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The Biology of Cannabis sativa L. (Cannabis, hemp, marijuana)

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Biology document BIO2020-02: A companion document to the Directive 94-08 (Dir94-08), Assessment Criteria for Determining Environmental Safety of Plant with Novel Traits.

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1 General administrative information

1.1 Background

The Canadian Food Inspection Agency's Plant and Biotechnology Risk Assessment (PBRA) Unit is responsible for assessing the potential risk to the environment from the release of plants with novel traits (PNTs) into the Canadian environment. The PBRA Unit is also responsible for assessing the pest potential of plants imports and plant species new to Canada.

Risk assessments conducted by the PBRA Unit require biological information about the plant species being assessed. Therefore, these assessments can be done in conjunction with species-specific biology documents that provide the necessary biological information. When a PNT is assessed, these biology documents serve as companion documents to Dir94-08: Assessment Criteria for Determining Environmental Safety of Plants with Novel Traits.

1.2 Scope

This document is intended to provide background information on the biology of Canabis sativa L.

Unless specified otherwise, information provided hereinafter concerns the whole genus Cannabis.

Such information will be used during risk assessments conducted by the PBRA unit. Specifically, it may be used to characterize the potential risk from the release of the plant into the Canadian environment with regard to

2 Identity

2.1 Name(s)

Cannabis sativa L.Footnote 23

2.2 Family

CannabaceaeFootnote 23.

2.3 Synonym(s)

Synonyms for C. sativaFootnote 23 include:

2.4 Common names

Cannabis sativa is commonly known as cannabis, hemp, Indian hemp, marihuana, and marijuanaFootnote 23 Footnote 199.

2.5 Taxonomy and genetics

C. sativa belongs to the Cannabaceae familyFootnote 23. The Cannabaceae family includes 12 genera and about 102 speciesFootnote 24, including other economically important species such

C. sativa is diploid (2n = 20)Footnote 193.

Taxonomic positionFootnote 23 Footnote 43

Taxon Scientific name and common name
Kingdom Plantae (plants)
Subkingdom Tracheobionta (vascular plants)
Superdivision Spermatophyta (seed plants)
Division Magnoliophyta (flowering plants)
Class Equisetopsida
Subclass Magnoliidae
Order Rosales
Family Cannabaceae
Genus Cannabis
Species Cannabis sativa L.

The taxonomic classification of C. sativa has long been a subject of differing opinions and botanical debateFootnote 53 Footnote 136 Footnote 197 Footnote 198. The majority of botanical treatments describe it as highly diverse but monospecific (that is, one species with intraspecific forms)Footnote 135 Footnote 197 Footnote 199 Footnote 200 Footnote 202. All forms of C. sativa are naturally diploid and sexually compatibleFootnote 202. The high geographical, morphological, and chemical variation in C. sativa results from extensive selection and domestication towards differing utilitarian needs (fibre, drug, oilseed, etc.). This document considers C. sativa to be monospecific. However, some taxonomists treat Cannabis as polyspecific (that is, multiple species), sometimes with infraspecific formsFootnote 52 Footnote 78 Footnote 111 Footnote 112 Footnote 189. Recent research demonstrates that marijuana and hemp are significantly differentiated at a genome-wide level, suggesting that the distinction between these two populations is not limited to genes underlying production of the cannabinoid Δ9-tetrahydrocannabinol (THC)Footnote 188 Footnote 223.

Small and Cronquist (1976)Footnote 202 identified a threshold for differentiating between industrial hemp (both fibre-type and oilseed-type) and marijuana (drug-type) forms of C. sativa based on the relative dry weight concentration of THC in the plant's female inflorescences. Plants accumulating levels above 0.3% Δ9-THC are considered marijuana/drug-type C. sativa and plants containing levels below this threshold are considered hemp in North America. In the European Union, the threshold is 0.2%Footnote 12. Modern assessments of cannabinoid content to delineate the differences between industrial hemp and drug-type varieties combine the total content of THC and Δ9-tetrahydrocannabinolic acid (THCA), given that THCA spontaneously decarboxylates to form THC (see section 4.2.1 Cannabinoids). Small and Cronquist (1976)Footnote 202 have proposed a model for classifying the subspecies and varieties of C. sativa based on the characteristics of the achenes (fruits, commonly called seeds) and tetrahydrocannabinol (THC)/ cannabidiol (CBD) ratios:

1. Cannabis sativa subsp. sativa

Plants of limited intoxicant ability, Δ9-THC comprising less than 0.3% (dry weight) of upper third of flowering plants and usually less than half of cannabinoids of resin. Plants cultivated for fibre or oilseed or growing wild in regions where such cultivation has occurred.

Cannabis sativa subsp. sativa var. sativa

Mature fruits relatively large, seldom less than 3.8 millimeters (mm) long, tending to be persistent, without a basal constricted zone, not mottled or marbled, the perianth poorly adherent to the pericarp and frequently more or less sloughed off.

Cannabis sativa subsp. sativa var. spontanea Vavilov

Mature fruits relatively small, commonly less than 3.8 mm long, readily disarticulating from the pedicel, with a more or less definite, short, constricted zone toward the base, tending to be mottled or marbled in appearance because of irregular pigmented areas of the largely persistent and adnate perianth.

2. Cannabis sativa subsp. indica (Lam.) E. Small & Cronquist

Plants of considerable intoxicant ability, Δ9-THC comprising more than 0.3% (dry weight) of upper third of flowering plants and frequently more than half of cannabinoids of resin. Plants cultivated for intoxicant properties or growing wild in regions where such cultivation has occurred.

Cannabis sativa subsp. indica var. indica (Lam.) Wehmer

Mature fruits relatively large, seldom less than 3.8 mm long, tending to be persistent, without a basal constricted zone, not mottled or marbled, the perianth poorly adherent to the pericarp and frequently more or less sloughed off.

Cannabis sativa subsp. indica var. kafiristanica (Vavilov) E. Small & Cronquist

Mature fruits relatively small, usually less than 3.8mm long, readily disarticulating from the pedicel, with a more or less definite, short, constricted zone towards the base, tending to be mottled or marbled in appearance because of irregular pigmented areas of the largely persistent and adnate perianth.

The terms "sativa" and "indica" have been applied inconsistently and haphazardly. 2 varieties of drug-type C. sativa were referred to by their common names beginning in the 1980s:

Extensive hybridization of these varieties has largely eliminated any distinction between modern strains. However, strains are often labelled as "sativa" or "indica" based on the THC:CBD ratios of the plants; this does not reflect their taxonomic classification or genetic background. Furthermore, "sativa" has been used to refer to either plants with a high THC:CBD ratio or to low-THC hemp forms ("C. sativa"). "Indica" may refer to plants with high THC and CBD or to high-THC, low-CBD forms ("C. indica")Footnote 139.

2.6 General description

C. sativa is an herbaceous dioecious annual species displaying considerable variability in phenotypic characteristics; monoecious plants can occur or be developed by breedingeffortsFootnote 26 Footnote 81. Cultivars may show differing shoot architectures dependent on selection towards various utilitarian needs, while plants escaped from cultivation may show degrees of reversion to non-domesticated characteristics. For instance, hemp cultivars selected for fibre production are generally tall, with reduced branching and less woody stem tissue to maximize bast fibre production, whereas drug-type C. sativa varieties are generally highly branched to maximize the production of female flowersFootnote 205.

In general, plants are erect with simple to well-branched stems and highly variable in height depending on genetic constitution and environmental factors, typically ranging from 0.2 to 5 meters (m) (though heights of over 12 m in cultivation are reported)Footnote 205. Root morphology is adaptable to soil characteristics and water availability. Generally, the root is a laterally branched taproot that may penetrate up to 2.5 m deep to access sub-surface moisture. The stems are erect, furrowed, and usually branched, with a woody interior, and may be hollow in the internodesFootnote 205.

The larger leaves (sometimes called "fan leaves") are compound with an odd number (3 to 13) of leaflets that radiate from a single point at the distal end of each petiole. The leaflets are lanceolate or occasionally ovoid or oblanceolate, with serrate (rarely doubly serrate) margins. The petioles are 2 to 7 centimeters (cm) in length, arranged in opposite pairs on the lower stem and alternately near the stem apex. C. sativa can have anthocyanin-streaked foliage and stems; plants can become increasingly purple following frostFootnote 205.

During the vegetative growth stage, male and female plants are not reliably distinguishable based on appearance. Sexually mature male and female plants are readily distinguishable; male plants typically appear less robust and taller, with more slender stems, smaller leaves, and less branching of the vegetative shoot than female plantsFootnote 199.

Flowers are imperfect (either staminate or pistillate), small, numerous, and congested in the inflorescences, with male and female flowers occurring almost invariably on different plants in the wild, but with both kinds on some modern hemp cultivarsFootnote 169 Footnote 205. Staminate flowers are produced in monoecious plants before the pistillate flowers, with occasional hermaphroditic flowersFootnote 205. For more information on floral and seed morphology, see section 4.1.

While selected traits in domesticated varieties become genetically fixed through continued selection, environmental conditions may impact morphology. For instance, planting density can influence branching, with high-density plantings resulting in taller, slender-stemmed plants with reduced branching ideally suited for maximizing fibre production in hemp. Conversely, low-density plantings result in less competition and more branching to maximize foliage and flowers containing cannabinoids for drug-type C. sativa productionFootnote 199. Nutrient deficiency (especially nitrogen), low-light conditions, and drought can contribute to poor growth and stunted plants.

3 Geographical distribution

3.1 Origin and history of introduction

C. sativa is one of the oldest domesticated species, being cultivated since antiquity for end uses including fibre, hempseed, and for its psychotropic phytochemicals. There is uncertainty where C. sativa was domesticated and whether there are multiple centres of origin. The extensive use and spread by humans of C. sativa in the last 6,000 years have made it difficult to distinguish between wild, native populations and escapes from cultivationFootnote 25 Footnote 52. Many areas have been proposed as the centre of origin for C. sativa, including countries in Asia and EuropeFootnote 64 Footnote 138 Footnote 191 Footnote 226.

It has been postulated that hemp plants and drug-type plants were historically selected in different geographic centres. In Europe and northern Asia, C. sativa was cultivated almost exclusively for its fibres, while in southern Asia, it was used as a drug for recreational, cultural, and spiritual purposesFootnote 199. Thus, there was a north-south separation of C. sativa forms grown mostly for fibre and those grown mostly for drug uses. Northern fibre-type germplasms are adapted to the relatively short growing seasons of such latitudes. Hemp was sequentially introduced to western Asia, Egypt, and Europe between approximately 1,000 and 2,000 Before the Common Era (BCE)Footnote 200. Drug-type C. sativa germplasms are conversely adapted to southern latitudes experiencing little seasonal changes in photoperiod. Certain forms of drug-type C. sativa flower comparatively earlier, which has been hypothesized to be an adaptation to a shorter growing season imposed by seasonal drought conditions occurring in southwestern AsiaFootnote 199. The varieties from which present C. sativa strains originated have become rare because of widespread crossbreedingFootnote 139. For a detailed discussion of these historically selected groups of C. sativa, see Chapter 18 of Ernest Small's monograph on CannabisFootnote 199.

3.2 Native range

C. sativa is widely believed to have originated in temperate, central or western Asia and perhaps eastern AsiaFootnote 125 Footnote 138 Footnote 199.

3.3 Introduced range

C. sativa is a globally cultivated and introduced species occurring in North and South America, Europe, Africa, Asia, and AustralasiaFootnote 14 Footnote 21. C. sativa is widely present in North America and as of July 2019 was listed as introduced in all Canadian provinces except Newfoundland and Prince Edward IslandFootnote 43, though other sources have reported it in all provincesFootnote 61 Footnote 205. Most wild populations occur where hemp was historically cultivated, and in Canada, it is well established along the St. Lawrence River and lower Great Lakes regions of Ontario and QuebecFootnote 61 Footnote 205. In the United States, the naturalized range includes the Midwest and Northeast where hemp was historically cultivatedFootnote 13 Footnote 205.

Wild-growing hemp populations are frequent in Eurasia, particularly in southeast and central Asia and many European countries. To a lesser extent, wild-growing populations are found in South America and AustraliaFootnote 199. C. sativa is generally said to be adapted to a northern-temperate climate and seldom escapes cultivation in tropical areasFootnote 199.

3.4 Potential range in North America

The current known distribution of outdoor production of C. sativa across the globe suggests that its potential global range comprises zone 4 through zone 13 of the global plant hardiness zone mapFootnote 128. C. sativa growth and development in zones 10 and 11 is conditional on adequate precipitations in those areas. Naturalized C. sativa is rare south of 37° degrees north latitude, uncommon in the western United States, and very rare in MexicoFootnote 205. Domesticated C. sativa tolerates heat well but not cold, with optimal growing temperature between 14 degrees Celsius (°C) and 27°CFootnote 205. C. sativa may tolerate light frosts (-6°C) but is killed by heavy frosts or extended periods of near-freezing temperatureFootnote 205. Canada's short growing season may prevent seed maturation and limit the establishment of C. sativa. However, C. sativa may adapt to the shorter photoperiods and cooler temperatures. With the recent increase of legal cultivation of both hemp and drug-type C. sativa in Canada, at least some expansion of the range of plants growing without human care is inevitable (E. Small, personal communication, 2019).

3.5 Habitat

Cultivated drug-type C. sativa and hemp can be grown in outdoor fields, greenhouses, or indoor environments. Wild C. sativa is a nitrophile and grows vigorously in moist but well-drained, well-manured, open and sunny locations situated close to water. C. sativa requires a moist climate or abundant soil moisture for growth, and is highly sensitive to light (that is, for cannabinoid production)Footnote 72. Plants grow optimally in fertile, sandy-loam soils but will also grow in very sandy soils. In nutrient-deficient soils, especially those low in nitrogen, plants are stunted. Heavy, water-holding clay soils are unsuitable due to the intolerance of C. sativa to waterlogged conditionsFootnote 199. In Eurasia, wild C. sativa has been observed on the edges of cultivated fields, in ravines, hollows, sunny patches in woodland valleys, and on rubbish heaps near settlements or habitationFootnote 72 Footnote 205. In North America, wild C. sativa tends to grow in well-manured, moist farmyards, and in open habitats, waste places (roadsides, railways, vacant lots), occasionally in fallow fields, and open woodsFootnote 13. C. sativa is generally poorly adapted for penetrating established stands of perennial vegetation; conversely, it is well adapted to sites with recent soil disturbancesFootnote 199.

4 Biology

4.1 Reproductive biology

C. sativa reproduces exclusively by seed and does not naturally reproduce vegetativelyFootnote 205. The life cycle of C. sativa usually takes 4 to 6 months to completeFootnote 54; this may be shortened to about 2 months in northern adapted C. sativa or under specific environmental conditionsFootnote 129. C. sativa is a wind-pollinated species; wind can carry pollen long distances. Pollen production lasts approximately 3 weeks, but this varies greatly based on the genotype and sowing dateFootnote 27 Footnote 201.

Wild plants, traditional hemp cultivars and landraces, and drug biotypes are dioecious. Dioecious plants are mostly or entirely cross-pollinated; male C. sativa plants tend to flower 1 to 3 weeks before female plants, therefore favouring outcrossingFootnote 197. Many recent fibre and oilseed cultivars are monoecious (containing both male and female reproductive organs). Male flowers on monoecious plants typically appear on the distal part of the plant and are produced before female flowers, which are located on the basal parts of the plantFootnote 197 Monoecious plants can self-pollinate to some degree (20 to 25%)Footnote 199.

Sex development in C. sativa is modifiable by environmental factors and hormonal applicationsFootnote 110. Once flowers have differentiated, they will not change, but subsequent flowers on the same plant may develop into the opposite sex. For example, application of auxins or ethylene feminizes C. sativa plantsFootnote 108 Footnote 147 whereas gibberellins have been reported to masculinize themFootnote 29 Footnote 48. Additionally, when C. sativa plants were subjected to ultraviolet light and modified day-length duration the proportion of female and male plants adjusted; female plants increased after seed exposure to ultraviolet light or carbon monoxide and decreased in response to shorter day-length and higher nitrogen levels in the root zoneFootnote 104 Footnote 109.

The initiation of some floral primordia may occur after the main period of vegetative growth, but the production of most flowers is induced in most strains by consecutive days with short photoperiods. For most drug-type C. sativa plants, flowering is triggered when the minimum uninterrupted period of darkness is increased to 10 to 12 hours for some weeksFootnote 54 Footnote 197. Some biotypes (a group of organisms with the same genetic constitution), especially those from the northernmost and southernmost extremes, are photoperiod insensitive ("autoflowering"). Many biotypes that normally require short-day photoperiodic induction to flower will eventually flower under continuous lightFootnote 37 Footnote 110.

Female flowers are developed in simple inflorescences known as racemes and are present in dense clusters (compound racemes). Female flowers possess a "perigonal bract" that arises under each flower and grows to envelop the fruit. These bracts have the highest density of glandular trichomes – tiny secretory resin glands that produce and accumulate cannabinoids (that is, tetrahydrocanabolic acid [THCA], cannabidiolic acid [CBDA]), and terpenes (that is, monoterpenes and sesquiterpenes)Footnote 126. The number of glandular trichomes varies amongst individual plants. On female flowers, 3 types of glandular trichomes have been identified based upon their morphology: bulbous, sessile, and stalkedFootnote 100. Bulbous trichomes are the smallest and produce limited specialized metabolites. The 2 main glandular trichome types, sessile and stalked, are similar architecturally; both have a globose head and sit above the epidermal surface by a multicellular stalkFootnote 101 Footnote 126. The main differences between the 2 types are that stalked trichomes have higher THC concentrations, are larger, and are more abundant. Other young aerial tissues also contain a relatively high concentration of these epidermal secretory glands (albeit substantially less than the perigonal bracts), suggesting a protective functionFootnote 199.

Individual male flowers are short-stalked, drooping, and arranged in larger, loose, determinate inflorescencesFootnote 171. The flowers appear in pairs, usually on special floral branches but they can also be found at the bases of some vegetative branches. Male flowers are greenish or whitish with five petals and prominent stamens, are small in size, extend on short pedicelsFootnote 13 Footnote 199 and bear glandular trichomes on their anthers and filamentsFootnote 203. Male flowers produce small, light, and dry pollen grains in large quantitiesFootnote 79 Footnote 169 and are highly-attractive to pollen-collecting bees and flies. Male plants shed pollen and die several weeks before seed ripening on female plants of the same populationFootnote 54 Footnote 169, while female plants continue to grow as seeds develop. The single achene (fruit, commonly called a seed) in each female flower ripens in 3 to 8 weeksFootnote 54.

The seeds of C. sativa are ovoid, small (generally 2 to 5 mm long), and protected by the perianth. They are generally brown or grey in cultivated forms, whereas wild C. sativa seeds are covered by a darkly coloured and mottled perianthFootnote 199. The seeds of wild C. sativa plants are smaller and lighter than those of domesticated plants, usually less than 3.8 mm in length. Some cultivated domestic plants have 15 seeds in a gram, whereas some wild plants have over 1000 seeds in a gramFootnote 197. Wild seeds have an elongated and narrowing base and a well-developed abscission zone, which promotes easy seed shattering upon ripening (seeds readily disarticulate from the pedicel)Footnote 149 Footnote 231. Wild C. sativa seeds mature sequentially on each plant, so that the seeds are dispersed at different times and do not interfere with each other's ability to fall off the plantFootnote 149 Footnote 199. Seeds of wild C. sativa exhibit long-term dormancy and irregular germination, and usually exhibit lower germination than domesticated seeds.

4.2 Cannabis sativa biochemistry

The C. sativa plant synthesizes over 100 terpenophenolic secondary metabolites known as cannabinoidsFootnote 65 Footnote 76 Footnote 77 Footnote 97 Footnote 167. C. sativa synthesizes about 140 terpenoids (hydrocarbon terpenes and their oxygenated derivatives); however, none is unique to CannabisFootnote 41 Footnote 140 Footnote 182 Footnote 187. C. sativa is valued for the psychoactive and potential pharmacological properties of cannabinoids, whereas certain terpene (monoterpene and sesquiterpene) components are responsible for much of the aroma and flavour. Cannabinoids and terpenes are found in resin synthesized in secretory cells inside the glandular trichome heads pyrophosphateFootnote 116 Footnote 156. Cannabinoid and terpenoid biosynthetic pathways partially overlap in their initial step with the synthesis of the common precursor geranyl pyrophosphateFootnote 36 Footnote 185.

4.2.1 Cannabinoids

In living plants of C. sativa and freshly harvested tissues, the cannabinoids exist predominantly in the form of carboxylic acids; for example, THC occurs as tetrahydrocannabinolic acid (THCA), and CBD occurs as cannabidiolic acid (CBDA). Non-enzymatic decarboxylation of the cannabinoids into their neutral counterparts occurs relatively slowly with aging, and catalyzed by heat, light, or alkaline conditions. cannabinoids are formed through decarboxylation of their respective 2-carboxylic acids (2-COOH), a process that is catalyzed by heat, light, or alkaline conditionsFootnote 82 Footnote 216.

Cannabinoids have been subdivided into 10 subclasses CannabisFootnote 41 Footnote 75 Footnote 179 Footnote 218 (for molecular structures see Brenneisen, 2007Footnote 41, p. 17-41):

  1. Cannabigerol (CBG) type: CBG was the first cannabinoid identifiedFootnote 85. Other cannabinoids of this group are the CBG precursor cannabigerolic acid (CBGA), the propyl side-chain analogs and a monomethyl ether derivative. CBG is the first cannabinoid synthesized in the plant's cannabinoid synthesis pathway. It is the precursor of Δ9-tetrahydrocannabinolic, cannabidiolic, and cannabichromenic acids, and normally appears in the plant at relatively low concentration because the majority is further metabolized to end products, except in specifically bred strainsFootnote 66 Footnote 213.
  2. Cannabichromene (CBC) type: To date, 5 CBC-type cannabinoids, mainly present as C5-analogs, have been identified. Its production is normally maximal at the earlier growth stages of the plantFootnote 67.
  3. Cannabidiol (CBD) type: 7 CBD-type cannabinoids with C1 to C5 side chains have been characterized. CBD and its corresponding acid, CBDA, are the predominant cannabinoids in industrial hemp. It should be noted that genes encoding the CBD and THC synthases are co-dominant such that one is expressed at the expense of the otherFootnote 223.
  4. Δ9-Tetrahydrocannabinol (THC) type: 9 THC-type cannabinoids with C1 to C5 side chains have been identified. THC acid A (THCA-A) and B (THCA-B) are the 2 biogenic precursors of THC, although THCA-B is present to a much lesser extent. THC is the main psychotropic principle; the acids are not psychoactive. Female C. sativa plants have up to 20 times the concentration of THC in comparison to male plants. When females are grown in the absence of males, higher concentrations of THC are produced in their reproductive partsFootnote 203.
  5. Δ8-THC type: Δ8-THC and its acid counterpart, Δ8-THCA, are considered as THC and THCA artifacts, respectively. The activity of Δ8-THC is estimated 20% lower than THC'sFootnote 41.
  6. Cannabicyclol (CBL) type: This group comprises CBL, its acid precursor, and the C3 side-chain analog. These three cannabinoids are characterized by a five-atom ring and C1-bridge instead of the typical ring A. CBL is known to be a heat-generated artifact from CBCFootnote 41.
  7. Cannabielsoin (CBE) type: This group includes CBE and its acid precursors A and B, and they are artifacts formed from CBDFootnote 41.
  8. Cannabinol (CBN) and Cannabinodiol (CBND) types: This subclass comprises 6 CBN- and 2 CBND-type cannabinoids which are oxidation artifacts of THC and CBD, respectivelyFootnote 41.
  9. Cannabitriol (CBT) type: 9 CBT-type cannabinoids have been described and they are characterized by additional hydroxy group substitutionFootnote 41.
  10. Miscellaneous types: 11 cannabinoids with unusual structures such as furano ring (dehydrocannabifuran, cannabifuran), carbonyl function (cannabichromanon, 10-oxo-δ-6a-tetrahydrocannabinol), or tetrahydroxy substitution (cannabiripsol), have been identifiedFootnote 41.

Pharmaceutical properties and medicinal uses of cannabinoids are described in the scientific literature, for details see RussoFootnote 184 Footnote 185, PertweeFootnote 163, Whiting et al.Footnote 229, CCSAFootnote 7, Grotenhermen and Müller-VahlFootnote 96, Russo and MarcuFootnote 187, Urits et al.Footnote 222, among others.

4.2.2 Terpenoids

The characteristic odor of Cannabis plants can be attributed to a mixture of volatile compounds, including monoterpenes, sesquiterpenes, and other terpenoid-like compoundsFootnote 199. C. sativa terpenoids include, but are not limited to, α-pinene, limonene, β-myrcene, D-linalool, caryophyllene oxide and β-caryophyllene which is typically the most common of all terpenoids in C. sativaFootnote 140 and predominates quantitatively in C. sativa extractsFootnote 99. The proportion of monoterpenes (such as limonene, myrcene, pinene) in the plant is typically greater than that of sesquiterpenesFootnote 113, but monoterpenes volatilize readily during curing, drying, and storage resulting in a higher relative proportion of sesquiterpenes such as caryophylleneFootnote 180 Footnote 218. The particular mixture of mono- and sesquiterpenoids determines the viscosity of the resinous content of the trichomesFootnote 185. Trichome exudate can trap insectsFootnote 137 and the phenomenon is illustrated by Small (2017, p. 219)Footnote 200.

Pharmaceutical properties and medicinal uses of terpenoids are described in the scientific literature, for further details see RussoFootnote 185 Footnote 186 and Russo and MarcuFootnote 187.

4.2.3 Biosynthesis of terpenoids and cannabinoids

Terpene synthesis in plants involves 2 compartmentalized pathways: the plastidial methylerythritol phosphate (MEP) pathway, and the cytosolic mevalonate (MEV) pathwayFootnote 36. Both biosynthetic pathways lead to the production of substrates that ultimately serve as precursors for not only terpene synthesis but also cannabinoid synthesis (for further details, see RussoFootnote 185; Andre et al.Footnote 28; Booth et al.Footnote 36).

The biosynthetic pathway producing the major cannabinoids with pentyl side chains (CBCA, CBDA, CBGA, and THCA) is now fully elucidated, with CBCA and THCA being described lately. For more details on cannabinoid biosynthesis see Taura et al.Footnote 214 Footnote 215, Sirikantaramas et al.Footnote 192, Flores-Sanchez and VerpoorteFootnote 83, RussoFootnote 185, van Bakel et al.Footnote 223, Gagne et al.Footnote 84, Stout et al.Footnote 208, Andre et al.Footnote 28, and Laverty et al.Footnote 122. Most of the minor cannabinoids, including those with propyl side chains, likely are produced by fatty acids with varying chain-lengths being fed into the "core" cannabinoid pathway.

Several factors influence the amount and quality of the cannabinoids produced in any given C. sativa plant including, the genotype and plant organs, the growth stage, environmental factors, stressors, and polyploidization.

  1. Genotype and plant organs

    The concentration of cannabinoids and terpenoids varies between plant tissuesFootnote 200 and among cultivars or biotypesFootnote 35 Footnote 168 depending on the genetic background of the plant. In general, in any given C. sativa plant, the cannabinoid concentration increases in the following order: roots, large stems, smaller stems, older and larger leaves, younger and smaller leaves, and perigonal bracts covering the female flowersFootnote 200. The density of resin-containing glandular trichomes, the size of the trichome heads, and biosynthetic efficacy considerations determine the amount of THC, cannabinoids and terpenes synthesizedFootnote 199.

  2. Growth stage

    Cannabinoid content in the plant generally increases from the seedling stage to the flowering stage because the glandular trichomes that synthesize cannabinoids are concentrated in the reproductive-stage leaves on the female inflorescenceFootnote 107 Footnote 120 Footnote 121 Footnote 165 Footnote 196 Footnote 219. Seedless drug-type female inflorescences are obtained by eliminating male plants from the growing area, which results in increased concentrations of THC, other cannabinoids, and terpenoidsFootnote 54, largely because seeds, if allowed to develop, are a diluent and a drain on the plant's carbon allocation to specialized metabolism. Most drug type C. sativa is produced today from female clones that are reproduced using cuttings and rarely produce seedFootnote 45.

  3. Environmental factors

    Soil, atmospheric, climatic, and management factors that contribute to vigorous growth and development of plants can increase the absolute production of resin and THC in drug-type C. sativa. Such factors include soil fertility, light, heat, and carbon dioxide (CO2)Footnote 199.

  4. Plant stress

    C. sativa hemp plants subject to abiotic stressors such as nutrient deficiencies or drought tend to produce more THC per unit of biomassFootnote 103 Footnote 148 Footnote 195.

  5. Polyploidization

    Polyploidization has been found to have varying effects in terms of cannabinoid and terpenoid production in hemp and drug-type C. sativa. For more detail on this relationship see De Pasquale et al.Footnote 69, ClarkeFootnote 51, Bagheri and MansouriFootnote 31, Mansouri and BagheriFootnote 130, and Parsons et al.Footnote 161. A polyploid form of drug-type C. sativa has not been commercialized.

4.3 Breeding and seed production

4.3.1 Breeding for cannabinoid content

The genetics and underlying biochemistry that regulates the overall ratio of the 4 major cannabinoids are now well known. The upstream portion of the cannabinoid biosynthetic pathway produces CBGA, a common substrate for the enzymes that produce CBDA, THCA, and CBCA. Thus, the overall cannabinoid ratio is dependent on the individual activities of these enzymes, which in turn is dependent on the genetic makeup of the individual plant. In general, most individual C. sativa plants are either CBDA-dominant or THCA-dominant, with the remainder of the major cannabinoids constituting a smaller percentage of the overall cannabinoid content. There are rare instances of genotypes that are dominant for CBCA or CBGA. The alleles that encode the enzymes THCA synthase and CBDA synthase are co-dominant, and thus crossing a CBDA-dominant plant with a THCA-dominant plant produces progeny with equal proportions of these cannabinoidsFootnote 28.

Throughout the ages, hemp largely has been bred for seed and fibre quality. In general, all industrial hemp produced today is CBDA-dominant with low total cannabinoid content compared to drug-type C. sativaFootnote 188. Regulatory bodies use the proportion of cannabinoids to differentiate drug-type C. sativa and industrial hemp. The upper concentration limit for THCA+THC content in industrial hemp was proposed as 0.3% (dry weight) by Small and Cronquist (1976)Footnote 202. This threshold is used in Canada and the United States, while the European Union uses a threshold of 0.2%Footnote 200. In some industrial hemp varieties, there can be individual plants found that are THCA-dominant or THCA/CBDA equal, which may account for why some hemp varieties more commonly fail the THC content criterion when randomly sampled (J. Stout, personal communication, 2020). Breeders could lower THC levels by targeting cannabinoid biosynthetic pathways or by disrupting the morphogenesis of cannabhen randomly sampled (J. Stout, personal communicationFootnote 68.

One of the main breeding objectives for drug-type C. sativa is to increase total cannabinoid content while maintaining THCA-dominance. Some commercial strains of drug-type C. sativa reportedly contain up to 21% THCA in dried female flowersFootnote 35. Biotechnology companies have developed strains that predominantly produce 1 of the 4 major cannabinoid compounds (THCA, CBDA, CBCA, and CBGA), as well as strains with mixed cannabinoid or terpenoid profilesFootnote 52. Several commercial drug-type C. sativa strains have been described by RosenthalFootnote 175-Footnote 178, SnoeijerFootnote 206, DankoFootnote 60, Grisswell and YoungFootnote 95, OnerFootnote 150 Footnote 151 Footnote 152 Footnote 153 Footnote 154 Footnote 155, and BackesFootnote 30. However, while numerous strains have been named, not all reflect unique biotypes largely due to the undocumented nature of drug-type C. sativa breeding programsFootnote 188. Strain names are not accepted as cultivars under the International Code of Nomenclature for Cultivated PlantsFootnote 42.

4.3.2 Seed production

Varietal purity standards for pedigreed seed production of both registered and certified industrial hemp seed have been developed by the Canadian Seed Growers' AssociationFootnote 11.

4.4 Cultivation and use as crop

C. sativa is used for its fibre, oil (for vegetable oil and oilseed products), and recreational or medicinal drug purposesFootnote 204. Claimed pharmacological properties attributed to Cannabis are discussed by RussoFootnote 185 Footnote 186, Whiting et al.Footnote 229, CCSAFootnote 7, and Russo and MarcuFootnote 187, among others. Hemp is universally cultivated as a field crop for its uses as oil, biomass, or both, while legal drug-type C. sativa is cultivated mostly indoors or in greenhouses, with low acreage in outdoor fieldsFootnote 28. In Canada, the majority of hemp is grown for seed productionFootnote 105.

Commercial cultivation of industrial hemp in Canada falls under the Industrial Hemp Regulation and the associated requirements from obtaining and maintaining a licence from Health Canada. Only varieties named in the "List of Approved Cultivars", published by Health Canada, are approved for planting in Canada.

The Cannabis Act and its regulations came into force on October 17, 2018. The Cannabis Act and its regulations provide the framework for the legal production of drug-type C. sativa. Commercial cultivators of drug-type C. sativa (not for personal use) are required to obtain a licence from Health CanadaFootnote 16 Footnote 17. Applicants may apply under the subclasses of micro-cultivation, standard cultivation, or nursery cultivation.

Crop guides for the cultivation of industrial hemp have been published by several provincial agriculture departments – AlbertaFootnote 1, ManitobaFootnote 18, OntarioFootnote 19, SaskatchewanFootnote 22 and the Canadian Hemp Trade AllianceFootnote 10. Many guides pertaining primarily to the non-commercial cultivation of drug-type C. sativa have been published, including ClarkeFootnote 50, RosenthalFootnote 174 Footnote 175 Footnote 176 Footnote 177 Footnote 178, GreenFootnote 93, and CervantesFootnote 47.

Vegetative propagation by cuttings and tissue culture techniques are widely practiced in drug-type C. sativa production systems to preserve a known genetic or biochemical profileFootnote 199 Footnote 221.

4.5 Gene flow during commercial production

C. sativa is a naturally outcrossing species, with rare instances of self-fertilization. In dioecious varieties, a single male flower can produce 350,000 pollen grains and a single plant contains many male flowersFootnote 201. C. sativa is wind-pollinated. Small and AntleFootnote 201 (2003) measured hemp pollen dispersal and found pollen density fell to less than 1% of the density within the field at 100 m, but the decrease measured at 400 m was proportionally less. Pollen dispersal of over 300 kilometers (km)Footnote 205 and even between North Africa and southwestern Europe has been reported Cabezudo et al.Footnote 44. C. sativa pollen can remain viable for days, if not over a week under optimal conditionsFootnote 33 Footnote 201. Intraspecific gene flow between industrial hemp and drug type lines cultivated in the field is a growing concern.

In Canada, isolation distances of up to 4.8 km are required for pedigreed industrial hemp seed productionFootnote 11.

4.6 Cannabis sativa as a potential weed of agriculture

C. sativa plants tolerate a wide range of conditions, have high genetic variability, and are adaptable to environmental conditions; these characteristics could increase weediness and the colonization of new locationsFootnote 72. Hemp has been documented to grow as a weed inFootnote 102 Footnote 103 Footnote 197.

Hemp, as a weed, has been documented in southeast and central Asia, Europe, South America, Australia, and AfricaFootnote 63. In North America, hemp has naturalized where its cultivation was concentrated historically in the U.S. midwest and southeast, southern Ontario, and southern Quebec. C. sativa has been reported growing outside of agricultural systems in Canadian provinces from British Columbia to New BrunswickFootnote 194 Footnote 205. Small et al.Footnote 205 observed hemp volunteers 4 years after the completion of a hemp trial in Ottawa, Canada.

Despite the historical prohibition of drug-type C. sativa production in Canada, insight on its weediness can be gained from the behaviour of hemp in areas where production has been authorized. Hemp has weedy tendencies, as indicated by SmallFootnote 195; hemp biotypes have been capable of escaping cultivation and adapting very well to growing without human intervention in about 50 generations. However, it is unlikely that drug-type C. sativa would display increased weediness compared to hemp. Throughout centuries of selection, the phenotypes of drug-type C. sativa and hemp have diverged, notably the plant architecture. The short stature of most drug-type C. sativa plants grown in Canada (in contrast to fibre-type C. sativa) minimizes the production of stem tissues while maximizing the production of floral tissuesFootnote 205. Minimizing harvest losses will reduce C. sativa volunteers in subsequent crops. Cold temperatures and short photoperiods would negatively impact the ability of C. sativa, especially types adapted to indoor cultivation and semi-tropical climates, to produce seeds before fall and thus, establish as a weedFootnote 205.

Many broadleaf herbicides will control volunteer C. sativa. Pre-plant or pre-emergent burndown using 2,4-D or glyphosate will generally control hemp in the springFootnote 205. Mechanical control, followed by chemical control the following year, is recommended for mature plantsFootnote 205.

4.7 Means of movement and dispersal

Humans, birds, and water are the primary dispersal agents of C. sativa seeds. C. sativa seeds are highly attractive to birds, hence the opinion of Haney and BazzazFootnote 102 that birds were the most important wild animals for disseminating seeds in North America. Some C. sativa seeds can survive the digestive tract of birdsFootnote 62, while others may adhere to claws or billsFootnote 141. Flood and runoff waters may also disperse seedsFootnote 102.

5 Related species of Cannabis sativa L.

5.1 Inter-species/genus hybridization

The Cannabaceae family, as currently described, comprises about 102 accepted species and 12 genera includingFootnote 24:

Cannabis and Humulus (hop) are phylogenetically closeFootnote 230. However, there is no reliable evidence reported in the literature of sexual hybridization between C. sativa and the 3 species of the genus Humulus (H. lupulus (common hop), H. japonicus, and H. yunnanensis).

5.2 Potential for introgression of genetic information from Cannabis sativa into relatives

In Canada, there are no relatives known to interbreed with C. sativa. Thus, the risk of interspecific gene flow is lowFootnote 45. Introgression of genetic information from C. sativa will be restricted to other C. sativa plants. All taxa within the species C. sativa readily crossbreed, often by way of long-distance pollination (see Section 4.5 Gene flow during commercial production).

6 Potential interaction of Cannabis sativa with other life forms

C. sativa plants display mechanical and chemical defense mechanisms including the occurrence of cystolith trichomes, resinous exudate from glandular trichomes, and emission of volatile terpenoidsFootnote 162. Upper surfaces of C. sativa leaves are covered by abrasive cystolith trichomes (that is, unicellular hairs that have particles of calcium carbonate in their base). Cystolith trichomes impart a roughness to the surface of leaves that can cause skin irritation or dermatitis in people handling C. sativa and may discourage herbivory by larger animalsFootnote 199; they also may impale small insects and damage the mouthparts of larger onesFootnote 124. C. sativa leaves and floral parts are also covered by glandular trichomes which secrete many organic compounds including terpenoids and cannabinoids. Glandular trichomes may rupture and release a viscous mixture that can trap insects, as illustrated by Small (2017, p. 219)Footnote 200 and described by McPartland and colleaguesFootnote 137, or be unpalatable to herbivores.

Several volatile terpenes produced by C. sativa including limonene, pinene, humulene, and caryophyllene have insecticidal propertiesFootnote 137 Footnote 142 and are synthesized and accumulated in trichomesFootnote 98. Although the biosynthesis of terpenoids with insecticidal properties occurs across all forms of C. sativa, drug-type C. sativa produces 3 to 6 times more resinous components, including limonene and pinene, than most hemp varietiesFootnote 140. Cannabinoids such as THC and THCA also possess insecticidal propertiesFootnote 134 Footnote 137 Footnote 181 Footnote 183 Footnote 215. The levels of exposure of insects to insecticidal compounds synthesized by C. sativa, such as limonene, pinene, and THC, are unknown.

Pollen-producing male C. sativa flowers are attractive to bees and pollen-collecting flies, particularly when nectar-producing species are absentFootnote 199. The pollen of C. sativa plants was reported to contain cannabinoids and volatile terpenesFootnote 157 Footnote 182; however, this is likely the result of contamination from staminal trichomes as the pollen itself has no trichomesFootnote 199. The potential impact of C. sativa pollen on bee health at the individual and colony level is unknown.

Herbivores have been known to ingest escaped C. sativa and the plant material (not the seeds) appears to have toxic potential if eaten in very large amounts. In general, C. sativa is not considered to be significantly poisonousFootnote 205.

According to McPartlandFootnote 133, nearly 300 insect pests have been associated with C. sativa, but very few cause economic losses. Some of the most common and serious pests are mites (e.g., two-spotted mite, Tetranychus urticae, and the hemp russet mite, Aculops cannabicola), borers (such as the European corn borer, Ostrinia nubilalis, and the hemp borer, Grapholita delineana), aphids (such as Phorodon cannabis), budworms (such as Helicoverpa armigera), and beetle larvae (such as Psylliodes attenuata, Ceutorhynchus rapae, Rhinocus pericarpius, Thyestes gebleri, and several Mordellistena spp.). For more detailed information on pests of C. sativa, see McPartlandFootnote 133.

For a list of species associated with C. sativa, please refer to Table 1.

Table 1. Examples of potential interactions of Cannabis sativa with other life forms present in Canada during its life cycle.

Bacteria
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Agrobacterium spp.
(crown gall, gall)
Synonym: Rhizobium spp.
Pathogen (Bradbury, 1986Footnote 40)
Erwinia tracheiphila (Smith)
Bergey et al., Hauben et al.
(bacterial wilt)
Pathogen (Bradbury, 1986Footnote 40)
Pseudomonas syringae pvs
(mulberry blight, Wisconsin tobacco disease)
Pathogen (CABI/EPPO, 2009Footnote 5; Bradbury, 1986Footnote 40)
Fungi
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Alternaria spp.
(blight)
Pathogen (Farr et al., 2018Footnote 80)
Aspergillus spp.
(stalk end rot of fruit).
Pathogen (Clear and Patrick, 1995Footnote 56; Conners, 1967Footnote 57; Elmhirst and Joshi, 1995Footnote 74; Ginns, 1986Footnote 91; Miller et al., 1985Footnote 143; Mills and Abramson, 1981Footnote 144)
Botrytis cinerea Pers.
(gray mold)
Synonym: Botryotinia fuckeliana (deBary) Whetzel
Pathogen (Conners, 1967Footnote 57; Gossen et al., 1994Footnote 92; Legault et al., 1989Footnote 123; Parmelee, 1983Footnote 159; Rodriguez et al., 2015Footnote 172)
Cladosporium herbarum
(Persoon) Link
(cladosporium stem canker)
Pathogen (McPartland et al., 2000Footnote 137)
Colletotrichum dematium (Pers.) Grove
(leaf spot)
Synonym: Vermicularia dematium (Persoon) Fries
Pathogen (Cerkauskas et al., 1991Footnote 46; Ginns, 1986Footnote 91)
Fusarium spp.
(canker)
Pathogen (Clear and Patrick, 1990Footnote 55; Duthie et al., 1986Footnote 71; Farr et al., 2018Footnote 80; Martin and Johnston, 1982Footnote 131; Sturz and Bernier, 1991Footnote 209; Sturz and Johnston, 1983Footnote 210; Wall and Shamoun, 1990Footnote 225)
Glomus mosseae (T.H. Nicolson & Gerd.) Gerd. & Trappe Symbiont (Dalpe et al., 1986Footnote 59; Kucey and Paul, 1983Footnote 119; Traquair and Berch, 1988Footnote 217)
Macrophomina phaseoli
(Maubl.) S.F. Ashby
(charcoal rot, damping-off)
Synonym: Macrophomina phaseolina (Tassi) Goid
Pathogen (Conners, 1967Footnote 57; Desjardins et al., 2007Footnote 70; Joshi and Hudgins, 2002Footnote 114)
Nectria haematococca Berk. & Broome
(dry rot of potato)
Synonym: Fusarium solani (Martius) Sacc.
Pathogen (Conners, 1967Footnote 57; Duthie et al., 1986Footnote 71; Joshi and Elmhirst, 1998Footnote 115; Sturz and Bernier, 1991Footnote 209; Sumar et al., 1982Footnote 211)
Ophiobolus anguillides (Cooke in Cooke & Ellis) Sacc.
(stem canker)
Pathogen (Conners, 1967Footnote 57; Ginns, 1986Footnote 91)
Pythium aphanidermatum (Edson) Fitzp.
(damping-off)
Pathogen (Farr et al., 2018Footnote 80; Gilbert et al., 2008Footnote 88)
Sclerotinia sclerotiorum (Lib.) de Bary
(hemp canker, soft rot or stem rot)
Pathogen (CABI, 2018aFootnote 2; Farr et al., 2018Footnote 80)
Sclerotium rolfsii Sacc.
(southern blight)
Synonym: Athelia rolfsii (Curzi) C. C. Tu & Kimbr.
Pathogen (Chang and Mirza, 2007Footnote 49)
Septoria spp.
(blight of hemp, yellow leaf spot)
Pathogen (CABI, 2018aFootnote 2; Conners, 1967Footnote 57)
Sphaerotheca macularis (Wallr.) Magnus
(powdery mildew)
Synonym: Podosphaera macularis (Wallr.) U. Braun & S. Takam.
Pathogen (Ginns, 1986Footnote 91; Parmelee, 1982Footnote 158; Parmelee, 1984Footnote 160; Wall and Shamoun, 1990Footnote 225)
Trichothecium roseum
(false powdery mildew)
Pathogen (Ginns, 1986Footnote 91; Mittal and Wang, 1987Footnote 145)
Trichothecium roseum
(false powdery mildew)
Pathogen (CABI, 2018bFootnote 3)
Viruses
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Alfalfa mosaic virus (AMV) Pathogen (CABI/EPPO, 2002Footnote 4; Conners, 1967Footnote 57)
Arabis mosaic virus (ArMV) Pathogen (CABI/EPPO, 2015Footnote 6)
Cucumber mosaic virus (CMV) Pathogen (Conners, 1967Footnote 57)
Phytoplasma
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Candidatus Phytoplasma asteris
(yellow disease phytoplasmas)
Pathogen (Wang et al., 1998Footnote 227)
Nematodes
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Heterodera spp.
(cyst nematode)
Pathogen (Ebsary, 1986Footnote 73)
Meloidogyne spp.
(root-knot nematode)
Pathogen (Conners, 1967Footnote 57; Ebsary, 1986Footnote 73; Sewell, 1977Footnote 190; Tyler, 1964Footnote 220)
Ditylenchus dipsaci (Kühn) Filipjev
(stem nematode)
Pathogen (Creelman, 1962Footnote 58; Kimpinski, 1985Footnote 117)
Insects and mites
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Acalymma vittatum (Fabricius) Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Acheta domesticus (Linnaeus)
(house cricket)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Adalia bipunctata (Linnaeus)
(two spotted ladybeetle)
Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Agriotes spp.
(lined click beetle, wireworm click beetle)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Agromyza reptans Fallén Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Spencer and Steyskal, 1986Footnote 207)
Agrotis gladiaria Morrison
(claybacked cutworm)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Aleochara bilineata Gyllenhal Beneficial organism (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; Gavloski et al., 2011Footnote 87; McPartland et al., 2000Footnote 137)
Anagrus atomus (Linnaeus)
(leafhopper egg parasitoid)
Beneficial organism (CABI, 2018dFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; Bostanian et al., 2012Footnote 38; McPartland et al., 2000Footnote 137)
Anoplophora glabripennis (Motschulsky)
(Asian long-horned beetle)
Consumer (CFIA, 2016Footnote 8; McPartland et al., 2000Footnote 137)
Aphis spp.
(black bean aphid, cotton aphid)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Apion spp. Herbst Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Arctia caja (Linnaeus)
(garden tiger moth)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Bemisia spp.
(silverleaf whitefly, tobacco whitefly)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Blattella germanica (Linnaeus)
(German cockroach)
Consumer (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Bradysia germanica spp. Winnertz
(fungus gnats)
Consumer (Gillespie and Quiring, 2012Footnote 90; McPartland et al., 2000Footnote 137)
Camnula pellucida (Scudder)
(clearwinged grasshopper)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Ceutorhynchus spp.
(cabbage curculio, cauliflower weevil)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Chaetocnema spp.
(corn flea beetle, flea beetle)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Chelonus insularis Cresson Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Krombein et al., 1979Footnote 118; McPartland et al., 2000Footnote 137)
Chloealtis conspersa (Harris & T.W.)
(sprinkled locust)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Chrysopa spp.
(goldeneye lacewing)
Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Garland and Kevan, 2007Footnote 86; McPartland et al., 2000Footnote 137)
Chrysoperla spp.
(green lacewing, pearly green lacewing)
Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; Garland and Kevan, 2007Footnote 86; McPartland et al., 2000Footnote 137)
Closterotomus norvegicus (Gmelin)
(strawberry bug, potato bug)
Synonym: Calocoris norvegicus (Gmelin)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Cnephasia asseclana (Denis & Schiffermüller)
(chrysanthemum web worm)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Coccinella undecimpunctata Linnaeus
(eleven-spotted ladybeetle)
Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Cotesia marginiventris (Cresson) Beneficial organism (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Philip, 2015Footnote 164)
Cyrtepistomus castaneus (Roelofs)
(asiatic oak weevil)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Delia spp.
(bean seed fly, cabbage maggot, seedcorn maggot)
Consumer (CABI, 2018Footnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137)
Delphastus pusillus (LeConte)
(whitefly predatory beetle)
Beneficial organism (CABI, 2018Footnote 2; Bousquet et al., 2013Footnote 39; CFIA, undatedFootnote 9; McPartland et al., 2000Footnote 137)
Deraeocoris brevis (Uhler)
(Mirid plant bug)
Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Empoasca spp.
(potato leafhopper)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Encarsia formosa Gahan
(greenhouse whitefly parasitoid)
Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; PMC, 2014Footnote 20; McPartland et al., 2000Footnote 137)
Feltiella acarisuga (Vallot)
(red spider mite predatory gall midge)
Synonym: Therodiplosis persicae
Beneficial organism (CFIA, undatedFootnote 9; Footnote 20; McPartland et al., 2000Footnote 137; Mo and Liu, 2007Footnote 146)
Forficula auricularia Linnaeus
(European earwig)
Consumer (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Frankliniella occidentalis (Pergande)
(western flower thrips)
Consumer (CABI, 2018aFootnote 2; Hemming, 2000Footnote 106; McPartland et al., 2000Footnote 137)
Graphocephala coccinea (Forster)
(redbanded leafhopper)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Grapholita delineana (Walker)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Harmonia axyridis Pallas
(multicolored Asian ladybeetle)
Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Helicoverpa zea (Boddie)
(bollworm)
Consumer (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Heliothrips haemorrhoidalis (Bouché)
(greenhouse thrips)
Consumer (Hemming, 2000Footnote 106; McPartland et al., 2000Footnote 137)
Hippodamia convergens Guérin-Meneville
(ladybird)
Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Liriomyza eupatorii (Kaltenbach) Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Lonsdale, 2017Footnote 127; McPartland et al., 2000Footnote 137)
Lixophaga variablis (Coquillett) Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Tachinidae resources, 2017Footnote 212)
Loxostege sticticalis (Linnaeus)
(beet webworm)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Lygus lineolaris (Palisot de Beauvois)
(tarnished plant bug)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Macrocentrus spp. Beneficial organism (CABI, 2018aFootnote 2; Krombein et al., 1979Footnote 118; McPartland et al., 2000Footnote 137)
Mamestra configurata Walker
(bertha armyworm)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Melanoplus bivittatus (Say)
(two-striped grasshopper)
Consumer (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Myzus persicae (Sulzer)
(green peach aphid)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Nabis spp. Latreille Beneficial organism (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Neocrepidodera ferruginea (Scopoli)
(European rusted flea beetle)
Synonym: Crepidodera ferruginea
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Oecanthus celerinictus Walker & T.J. Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137)
Orius spp. Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Ostrinia nubilalis (Hübner)
(European corn borer)
Consumer (McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Oulema melanopus (Linnaeus)
(oat leaf beetle)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Papaipema spp.
(burdock borer, common stalk borer)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Pohl et al., 2018Footnote 166)
Parthenolecanium corni (Bouché)
(European fruit lecanium)
Consumer (CABI, 2018aFootnote 2; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Peristenus digoneutis Loan Beneficial organism (CABI, 2018aFootnote 2; McPartland et al., 2000Footnote 137; Whistlecraft et al., 2010Footnote 228)
Philaenus spumarius (Linnaeus)
(meadow froghopper, spittlebug)
Consumer (CABI, 2018aFootnote 2; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Phorodon humuli (Schrank)
(hops aphid)
Consumer (Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Podisus maculiventris (Say)
(spined soldier bug)
Beneficial organism (CFIA, undatedFootnote 9; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Popillia japonica Newman
(Japaneese beetle)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Psylliodes punctulatus Melsheimer
(hops flea beetle)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Rhinoncus pericarpius (Linnaeus)
(hemp weevil)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Scambus pterophori (Ashmead) Beneficial organism (GBIF Backbone Taxonomy, 2017Footnote 15; Krombein et al., 1979Footnote 118; McPartland et al., 2000Footnote 137)
Schizocerella pilicornis (Holmgren)
(purslane sawfly)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Krombein et al., 1979Footnote 118; McPartland et al., 2000Footnote 137)
Sitona lineatus (Linnaeus)
(pea leaf weevil)
Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Stethorus lineatus spp. Beneficial organism (CFIA, undatedFootnote 9; GBIF Backbone Taxonomy, 2017Footnote 15; Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Supella longipalpa (Fabricius) Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; McPartland et al., 2000Footnote 137; Vickery and Kevan, 1986Footnote 224)
Systena spp. Chevrolat Consumer (Bousquet et al., 2013Footnote 39; McPartland et al., 2000Footnote 137)
Thrips tabaci Lindeman
(onion (tobacco) thrips)
Consumer (CABI, 2018aFootnote 2; GBIF Backbone Taxonomy, 2017Footnote 15; Hemming, 2000Footnote 106; McPartland et al., 2000Footnote 137)
Tipula paludosa Meigen
(European crane fly)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Gillespie, 2001Footnote 89; McPartland et al., 2000Footnote 137)
Trialeurodes vaporariorum (Westwood)
(greenhouse whitefly)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Maw et al., 2000Footnote 132; McPartland et al., 2000Footnote 137)
Trichogramma spp.
(minute egg parasitoid, moth egg parasitoid)
Beneficial organism (CABI, 2018aFootnote 2; CFIA, undatedFootnote 9; Krombein et al., 1979Footnote 118; McPartland et al., 2000Footnote 137)
Tetranychus urticae Koch
(two-spotted spider mite)
Consumer (Beaulieu and Knee, 2014Footnote 34; McPartland et al., 2000Footnote 137)
Molluscs
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Arion spp.
(black slug, brown-banded slug, chocolate slug, dark-face slug, dusky slug, forest slug, garden slug, hedgehog slug, orange-banded slug)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Barker, 2002Footnote 32; Grimm et al., 2009Footnote 94; Ranalli, 1999Footnote 170; Rollo, 1974Footnote 173)
Deroceras reticulatum (Müller)
(meadow slug)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Grimm et al., 2009Footnote 94; Ranalli, 1999Footnote 170)
Limax maximus Linnaeus
(giant garden slug)
Consumer (GBIF Backbone Taxonomy, 2017Footnote 15; Grimm et al., 2009Footnote 94; Ranalli, 1999Footnote 170)
Animals
Other life forms Interaction with Cannabis sativa (pathogen; symbiont or beneficial organism; consumer; gene transfer) Reference(s)
Birds Consumer (McPartland et al., 2000Footnote 137)
Animal browsers (for example, deer, rabbits, rodents) Consumer (McPartland, 1996Footnote 133; McPartland et al., 2000Footnote 137)
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