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Challenges and Opportunities

for Pest Management of

Cannabis in Colorado

Iowa State Department Seminar

March 7, 2014

Whitney Cranshaw

Some Background – Key Date

• November 2000 – Passage of

Amendment 20

– Allows usage of Cannabis for patients with

written medical permission (“medical

marijuana”)

– Patients may grow up to 6 plants

– Patients may acquire Cannabis from a

caregiver or from non-state affiliated

clubs/organizations (dispensaries)

Some Background – Key Date

• November 2012 – Passage of

Amendment 64

– Allows personal use of Cannabis

– Establishes regulations on production and

sale of Cannabis

– Sets excise tax on wholesale sales

• Additional taxes are on November 2013 ballot

– Industrial hemp also included in ballot

initiative

Cultivated Cannabis involves the use

of two species (subspecies?) that

freely interbreed

Cannabis indica

Cannabis sativa

Excellent introduction

to the history and

recent developments

related to production

of psychoactive

Cannabis

Note: Cultivars grown to

produce fiber (hemp) are

selections of Cannabis

sativa with low levels of

psychoactive

compounds.

Under federal law all

Cannabis is classified as

“marijuana” and regulated

as an illegal drug

Federal Laws on Cannabis

• Marijuana classified as Schedule I

Controlled Substance

– Substances in this schedule have no currently

accepted medical use in the United States, a

lack of accepted safety for use under medical

supervision, and a high potential for abuse

• Other examples of Schedule I drugs

include:

– Heroin, LSD, peyote, methaqualone, Ecstasy

– Schedule II drugs include cocaine, most

opiates, amphetamines

Cannabis Production Practices

State laws

specify that all

production is

grown indoors

Propagation is by seed

or by cloned cuttings

Production Size Varies

It can be expected that there will be a

proliferation of small “home grows”

and very large production grows in

near future.

Cultivation is extremely

intensive, expensive, - and

produces a crop of very

high value per unit area

Intense lighting

and extensive use

of fans is part of

standard practice.

Most growers

use a pot or bag

to culture, with

drip irrigation.

Some growers utilize

hydroponics for

production.

Primary crop outcome

– Sinsemilla

Unfertilized,

grossly enlarged,

female flowers (aka

“bud”)

Primary Pest Problems of Indoor

Grown Cannabis

• Abiotic disorders

• Pathogens – Powdery mildew

– Pythium root rots

• Arthropods – Twospotted spider mite

– Hemp russet mite

– Rice root aphid

– Fungus gnats

Twospotted spider

mite Tetranychus urticae

Hemp russet mite Aculops cannabicola

Rice root aphid Rhopalosiphum abdominalis

Darkwinged fungus

gnats Bradysia spp.

Powdery mildew

of Cannabis

Sphaerotheca macularis

Pythium root rots Pythium spp.

Federal Laws and Pesticides

• Marijuana is classified as Schedule I

Controlled Substance

– As a result no federal agency will recognize the

crop for any purpose – other than drug law

enforcement

• EPA will not establish a crop category for

cannabis under pesticide laws

– EPA regulates the use of pesticides under

provisions of law defined by FIFRA

– No pesticides can be used legally on a crop if

the use is not allowed for that crop category

Present Status of Pesticide for Use on the

Crop: Any pesticide that is a registered

pesticide is illegal to use on Cannabis under

federal law

A “Catch-22”

Definition: A problematic situation

for which the only solution is denied

by a circumstance inherent in the

problem or by a rule

Suggested Crop Site

Classification • Best fit – Indoor grown “Herbs and

Spices” crop category (Category 19)

• Examples of Category 19 pesticides – Insecticidal soaps

– Horticultural oils

– Pyrethrins

– Neem

– Phosphorous acid

– Some microbial insecticides

– Some microbial fungicides

Legal Products in Absence of

Federal Registration

• Biological control agents other than

microbes

– Entomopathogenic nematodes

– Predatory mites

– Insect predators/parasitoids

• Section 25b Minimum Risk Pesticides

– Primarily various vegetable/essential oils of

botanic origin

Result of Federal Resistance

to Cannabis Production • Inability to disseminate information on

diagnostics

• Inability to disseminate information on IPM

practices

– Inability to conduct research to improve pest

management practice

• Unregulated, illegal and often unsafe use

of pesticides to manage pests

August 14 Letter from a Cannabis Producer

Checklist of treatments July 18-August 12

• BioWar (unspecified “beneficial soil microbes)

• Sulfur/pyrethrins

August 14 Letter from a Cannabis Producer

Checklist of treatments July 18-August 12

• BioWar (unspecified “beneficial soil microbes)

• Sulfur/pyrethrins

• Abamectin (Avid)

• Chlorfenapyr (Pylon)

• Abamectin/binfenzate (Scirocco)

• Fenpyroximate (Akari)

• Abamectin

• Fenazaquin (Magister)

Washington State Finesse on the Subject

of Pesticide Use on Cannabis

• Pesticides that require federal

registration under Section 3 of FIFRA

– Active ingredient is exempt from the

requirements of tolerance, and

– Label has directions for use on

unspecified food crops, including

unspecified food crops grown as bedding

plants

– EPA and WSDA registration is required

• Section 25b minimum risk pesticides

(exempt from federal registration)

Washington State Finesse on the Subject

of Pesticide Use on Cannabis

• Pesticides that require federal

registration under Section 3 of FIFRA

• Section 25b minimum risk pesticides

(exempt from federal registration)

– WSDA registration is required

– Use allowed if product is labeled for use

on unspecified food crop, home gardens,

or herbs (including bedding plant uses)

Note: Net effect of the WSDA guidelines are to allow the

types of pesticides allowed under Category 19 Site

established by EPA

Products allowed with WDA

Finesse • Azadirachtin

• Bacillus pumilus

• Bacillus subtilis

• Bacillus thuringiensis

• Canola oil

• Chromobacterium

• Gliocladium virens

• Hydrogen peroxide

• Mineral oils

• Neem oil

• Phosphorous acid

• Potassium

bicarbonate

• Insecticidal soaps

• Pyrethrins

• Streptomyces spp.

• Trichoderma spp.

Cannabis Regulatory Status In Colorado?

• Department of Revenue

– Controls almost all regulations affecting

recreational/medical Cannabis

• Department of Agriculture

– Involved in developing regulations related

to industrial hemp

– Sometime in the future will produce

guidelines related to pesticide use on all

types of Cannabis production in the state

Present Options for Pesticide use in Colorado Cannabis Production

Option One. Use products that are typically

registered as pesticides but do not overtly sell

them with pest control claims.


Option Two. Use products as pesticides that are

not registered as pesticides

Sulfur

fogs

CO2 fumigation

25(b) exempted (?) products


Option Three. Ignore the law and use pesticides

that are not registered for the crop


Option Three. Ignore the law and use pesticides that are not

registered for the crop

Illegal and

unsafe

Abamectin

Bifenazate

Fenpyroximate


Option Three. Ignore the law and use pesticides that are not

registered for the crop

Illegal due to regulatory indecision

Horticultural

oils

Pyrethrins

Azadirachtin

Microbial controls

Thoughts on Pest Management

Approaches for Key Pests

Powdery mildew

Some IPM Tools for

Powdery Mildew

• Exclusion of causal organism

• Oils, desiccants to kill stages

on leaf surfaces

• Biological control agents

• Improved air circulation

Horticultural Oils (Petroleum/Paraffinic Derived)

A highly refined

petroleum oil that

has labeling for use

on herbs and

spices

Trilogy and Triact 70 are neem oil products that

specify use on greenhouse-grown herbs and spices

Herb use is not on

these labels

Sodium bicarbonate Potassium bicarbonate

Potassium

Bicarbonate

Products

Bacillus subtilis QST 713 Strain

Cease

A biological control

to suppress plant

pathogenic fungi on

leaves and in soil.

Odor issue??

Conditions that Promote

Powdery Mildew

• High humidity

• Moderate temperature

•Still air

Pythium

root rots

Some IPM Tools for

Pythium Root Rots • Exclusion of causal organism

• Avoid hydroponic production

• Avoid producing soil conditions

favorable for growth

• Incorporation of effective biological

control agents into root growing media

Trichoderma harzianum

(RootShield, PlantShield)

Bacillus subtilis QST 713 Strain

Cease

A biological control

to suppress plant

pathogenic fungi on

leaves and in soil.

Fungus Gnats

Some IPM Tools for

Fugnus Gnats

• Use growing media that do not favor

development of fungus gnats

• Trapping

• Azadirachtin drenches

• Biological control agents

– Soil-dwelling predatory mites

– Entomopathogenic nematodes

– Bacillus thuringiensis var. israelensis

Larvae primarily feed

on various decay fungi,

more incidentally

damaging healthy roots

Fungus Gnat Trapping

An azadirachtin-

rich neem-

derived

insecticide

labeled for use

on herbs and

spices

Steinernema feltiae – the nematode for use against certain Diptera larvae

A Steinernema feltiae product

Soil Predator Mite

Hypoaspis miles

Strains of Bacillus thuringiensis

• kurstaki, aizawi strains

– Caterpillars of moths, butterflies

• tenebrionis strain

– Larvae of leaf beetles

• israelensis strain

–Larvae of mosquitoes, certain midges and gnats

Rice root aphid

Some IPM Tools for Rice

Root Aphid


• Azadirachtin drenches (?)

• Biological control agents (?)

–Soil dwelling arthropod

predators

–Entomopathogenic fungi

Pest Management Products

that Might Have Promise for

Root Aphid Control

Azadirachtin

Soil dwelling

predators

Metarhizium anisopliae?

Beauveria bassiana

• Determine basic outlines of life history and

habits

• Identify methods of dispersal and use of non-

Cannabis hosts

• Identify effective biological and chemical

controls

Twospotted spider

mite Tetranychus urticae

“….Consider this situation, you spray your chemicals, the mites may not die right away depending on the mode of action, what happens next is the mites panic and start laying eggs like crazy. Before you know it, the mites have become twice as bad as before you hit them……”

Spider Mite Management on the Internet

Information from Legal Hydro web site

“….The best method to control this pest is to switch your mode of attack each and every day. Never spray them with the same stuff twice in a row, if you choose the chemical approach, you want to use a Neem Oil along with as many other forms of Miticides as you can get your hands on…”

Spider Mite Management on the Internet

Information from Legal Hydro web site

Some IPM Tools for Mites (Twospotted spider mite, Hemp russet mite)


• Oils

• Azadirachtin?

• Predatory mites?

Exclude Mites from

Growing Area

Cuttings, if used, must

be disinfested of all

living stages of mites

before introduction

into a growing area

Avoid conditions that allow “steamrolliing” of

mite populations

Monitor to detect

incipient outbreaks

Spider Mite

Predators

Predatory Mites

Predatory Mites for Potential Use

on Medical Marijuana

• Mesoseiulus longipes

• Neoseiulus californicus

• Galendromus occidentalis

Note: The above species are the predatory mites that are

most tolerant of low humidity. However, performance of

all is reduced under low humidity.

Predatory Mite: Galendromus occidentalis

Optimal environmental conditions

80-100 degrees F > 50% RH

Predatory Mite: Mesoseiulus longipes

Can only tolerate the very low humidity of 40% when the temperature is 70°F.

Requires increasing humidity as temperature rises.

Development of Banker Plant Systems for Mite

Management

Graphics courtesy of University of Florida

Twospotted spider mite

– Pest of Cannabis

Banks grass mite

– Pest of grasses

Introduce generalist predator of both mite species

Development of Banker Plant Systems for Mite

Management

Graphics courtesy of University of Florida

Summary

• Cultivated Cannabis has several pest

problems, some of which can destroy

the crop

• Present pest management practices are

not guided by science, but by Internet

gossip

• Present pest management practice on

the crop is often misguided, ineffective,

and, on occasion, hazardous

Summary

• Federal obstructions produce the

biggest impediments – and biggest

challenges – to improved IPM

– Ability to discuss IPM with growers would

have immense value

– Resolution of pesticide registration issues

is needed to produce effective IPM

strategies

• Rapid progress in developing optimal

IPM practices can be expected following

release of these federal obstructions

for pest management of cannabis in coloradowebdoc.agsci.colostate.edu/bspm/cannabis ipm iowa march...

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