Technical Aspects of Paddy Weedicides

Presents by: Krishan F. Motha B.Sc.(Agric) Hons (Sp)

TECHNICAL ASPECTS &

ADDRESSING FIELD ISSUES OF KISEKI

MY DISCUSSION TODAY! Basic Technical Aspects of Pesticides Development of Herbicide Resistance &

Resistance Management Technical Aspects of Kiseki How to Address Field Issues of Kiseki

• How would you claim a product is superior in quality than the other products?Ex:- Round Up over other Glyphosate brands?Ex:- Nominee over other Bispyribac sodium brands?

• What decides the quality of a product?

Answer: An unique formulation of the product decides the superior quality

• Then what is a formulation ?

A mixture of chemicals which effectively controls a pest

Eg: Nominee product is a formulation, and bispyribac sodium is its Active Ingredient

• Formulation

• AI + Inert ingredients

Decides the Efficacy, Toxicity & Stability of the product

Active ingredient/s - listed in the product label

Inert ingredients -are the company secretsBut

Decides storage, handling, safety, application, or effectiveness

• What do manufacturers consider when creating a formulation?

• The type of surface

• Habits & Nature of the pest

• Stability, Toxicity, Safety

• Price

• Spray equipment

• Runoff & Drift

AI(Liquid or

Solid)

Inert Ingrediants Surfactants-Dispersants,Wetting agentsSolventsEmulsifiersDefoamerStabilizerAnti-microbialsAnti-freezePigments/ColorantsBuffers etc.

Formulation

Commercial Product

Formulation

FORMULATION TYPES

Liquid Sprayable

SL –Soluble ConcentrateSC –Suspension ConcentrateEC –Emulsifiable ConcentrateSE- Suspo EmulsionME -MicroemulsionOD –Oil DispersionCS –Microencapsulated Particles

Dry -Sprayable

WP –Wettable powdersWG or WDG –Water dispersible granule

Dry –Spreadable GranuleGR –Soil applied Granule on inert or fertilizer carrier

SUSPENSION CONCENTRATE (SC)

• A stable suspension of solid pesticide(s) in a fluid usually intended for dilution with water before use

• Suspension is stable & not settling out

AI= 0.1- 60%

EMULSIFIABLE CONCENTRATE (EC)

• A solution of a pesticide with emulsifying agents in a water insoluble organic solvent which will form an emulsion when added to water

• Complete Hydrophilic-lipophilic balance is reached for stable formulation

AI= 0.1- 40%

Eg: Matari Metamifop 10% EC

SUSPO EMULSION(SE)• A solution of a pesticide with two AI components which one is in a emulsifying agent

in a water insoluble organic solvent which will form an emulsion when added to water and the other AI is suspended in the same water

• Practiced when mixing two AIs when one is water soluble and one is soluble in organic solvents.

Eg:- Kiseki Bispyribac-sodium 4% + Metamifop 10%

• What is herbicide Mode of Action?

How a herbicide affects a plant at the tissue or cellular level

Herbicides with the same mode-of- action will have the same absorbance type, translocation (movement) pattern and produce similar injury symptoms

PADDY SELECTIVE MOA IN SRI LANKAMode of Action Importance Examples

Amino acid synthesis (ALS) inhibitors

Total killersSulfonyl ureas- Sedge killers

Bispyribac sodium, Sulfonyl ureas, Pyribensosim, Phenoxylam

Lipid synthesis (ACC ace) inhibitors

All are grass killersHigh doses cause phytotoxicity

Fenoxyfop-p-ethyl, cyhalofop-butyl, Metamifop

Cell division inhibitors Form a thin layer on soil Pretilachlor, Pendimethilene

Inhibition of emerging shoots Stop cell elongation Thiobencarb

Photosynthesis inhibitors Propanil

Pigment inhibitors Cause to bleaching effect Clomazone

Synthethic auxins Hormonal effect MCPA, Quinclorac

• What are the pesticide Interactions when mixing different MOA molecules together?

1. Additive effect

2. Synergistic responses

3. Antagonism

4. Enhancement

5. Incompatibility

PESTICIDE INTERACTIONS

01.Additive effect• Mixture’s response is as the combined effects of each material applied alone

• The products neither hurt nor enhance each other

• These mixtures save time, labor & equipment use

02.Synergistic responses• When two pesticides provide a greater response than the added effects of each material applied

separately

03. Antagonism• When two pesticides applied together produce less control than if applied each material

separately

• In addition antagonistic responses also may increase damage, or phytotoxicity, to plants antagonism is one kind of incompatibility

• Eg: Fenoxyfop-p-ethy + MCPA mixture cause antagonism

04. Enhancement • Occurs when a pesticide is mixed with an additive to provide a greater response than if you

applied the pesticide alone

• Eg:- Mixing a surfactant with a pesticide

05. Incompatibility• Two or more pesticides, or a pesticide and a fertilizer, are compatible if no adverse effects

occur as a result of mixing them together

• Conversely, deactivation of an active ingredient often occurs with chemical incompatibility

• Most affected by temperature, tank pH and length of time that you hold a spray mixture in the tank

• Physical incompatibilities occurs by inert ingredients of a formulation

• Mixture may become unstable, forming crystals, flakes, gel, oil, grease or sludge that may clog spray equipment.

PESTICIDE INTERACTIONS

• What is Herbicide Resistance?

Inherited ability of a weed to survive against a herbicide application to which the original population was susceptible

HERBICIDE RESISTANCE

HERBICIDE RESISTANCE

•How does it occur?

Season 1

Season 2……7, 8

284 Resistant weeds

171 Species (101 dicots & 69 monocots)

Over 270,000 places/fields

HERBICIDE RESISTANCEAROUND THE WORLD

HERBICIDE RESISTANCE

AROUND THE WORLD

WEED CHARACTERISTICS THAT FAVOR RESISTANCE

• High reproductive rate• Seed dispersal mechanisms

Most Important Resistant Weeds

Cyperus spp. I. rugossum E. crusgalli

HERBICIDE CHARACTERISTICS THAT INFLUENCE WEED RESISTANCE

• Using herbicides with a single site of action

• Use one herbicide multiple times during the growing season

• Use same herbicides consecutive growing seasons

• Herbicides used without other control strategies

• Repeated use of a product for more than 2 years could develop a herbicide resistance problem!!

HERBICIDE RESISTANCE SHOULD ONLY BE SUSPECTED WHEN .……...

• Other causes of herbicide failure have been ruled out

• The same herbicide or herbicides with the same mode of action have been used for years

• One weed that is normally controlled is not controlled while other weeds are

• A patch of uncontrolled weed is spreading

CAUSES OF HERBICIDE FAILURES

• Weed density• Moisture level• Temperature• Humidity

• Rate• Application method• Organic mater content• Run off etc..

All possible reasons for poor performance should be investigatedbefore considering the possibility of resistance!!!

STRATEGIES FOR CONTROL / PREVENTION

• Proactive vs. reactive

• Utilize other good weed control tactics

• Rotate herbicides with different MOA• Rotate crops

• Prevent seed production

• Clean tillage and harvesting equipment

PROACTIVE MEASURES TO OVERCOME

1. Avoid continuous application of same AI for consecutive seasons

2. Do not mix two critical mode of action chemicals for consecutive seasons

• Sulfonyl urea + ALS inhibitors

• Sulfonyl urea + Sulfonyl urea

3. Avoid resistant management through increasing the dose of the chemical

• 10% 20% 40%

4. Avoid mixing two incompatible formulations together

• Fenoxyprp-p-ethyl + MCPA

120ml70ml

100%

Weed control

Formulation volume

5. Always avoid underdose

6. Always tank mix 02 compatible different MOA chemicals

• ACCase + ALS inhi

• Cell division inhi + ALSinhi

• Cell divi + Photosynthesis inhi

• Photosynthesis inhi+ Photo pigment inhi

7. Apply chemicals at correct time & weed stage

THANK YOU!

Presented: Krishan F. Motha B.Sc. Hons (Sp)