This chapter provides information on the pre-harvest, harvest and post-harvest practices, considered to be standard practices in Korea for the production of strawberries for export. The export capability of Korea is also outlined.
3.1Assumptions used in estimating unrestricted risk
Korea provided Australia with information on the standard commercial practices used in the production of strawberries in different regions of Korea. The information covers all commercially produced strawberry cultivars in Korea and is limited to production in greenhouses. This information was complemented with data from other sources and has been taken into consideration when estimating the unrestricted risks of pests that may be associated with the import of this commodity.
Officers from the department visited strawberry greenhouse production areas in Korea in March 2016, to verify the pest status and observe harvest and packing procedures for the export of strawberries. The department’s observations and additional information provided during the visit confirmed the production and processing procedures described in this chapter as standard commercial greenhouse production practices for strawberries for export.
In estimating the likelihood of pest introduction it was assumed that the pre-harvest, harvest and post-harvest production practices for strawberries, as described in this chapter, are implemented for all regions and for all strawberry cultivars within the scope of this analysis. Where a specific practice described in this chapter is not taken into account to estimate the unrestricted risk, it is clearly identified and explained in Chapter 4.
3.2Climate in production areas
The major strawberry growing regions in Korea are Gyeongsangnam-do (accounting for 34 per cent of total production) and Chungcheongnam-do (32 per cent), followed by Jeollanam-do (10 per cent) and Jeollabuk-do (nine per cent). The cities of Jinju and Miryang (in Gyeongsangnam-do), Nonsan (in Chungcheongnam-do), and the county Damyang (in Jeollanam-do ) account for up to 35 per cent of Korea’s total strawberry production (QIA 2015b). In Map 3 the main strawberry production areas are depicted.
Korea has a temperate climate. Winters in Korea are typically characterised by snow and low temperatures; spring is mild, dry and clear; summers are warm, humid with heavy rainfall and typhoons; and autumn is dry and clear, with some heavy rainfall through September (KMA 2011). Figure 2 summarises the annual mean maximum and minimum temperatures as well as precipitation in the cities of Jinju, Miryang and Nonsan and in the Damyang county.
Map Main strawberry production areas in Korea
Based on information provided by QIA (2015b)
Figure Monthly maximum and minimum temperatures and mean rainfall climate data in strawberry production areas of Korea
Monthly mean maximum (—♦—) and minimum (—■—) temperatures (°C) and mean monthly rainfall (millimetres) (—▲—) from climate data collected in 2015 (Climate-data.org 2015) in strawberry production areas of the county Damyang and the cities of Jinju, Miryang and Nonsan, in Korea
3.3Pre-harvest 3.3.1Cultivars
The main strawberry cultivars grown in Korea are Maehyang, Akihime, Seol-hyang, Seonhong, and Flamengo (QIA 2015b). Of these, Maehyang and Flamengo are the main export cultivars and it is expected that these are the main cultivars Korea intends to export to Australia. The characteristics of these two cultivars are described below.
Maehyang
The fruit of the Maehyang cultivar is long and oval in shape. The average weight is 15 grams. It has a comparatively high sugar content, with soluble solids at an average of 11.4 degrees Brix (QIA 2015b).
Flamengo
Whilst the shape and weight of the fruit is similar to the Maehyang cultivar, Flamengo fruit has a lower sugar content and therefore has a more sour taste, with soluble solids at an average of 9.4 degrees Brix (QIA 2015b).
3.3.2Cultivation practices Production of registered plantlets
Strawberry fruit in Korea is harvested from the progeny of ‘registered’ plantlets, which are supplied by the Yeongnong Johap Association for Registered Plantlets to nurseries. The production process for registered plantlets is detailed below.
First, plantlets are grown from tissue culture, and in their first year, they are tested for virus freedom as detailed later in this section. In the second year, healthy plantlets are each multiplied 30 times, and in the third year, their progeny are each multiplied a further 100 times. The resulting plants, known as foundation plantlets, are supplied to specialised nurseries, who multiply each plantlet a further 30 times in the fourth year. The resulting plantlets are the registered plants supplied to growers, who perform their own multiplication in the fifth year to produce certified plantlets, which are then used for strawberry fruit production. The entire process is summarised in Figure 3.
Figure Schedule for production of certified plantlets
The progression from plants grown in tissue culture to plants producing commercial strawberries takes five years in total. A rolling production system is in place; newly grown tissue cultured strawberry plants are produced every year, in order to ensure a fresh supply of registered plants for commercial production sites.
Multiplication process
The multiplication process occurs in greenhouses using a hydroponics system (Figures 4 and 5).
After a plant is planted, runners grow from the plant sideways, and in a suitable place, take root to form new self-sustaining plants (‘daughter’ plants). Once established, a daughter plant also grows runners, which go on to form more daughter plants. The hydroponics system used is built specifically to facilitate this, and the arrangement of plants for the multiplication process in greenhouses is shown in Figures 4 and 5.
Figure Hydroponics system set up to facilitate strawberry plant multiplication
Sites for daughter plants
Location of mother plants
Figure Layout for multiplication of registered plants
Daughter plants of registered plants (certified plantlets) grown in this system are then cut and used for strawberry fruit production. Multiplication of strawberry plants and production of strawberry fruit occur in separate greenhouses. Methods for strawberry fruit production are described below.
Greenhouse strawberry fruit production
In Korea, 97 per cent of strawberries are produced in greenhouses (QIA 2015b). An intrinsic benefit of greenhouse strawberry production is that temperature can be manipulated, which allows for control of strawberry growth. Plants may be grown either hydroponically or in soil.
Hydroponically grown strawberries
In greenhouses that use a hydroponic system, elevated bed systems are generally used. Beds are spaced between 90 and 120 centimetres apart, with two rows of plants in each bed, 20-25 centimetres apart, as shown in Figure 6. Spacing between plants within a row is 18-20 centimetres (Figure 6). Both single-layered bed systems and double-layered bed systems, where one bed is stacked on top of another (Figure 7), are used.
Soil grown strawberries
In soil grown strawberries, the soil is covered by plastic which prevents contact with the fruit. The soil is also fumigated, to manage soilborne pests. The beds are also between 90 and 120 centimetres apart.
Three cultivation methods are used, and these methods are outlined below.
Figure Arrangement of strawberry plants in greenhouse production
Figure Layout of stacked-bed production
Semi-forcing culture
After flower bud differentiation, induced by dropping temperatures in mid to late September, the plants enter a dormant period. They are then stimulated to grow in December, by increasing the temperature, and fruits are harvested from February through May (QIA 2015b).
Forcing culture
After flower bud differentiation, again induced by dropping temperatures in mid to late September, plants are grown immediately, by increasing the temperature, and the earlier warm temperatures lead to a much shorter, or complete lack of, a dormant period. This leads to an earlier fruit harvest, from December through March (QIA 2015b).
Super-forcing culture
Flower bud differentiation is brought about in early August, by exposing plants to artificial cold conditions, using either cold water treatment or by exposing plants to colder night temperatures. The plants are then planted and kept heated in greenhouses, as with forced culture plants. The earlier flower bud differentiation leads to a much earlier fruit harvest, from October to November (QIA 2015b).
Tissue culture plantlets are screened for viruses. The viruses tested for and the test procedures used are shown in Table 3.1 (QIA 2015b):
Table 3. Viruses targeted by virus tests in tissue culture plantlets and the method of detection used
Virus
|
Methods
|
Strawberry mottle virus
|
RT-PCR
|
Strawberry mild yellow edge virus
|
ELISA, RT-PCR
|
Arabic mosaic virus
|
ELISA, RT-PCR
|
Strawberry pallidosis associated virus
|
RT-PCR
|
Strawberry crinkle virus
|
RT-PCR
|
Strawberry vein banding virus
|
PCR
|
Strawberry necrotic spot virus
|
ELISA, RT-PCR
|
Strawberry latent ringspot virus
|
ELISA, RT-PCR
|
Normal and foundation plantlets in the second and third year of the process follow the pest management schedule shown in the Table 3.2.
Table 3. Pest management schedule for second and third year foundation plantlets
Time of year
|
Pest/pathogen
|
Chemical spray
|
Number of applications
|
Early-April
|
anthracnose, grey mould rot
|
-Sporgon (fungicide; active ingredient prochloraz; leaves + soil drench)
-Cabrio (fungicide; active ingredient Pyraclostrobin)
|
2
|
Late-April
|
anthracnose
|
-Antracol (fungicide; active ingredient Propineb)
|
1
|
Early-May
|
|
NaDCC (disinfectant; Sodium Dichloroisocyanurate) 1000×
|
|
Late-May
|
anthracnose, wilt disease, aphids, mites
|
-Sporgon (leaves + soil drench)
-Berry Mate (biopesticide; contains Bacillus velezensis)
-All Star (insecticide; active ingredient Abamectin)
-Setis (insecticide; active ingredient Flonicamid)
|
3
|
Early-June
|
anthracnose, aphids, mites
|
-Antracol
-Mospilan (insecticide; active ingredient Acetamiprid)
-Milbeknock (insecticide; active ingredient Milbemectin) + Zoom (insecticide; active ingredient Etoxazole)
|
3
|
Mid-June
|
aphids
|
Setis (Flonicamid)
|
1
|
Late-June
|
anthracnose, aphids, mites
|
-Ortiva (fungicide; active ingredient Azoxystrobin)
-Setis
-Milbeknock + Zoom
|
3
|
Early-July
|
leaf beetles, anthracnose
|
-Steward Gold (insecticide; active ingredient Indoxacarb)
-Sporgon
|
2
|
Mid-July
|
anthracnose, phytophthora blight, aphids
|
-Baybong (fungicide; biopesticide using Bacillus subtilis Y1336)
-Forum (fungicide; active ingredient Dimethomorph)
-Setis
|
2
|
Late-July
|
anthracnose, mites
|
-Cabrio
-All Star
-NaDCC
|
2
|
Early-August
|
anthracnose, moths
|
-Salimkkun (fungicide; active ingredient Metconazole)
-Avata (insecticide; active ingredient Indoxacarb)
|
2
|
Mid-August
|
anthracnose, moths
|
-Sporgon
-Steward Gold
|
2
|
Late-August
|
anthracnose, wilt disease
|
-Baybong
|
2
|
Early-September
|
anthracnose, moths
|
-Cabrio
-Affirm (insecticide; active ingredient Emamectin benzoate)
|
2
|
Mid-September
|
anthracnose
|
-Baybong
|
1
|
Late-September
|
anthracnose
|
-Ortiva
|
1
|
Early-October
|
anthracnose, mites
|
-Salimkkun
-All Star
|
2
|
Mid-October
|
mites, moth pests
|
-All Star
-Steward Gold
|
2
|
Late-October
|
anthracnose
|
-Ortiva
|
1
|
Early-November
|
anthracnose
|
-Salimkkun
|
1
|
Mid-November
|
anthracnose, grey mould rot
|
-Cabrio
-Gyunmori (fungicide; active ingredient Fenhexamid.iminoctadin tris[albesilate)]
|
2
|
Late-November
|
anthracnose, grey mould rot
|
-Sporgon
-Switch
|
2
|
Late-December
|
anthracnose, mites
|
-Sporgon
-Milbeknock + Zoom
|
|
In general, Korea uses an integrated pest management system for fruit production in greenhouses including the use of biological controls, such as the predatory mites Phytoseiulus persimilis and Neoseiulus californicus to control mites. Pest management programs include preventative sprays, and monitoring programs. The control scheme for pests of strawberries is shown in Table 3.3 (QIA 2015b):
Table 3. Pest management schedule
Time of major pest occurrences
|
Pest species
|
Control strategy
|
March-June
|
wilt disease, slug, Acusta despecta
|
Only disease-free plantlets are used and hiding places for gastropods such as weeds and surrounding crops are removed
|
June
|
anthracnose, Spodoptera litura, S. exigua
|
Only disease-free plantlets are used, damaged fruits are removed, adult insects prevented entry by using insect-proof nets and chemical sprays are used
|
Occurs throughout the year
|
Botrytis cinerea, Tetranychus urticae, T. kanzawai
|
Preventative chemical sprays applied, and target bottom leaves of host plants (the main incursion area) with chemical control.
|
Occurs throughout the year
|
Sphaerotheca aphanis, Aphis gossypii, A. forbesi, Chaetosiphon (Pentatrichopus) minor, Myzus persicae
|
Apply chemical controls at the early stage of incursions and prevent entry of imagoes (mature adults) into greenhouses
|
Occurs throughout the year
|
Mycosphaerella fragariae, Thrips palmi, Frankliniella occidentalis
|
Apply chemical controls at the early stage of incursions
|
Occurs throughout the year
|
viral diseases, Aphelenchoides fragariae, Pratylenchus sp.
|
Virus free plantlets used, and plants are only cultivated in disease-free greenhouses and any runners affected are removed early on
|
Sticky traps are used to monitor the presence of flying pests in greenhouses.
Imported seedlings and seeds used for Korea’s breeding programme
Imported seedlings are not a major part of strawberry production in Korea, with only about 0.2 per cent of runner daughter plants being imported. Out of imported daughter plants from 2013 to 2015, the majority were from China (46 per cent) followed by the Netherlands (29 per cent). The remaining were from France, United Kingdom, United States and Spain (QIA 2016).
Samples from each consignment of imported daughter plants are tested for the presence of bacteria and viruses shown in Table 3.4 (QIA 2016).
Table 3. Bacteria and Viruses targeted by tests for imported runner daughter plants
Pathogen type
|
Scientific name
|
Main test method
|
Bacterial
|
‘Candidatus Phlomobacter fragariae’
|
Electron microscope
|
Xanthomonas fragariae
|
ELISA
|
Rhodococcus fascians
|
PCR, ELISA
|
Arabis mosaic virus
|
PCR, ELISA
|
Viral
|
Fragaria chiloensis virus
|
Electron microscope
|
Raspberry ringspot virus
|
PCR, ELISA
|
Strawberry latent ringspot virus
|
PCR, ELISA
|
Tobacco necrosis virus
|
PCR, ELISA
|
Tobacco streak virus
|
PCR, ELISA
|
Tomato black ring virus
|
PCR, ELISA
|
Tomato bushy stunt virus
|
PCR, ELISA
|
Tomato ringspot virus
|
PCR, ELISA
|
The samples are also subject to microscope inspections to determine the presence of insects and other invertebrates. Plant tissues that show the symptoms of fungal infection are incubated to encourage fungal growth and any resulting cultures identified using a microscope. The presence of nematodes is tested using a modified Baermann Funnel Method (Baermann 1917).
When seeds are imported, they are inspected by Korean officials for any sign of pests and pathogens, before laboratory tests of samples from each consignment. Samples are inspected using a microscope to detect arthropods. Fungi are detected via incubation of any culture that results from blots of the seeds. Viruses are detected via PCR/ELISA. In the period from 2013 to 2015, strawberry seeds were imported 11 times, for a total of 3.65 kilograms.
3.4Harvesting and handling procedures
Strawberry fruit is harvested after 60 to 70 per cent colouration to allow for a longer transportation time as the fruits will continue to mature during the storage and transportation period (QIA 2015b).
Strawberries are picked individually by completely cutting off the peduncle, leaving only the calyx on the fruit, in order to prevent damage to other fruit during transport and when packaged in punnets.
3.5Post-harvest
Fruits are packed on the same day they are harvested. Fruits are transported to packing houses in plastic tubs, crates, or baskets (an example is shown in Figure 8), by trucks.
Figure Basket containing freshly harvested strawberries
3.5.1Packing house
All strawberries for export are packed in packing houses. Sorting occurs here, and deformed or injured fruits are removed at this step. Fruit is then graded according to quality and size standards set by the National Agricultural Products Quality Management Service, shown in Tables 3.5 and 3.6 (QIA 2015b).
Table 3. Strawberry quality standards
Factor
|
Super-premium
|
Premium
|
Good
|
Evenness
|
No more than 10 per cent difference in weight
|
No more than 20 per cent difference in weight
|
Those that fail to meet Super-premium and Premium grades
|
Weight
|
More than 17 grams
|
More than 12 grams
|
Not applied
|
Colour
|
Shows excellent colour for its variety
|
Shows good colour for its variety
|
Those that fail to meet Super-premium and Premium grades
|
Sugar content
|
At least 11 degrees Brix
|
At least nine degrees Brix
|
Not applied
|
Freshness
|
Must have glossy surface
|
Must have glossy surface
|
Not applied
|
Slight defects
|
Less than five per cent
|
Less than 10 per cent
|
Less than 20 per cent
|
Table 3. Strawberry size standards
Grade
|
2L
|
L
|
M
|
S
|
Weight of strawberry
|
More than 25 grams
|
Between 17 and 25 grams
|
Between 12 and 17 grams
|
Less than 12 grams
|
After this step, they are packed by hand into plastic punnets with a capacity of typically either 250 or 500 grams, and packed punnets are placed on a conveyor belt as shown in Figure 9. Packers wear gloves during operations.
Figure Strawberry sorting and packing process
The punnets are then packed into cardboard boxes which carry typically either eight 250 gram punnets or four 500 gram punnets, shown in Figures 10 and 11.
Figure Box with eight 250 gram punnets of strawberries
Figure Box with four 500 gram punnets of strawberries
If there is a surplus of supply, fruits may be kept in cold storage facilities at the packing house. Fruits are first kept at 3 °C for 24 hours, then at 7 °C for the remainder of the cold storage (QIA 2015b).
Export procedures
Prior to export, samples from each consignment are randomly inspected by personnel approved by Korea’s Animal and Plant Quarantine Agency (QIA) at the packing house. If the consignment is found to be free of pests and meets the requirements of the importing country and is found free of pests, it is issued a phytosanitary certificate.
3.5.2Transport
Consignments issued with a phytosanitary certificate are wrapped in plastic to prevent contamination post-inspection and are loaded into refrigerated trucks for transport to the export facility or kept in a separate storage facility at the packing house. The majority of strawberries for export will be transported by air freight, although some may be transported by sea freight. Air freight to Australia takes approximately 10 hours, and no temperature controls are in place since temperatures in the aircraft cargo hold are naturally low. Sea freight to Australia takes approximately 13 days and consignments are refrigerated.
Figure 12 summarises the operational steps from harvesting to export for Korean strawberries.
Figure Summary of operational steps for strawberries grown in Korea for export
3.6Export capability 3.6.1Production statistics
Most of Korea’s strawberry production is for domestic consumption. For example, in 2013 a total of 196,680 tonnes of strawberries were produced (QIA 2015b), of which only 2553 tonnes were exported (International Trade Centre 2015). The area dedicated to strawberry production is shown in Table 3.7.
Table 3. Area dedicated to strawberry production in Korea
Region
|
Production area (hectares)
|
Gyeongsangnam-do
|
2,383
|
Chungcheongnam-do
|
2,258
|
Jeollanam-do
|
707
|
Jeollabuk-do
|
631
|
Gyeongsangbuk-do
|
390
|
Others
|
521
|
Total
|
6890
| 3.6.2Export statistics
Korean strawberry exports have been increasing during the recent years from 2553 tonnes in 2013, to 2780 tonnes in 2014, and 3005 tonnes in 2015 (International Trade Centre 2015). A breakdown of Korea’s strawberry exports by destination country in 2015 is shown in Table 3.8.
Table 3. Amount of Korean strawberries exported to destination country in 2015
Nation
|
Volume (tonnes)
|
Hong Kong, China
|
1200
|
Singapore
|
982
|
Malaysia
|
377
|
Thailand
|
280
|
Mongolia
|
35
|
Indonesia
|
34
|
Japan
|
30
|
United States Minor Outlying Islands
|
19
|
Russian Federation
|
18
|
Taiwan
|
15
|
United Arab Emirates
|
4
|
Myanmar
|
4
|
Cambodia
|
4
|
Canada
|
2
|
Vietnam
|
1
|
Total
|
3005
| 3.6.3Export season
Strawberry harvest occurs from October (super-forcing culture) through to May (semi-forcing culture), depending on the method of cultivation in greenhouses. However, the bulk of harvesting for exports of strawberries occurs from January to March.
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