhat in nutrient requirements. As the grower gains experience with the variety and management system, nutrient inputs can be more exactly managed.

Ridging
Ridging and polythene laying should be done when the soil is at a moist fine tilth, before planting. At least 10 days should be allowed for ridges to settle before planting.

Soil must be in good tilth, moist and free from lumps. Poorly prepared or cloddy soil will rip polythene, reducing its effectiveness and provide an unfavourable environment for strawberry plant establishment.

Wet soil is not suitable for ridging and should be allowed to dry first. Irrigate dry soil if rain is not forecast. In practice, ridging and polythene laying are best done in late summer or autumn, before it is too wet to carry out this machinery based operation.

Ridge height, width and spacing will be determined by the growing system and dimensions of machinery and equipment to be used.

For single rows or double/alternate row ridges, height may be 150mm to 300mm, and width of 300mm to 450mm, with smoothly sloped tops and sloping sides. High ridges allow for cleaner and easier access to strawberries at harvest, particularly for varieties with long fruit trusses.

Polythene Laying
Polythene plastic is used for mulching to provide weed control, to keep developing fruit out of direct contact with the soil, and warming soil to encourage early plant establishment and development.

Only black polythene is effective. Clear polythene and white polythene are ineffective in suppressing weeds under the mulch. Polythene is typically 30µm thick, available in 500m lengths.

Brown polythene has been trialled in New Zealand. It is effective as a mulch, but tends to shatter when being removed, compared with black polythene.

Polythene is available in several widths, with planting system and drainage requirements determining width. Typical widths used currently are 900mm for single row lower mounds and 1200mm for higher and wider mounds.

Small areas can be laid by hand, but commercial gardens use special plastic-laying machines operated behind a tractor.

Plastic-laying machines vary in design, but the methods are similar. Small discs running ahead of the plastic open furrows alongside the ridge, a roller consolidates the top of the ridge, then the plastic is unrolled and stretched along the top. Rubber wheels press the plastic into the furrows on each side of the ridge and discs turn the soil back on to the plastic to hold it down.

As each ridge is covered, square off the end and bury the plastic. The plastic must be kept snug and taut over the ridge by covering all loose edges with soil as soon as the plastic is laid. Loose plastic can be damaged through billowing. Polythene should be laid on a calm day.

Plants

The New Zealand Berryfruit Propagating Company owns the propagating rights to most of the commercial strawberry varieties in New Zealand. The company licenses propagators, who under license, have the right to propagate these varieties. The propagators must abide by the requirements of the Strawberry Runner Plant Certification Scheme.

The primary aim of the scheme is to produce commercially available high health plants, by eliminating pests and diseases such as viruses, foliar nematodes and soil borne diseases. A secondary aim of the scheme is to produce planting material which is true to variety and selected as the best strain available, of each variety.

Most of the plants supplied to growers are raised in the Bay of Plenty and Levin areas. Only strong, healthy runners, free of virus, fungal diseases and pests should be planted out.

After the plants have been lifted from the nursery bed, they should be quickly transported and planted out. Any delay which may cause the plants to dry out can greatly reduce the rate of recovery after planting and subsequent growth. Already dug plants should be kept moist and cool before, and during consignment.

Ideally planting should be complete by early May. In practice, planting is limited to the time at which plants become available from the nursery. Planting should be complete by early June. Planting is often delayed till late August and early September in Southern districts. Plants can be held in cool store until required, or not lifted until that time.

Planting
Pajaro is normally planted in single rows at a spacing of 150mm, up to 200mm between plants. Very leafy varieties are more widely spaced, with less space for more compact varieties. Row spacing is normally 0.9m to 1.5m.

Some growers plant double alternate rows along each ridge with plants set out in a staggered pattern. Planting distances are usually 150mm between plants and 150mm between rows. In districts where strawberry beds are cropped for several years, plants may be spaced as far apart as 250mm.

Table 2:Plants/ha for Different Planting Distances

Where plant densities become too high, management problems occur. These could include poor spray penetration and coverage, berry rot, while berries, delayed ripening and slower harvesting rate because berries are hard to find amongst foliage.

Before planting, puncture the plastic at the appropriate spacings. Various methods can be used to do this, e.g. use a board about 3m long, with nails driven through the wood at the required spacing.

The disadvantage with this is the need for two people to handle it. A simple one-man method is to mount nails at the correct spacing on a suitable sized wheel and then roll this along the top of the ridge. Some experienced planters judge the correct spacing by eye and do not use marking devices.

Keep the plants cool and moist until planted; put dry plants in water for about an hour before planting. Healthy foliage should be left intact to assist early root development.

A 250mm long, blunt steel blade, flat across the bottom and about 25mm wide makes a simple planting tool. Fold the roots over the bottom edge of the blade just far enough for them to be pressed through the plastic and straightened out in the soil.

The crown of the plant should be level with the ground and the soil firmed down. Make sure that the crown is in firm contact with the soil and the plastic not tight around the crown.

Experienced planters can put in up to 550-600 plants/hour, but careful placing and soil firming are more important than speed.

Watering in of autumn planted strawberries encourages rapid plant establishment and root system development before winter. Plants establish better in cool, overcast conditions.

Weed Control
As strawberries have small root systems, and in many instances are grown as annual or biennial plants, avoiding weed competition for moisture and nutrients is important. Most weeds are controlled by the use of black polythene, but herbicides are necessary to maintain control of weeds between the rows.

Pre-weed emergence, use simazine at 1.0 -1.6 active ingredient (a.i.) per hectare of bare soil. Check label rates for actual product rates per treated hectare. This application is normally carried out in late winter. Where polythene covers some of the soil area, reduce the product rate per hectare, accordingly. Simazine can be applied by boom spray or knapsack to bare ground. Strawberry varieties differ in their tolerance to simazine, so try a small area first to ensure safety.

Simazine can cause damage through careless use, but factors beyond the control of the grower may also be responsible. For example, if heavy rain falls soon after application to slopes or uneven ground, damaging concentrations may accumulate on lower areas.

To reduce the chance of such failures, growers gaining experience with simazine should apply it at a low rate. Repeated treatments may be necessary, but with experience the strength can be raised to suit the soil type and slope.

For control of seedlings and established weeds, contact materials such as paraquat and diquat desiccate plant growth. Paraquat is more effective against grasses and diquat against other weeds.

For use between polythene strips, use a mixture of paraquat and diquat, such as Preeglone with a wetting agent. Apply the mixture at comparatively low rates, on newly germinated weed seedlings. A contact material such as Buster is normally applied just before straw is laid. Roundup is an alternative. Great care must be taken to avoid spray drift onto strawberry plants, particularly with translocated materials such as Roundup.

About 400 litres of the spray mixture will cover light weed growth on one hectare of garden, but more is needed for dense weed growth or larger weeds.

Paraquat and diquat do not leave any residue in the soil but direct contact is damaging to strawberries. Take special care to avoid spray drift on the strawberry plants during application. Use low pressures and only spray on calm days. Keep the nozzle reasonably close to the ground to be sprayed.

Hand weeding with a push-hoe through the straw or spot spraying, is very effective for December weed control, in strawberry beds which are continuing in production into summer or autumn.

Plant Management
For plantings which are to be cropped for several years regular monitoring and taking appropriate action should be done, for pests and diseases.

Flowering can start soon after growth begins. To encourage plant growth the first flowers and flower buds that emerge in the spring can be removed by deblossoming. The small weak first truss is often removed. Energy is directed first into foliage growth and root system development to support later flowering and fruiting.

The first August fruit truss of Pajaro is not of good quality, so de-blossoming can be beneficial. Later trusses tend to have 5-7 berries, for Pajaro. The need for de-blossoming tends to be variety specific. De-blossoming is not usually necessary in southern districts, particularly if the early flowers have been frosted.

Day neutral strawberry varieties tend to produce fruiting trusses on rooted runners, but the fruit on these plants is growing in wet conditions between the strawberry rows, is very much more prone to damage and disease, and creates a difficult environment to manage. If fruiting plants produce runners during the season these should be removed by either cutting off or killing with a carefully directed desiccant spray.

Irrigation
The polythene mulch helps conserve water, but strawberries require irrigation during dry conditions to maintain fruiting over an extended period. Irrigation is essential to encourage plant establishment and to maximise growth and cropping, particularly on annual strawberry plantings.

Irrigation can be done by overhead sprinkler systems. Irrigation systems placed under the polythene mulch can also be used successfully and make better use of limited water supplies.

Mulching
Late October straw mulching helps to reduce the amount of Botrytis spore splash from overwintered trash, back on to the planted strawberries. It also helps keep berries clean of dust drift from the between row paths.

Mulch the gullies between the ridges with fresh, dry stored hay, barley or wheat straw about the time the first fruit is sizing. About 150 bales are needed for 1ha of berries. Barely straw is preferred because it is easy to hand spread and has reasonable persistence. Spreading rate is about 5 bales/hour.

Harvesting

Development of fruit from flower takes 35-42 days early in the season and about 21-23 days in summer. An entire fruit truss will take about 35 days from first flower, to last fruit picked. Later flowers on a truss take longer to reach harvestable fruit stage than earlier flowers on the truss, irrespective of the stage in the season.

Care and gentle handling are essential during harvesting. Harvest method is determined by market preference. Fruit can be picked by the stalk for soft-fruited varieties. ‘Flick’ picking using a quick twisting action with the fruit held lightly in the fingers, removes the fruit from the stalk, but keeps the calyx intact. Picker efficiency is enhanced if detailed grading is left to experienced graders working in conditions suitable for grading.

Fruit picked with the stalk on must be handled and packed very carefully to avoid stalk damage on nearby fruits.

Fruit is graded and packed in the packing shed. Because of its highly perishable nature, avoid any delay in removing the fruit from the field. Packing sheds should be well ventilated or insulated to maintain cool conditions.

The pickers use a tray to carry punnets. Once picking starts, the average picking rate (kg/hour) is determined by the time of season, weather conditions from day to day, and the ability of the pickers. Picking rate may be between 15kg to 25kg/hour.

Export picking needs to be done frequently. Typically, export picking is done every second day, but in hot weather, the planting may need to be picked every day. Other picks may need to be done every 2nd to 3rd day, depending on market requirements for fruit quality and shelf life.

For freezing, the strawberries can be picked directly off the truss, leaving the calyx behind. Otherwise, the calyx is removed after picking. The fruit is placed directly in bulk containers.

Yields for Pajaro should be at least 350g/plant.

Field Heat Removal
Remove field heat from the berries as soon as possible after picking so that they retain maximum quality and potential shelf life.

Cool fruit as soon as possible. The cool store temperature should be between 2 - 5°C and the humidity at 85-90%. Strawberries can be held for a maximum 7-10 days at 0°C depending on fruit ripeness and environmental conditions at harvest. Strawberries freeze at -1 °C.

Cool store designs vary, but a volume of about 15m³ to 20m³ is usually adequate for strawberry gardens of 2ha to 3ha.

Marketing
Packaging depends on market requirements, cost and supplier preference.

Strawberries for local market are packed in punnets or chips. Punnet sizes and styles vary. The 340g net fruit weight punnets are most common although some growers 400g punnets. As fruit is sold on a per punnet basis, lower fruit weights per punnet are an advantage to the grower. Punnet styles are either unlidded, with cellophane and rubber bands used to provide a lid, or complete ‘clamshell’ type lidded containers. These are very convenient for fruit handling, storage and display in markets.

Growers are also experimenting with a machine that applies and heat seals a cellophane cover. Some modified atmosphere punnets are also being trialled.

To pack each punnet, place the fruit loosely in the bottom of the punnet without any definite layer system. When the lip of the punnet is reached, use berries of similar size and quality to complete the pack weight. Pack the fruit onto the outside rim of the punnet and add in layers so that the outside of the mound is faced with the sides of the fruit. For clamshell punnets, ensure that fruit height allows for the lid to be closed without causing berry damage. The number of layers depends on the size of the fruit; with large fruit there may be only two layers. The top layer must fairly represent the contents of the pack.

The berries are packed, transported and sold in cardboard cartons, usually holding 12 or 15 punnets.

Most strawberries are sold on the local markets by auction or negotiated price. Many are sold direct to retailers. Gate sales is also a significant market outlet.

Only good quality, pest and disease free berries are exported. Packaging and quality requirements are usually outlined by the exporter and must be carried out to suit the particular overseas market.

The strawberry industry operates a residue assurance programme for exports. Prior to first export pick, each strawberry garden supplies a fruit sample for agrichemical residue analysis, and the spray diary for audit. Export certification must also be obtained. This takes the form of a phytosanitary certificate, which is issued on the basis of export fruit inspection, either at the grower or exporter premises, and audit of exporter quality assurance systems.

Mostly 250g and some 340g plastic punnets, packed in cardboard cartons are used for export packaging.

Multi-Year Cropping
This practice is losing favour, because of the very poor quality of fruit harvested in the second and subsequent season(s). If multi-year cropping is planned, then retain only healthy, vigorous plants.

Control weed growth with a paraquat/diquat spray applied to the gullies in late autumn and again in spring before mulching. Straw must be applied subsequently, as straw laid in the first growing season will have completely broken down.

Runners and old leaves are removed by mowing at about 7cm to 8cm height. Uncut runners which still need to be removed after mowing can be removed using secateurs or road sweeper brushes. Avoid strawberry plant crown damage. Trash should be thrown into the between row space, then sprayed once or twice with a contact material to encourage rapid breakdown. Ensure plastic is not covering or restricting growth from the crowns. Where crowns have multiplied, reduce to 2 - 3 crowns per plant. Also, maintain a spray programme to ensure the plants remain free of pests and diseases over this period.

Buster should be applied for weed control between rows after plants have been de-runnered, cleaned up and trash has broken down.

Bees and Pollination
Many insecticides are very toxic to bees. Leaf roller, mites and aphids can be controlled with materials such as dichlorvos which are safer to bees but must be applied in the evening after the bees have stopped working the flowers. Because bees are not particularly attracted to strawberry flowers, wind pollination is important. Once harvesting begins, the movement of the pickers hands in amongst the strawberry plants helps considerably to spread pollen. New strawberry varieties appear to have better self-fertility than many of the superseded older varieties.

Production Costs
Strawberries are an expensive crop to produce, because of the land preparation, plants and planting, harvesting, grading and packing costs incurred annually.

A cash flow budget which shows the timing of all expected costs and returns is very useful for the new grower in planning and managing finances.

A sensitivity analysis which shows how changes in significant factors such as yield and price affect net return, can indicate the level of risk associated with strawberry growing.

Pests and Diseases

Adequate control of pests and diseases is necessary in commercial strawberry production, to obtain high yields of good quality fruit, and to ensure the productive capacity of plants retained for longer than one season.

Soil pests such as black beetle, grassgrub, black vine weevil and strawberry root weevil can severely damage strawberry roots, affecting plant performance. Cultivation and fumigation before planting, controls these pests.

Damage by birds to the ripening fruits can be severe during the season. Rotation of available bird control options is more effective than relying on one option alone. Options include gas gun bird scarers, shotguns, floating cats eye balloons, flickering tape, tape recorded bird alarm sounds, poisoning and energetic small dogs and cats.

For pest and disease control, spray only when necessary. Unnecessary spraying leads to resistance build-up and potential chemical residue problems, as well as being costly. Spray decisions should be based on observations and monitoring of pest and disease status in the strawberry block. Consider plant health status at planting, previous and expected weather, current pest and disease levels, whether these levels require treatment or can be tolerated and previous chemical applications and persistence. These factors must be integrated in deciding whether to spray or not and which spray option to choose.

Early detection is essential to enable treatments to be applied before there is a build-up of pests or diseases. There are many restrictions to pesticide choice once strawberry flowering starts, so establishment of good control early in the season is important.

The following notes will assist in recognising the more important pests and diseases. If difficulty in diagnosing diseases or identifying pests is experienced, contact NZ Berryfruit Growers Federation or your horticultural consultant.

Insect pests	Symptoms	Treatment
Aphids	Small green or straw coloured soft-bodied insects on plant. Cause foliage distortion. Some are capable of transmitting virus diseases.	Spray on appearance and also after harvest.
Leaf Roller Caterpillar	Leaves webbed together and surface of leaves eaten. Small green caterpillar sheltering between leaves.	Spray immediately before flowering, and immediately after harvest.
Two-Spotted Mite	Leaves rusty brown or bronze in colour. Under-surface of foliage covered with fine webbing and reddish brown mites. May be isolated patches in crop.	Spray as soon as mite appears in early spring. Omite berry burning is applied soon before heavy rain.Establish the predatory mite Phytoseiulus persimilis (sold as Mite-E). Check spray safety to predator mites.
Cyclamen Mite	Crown damage. Distorted foliage and fruit	Chemical control early
Soil pests
Grassgrub Black Beetle Black Vine Weevil	Stunted, unthrifty growth of plants. Roots damaged by feeding grubs.	Soil cultivation prior to ridging. Fumigation
Fungal diseases
Botrytis	Greyish rot on ripening berries, usually following flowering infection. The fungus may also infect blossoms and cause death of blossom trusses. Rots in fruit usually occur after humid wet weather.	Control over flowering is critical. Aim for good spray coverage on open flowers. With a frequent spray interval to ensure all open flowers are protected. Under warm wet conditions, the interval between sprays may be just a few days. Under less intense disease pressure conditions, the interval may be 7 - 10 days. Restrict the use of curative fungicides to conditions when disease pressure is greatest. Check for Botrytis resistance to these materials BEFORE they are used. Use protectant materials otherwise.
Mycosphaerella Leaf Spot (frog’s eye)	Greyish/white spots with reddish margins on leaves.	Regular application of Botrytis fungicides will give control. Use broad spectrum protectants when disease pressure is low. Use specific/or curative materials under more intense disease pressure, or when a spray has been missed and there has been recent rainfall.
Anthracnose	Often worse on second-year crops. Sunken black spots on fruit.
Colletotrichum acutatum Black Fruit Rot	Watery brown spots develop on fruit, after dry weather, spots develop as sunken black lesions.	Botrytis fungicides will provide control.
Alternaria Leaf Spot	Brown spots with purplish/brown margins on leaves. Red gauntlet variety is very susceptible.	Broad spectrum materials such as mancozeb and captan are effective.
Rhizopus sp.	Whiskery white fungal growth on fruit. Fruit collapses and juices leak out hence known also as "Leak" may have black spore buds on roots.	Trouble may be reduced by cooling fruit after harvest to below 7 degrees C. Choose firm berries for storage
Root rots
Black Root Rot Red-core Root Rot Phytophthora fragariae	In spring, plants are unthrifty fail to grow and may die. Effects are worse in poorly drained soil. Caused by soil fungi attacking roots - black root rot (a fungus complex)or red-core root rot. The latter causes the core of infected roots to change from white to red. Pajaro is sensitive to these diseases.	Improved drainage will reduce incidence of these diseases. Do not replant in same area unless drainage and/or soil sterilisation are carried out. Trichoderma extracts?
Verticillium Wilt Verticillium dahliae	Stunting of plants, wilting of foliage and death of older leaves. Brown staining of vascular tissue in roots.	As above. Sterilise with chloropicrin and methyl bromide high rates.
Viral and viral-like diseases
Yellow Edge	Dwarfing and up-cupping of young leaves, shortening of petioles and yellowing of leaflets, especially at the edges. Plant appears flattened compared with healthy plant. Symptoms most obvious in spring and autumn.	Remove infected plants and destroy. Adequate control of strawberry aphid is necessary to reduce virus transmission from plant to plant.
Crinkle	Crinkling and yellow or red spotting of young leaves and dwarfing of plants. Symptoms more obvious in autumn in cooler temperatures with both diseases .	As above.
Phormium Yellow Leaf	Similar symptoms to yellow edge. Fruit production continues but is smaller. Red gauntlet appears susceptible.	Control of leaf hoppers is essential.

Application Techniques
Use the optimum material for the circumstances. Follow the directions given on the labels of spray materials and use the correct amount of material per hectare, at the right times.

Obtain thorough coverage of the plants. Dilute application is best, but semi-concentrate sprays are satisfactory if special care is taken to obtain coverage. Dilute rates are typically around 600litre/ha.

When using pesticides during or near the harvesting season, closely observe the withholding period between application and harvesting. The withholding period is on the pesticide label. For export product, check with your exporter before spraying.

Spray is usually applied by tractor-mounted boom rigs or by motorised knapsack. For motorised knapsack application, use quarter of the amount of water used per hectare in dilute (high volume) spraying but maintain the same quantity of spray material per hectare.

When using high concentrations (low volume), the application rate per ha must be checked. Spray only one row at a time and keep moving to avoid over-spraying.

Resistance Management
Trade names appearing in this publication have bean used only for easy identification of the chemical.