The Biology of Malus domestica Borkh. (Apple)
6. Potential Interaction of Malus domestica with Other Life Forms

M. domestica is susceptible to a number of plant diseases and insect pests. The most economically important disease of apples in North America is apple scab (Jones and Aldwinckle 1990) caused by the fungal pathogen, Venturia inaequalis (Cooke) Wint. Apple scab is reported as having widespread yearly occurrence with high pest pressure in all major apple production regions within Canada (AAFC 2011; BCMA 2012). Another significant disease reported as having widespread yearly occurrence with high pest pressure (in Ontario) is fireblight caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., which can, under the right conditions, wipe out entire orchards within a growing season (AAFC 2011). Other significant diseases reported as having localized yearly occurrence with high pest pressure or widespread sporadic occurrence with high pest pressure in Canada include black rot (in Ontario), caused by the fungal pathogen Botryosphaeria obtusa (Schwein.) Shoemaker, powdery mildew (in Ontario and British Columbia), caused by the fungal pathogen Podosphaera leucotricha (Ellis & Everh.) E.S. Salmon, replant disease complex (in Nova Scotia, Quebec and British Columbia), a combination of fungal and bacterial soilborne organisms, as well as nematodes, which affects newly planted apples in locations previously planted as apple orchards (AAFC 2011).

Apple maggot, Rhagoletis pomonella (Walsh) and codling moth, Cydia pomonella (L.) are serious insect pests for apple each with the potential to cause 100% yield loss and are both reported as having widespread yearly occurrence with high pest pressure for eastern Canadian apple producing regions (Nova Scotia, Quebec and Ontario) (AAFC 2011). Other significant insect pests reported as having widespread yearly occurrence across the major apple producing regions in Canada include: plum curculio, Conotrachelus nenuphar (Herbst) in Ontario and Quebec, oblique banded leaf roller, Choristoneura rosaceana (Harris) in British Columbia, Ontario and Quebec, three lined leaf roller, Pandemis limitata (Robinson), fruit tree leaf-roller, Archips argyrospila (Walker), European red mite, Panonychus ulmi (Koch) and two-spotted spider mite, Tetranychus urticae (C.L.Koch) in Quebec and mullein plant bug, Campylomma verbasci (Meyer-Dür) in British Columbia (AAFC 2011). Chemical, biological and cultural control methods are used to limit or eradicate disease and insect pests on apple (AAFC 2011).

Some vertebrates can also be considered pests to apple growers. Birds can become a nuisance by pecking holes in the fruit or wood (AAFC 2011). Various mammals, including rodents, rabbits and deer have been associated with various damage to tree tissues including girdling of bark and feeding on young branches, leaves and buds (AAFC 2011). Bears will also eat the fruit and can damage trees in doing so.

For a list of species associated with M. domestica, please refer to Table 4.

Table 4a: Examples of potential interactions of Malus domestica with Fungi during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Alternaria alternata (alternaria rot)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Botryosphaeria spp. (white rot, black rot)PathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Botrytis cinerea (dry eye rot; grey mold)PathogenPresent(AAFC pathologydatabase undated; Brown 2012; Jones and Aldwinckle 1990)
Colletotrichumgloeosporioides (bitter rot) (= Glomerella cingulata)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Gloeodes pomigena (sooty blotch and flyspeck)PathogenPresent(Farr andRossman undated)
Gymnosporangiumjuniperi-virginianae (cedar apple rust)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Mucor piriformis (mucor rot)PathogenPresent(Farr andRossman undated)
Mycorrhizal fungiSymbiont orbeneficial organismPresent(Dalpé 2003)
Nectria galligena (nectria canker) (= Neonectriagalligena)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Penicillium spp. (blue mold)PathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Pezicula malicorticis (anthracnose perennial canker; bull's eyerot)
(= Neofabraea malicorticis)
PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Phytophthora spp. (phytophthora crown collar and rootrot)PathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Podosphaeraleucotricha (powdery mildew)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Rhizopus stolonifer (rhizopus rot)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Venturiainaequalis (apple scab)PathogenPresent(Farr and Rossman undated; Jones and Aldwinckle 1990)
Table 4b: Examples of potential interactions of Malus domestica with Virus during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Apple chloroticleafspot virusPathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Apple mosaicvirusPathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Apple scar skin viroid (dapple apple viroid)PathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Tomato ringspotvirusPathogenPresent(AAFC pathology database undated)
Table 4c: Examples of potential interactions of Malus domestica with Bacteria during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Agrobacterium spp. (crown gall, hairy root) ( = Rhizobium radiobacter; R.rhizogenes)PathogenPresent(AAFC pathologydatabase undated; Jones and Aldwinckle 1990)
Erwinia amylovora (fire blight)PathogenPresent(CABI 2012; Jones and Aldwinckle 1990)
Pseudomonas syringae pv. papulans (blister spot)PathogenPresent(CABI 2012; Jones and Aldwinckle 1990)
Soil microbesSymbiont orbeneficial organismPresent 
Table 4d: Examples of potential interactions of Malus domestica with Insects and Mites during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Aculusschlechtendali (apple rust mite)ConsumerPresent(CABI 2012))
Ametastegia glabrata (dock sawfly)ConsumerPresent(Smith 1979)
Aphis pomi (apple aphid)ConsumerPresent(CABI 2012)
Apis mellifera (European honeybee)Symbiont orbeneficial organismPresent(Free 1966)
Archips spp. (fruittree leafroller, Europeanleafroller)ConsumerPresent(CABI 2012)
Atractotomus mali (apple brown bug)ConsumerPresent(AAFC 2011)
Campylomma verbasci (mullein bug)ConsumerPresent(Macnay and Creelman 1958; Thistlewood et al. 1990)
Choristoneura rosaceana (obliquebandedleafroller)ConsumerPresent(CABI 2012)
Conotrachelus nenuphar (plumcurculio)ConsumerPresent(AAFC 2011)
Cydia pomonella (codling moth)ConsumerPresent(CABI 2012)
Diaspidiotus spp. (San Jose scale, European fruit scale)ConsumerPresent(Ben-Dov and German 2003)
Dysaphis plantaginea (rosy appleaphid)ConsumerPresent(CABI 2012)
Epiphyaspostvittana (light brown apple moth)ConsumerAbsent(Brown et al. 2010)
Eriosoma lanigerum (woolly apple aphid)ConsumerPresent(CABI 2012)
Euschistus variolarius (onespottedstinkbug)ConsumerPresent(Jamison 2005)
Frankliniella occidentalis (western flowerthrips)ConsumerPresent(CABI 2012)
Grapholitamolesta (oriental fruit moth)ConsumerPresent(AAFC 2011)
Halyomorpha halys Stal (brown marmorated stink bug)ConsumerPresent(CABI 2012)
Hoplocampa testudinea Klug (Europeanapple sawfly)ConsumerPresent(AAFC 2011)
Hyphantria cunea (fall webworm)ConsumerPresent(Drooz 1985)
Lepidosaphes ulmi (oystershell scale)ConsumerPresent(Kosztarab 1996)
Lithophane georgii (green fruitworm)ConsumerPresent(Troubridge and Lafontaine 2002; Troubridge and Lafontaine 2003)
Lygus lineolaris (tarnished plant bug)ConsumerPresent(AAFC 2011)
Operophterabruceata (Bruce spanworm)ConsumerPresent(Drooz 1985)
Operophtera brumata (winter moth)ConsumerPresent(AAFC 2011)
Orthosia hibisci (speckled green fruitworm)ConsumerPresent(AAFC 2011)
Pandemis limitata (threelined leafroller)ConsumerPresent(BCMA 2010)
Phenacoccus aceris (apple mealybug)ConsumerPresent(Macnay and Creelman 1958)
Phyllonorycter blancardella (tentiformleafminer)ConsumerPresent(CABI 2012)
Rhagoletis pomonella (applemaggot)ConsumerPresent(AAFC 2011)
Rhopalosiphum fitchii (apple grainaphid)ConsumerPresent(Macnay and Creelman 1958)
Spilonota ocellana (eyespotted budmoth)ConsumerPresent(CABI 2012)
Tetranychus spp. (McDaniel spider mite, twospottedspider mite)ConsumerPresent(CABI2012; Macnay andCreelman 1958))
Typhlocyba pomaria (white apple leafhopper)ConsumerPresent(Macnay and Creelman 1958)
Table 4e: Examples of potential interactions of Malus domestica with Animals during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Animal browsersConsumerPresent(AAFC 2011)
BirdsConsumerPresent(AAFC 2011)
EarthwormsSymbiont orbeneficial organismPresentExpert knowledge
NematodesConsumer;symbiont or beneficial organismPresent(Jackson 2003)
Table 4f: Examples of potential interactions of Malus domestica with Plants during its life cycle in a natural environment.
Other life forms Interaction with M. domestica (pathogen; symbiont or beneficial organism; consumer; gene transfer) Presence in Canada Reference(s)
Other M. domesticaGene transferPresent(Kron et al. 2001)
Native crabapple(M. fusca and M. coronaria) and other introduced crabapplespecies and hybridsGene transferPresent(Kron and Husband 2007)
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