organic-pesticides

No chemicals…
No man-made chemicals…
Only plant derived products…
Homemade products…
What does organic mean to you?

Organic Materials Review Institute
Founded in 1997, the Organic Materials
Review Institute (OMRI) provides organic
certifiers, growers, manufacturers, and
suppliers an independent review of products
intended for use in certified organic
production, handling, and processing. OMRI
is a 501(c)3 nonprofit organization. When
companies apply, OMRI reviews their
products against the National Organic
Standards. Acceptable products are OMRI
Listed® and appear on the OMRI Products
List.

Organic growers work in conjunction with
Government Certifiers to maintain
compliance with National Organic
Standards.
OMRI is the ‘safe list’

Common Organic Pesticides
Bt or Bacillus thuringiensis
Copper
Neem
Pyrethrum
Oils

“Organic pesticides are safe
for me and the environment.”
True or False?

“Organics are safe for me and the
environment.”
False!!!
‘safe’
Signal Words????

Bt – “Caution”
Non Synthetic
AI- proteins produced by Bt bacteria
Spore forming bacteria
Common in terrestrial habitat
Soil, dead insects, plants, granaries

How Bt works
MUST be eaten by susceptible pest
Endotoxin binds to gut creating a hole/pore
Contents enter the body cavity/bloodstream
No immediate knock-down
But does slow feeding

Bt – know your Latin
Imperative to match subspecies with pest
Bt kurstaki – Lepidoptera
Bt tenebrionis – Coleoptera
Bt israliensis - Diptera

Residual Effect
Only a few days
Broken down by sunlight
Can be used with ‘stickers’ or UV blockers

Best control
Early detection
Proper application
Timing
Location
Pest compatibility

The ‘green’ aspect of Bt
Humans – Gut structure completely different
Rapid UV breakdown
Wildlife
Fed to birds and fish – no adverse effects
Natural Enemies
Parasites and predators – not harmed directly, but loss
of host site could be a problem
NonTargets
Other moths and butterflies

Copper Products –
“Danger, Warning & Caution”
Mineral based fungicide/bactericide
Considered synthetic
Allowed
Fixed coppers – minimize accumulation in soil
Copper hydroxide, copper oxide
Copper sulfate
Terrestrial
Aquatic

How Copper works
Cu ions disrupt the functions of proteins
after being absorbed into fungus or
bacterium
‘Non-specific denaturation’ of cellular
proteins
Best absorbed by germinating fungal
spore
Multiple applications typically necessary to
protect new plant growth

Cu is more soluble (releases Cu ions) in
low pH
If applied with water pH lower than 6
phototoxicity can occur
Bordeaux mixes are Copper Sulfate and
hydrated lime to avoid this efffect

Efficacy
Listed on over 100 crop plants to control
fungal and bacterial diseases
More effective on bacterial than fungal,
but widely recommended for both.
Tomatoes, Pines, Algae

‘Green’ Aspect
Small amounts of Cu are needed for plant
and animal life. Excessive amounts are
dangerous
Leaf persistence
Can remain for 1-2 weeks
Or until it is washed off (rain, irrigation)

Fate in water and soils
Because it is so soluble, leaches well
Also binds tightly to soil
So only leaches well in very sandy soils
Very high levels have been found in ag
settings after only a few decades

Wildlife
Practically non-toxic to birds
Highly toxic to fish – especially in acid
water
Bees – endangered by bordeaux mix
Poison to sheep and chickens
As soil levels build, soil life diminishes
Worms, Rhizobium bacteria, etc
Will also control all forms of Bt

Human aspect
“Vineyard sprayers experienced liver
disease after 3-15 years of exposure to
copper sulfate solution in Bordeaux
mixture.”
Nasty stuff!
Vomiting normally triggered instantly, but
acid conditions of stomach encourage
absorption.
Be cautious!!!

Neem (caution, warning)
Non-synthetic botanical pesticide
Derived from the neem tree, Azadiracta
indica
Native to southern Asia (sub-
tropical/tropical)
Cure of all ailments
Used for centuries for medical, cosmetic and
pesticidal purposes

Research
As early as 1920
1959 – German ento noticed that neem
trees in the Sudan resisted an attack of
migratory locust

How it’s made
Crushing neem tree seeds
Water or solvent such as alcohol to
extract pesticidal constituents
Different extraction process leads to
different amounts of chemical present
Efficacy of different products may vary
Neem cake is residual seed – used as
fertilizer

How it works
AI – Azadirachtin, one of the more than 70
compounds produced by the neem tree
Acts as an IGR and anti-feedant and
oviposition deterrent
Works by contact or ingestion
Prevents molting (inhibits ecdysone production)
Stops feeding – physiological effect
Egg laying – volatile compounds repel insects

General application guidelines
Multiple applications
Broken down by UV and washed off easily
Use on immature insects
Use on low populations
Works best under warm temperatures
Apply to transplants before planting
Systemic properties are better than foliar
applications (drench)

‘Green’ aspect
Breaks down within 100 hours of light or
water – mix and use
Wildlife – relatively non-toxic
Natural enemies – little or no effect on
adult beneficials
Relatively harmless to: bees, spiders,
ladybeetles parasitoid wasps, and adult
butterflies.
Suitable for IPM inclusion

‘green’ continued
Non target organisms – generally nontoxic
Neem leaves added to the soil increased
earthworm weight and survival
More research needed
Human effects – likely does not pose a
significant risk
Irritation to mucous membranes from seed dust
Most studies done on azadirachtin – not entire
neem product

Efficacy
Affect over 200 insect species
Whiteflies, thrips, leafminers, caterpillars
aphids, scales, beetles, true bugs and
mealybugs, squash bugs, etc.
Efficacy can vary on species

Oils (caution)
Synthetic and natural
AI – 3 types
Petroleum (mineral)
Fish
Plant
Petroleum has the most available info and
has been developed the most

How it works
Pet Oils – control the egg stage by
interfering with gas exchange or egg
structure
Other stages, can block respiratory
system or cuticle break down
Plant and fish probably similar
All oils could disrupt insect behavior –
feeding,oviposition
Plant vectored virus control – stylet oil

Pests controlled
Soft bodied insects
Aphids, mites, thrips, whiteflies, mealybugs,
psyllids
“the only widely used class of pesticides
to which insects or mites have not
developed resistance.” (Sams and Deyton
2002)

Phytotoxicity
Visible leaf damage or yield reduction
The slower the oil evaporates, the higher
the risk of damage
Avoid application on humid days

‘Green’ aspect
Pet oils used on plants are light weight
and generally evaporate quickly.
Effects of vapors not known
Negligible ability to contaminate soil or
groundwater
Plant and Fish oils not as volatile, but
break down quickly by microbes
Unlikely to have any effect on wildlife or
non target species

Natural enemies –Can kill beneficial mites
and cause flare up in population
Humans – low toxicity to those applying,
typically gone by time of harvest

Efficacy
Long history of dormant spray in fruit
crops to control mites and scale
Less experience with vegetable crops
Generally found to be more effective
when mixed or used in combination with
another pesticide

Pyrethrum (caution)
Botanically derived
Non-synthetic
Powdered, dried flowerheads of the
pyrethrum daisy chiefly, Chrysanthemum
cinerariaefolium
Native to SW Asia, Kenya is leading
producer then Australia

Rums and Roids
Pyrethroids are synthetic compounds
Mode of action is similar
But not OMRI approved

How it works
Fast acting contact poison that ‘knocks
down’ susceptible insects
Effects nervous system
Repetitive nerve discharges
Left paralyzed by toxic effects
If dose is too low, some insects can
recover

Synergists
Enhanced mortality
Adding a non-insecticidal chemical
heightens response
Reduces ability to detoxify pyrethrum
PBO – piperonyl butoxide is common but
not OMRI approved
Use care when shopping
Others are now adding oils

This may be
one example of
an oil synergist
Not sure if it is
OMRI approved
Found at Horns

Application Tips
Broken down by both acid and alkaline
solutions : do not mix with lime, sulfur or
soap
Rapidly broken down by UV
Contact poison
Spray flying insects (cuc beetle) in early
morning while less active and before bee
activity

‘Green’ aspect
Little to no leaf persistence
Broken down in water to nontoxic
products
Soil persistence – half life of 1-2 hours
Indoors – can persist up to two months in
carpet dust
Wildlife – Extremely toxic to fish, slightly to
birds.
Unlikely to concentrate in food chain:
easily metabolized

‘Green’ cont
Beneficial arthropods – broad spectrum,
but low residual
Highly toxic to bees
Humans –relatively nontoxic to humans,
still use with ‘caution’
Can easily be inhaled

Efficacy
Victims
True bugs, caterpillars, beetles, aphids, flies,
mites, whiteflies, thrips and leafhoppers

Moral of the story…
Know the pest
Know the plant
Know the options
Use caution with any pesticide
None of them are ‘safe’
Be it organic or synthetic

organic-pesticides

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organic-pesticides