Corn Grain Mould Used as Pesticide

[Guest guest]

OMAHA (DTN) -- In the early 1960s more than 100,000 turkeys died in

Britain of cancer of the liver. Eventually, researchers identified

moldy peanut flour from Brazil containing large amounts of aflatoxin

as the cause of this mysterious 'turkey X' disease. Even today the

toxin is regarded as one of the most virulent natural carcinogenic

substances.

The tasteless toxin is produced by the mould aspergillus flavus. It

grows in hot, arid regions, in the south-west of the U.S. and in

many regions of Africa and Asia. In Third World countries,

particularly, this dangerous paintbrush-shaped mould is ubiquitous.

This may be one reason for the high rate of liver cancer in Africa.

" Our colleagues from the International Institute of Tropical

Agriculture (IITA) in Nigeria recently succeeded in proving that 99

out of 100 children from Benin and Togo had aflatoxin in their

blood, " Professor Sikora of the Bonn Institute of Plant

Diseases explains. " The consequence is drastic impairment of growth

and of other types of development. "

The remedy may lie in the idea of U.S. researchers Dr. J.

Cotty, which is both simple and ingenious.

" In addition to the dangerous strain aspergillus flavus there are

also others which cannot produce any toxin, " the Bonn plant

pathologist Dr. Sebastian Kiewnick explains. " Cotty propagated this

non-toxic strain of aspergillus on grains of corn and spread the

mould-infected grains in fields of cotton. As a result, the non-

toxic strain was present in substantially larger amounts and was

thus able to almost entirely supplant the toxic variety. "

The success was overwhelming: aflatoxin infection of the cotton cobs

dropped from an average of 1,000 ppb (parts per billion) to below 20

ppb, thereby lying within the U.S. safety limit for animal food --

cotton seeds serve as food e.g. for dairy cattle.

Two years ago the 'good' mould was permitted in the U.S. as an

organic pesticide. Five kilos of mould-infected grains of corn are

sufficient to 'inoculate' an area of one hectare -- this means that

the method is relatively inexpensive.

" For developing countries, particularly, this would be the ideal

strategy to get the upper hand of the aflatoxin problem, " Professor

Sikora thinks.

He has had quite a lot of experience with combating tropical plant

diseases. For two years the Bonn team, together with colleagues from

the IITA in Benin and Nigeria, have been looking for a mould isolate

which is guaranteed to be unable to produce aflatoxin -- after all,

they do not want to fight Satan with Beelzebub.

" Apart from that the aspergillus variant has to be so sturdy that it

can assert itself against its toxic cousin in the wild, " Professor

Sikora says.

The Federal Ministry of Economic Co-operation and Development (the

BMZ) is supporting the project until 2006 to the tune of a total of

1.2 million euros. The researchers have made an important

advance: " We have examined 3,000 isolates in all and have come

across several promising strains, " Sebastian Kiewnick states. " Now

we'll soon be conducting the first field trials. " Should they be

successful, the team want to develop a quick and easy method for

propagating the non-toxic mould for use en masse.

There is no danger of additional damage as a result of 'inoculating'

the fields with mould, it is claimed. " It can scarcely be prevented

that maize or nuts will be infected to a certain extent with brown

mould, " Sebastian Kiewnick emphasizes. " We can only influence which

strain of aspergillus grows on it: a dangerous producer of toxins --

or the non-toxic variant. "