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CROP PROTECTION
Blackcurrants are one of the new super fruits

Nowhere is this more so true than in the
United Kingdom (UK). Blackcurrant has
always had prime place in British culture
and cuisine, traditionally treasured for un-
rivalled vitamin C (ascorbic acid) content
and more recently elevated to ‘super-fruit’
status. Ribes nigra is one the tiniest com-
mercially-grown fruit but packs one of the
biggest punches for health giving proper-
ties. Hugely rich in antioxidants and nota-
bly anthocyanins, which impart unrivalled
character and rich colour, blackcurrant is Undulating !elds with rows of well tended blackcurrant
bushes
now regarded as a ‘superfood’ by an in-
creasingly health conscious society.
The UK commercial crop, harvested from
2,600 ha and averaging at least 6 t/ha is
DR TERRY MABBETT almost entirely sent to the processing in-
Blackcurrants are not difficult crop to dustry that demands pest and disease free
grow providing you can find areas with fruit with ‘nil’ chemical pesticide residue.
the right conditions for commercial pro- These seemingly conflicting requirements
duction. Ribes nigra has one of the sharp- place blackcurrant growers in the most
est and exacting cold requirements of any difficult of situations, even by the general
bush fruit for solid winter dormancy, sound exacting standards of the highly sensitive
bud development and uniform bud burst horticultural crop market. But UK grow-
and flowering in spring. That said new foli- ers have risen to the challenge with high Growers establish grassy area around !elds to encourage
age and flowers are very susceptible to late yields of premium quality fruit using sound natural enemies
spring frost, which means blackcurrant has integrated crop and pest management sys-
developed as a niche crop constrained in tems. Chemical pesticides are only used
area and volume by uniquely demanding when absolutely necessary and delivered
environmental requirements. As such com- by the least environmentally impacting ap-
mercial production in Australia is confined plication technology.
to cool temperate areas of the country like Blackcurrants are famed for their high
Tasmania which has a small but important vitamin C content (three times that of cit-
crop centred on the Derwent Valley and rus) but the tiny purple fruit is very much
Huon Valley regions. a ‘dark horse’ when it comes to healthy
Blackcurrant has also found a natural eating. Blackcurrants are brimming with
home in New Zealand. Over 12,000 tonnes anthocyanins the health-promoting anti-
of the world’s best quality blackcurrants oxidants imparting the deep purple colour
are produced in the Nelson and Canterbury to fruit and mopping up potentially dan- Inspecting blackcurrant bushes for arthropod pests and
regions of South Island said to provide al- gerous ‘free radicals’ in the human body. natural enemies
most perfect conditions for the perfidious It is entirely fitting that the UK’s number when introduced in the 1970’s but is now
blackcurrant. In addition to satisfying win- one healthy-eating and drinking fruit is highly susceptible and superseded by
ter cold requirement, the areas’ long hot produced within environmentally sensitive more modern varieties like ‘Ben Hope’ and
summer days with cool nights give the op- growing systems offering protection for ‘Ben Gairn’ and regarded as ‘IPM’ (Integrat-
timum ‘degree-days’ and temperature dif- workers, consumers and wild plants and ed Pest Management) varieties. They have
ference which allow blackcurrant to build animals alike. transformed blackcurrant crop protection
up a high dry matter content with rich con- Pests%and%diseases%of%blackcur2 and allowed growers to meet the single
centrations of important health promoting rant biggest pest and disease challenge in the
nutrients and natural chemicals. Moreover, industry, the blackcurrant gall mite (big
the hot dry summers naturally suppress For a small rugged bush bearing tiny fruit bud mite) [Cecidophyopsis ribis] which
fungal diseases, many insect pests and Ribes nigra is troubled by more than its
most weeds, thereby minimising the ex- fair share of arthropod pests, diseases and lives in large and overgrown buds.
tent and level of chemical control required. weeds. Many are successfully managed us- Available chemical control options are
ing cultural control such as resistant vari-
The food processing industry where al- eties from the ‘Ben’ series of cultivars bred increasingly limited for this arachnid pest
most all blackcurrant crops go to make by the Scottish Crop Research Institute. which was always difficult to kill by spray-
juice, cordials, jams and other products Breeders combined frost hardy germplasm ing chemicals. The gall mite carries and
demands fruit which are essentially pesti- from Scandinavia within traditionally early transmits an even more damaging prob-
cide free, as well as containing high con- UK varieties to produce a range of high lem, the virus particle responsible for ‘Re-
centrations of all the natural health giving yielding varieties with increased fruit qual- version Disease’. Plants become sterile and
chemicals. Moreover it is this combination ity and the added bonus of frost resistance. fail to fruit. The disease may take hold and
of factors essential to renaissance of black- spread rapidly throughout the plantation
currant and its reinforced reputation as a ‘Ben Lomond’ (first in the series) was re- with all ‘reverted’ bushes carrying no crop.
health giving food. sistant to mildew (Spherotheca mors uvae) In addition to high yield and good flavour
4 Vol. 40 No. 7