Microencapsulation of Insecticide What is Microencapsulation? Microcapsule and its type Techniqes for microencapsulation Application of microencapsullation Application in Agriculture Its Advantage and disadvantage Different marketed formulations Conclusion

1. 1
Welcome

2. Microencapsulation of
Insecticides
Speaker
PATEL MEET M.
Dept of Agril. Entomology
2

3. Contents
History of Microencapsulation
Components of microencapsulation
Classification of microcapsule
Technique to manufacture microcapsule
Release mechanism
Disadvantage of Microencapsulation
Conclusion
Introduction
Advantage of Microencapsulation
3
What is Microencapsulation?
Characters of Microcapsule
Application of Microecapsulated isecticide

4. Introduction
• Agriculture is always most important and stable sector as it
produces /provides raw materials for food industries.
• Agriculture industry is highly depending upon on synthetic
pesticides.
• Pesticide use was widespread after the World war II.
• Million tons of pesticides are made and sprayed as a tool of
crop protection as they can effectively reduce plant pests
(insects, microorganisms, animals etc.) to improve crop yields.
“From an estimation of the total agrochemicals used in crop
protection, only 0.1 % reaches to the target pests while the rest
enters the environment and may cause hazards to non-target
organisms including humans.
- (Anonymous, 2017)4

5. • Traditional pesticide formulations have several disadvantages
 High organic solvent contents
 Dust drift
 Poor dispersibility
 Build up resistance in insect pest
 Toxic effect on honey bees and also for beneficial insect
and microorganisms.
 Pest resurgence and secondary pest outbreaks
 Higher cost
 Cause phytotoxicity
5

6. • Among several forms of pesticides formulations, the encapsulated
formulations viz., capsule suspension (CS) and zeon® capsule (ZC)
has got the ability to bypass the maladies for environment, while
accomplishing its objective of crop protection.
• As of now, reference of 20,000 patents appear in literature on
encapsulation.
• These include drugs, dyes, flavors, agrochemicals etc,.
Approximately 400 different shell material are known and more
than 600 encapsulated products are present in the global market.
6
-Source: Microencapsulation of Agrochemicals by Impact
Group, 2017

7. Source: https: // www.businesswire.com /news /home /20171218005616 /en
/Microencapsulated – Pesticides – Herbicides – insecticides –
Fungicides – Rodenticides - Market
7
• Insecticides accounted for the largest share in the
microencapsulated pesticides market in 2016.
• Globally, the research & development activities and product
commercialization trends are more concentrated toward
microencapsulated insecticides.
• Hence, it accounted for the largest share in the
microencapsulated pesticides market.

8. • It is a process in which very tiny droplets or particles of liquid,
solid or gas material are suspended or coated with a
continuous film of polymeric material. The product obtained
by this process is called Microcapsule.
OR
• Microencapsulation may be defined as the process of
surrounding or enveloping one substance within another
substance on a very small scale, yielding capsules ranging
from less than one micron to several hundred microns in
size. 8

9. • The process of encapsulation gives
a resultant product called as a
capsule.
• Microcapsule is a tiny capsule,
containing material such as
insecticide, which is released when
the capsule is broken, melted or
dissolved.
• Microcapsules contain an active agent
and surrounded polymeric shell or
dispersed in polymeric matrix.
• Capsules can primarily serve as
storage vessels, delivery vehicles or
as a physical barrier between poorly
compatible ingredients in a liquid
formulation . 9

10. History of Microencapsulation
• Microencapsulation was first studied in 1931 by Barett K.
Green using the coacervation technique to prepare gelatin
sphere.
• The pharmaceutical industry later investigated the coating
materials and the technique to generate various dosage forms
such as powders, capsules, tablets, creams, ointments, gels,
suspension and emulsion.
1953: The first microencapsulated product i.e, carbonless copy
paper were developed commercialy at the National Cash
Register (NCR) of America
-Barrett K. Green
10

11. 1970: CRF (Controlled release formulation) of aquatic herbicide
(2,4-d) were developed.
-Harris and Cardarelli
1976: A patent of “microencapsulated methyl and ethyl parathion
insecticide in aqueous carrier” was registered in USA.
-DeSavigny C. B.
1979 & 1980: California obtained a registration for
microencapsulated permethrin (pounce) and methyl
parathion (Penncap M) against leaf miner on greenhouse-
grown chrysanthemums.
-(As per report of Parrella et al., 1984)
1984: Sumithion (insecticide) was encapsulated by interfacial
polymerization
-Tsuji et al.
11

12. 1985: A patent of “microencapsulated agricultural chemical and
process of preparation there of” was registered in Japan.
-Takahashi et al.
1987: A patent of “Microencapsulated insecticidal bat formulations
as fumigants” was registered by Dow chemical company in
Midland, Mich.
1991: Demonstrated release rate of dichlorvos (DDVP) by forming
PU as a shell wall barrier
-Chang et al.
1996: A patent of “Herbicidal microencapsulated clomazone
compositions with reduced vapour transfer” was registered
by Monsanto Company.
2005: Optimized herbicide (2,4-D) release from ethyl cellulose
microspheres
-Taverdet et al.
12

13. Reasons for encapsulation
 It is mainly used to increase the stability and life of the
active ingredient/insecticide being encapsulated.
 To give greater persistence effect.
 Conversion of liquid component (active functional
compound) to free-flowing powder i.e. formation of solid
system.
13

14. Masking objectionable odour, taste and activity due to
chemical properties.
Increased physical or chemical stability.
Targeting the specific site for release of active
encapsulated material.
Reduced phytotoxic effect.
Improved handler safety.
Reduced losses of core by vapour activity.
14

15. Some Commercial Uses of Microencapsulation
Self-locking bolts Seed coatings
Carbonless copy paperAdvertising perfumes 15

16. Flavourings in foodstuffs
Medicines 16

17. 17

18. CHARACTERISTICS OF MICROCAPSULE
• Microcapsules are spherical in shape and it should be
hollow/empty particles/structure.
• It should be free flowing powders consisting of proteins or
synthetic polymers, which are biodegradable in nature.
• Should have high Stability with the microcapsules.
• It should be easily dispersible in aqueous vehicle.
• Should have potentiality to release of active agent with good
control over wide time scale.
• Should have capability to protect the active ingredient.
Azagheswari et al., 2015 18

19. 19
Core material
(Insecticide or Active
ingredient)
Coating around core
material

20. Components of microencapsulation
• Micro capsule consist of two
components,
1. Core material and
2. Coat/wall/shell material
1. Core material (Insecticide or active
ingredient):
• The interior contents of capsules i.e. the
core can also be called as ingredient,
substrate, fill, active agent, internal
phase and nucleus or payload phase.
• The material to be coated is the core
material. It may be liquid or solid
• Liquid core may be dissolved or
dispersed material. 20
Active
ingredient

21. 2. Coating Material:
The external layer or layers that cover the core material is
the coating material and denominated as the wall, shell, membrane,
carrier, coat, external phase or matrix etc.
• Shells can be made from natural, semi-synthetic or synthetic
polymers.
• It should be compatible with the core material.
• Should be stabilize with core material.
• Should be inert toward active ingredients.
• The coating can be flexible, brittle, hard and thin.
• Should be abundantly and cheaply available
21

22. Table 1: Types of coating material use in microcapsule
POLYMERS EXAMPLE
 Depending upon origin
1. Natural polymers
A. Proteins Albumin, Gelatin, Collagen
B. Carbohydrates Agarose, Chitosan, Starch, Carragenan
C. Chemically modified
carbohydrates
Ploystarch, Polydextran
2. Synthetic polymers
A. Biodegradable Lactides, Glycolides and co ploymers,
Poly alkaly cyanoacrylates, Poly
anhydrides
B. Non Biodegradable Poly methyl methacrylate (PMMA),
Acrolein, Glycidyl methacrylate, Epoxy
polymers
22

23.  Depending upon solubility:
1. Water soluble resins Gelatin, Gum arabic, Starch, Poly vinyl
pylorridine, Methyl cellulose
2. Water insoluble resins Ethyl cellulose, Polyethylene, Poly
methacrylate, Polyamide (Nylon), Cellulose
nitrates, Silicones.
3. Waxes and lipids Paraffin, Carnauba, Beeswax, Stearic acid,
Spermaceti, Stearyl alcohol etc,.
4. Enteric acid Shellac, Cellulose acetate phthalate, Zein.
Sailaja et. al, 2015
• If the solid or crystalline material is used as the core, the
resultant capsule may be irregularly shaped.
• If the core material is liquid, simple spherical capsules
containing a single droplet of encapsulate may be formed.
23

24. Utilisation of different wall materials in capsule
suspension formulations.
37%
2%
7%
7%
2%
7%
2%
4%
1%
31%
Polyurea
Polyamide
Mixed polyurea/poluamide
Polyurethane
Urea/formalydehyde
Melamine resin
Nylon
Gelatin/guar gum
Phenol formaldehyde
Others
24
Hedaoo, R.K. (2013)Jalgoan

25. Cross section
25

26. 0
Classification of Microcapsule
Microcapsule
Mononuclear Polynuclear Matrix
The morphology of the internal structure of a microparticle depends
largely on the selected shell materials and the microencapsulation methods
that are employed. 26

27. Mononuclear microcapsules have a single hollow
chamber within the capsule.
The matrix type micro particle has the active
ingredients integrated within the matrix of the shell
material.
The polynuclear microcapsules have a number of
different sized chambers within the shell.
27

28. Technique to manufacture Microcapsule
1. Physical method
• Air suspension coating
• Pan coating
• Vibrational nozzle
• Centrifugal extrusion
• Spray – drying
• Electrospray
2. Chemical method
• Solvent evaporation
• Polymerization
3. Physico - Chemical method
Method
• Ionotropic Gelation
• Coacercevation phase separation
28

29. Table 2: Different method of encapsulation, applicable
material, production scale and cost
Sr.
No
Method Applicable
material
Particle
size
Time
required
Cost
1 Air Suspension Solid 35-5000 More High
2 Pan coating Solid 600-5000 More High
3 Coacervation &
phase Separation
Solid and
liquid
2-5000 Less Low
4 Centrifugal
extrusion
Solid and
liquid
1-5000 More High
5 Spray – drying Liquid 600 More High
6 Solvent
evaporation
Soli and
liquid
5-5000 Less Low
29

30. Complex coacervation, interfacial polymerization and In Situ
Interfacial polymerization are the most widely used processes
for microencapsulation of pesticides. The resulting product of
these processes is an aqueous dispersion.
Pesticide microcapsule powders can also be produced by multi
orifice centrifugation or electrostatic encapsulation. The
diameters of the microcapsules produced are limited to 80 um
and larger.
30

31. Advantage of microencapsulation
• Eco friendly and less expensive.
• Reduces the number of sprays.
• It is safe for honey bees, aquatic and terrestrial animal
and mammals.
• Enhance the self life of active ingredient.
• Reduce evaporation loses.
• Handling liquid as solids for convenience.
• Handling is safe and convenient for toxic materials.
• Masking of odor/smell of active agent.
• Controlled and targeted delivery of active ingredient.
• Reduces the plant stress and phytotoxicity.
31

32. Increased Stability for Bio pesticides
• Living organisms and bioactive compounds aren’t as hardy and
shelf stable as their synthetic alternatives.
• They tend to degrade rapidly in sunlight and have limited
storage lives and to be delivered at the right time and place
according to the target pest’s lifecycle.
• Encapsulation can help to increase the shelf stability of bioactive
compounds and living organisms such as bacterial spores.
• It can also help to ensure perfectly timed delivery for
biopesticides.
32

33. New microbial insecticide, Bacillus
thuringiensis var. israelensis
known as Bti is now being
incorporated into slow release
formulations and is reported to give
30 days or more control.
33
Source: https://inside.battelle.org/blog-details/encapsulation-is-changing-agriculture

34. Release mechanism
• Different release mechanisms of encapsulated materials
provide controlled, sustained or targeted release of core
material.
• There are three different mechanisms by which the core
material is released from a microcapsule i.e.
1. Mechanical rupture of the capsule wall
2. dissolution or melting of the wall, and
3. diffusion through the wall.
- Dubey, et al., 2009
34

35. Why controlled release mechanism is
necessary???
• Under certain conditions, the microencapsulated materials
may break down more slowly than expected.
• This could leave higher residues of pesticide active
ingredient in treated areas beyond normal restricted-entry
or harvest intervals with the potential to injure
fieldworkers.
• For this reason, regulations require long restricted-entry
intervals for some microencapsulated formulations.
35

36. 36

37. APPLICATION OF MICROENCAPSULATION TECHNIQUES
APPLICATION OF
MICRO
ENCAPSULATION
Medicine &
Veterinary
Household and
Personal care
Pharmaceutical
AGRICULTURE
Biotechnology &
Chemical industry
Food & Feed
Textile and waste
treatment
Electronics, Graphics
& Painting
Jyothi et al., 2012Guntur, A.P
37

38. Application of microencapsulation in Plant
Protection
• Encapsulating pesticides and other agrichemicals allows
growers to precisely control the conditions under which the
active ingredient is released.
• For example, a pesticide may be most effective at certain
humidity or ph levels or need to be targeted to the leaves or the
roots of the plant.
• Pesticide that works on the leaves of the plant, it may be
triggered by uv exposure.
• Another agrochemical that needs to be applied to the roots in
wet conditions may only be released when rain washes it down
into the soil.
• With encapsulation, growers don’t need to wait for perfect
conditions to lay down the product.
38

39. Now a days DEET are
encapsulated and this extends
efficacy from a few minutes to
several hours. This should prove
very useful extending the
effectiveness of other mosquito
repellents for Human's as well as
livestock.
DEET (N,N-diethyl-m-
toluamide) is a slightly
yellow chemical oil that is a
common active ingredient
in insect repellents . It is
considered one of the most
effective mosquito
repellents.
39

40. • Now a days insect pheromones are becoming viable as a bio
rational alternative to conventional hard pesticides.
• Microencapsulation delivered the pheromone in sufficient dose
and for longer period. It protects the pheromone from oxidation
and light during storage and release.
-(Dubey et al., 2009)
• Microencapsulated pheromone:
a. Deliver and effective amount of pheromone over an extended
period
b. prevent chemical degradation
c. deliver pheromone to the target insect
d. use minimum amounts of lure and be commercially feasible.
40
Insect Pheromone

41. Microencapsulation is successfully used for
various agrochemical formulations
41

42. Table 3: Control of Helicoverpa zea (cotton bollworm) in US
cotton with capsule and EC formulations of lambda-
cyhalothrin applied at 33gAI ha 1
Reduction in damage (%)
Formulation 3 DAA 7 DAA 14 DAA
EC 79 97 91
Zeon capsules 92 91 96
Shirley et al. (2001)California
42
DAA = Days After Application

43. Table 4: Toxicity of Insecticide formulation to first instar
larvae of Grapholita molesta (Oriental fruit moth)
Insecticide Formulation *LC50
Lambda-cyhalothrin EC 0.64 (0.49-0.84)
MEC 0.56 (0.41-0.75)
Pogoda et al. (2001)Ontario, Canada
43
* = 95 % confidence limit

44. Response of the subterranean termite Coptotermes formosanus
(Isoptera: Rhinotermitidae) to soil treated with microencapsulated
fenobucarb
• Microencapsulated fenobucarb is a fast‐acting termiticide, with a
good barrier effect as a soil treatment, that also acts as a reduced
repellent, retarding entry of termites into treated soil.
Kubota et al. 2007https://doi.org/10.1002/ps.1442
44

45. Table 5: The bioassay result of CEFs and CCFs against 3rd instar
Spodoptera litura larvae
Formulation Time
(day)
Mean 24-hr mortality (%)
160
(mgl-1)
80
(mgl-1)
40
(mgl-1)
20
(mgl-1)
10
(mgl-1)
LS
D
LC50
CEF
1 100.0 80.0 66.7 46.7 26.7 16.3 22.5
4 93.3 66.7 54.0 30.0 20.0 13.3 34.8
8 73.3 53.3 30.0 23.3 16.7 9.4 67.6
16 56.7 36.7 16.7 13.3 6.7 10.5 141.8
CCF
1 86.7 73.3 56.7 46.7 20.0 12.4 29.8
4 90.0 76.6 53.3 41.0 23.3 11.5 29.3
8 86.6 73.3 52.6 40.2 16.7 12.4 33.9
16 85.7 70.0 51.5 33.3 13.3 9.4 38.2
CEF = Chlorpyriphos emulsion formulation CCF = Chlorpyriphos containing microcapsule formulation
Ling Zhu et al,. 2010China
45

46. 100 fold increase in dead bees, in dead bee traps on the
first day after the honey bees were exposed to EC formulation
of methyl parathion as compared to 10 fold increase in dead
bees in Penncap M (Encapsulated methyl parathion) tests.
- Moffatt et al. (1983)
46

47. Blooming Helianthus annuus was treated with
microencapsulated methyl parathion, nearby honey bee
colonies showed a mean loss of 460 honey bees (A.
mellifera), while those treated with EC methyl parathion
had a mean loss of 1990 bees during the same period.
- (Waller et al. 1984)
47

48. Table 6: Activity of different formulation of insecticide against
two spotted spider mites
Per cent (%) kill after
Rate (active
agent lb./acre)
1
day
3
day
7
days
10
days
13
days
19
days
Microcapsule of
Methyl
parathion
5 lb. 100 100 100 100 100 75
1 lb. 50 100 100 100 99 50
0.5 lb. 25 90 100 100 95 25
Methyl
parathion EC
formulation
5 lb. 100 100 100 75 50 0
1 lb. 90 100 50 25 0 0
0.5 lb. 50 90 0 0 0 0
United States Patent, Patent Number: 3,959,464DeSavigny, 1976
48

49. Table 7: Activity of different formulation of insecticide (ethyl
parathion) against boll weevil in cotton
% kill after days
1 2 4 6 8
Encapsulated ethyl parathion 80 68 56 50 30
Unencapsulated ethyl parathion 36 20 12 0 5
United States Patent, Patent Number: 3,959,464
0.2 lb. active ingredient/acre
DeSavigny, 1976
49

50. Table 8: Activity of methyl parathion against boll
weevil in cotton
Rate lb./acre % kill after 3 DAA
Encapsulated methyl parathion ¼ 100
½ 100
Unencapsulated methyl parathion ½ 40
United States Patent, Patent Number: 3,959,464DeSavigny, 1976
50

51. Table 9: Activity of encapsulated and unencapsulated
formulation of methyl/ ethyl parathion against
boll weevil in cotton
% kill after days
4 9 32
Encapsulated methyl parathion 100 100 87
Encapsulated ethyl parathion 100 100 87
Unencapsulated methyl parathion 48 0 0
United States Patent, Patent Number 3,959,464DeSavigny, 1976
51

52. 52

53. Features:
 Longer-lasting
 More effective against insects including bed
bugs, roaches, ants, mosquitoes, beetles, flies,
stink bugs, carpenter bees, and more.
 It can be used for a variety of indoor and
outdoor pest applications, including residential
areas.
Cyzmic CS
53

54. Features:
 Offering long-term protection and fast knock-
down.
 Controls more than 30 common insects
including:
mites, crickets, fleas, ticks, spiders, ants, flies,
wasps and bed bugs. It can be used both
indoors and outdoors with little to no odour or
staining.
Demand CS (Lambda cyhalothrin)
54

55. Features:
It can be used inside place such as,
homes, offices and other man-made
structures.
It also is safe and effective to use
outdoors on places like turf and
livestock sites.
LAMBDASTAR 9.7% CS
Active ingredient: Lambda cyhalothrin 9.7%
55

56. Features:
 Provides long-lasting residual control of a
broad spectrum of insects.
 Effective against bed bugs, spiders,
scorpions, and more
 Kills bed bugs on contact with a residual
of up to 12 months
 Low odour
Active ingredients:
Fenvalerate.............................6.40%
Prallethrin.............................. 1.60%
Piperonyl butoxide..................8.00%
Other ingredients*..................84.00%
Total 100.00%
*Contains petroleum distillates
Onslaught Fastcap
56

57. Active ingredient: Chlorpyrifos
Pyrinex 25 CS
Features:
• Organophosphorus insecticide with a broad
spectrum of control.
• It is widely used as a foliar treatment.
• The active substance, chlorpyrifos, is an
inhibitor of cholinesterase that acts by
contact, ingestion and breathing.
57

58. Cy Kick CS
Active ingredient: Cyfluthrin 6.0%.
Colorado Beetle Beater M-One Microencapsulated
Active ingredient: Spinosad 0.5%
• Beneficial for organic production
• Controls the Colorado potato beetle larvae, as
well as selected leaf beetle larvae and adults -
naturally
58

59. Optimate CS
Active Ingredient: Gamma Cyhalothrin 5.9%
ABBA CS
Active ingredient: Abamectin 1.9%
Features:
 Can improve residual length up to 50%
 Low odour
 Reduces applicator exposure
 Controls mites and leaf miners
 Suppresses aphids, whiteflies, and
thrips 59

60. Product trade
designation
Active agent Polymer Application
Penncap M Methyl parathion Polyamide Insect control
Knox out 2FM Diazion Polyamide Insect control
Penncap E Ethyl parathion Polyamide Insect control
Tox - hyd Warfarin -- Rodent control
Fulkil Methyl parathion Insecticide
Pectimone Gossyplure
pheromone
Polyurea Insect mating
Distribution
Table 10: Different trade product, active ingredient and it’s
application
60
Source: Report by International atomic energy agency and the Food and Agriculture
Organization, Vienna.

61. Table 11: A list of studies on microencapsulated insecticides and its
application
Carrier system Agent Purpose Method Reference
Chitosan
Imazapic and
Imazapyr
Cytotoxicity
assays
Encapsulation
Maruyama
et al., 2016
Polyacetic
acid-polyethylene
glycol-polyacetic
acid
Imidacloprid
Decrease the
lethal
concentration
Encapsulation
Memarizade
h et al.,
2014
Carboxy methyl
chitosan
Methomyl
Control release
for longer time-
period
Encapsulation
Sun et al.,
2014
Alginate Azadirachtin Slower release Encapsulation
Jerobin et
al., 2012
61

62. 62

63. AMPLIGO 150 ZC
Active ingredient: Chloratranilprole (10 %)+
Lambdacyhalothrin (5%) ZC
Alika
Active ingredient: Thiamethoxam (12.6%) +
Lambdacyhalothrin (9.5%) ZC
Active ingredient: Lambda Cyhalothrin 5 ZC
Matador
Company: Syngenta India Ltd.
Company: Syngenta India Ltd.
Company: Syngenta India Ltd.
63

64. Karate 5 CS
Active ingredient: Lambda Cyhalothrin 5 CS
Company: Syngenta India Ltd., Dhanuka Agritech Ltd.
traded as Jakal and many well-known and
companies
64

65. Disadvantage of microencapsulation
 Possible cross reaction between core and shell
material.
 Difficult to achieve continuous and uniform film.
 Shelf life of hygroscopic ingredient is reduced.
 More production costs (depending upon coating
material and techniques).
 More skill and knowledge is required
65

66. 66

67. 67
• Encapsulated pesticides is targeting the specific site of plants
/insects and so it reduces the number of sprays and thus
phytotoxic effect.
• Due to encapsulation, shelf stability of entomopathogens is
increases.
• Microencapsulation delivers pheromone in sufficient dose and for
longer period of time.
• Encapsulated formulations viz., capsule suspension (CS) & zeon®
capsule (ZC) of insecticides controls the foliage feeders, plant
suckers and internal borers than the traditional formulations
(EC, SC, G, etc.) for longer period of time. It is also safer to honey
bees, aquatic and terrestrial animals.
• Microencapsulated insecticides having long lasting; knock-down
(against bed bugs, cockroaches, ants, mosquitoes, beetles, flies,
stink bugs, mites, crickets, fleas, ticks, spiders and wasps) as well
as repellent (termite) effects.

68. 68