Botanical pesticides

1. BOTANICAL PESTIIDES

3. Plant families that have been used as sources of bioactive
compounds with activity against important crop pests
include
Myrtaceae,
Lauraceae,
 Rutaceae,
 Lamiaceae,
Asteraceae,
Apiaceae,
Cupressaceae,
 Poaceae,
Zingiberaceae
 Piperaceae,
Liliaceae,
Apocynaceae,
Solanaceae,
Caesalpinaceae,

5. Current Botanicals in Use and Their Mode of Action
The botanical pesticides could be divided into two
generations:
The 1st generation included
 Nicotine,
 Roteno
Sabadilla,
Ryania,
Pyrethrum
 Plant essential oils;
2nd generation Botanicals
Synthetic Pyrethroids and
Azadirachtin, as well Potential
New Botanicals as stated by Regnault-Roger et al. (2005) in the book:
Biopesticides of plant origin

6. The major stages included in acquiring quality bioactive
molecule are
The selection of an appropriate solvent,
1. Extraction methods,
2. Phytochemical screening procedures
3. Fractionation methods, and
4. Identification techniques.
The essential of these methods and the exact road map
followed solely depends on the research design.
 Solvents commonly used in extraction of medicinal
plants are
Polar solvent: water, alcohols
Intermediate polar :acetone, dichloromethane and
 Nonpolar hexane, ether, chloroform.

7. In general, extraction procedures
include
Maceration,
 Digestion,
 Decoction,
Infusion,
Percolation,
Soxhlet extraction,
 Superficial extraction,
 Ultrasound-assisted, and microwave-
assisted extractions.

8. Fractionation and purification of phytochemical
substances are achieved through application of various
chromatographic techniques such as
 paper chromatography,
thin-layer chromatography,
gas chromatography, and
high-performance liquid chromatography.
Finally, compounds obtained are characterized using
diverse
identification techniques
such as mass spectroscopy,
infrared spectroscopy,
ultraviolet spectroscopy, and
nuclear magnetic resonance spectroscopy.
Subsequently, different methods described above can be
grouped and discussed according to the intended
biological testing

9. vi) Nature of constituents:
a) If the therapeutic value lies in non-polar constituents, a non-
polar solvent may be used. For example, lupeol is the active
constituent of Crataeva nurvala and, for its extraction,
hexane is generally used. Likewise, for plants like Bacopa
monnieri and Centella asiatica, the active constituents are
glycosides and hence a polar solvent like aqueous methanol
may be used.
b) If the constituents are thermolabile, extraction methods like
cold maceration, percolation and CCE are preferred.
c) For thermostable constituents, Soxhlet extraction (if
nonaqueous solvents are used) and decoction (if water is the
menstruum) are useful.
d) Suitable precautions should be taken when dealing with
constituents that degrade while being kept in organic
solvents, e.g. flavonoids and phenyl propanoids.

10. Nature of constituents:
d.In case of hot extraction, higher than required
temperature should be avoided. Some glycosides are
likely to break upon continuous exposure to higher
temperature.
e. Standardization of time of extraction is important, as
Insufficient time means incomplete extraction.
f. If the extraction time is longer, unwanted constituents
may also be extracted. For example, if tea is boiled for
too long, tannins are extracted which impart
astringency to the final preparation.
g.The number of extractions required for complete
extraction is as important as the duration of each
extraction.

11. Parameters for Selecting an Appropriate Extraction Method
i) Authentication of plant material should be done before performing
extraction. Any foreign matter should be completely eliminated.
ii) Use the right plant part and, for quality control purposes, record
the age of plant and the time, season and place of collection.
iii) Conditions used for drying the plant material largely depend on
the nature of its chemical constituents.
Hot or cold blowing air flow for drying is generally preferred. If a
crude drug with high moisture content is to be used for extraction,
suitable weight corrections should be incorporated.
iv) Grinding methods should be specified and techniques that
generate heat should be avoided as much as possible.
v) Powdered plant material should be passed through suitable sieves
to get the required particles of uniform size.

13. The plant parts are dried and ground into fine powder and
extracted with organic solvents that will maximize
extraction of the targeted compounds (Chougule and
Andoji, 2016).
Some of the botanical compounds with pesticidal activity
that have successfully been isolated and commercialized
include
Azadiractin from neem (Azadirachta indica)
Pyrethrin from pyrethrum (Tanacetum cinerariifolium)
Other plants with pesticidal properties include
Garlic (Allium sativum),
Turmeric (Curcuma longa)
Rosemary (Rosmarinus officinalis),
 Ginger (Zingiber officinale) and
Thyme (Thymus vulgaris) ).

23. Natural biodegradation of botanical pesticide
The biological nature of botanical pesticides makes their
degradation swift and therefore, do not accumulate in the
environment such as in water and soils therefore
eliminating chances of pollution .
Their exposure to air, sunlight, moisture and high
temperatures is enough to break down their constituents
Thymol, a compound found in Thymus vulgaris, Satureja
hortensis, Zataria multiflora and Piper nigrum takes about
28 hours to degrade under sunlight and about 8 days in
soils (Liu et al., 2016)
The half-life of azadirachtin, isolated from neem
(Azadirachta indica), is between one and two days in crops
and soil respectively .
Storage of plant extracts such as neem under sunlight
degrades their effectiveness as pesticides, indicating that
they degrade just as fast after application
 Pyrethrum-based insecticides last for only few hours
after application under field conditions

24. Bacteria species reported to degrade pyrethroids,
carbamates, organophosphates and
organochlorine pesticides include
Bacillus,
Serratia,
 Pseudomonas,
 Spingobium, Aerobacter,
 Escherichia, Ochrobactrum,
Arthrobacter,
Flavobacterium,
 Brevibacillus,
Sphingobacterium and Streptomyces

25. Factors Affecting Use of Botanical Pesticides
1. Raw material availability
2. Standardization of botanical extracts
containing a complex mixture of active
constituents
3. Solvent types,
4. Plant species and part of plant
5. Rapid degradation
6. State registration
7. Market opportunities for botanical pesticides
8. Weather conditions

26. Challenges in adoption of botanical pesticides.
Despite availability of proof of efficacy of botanical
pesticides against a wide range of crop pests, they are
still not well represented in the pesticide market.
Commercialization of botanical pesticides is
dependent on availability of the source plants in large
quantities and the plants should be readily cultivated.
 The source plants are either grown for other uses
such as food, medicinal, shade, ornamental or growing
naturally.

27. Neem Products (Azadirachtin)
Two types of botanical pesticides can be obtained from
seeds of the Indian neem tree, Azadirachta indica
(Meliaceae) (Schmutterer 1990, 2002).
Neem oil, obtained by cold-pressing seeds, can be
effective against soft-bodied insects and mites but is also
useful in the management of phytopathogens.
Apart from the physical effects of neem oil on pests and
fungi, disulfides in the oil likely contribute to the bioactivity
of this material (Dimetry et al. 2010; Dimetry 2012).
 More highly valued than neem oil are mediumpolarity
extracts of the seed residue after removal of the oil, as
these extracts contain the complex triterpene azadirachtin .
Neem seeds actually contain more than a dozen
azadirachtin analogs, but the major form is azadirachtin and
the remaining minor analogs likely contribute little to
overall efficacy of the extract.

28. Neem Products (Azadirachtin)
Seed extracts include considerable quantities of other
triterpenoids, notably salannin, nimbin, and derivatives
The role of these other natural substances has been
controversial (El-Sayed 1982– 1983a, b), but most evidence
points to azadirachtin as the most important active principle
(Isman et al. 1996).
Neem seeds typically contain 0.2–0.6% azadirachtin by
weight, so solvent partitions or other chemical processes
are required to concentrate this active ingredient to level
10–50% seen in the technical grade material used to
produce their products (Sallena 1989; Schmutterer 1990).

29. Special trial on Essential oils
Treatments Dosage Leaf Blast PDI Yield Kg/ha
Citronella oil 1ml/l 41.75(40.27) 4975
Eucalyptus
oil
1ml/l 32.98(35.07) 6393
Cedarwood
oil
1ml/l 36.00(36.89) 5692
Nirgundi oil 1.5ml/l 34.88(36.22) 6357
Lemon grass
oil
1.25ml/l 30.06(33.27) 6567
Clove oil 1.25ml/l 28.59(32.34) 6650
Neem
essential oil
1ml/l 32.63(34.85) 6527
Emulsifier 1ml/l 52.22(46.30) 4347
Carbendaizi
m 50WP
1ml/l 29.98(33.21) 6517
Control 60.03(50.81) 3945
CD @ 5% 4.33 741.6

30. Invitro evaluation of essential oils against Pyricularia oryzae and
Helminthosporium oryzae
Special trial on Essential oils

31. Special trial on Essential oils

32. Special trial on Essential oils

33. In vitro evaluation of fresh extracts of botanicals against A.porri by
poison food technique (Fresh )

34. In vitro evaluation of fresh extracts of botanicals against A.porri by poison food
technique (boiled )

35. Sl.
No
Botanicals/plant
products
% inhibition of mycelial growth (fresh extract)
% inhibition of mycelial growth(boiled extract)
Concentration (%)
Mean
Concentration (%)
Mean
5 10 15 20 5 10 15 20
1
Cinnamon bark
extract
13.25 a b
(21.16)
20.28 a b
(26.71)
22.22 a b
(27.52)
34.44 a b
(35.75
22.29
(27.79)
6.83 a b
(15.14)
10.50 a b
(18.89)
14.45 a b
(22.29)
33.33 a b
(35.17)
16.28
(22.8
8)
2
Clerodendron
leaf extract
10.50 a b
(18.86)
18.13 a b
(25.18)
24.44 a b
(30.51)
31.28 a b
(33.96)
21.43
(27.13)
2.77 a b
(9.55)
9.50 a b
(17.94)
13.88 a b
(21.78)
30.90 a b
(33.72)
14.26
(20.7
5)
3 Garlic extract
42.33 a b
(40.51)
52.50 a b
(46.41)
88.50 a b
(70.18)
100.00 a
b
(81.87)
73.71
(66.71)
3.17 a b
(10.19)
5.95 a b
(14.06)
9.17 a b
(17.60)
19.44 a b
(26.14)
9.43
(17.0
0)
4 Neem oil
50.47 a b
(45.25)
65.83 a b
(54.21)
72.22 a b
(57.46)
76.94 a b
(57.46)
64.63
(53.6)
10.33 a
b
(18.72)
15.47 a b
(23.11)
21.33 a b
(27.49)
28.17 a b
(32.04)
18.83
(25.3
4)
5 Pongamia oil
35.03 a b
(36.26)
43.61 a b
(41.31)
55.55 a b
(48.0)
66.94 a b
(54.88)
50.22
(45.11)
17.42 a
b
(24.65)
24.46 a b
(29.62)
26.33 a b
(30.85)
32.92 a b
(34.99)
25.28
(30.0
3)
6
Turmeric
rhizome extract
8.29 ab
(16.72)
10.33 a b
(18.72)
12.50 a b
(20.63)
17.31 a b
(24.56)
11.59
(19.64)
3.50 a b
(10.76)
6.74 a b
(15.03)
11.50 a b
(19.79)
15.45 a b
(22.99)
9.30
(17.1
4)