A comparison: whydo neem products lag behind?

David Morgan,Chemical Ecology Group, Keele University, UK

E. D. MorganDepartment of ChemistryKeele University 1999

The background:13% of food crops destroyed by insects25% lost to weeds and pathogens42% of all rice planted is lost to insects

Synthetic pesticides:In U.S.A.

1945, total of 6,800 tons of synthetic insecticides used1990, total of 225,000 tons usedIn this time, crop losses increased from 31% to 37%

There is a strong,and growing demand for moreacceptable methods for pest controlAzadiractin is known and available yet it is little used

Why?

Amount of limonoids in seeds

0

50

100

150

200

250

Azadira

chtin

Salannin

Azadira

chtol

Desac

etylsa

lannin

Nimbin

Desac

etylnim

binAza

dirach

tin D

Salanninolid

eAza

dirach

tin I

azad

irach

tinin

Isosa

nanninolid

e

Compound

E D MorganChemical Ecology GroupKeele University 2006

“Neem” is not an accurate description of anything.I have suggested the term “azadirex”

Is an insecticidally active extract(however obtained) of the seed

Kernels of the neem tree that containsazadirachtin as its principal componentbut also contains other related biologicallyactive compounds of the limonoid type from the seeds

E D MorganChemical Ecology GroupKeele University 2006

0

5

10

15

20

25

30

35

40

45

50

half life in days

1 2 3 4 5 6 7 8 9 10 11 12 13 14pH

stability of azadirachtin in water

Series1

Booklet prepared by GTZ, the German organization for technical co-operation, for third worldfarmers to use simple neem technology

E D MorganChemical Ecology GroupKeele University 2006

Pyrethrum is a natural pesticidein increasing world demand

It is instructive to compare it with azadirex Growth

ProductionExtraction,PropertiesPriceMarket

Demand is four times world production

East Africa is the chief producer of pyrethrum,But production is very dependant upon rainfall

0

2000

4000

6000

8000

10000

12000

metric tonnes

1999 2000 2001 2002 2003 2004 2005 2006(projected)

2007(projected)year

Pyrethrum production in East Africa 1999-2007

E D MorganChemical Ecology GroupKeele University 2006

Pyrethrum has been studied as areplacement crop for tobacco in theCarolinas (USA)

New cultivars of plants with high pyrethrum contentMechanical harvesting of flower heads

E D MorganChemical Ecology GroupKeele University 2006

The government of Australia has invested an estimated $25 million in developing the pyrethrum industry and mechanizing it

The state of Tasmania now produces one third of world supply

Property Pyrethrum Azadirex Source Flowers Seeds Countries where grown About 10 About 80 Soil requirements Rich volcanic Poor, low fertility Water requirement High Low Replanting Every 4 years Permanent plants Harvesting Every 2 weeks Once a year Processing Solvent extraction Solvent extraction Yield per hectare 55 kg dried flowers 2000 kg seeds* Concentration 1-2% in dried flowers 0.5% in seed kernels Price per kg US $1 dried flowers US $ 2 dry seeds Gross income per hectare $55 $4,000 Number of compounds 6 10+ Effectiveness of compounds Varies widely Varies widely Range of insects Very wide Very wide Speed of action Very rapid Very slow Systemic action in plant No Yes Beneficial insects Toxic Non-toxic Toxicity to others Very toxic to fish, slight to birds Non-toxic LD50 500-1000 mg/kg rats >3540 mg/kg rats Human toxicity Very low Very low Problem in use Allergies possible Aflatoxin testing Stability in storage Very good Very good Stability on plants Very low Very low (?) Residues on food None None Stability in water Rapidly hydrolysed in acid or base Stable between pH 3.5 and 6 Licensed for use Most countries Few countries Value, annual production US $500 million Unknown but small *Depends upon density of planting, based on spacing of trees at 10 m

E D MorganChemical Ecology GroupKeele University 2006

Neem products have never received theinvestment that has been put into the

development of pyrethrum

If $2 per kgm is the true cost of neem seedsEither: cost must be reduced by mechanical

harvestingOr: a by-product must be found to offset the costHas neem oil a future?Herbal medicines are not the answerThe commercial future of the neem insecticide industry passes from chemists to engineers, economists and investors

Table 2. The fatty acid composition of neem seed oil, compared with palm oil and lard or pork fat. Minor fatty acids present in all these oils have been ignored here.

Fatty acid Neem seed oilMyanmar1 Neem seed oilKenya1 Neem seed oil

India2 Palm oil3 Lard or pork fat3Palmitic C16:0 20.3 30.8 16.9-22.7 32-59 20-32Stearic C18:0 19.3 17.3 9.1-18.8 1.5-8.0 5-24

Oleic C18:1 49.1 48.6 39.9-49.1 27-52 35-62Linoleic C18:2 11.3 3.28 17.3-24.3 5-14 3-16

1 EDM, unpublished results2 Kaushik (32)

3 Gunstone et al. (33)

E D MorganChemical Ecology GroupKeele University 2006

Table 2. The fatty acid composition of neem s eed oil, compared with palm oil and lard or pork fat. Minor fatty acids present in all these oils have been ignored here. Fatty acid Neem seed oil

Myanmar1 Neem seed oil Kenya1

Neem seed oil India2

Palm oil3 Lard or pork fat3

Palmitic C16:0 20.3 30.8 16.9-22.7 32-59 20-32 Stearic C18:0 19.3 17.3 9.1-18.8 1.5-8.0 5-24 Oleic C18:1 49.1 48.6 39.9-49.1 27-52 35-62 Linoleic C18:2 11.3 3.28 17.3-24.3 5-14 3-16 1 EDM, unpublished results 2 Kaushik (32) 3 Gunstone et al. (33)

The fatty acid composition of neem oil is unremarkable, But the presence of volatile sulphur compounds and bitterlimonoids limits its usefulness

Distribution of fatty acids within the glycerides has not been studied, and it affects the physical properties of the oil

E D MorganChemical Ecology GroupKeele University 2006

My thanks to a generation of students at KeeleCollaborators and correspondents around the world

Mrs Duan QiongfenMr Sunlong

Institute of Resource Insects, Kunming

The European Commissionfor the AZTEC project