Post on 21-May-2015
Botanical insecticides and their future perspectives
By,Bharati Singh
Characteristics of botanical insecticides
• Fast breakdown, Fast action
• Phyto toxicity, selectivity
• IPM friendly, cost and availability
Just because a pesticide is natural, does not mean it is safe
Limonene and linalool
• Extracted from orange and other
citrus fruits
• Limonene , a terpene, and purified
by steam distillation
• Linalool, a terpene alcohol, found
in small quantities in citrus peel
d- limonene
• Limonene often applied with PBO (pyperonil butoxide)
• Target pests: Fleas, aphids, mites, flies, paper wasp
• Mode of action:
• Act as nerve toxin and stomach poisons(limnonene)
• Affects ion transport and release of acetyl choline esterase(linalool)
Rotenone
• Isolated from the roots of two tropical legumes Lonchocarpus or Derris
• Extremely toxic to fish
Root of the Tuba
roots of the legume family (Fabaceae).
Rotenone structure
Deguelin structure
• Target pests: caterpillers, aphids, suckers and other pests found in fruits and vegetables , certain beetles
• Mode of action- inhibits the electron transport chain in the mitochondria
Electron Transport Chain
Rotenone’s safety is somewhat controversial
Sabadila
• Extracted from the seeds of the sabadilla
lilly (Schoenocaulon officinale)
• cevadine + veratridine = veratrine
2 : 1
White hellebore
S. Officinale
Mode of action• Similar to that of the pyrethrins as it affects
the voltage dependent sodium channels of nerve axons.
• Veratridine causes an increase in the duration of the action potential
Ryania
• Obtained from the roots and stems of a South American herbs (R. speciosa)
• contain alkaloids with insecticidal activity, collectively known as ryanoids
mode of action • Slow acting stomach poison• Block neuromuscular junction
Most active ryanoid is ryanodine and 9,21-dehydroryanodine
Ryanodine
Neuromuscular junction
Future Perspectives
• Botanical insecticides (BI) were major weapons (before 1940’s)
• Use of BI in California grew by almost 50% between 2006 and 2011
• Quite logical to expect coexistence of the two kinds of compounds i.e synthetic and natural insecticides
• Barrier to commercialization
scarcity of natural resources
standarization and quality control
Regulatory approval
References• Dayan et al (2009), Bioorganic and medical chemistry 17, 4022- 4034, Natural
products in crop protection
• Isman (1997) Phytoparasitica 25 (4): 339-344, Neem and other botanical insecticides:Barriers to commercialization
• Isman, Annu. Rev. Entomol.2006.51:45-66
• Martina et al, Agriculturae conspictus scientificus .Vol. 78 (2013) No .2 (85-93),Botanical insecticides in plant protection
• Nikoletta et al, pesticides laboratory,Pesticides of botanical origin: A promising tool in plant protection
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