soilswhere not enough care has been taken to protect the structure and keep the soil open. Youwill see excessive cracking on the soil surface. When trying to dig up a plant youwill notice that the soil is as hard as concrete and that there are very fewfeeder roots that are able to penetrate the compacted soil. The keywith heavy soils is to not overwork thembefore planting and to deeply incorporate generous amounts of sawdust.


PhytophthoraRoot


Rot Poor growth, slowdecline


and plant death occurs in general areas of the field. When a plant is dug, youwill notice that root systemis much smaller that it should be for the size of plant. A careful examinationwill show browning and death of fibrous roots. A lab test is needed for confirmation.


WeevilDamage Fields affected byweevils


will showan absence of new growthwhich is particularly evident inmid-summer through harvest. Affected areas usually showup as large circleswithin fields.When plants are dug-up the root system, at first glance,will seemto be unaffected. However,when roots are washed and carefully examined,weevil feeding damage on the roots can be easily seen – barkwill be stripped off large areas of main rootswhich results in girdling and direct death of roots and aswell as allowing entry of root rot pathogens.


Nematodes Look for spotty areas of


plant decline.Work by Tom Forge has confirmed that Paratrichodorus species (stubby root nematode) can contribute to plant decline. There are also species of Pratylenchus that can contribute to decline although this needs to be verified by more research. It is likely that


16 British Columbia Berry Grower • Summer 2013


nematodeswork in complexwith other root pathogens. A lab test is needed to confirm nematode presence.


Canker Damage is usually general throughout a


field, but unlikewith root problems, it is usually restricted to individual canes or branches, not thewhole plant. Late in the season, damagewill showas flagging – scattered dead brancheswith red leaves remaining attached.However, look closely at the youngerwood for signs of lesions around the buds. Canker can be caused by the fungal pathogens,Godronia (Fusicoccum) or Phomopsis. Phomopsis is a particular concern with the newvarieties,Draper and Liberty. Canker can also be caused by the bacterial pathogen, Pseudomonas. A lab test should be done to determine the causal organism.


ArmillariaRootRot First symptomof this disease is yellowing or reddening of all the leaves and general


decline of individual plants in the field. By the following year, the affected plants are usually dead. Scrape under the bark at the crown and look forwhitemycelium. Also look for black, root-like fungal growths (rhizomorphs)which may be found attached to the roots or under the bark. A lab test should be done to confirm. This disease has becomemore widespread in recent years.


Viruses Blueberry scorch virus and blueberry shock


virus are nowwidespread in BC and are familiar tomost growers. Look for individual plants that are severely blighted during the early tomid-bloomperiod. Plants next to affected plantswill usually look completely normal. If blighting is general through the field it is likely not viral but could be the result ofmany other causes including frost damage, bacterial blight ormummy berry. If virus is suspected be sure to submit samples to the lab for testing.


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