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 thuringiensisCopperNeemPyrethrumOils

“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 SyntheticAI- proteins produced by Bt bacteriaSpore forming bacteria

Common in terrestrial habitatSoil, dead insects, plants, granaries

How Bt works

MUST be eaten by susceptible pestEndotoxin binds to gut creating a hole/poreContents enter the body cavity/bloodstreamNo immediate knock-down

But does slow feeding

Bt – know your Latin

Imperative to match subspecies with pestBt kurstaki – LepidopteraBt tenebrionis – ColeopteraBt israliensis - Diptera

Residual Effect

Only a few daysBroken down by sunlightCan be used with ‘stickers’ or UV blockers

Best control

Early detectionProper application

TimingLocationPest compatibility

The ‘green’ aspect of Bt

Humans – Gut structure completely differentRapid UV breakdown

WildlifeFed to birds and fish – no adverse effects

Natural EnemiesParasites and predators – not harmed directly, but loss

of host site could be a problem

NonTargetsOther moths and butterflies

Copper Products – “Danger, Warning & Caution”

Mineral based fungicide/bactericideConsidered syntheticAllowed

Fixed coppers – minimize accumulation in soilCopper hydroxide, copper oxide

Copper sulfateTerrestrialAquatic

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 sporeMultiple applications typically necessary to

protect new plant growth

Cu is more soluble (releases Cu ions) in low pHIf 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 persistenceCan remain for 1-2 weeksOr until it is washed off (rain, irrigation)

Fate in water and soils

Because it is so soluble, leaches wellAlso binds tightly to soilSo only leaches well in very sandy soilsVery high levels have been found in ag

settings after only a few decades

Wildlife

Practically non-toxic to birdsHighly toxic to fish – especially in acid

waterBees – endangered by bordeaux mixPoison to sheep and chickensAs soil levels build, soil life diminishes

Worms, Rhizobium bacteria, etcWill 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 pesticideDerived from the neem tree, Azadiracta

indicaNative to southern Asia (sub-

tropical/tropical)Cure of all ailments

Used for centuries for medical, cosmetic and pesticidal purposes

Research

As early as 19201959 – German ento noticed that neem

trees in the Sudan resisted an attack of migratory locust

How it’s made

Crushing neem tree seedsWater or solvent such as alcohol to

extract pesticidal constituentsDifferent extraction process leads to

different amounts of chemical presentEfficacy 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 ingestionPrevents molting (inhibits ecdysone production)Stops feeding – physiological effectEgg laying – volatile compounds repel insects

General application guidelines

Multiple applicationsBroken down by UV and washed off easily

Use on immature insectsUse on low populationsWorks best under warm temperaturesApply 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-toxicNatural enemies – little or no effect on

adult beneficialsRelatively harmless to: bees, spiders,

ladybeetles parasitoid wasps, and adult butterflies.

Suitable for IPM inclusion

‘green’ continued

Non target organisms – generally nontoxicNeem leaves added to the soil increased

earthworm weight and survival

More research neededHuman effects – likely does not pose a

significant riskIrritation to mucous membranes from seed dustMost studies done on azadirachtin – not entire

neem product

Efficacy

Affect over 200 insect speciesWhiteflies, thrips, leafminers, caterpillars

aphids, scales, beetles, true bugs and mealybugs, squash bugs, etc.

Efficacy can vary on species

Oils (caution)

Synthetic and naturalAI – 3 types

Petroleum (mineral)FishPlant

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 similarAll oils could disrupt insect behavior –

feeding,ovipositionPlant vectored virus control – stylet oil

Pests controlled

Soft bodied insectsAphids, 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 reductionThe slower the oil evaporates, the higher

the risk of damageAvoid 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 cropsGenerally found to be more effective

when mixed or used in combination with another pesticide

Pyrethrum (caution)

Botanically derivedNon-syntheticPowdered, 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 compoundsMode of action is similarBut not OMRI approved

How it works

Fast acting contact poison that ‘knocks down’ susceptible insects

Effects nervous systemRepetitive nerve discharges Left paralyzed by toxic effects If dose is too low, some insects can

recover

Synergists

Enhanced mortalityAdding a non-insecticidal chemical

heightens responseReduces ability to detoxify pyrethrum

PBO – piperonyl butoxide is common but not OMRI approved

Use care when shoppingOthers 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 UVContact poison

Spray flying insects (cuc beetle) in early morning while less active and before bee activity

‘Green’ aspect

Little to no leaf persistenceBroken down in water to nontoxic

productsSoil persistence – half life of 1-2 hoursIndoors – can persist up to two months in

carpet dustWildlife – 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 beesHumans –relatively nontoxic to humans,

still use with ‘caution’Can easily be inhaled

Efficacy

VictimsTrue bugs, caterpillars, beetles, aphids, flies,

mites, whiteflies, thrips and leafhoppers

Moral of the story…

Know the pestKnow the plantKnow the optionsUse caution with any pesticideNone of them are ‘safe’

Be it organic or synthetic