By : Dr. Mohammad Akhtar
Institute of Agriculture,
Aligarh Muslim University, Aligarh.

Research in pest management usually aims to improve our understanding of the underlying biological and ecological processes associated with pest problems or to develop specific control measures. During the past twenty years there has been increasing concern over the adverse effects that certain nematicides / insecticides might have on the environment. As with pesticides, there is now much greater emphasis on seeking natural nematicides (biopesticides) and natural enemies for controlling plant - parasitic nematodes.

Plant - parasitic nematodes are one of the major factors limiting agricultural productivity. Chemical nematicides, though effective in providing rapid kills of nematodes are now being reappraised concerning their environmental hazardousness high cost and limiting availability in India. Attention of nematologies is now focussed on alternative control strategies, including cultural and biological methods. Numerous cultural practices can be beneficial by reducing population densities of plant - parasitic nematodes. Plant products are receiving greater attention as an effective means of control for nematode pests mainly because of their presumed safety to non - target organisms. NEEM (Azadirachta indica) products including leaf powder, seed kernel, seed powder, sawdust, oil and oil cake, and a number of commercially available products have been effective in managing several species of plant - parasitic nematodes in commercial crops.

Interest in using plant - based products (biopesticides) for suppressing plant - parasitic nematodes in the soil is receiving attention in the recent past. Only, a few studies have investigated on the use of neem as a nematicide during past decades.

The objective of my research was to determine the effects of different amounts of neem - by - products and commercial neem - based products on populations of plant - parasitic nematodes and the growth of pulses and vegetables in agricultural soils. Research experiments are mainly categorized on the following topics:

1. Neem tree parts as soil amendments:

Every part or product of the neem tree ( i.e. leaves, stem, barks, oils, oilcake, sawdust etc. ) have been shown to have a significant role to play in nematode management.

2. Seed treatments with neem formulations and by-products:

Neem oil, oilseed cake extracts, commercial neem - based products such as Suneem, Suneem G, Nimin, Achook, and Jawan when used as a seed - coating were found to be highly effective as prophylactic and therapeutic against nematodes.

3. Bare - root - dip treatments with neem formulations and by - products:

Bare - root - dip treatments in neem oil and other neem - based products have been reported nematicidal.

4. Nitrogen fertilizer efficiency improvement:

Inorganic fertilizers containing ammonia, nitrogen or formulations releasing this form of nitrogen in the soil can suppress nematode populations. Triterpene compounds in neem cake and neem - based products inhibit the nitrification process and provide more available nitrogen in the form of ammonium to the plants for the same amount of nitrogen applied by the amendments.

5. Longevity of neem by-products:

Neem oilcakes, leaves, sawdusts and other by - products are heavy organic compounds, therefore their decomposition into simple substances takes place rather slowly and is a time consuming process. Thus application of such materials leads to sustained release of nutrients to the plants, which ultimately results in suppression of the population of plant - parasitic nematodes.

Mechanisms result in nematode control:

Nematode populations may have been affected by these treatments through leached chemicals, either coating the seeds or being absorbed by the roots during bare - root - dip treatment into rihzosphere which repelled or killed nematode juveniles that attacked the host root.

The mechanisms by which nematode pests are controlled by neem by - products amendments is not yet fully understood, mainly because the complex nature of the soil environment hampers the elucidation of the different activities and interactions that occur. Presumably, nematode control resulted from a release of toxic compounds which either were present at sublethal concentrations in the rhizosphere of crop plants.

Since neem is known to contain several chemicals ( e.g. azadirachtin, nimbocinol, nimbin, etc. ), that have been reported to have nematicidal properties. Crop protection is an integral part of current food production.High losses are incurred in some economically important crops as a result of plant - parasitic nematodes, because of this, they are considered a serious constraint to agricultural production - particularly where intensive levels of some plant - parasitic nematodes ?

Knowledge of the extent of yield losses caused by various pests including plant - parasitic nematodes in a cropping systems provides baseline information which can be used to determine priorities for Research and Development in pest management, to assess the likely costs and benefits and control and as a decision making aid to governments and farmers. The future of crop protection in developing countries like India, depends upon the use of integrated pest management approaches within the context of holistic development of natural resource production systems. It is important that biopesticides like those derived from NEEM need to be studied extensively and their potential benefits brought to the attention of farmers.

ACKNOWLEDGED WITH THANKS!

Prof. Murray B. Isman, Meeting Chairman,
Faculty of Agricultural Sciences,
University of British Columbia,
Vancouver, Canada V6T 1Z4

Dear Ms. Thakkar,
Please find enclosed a money order in the amount of US$ 670.15 ( the total following conversion from $1,000 Canadian ) that I wish to donate to the neem foundation. This donation arises from surplus funds remaining after accounts were settled for NEEM 99, the World Neem Conference held in Vancouver last May. The funds can be used completely at your discretion. I am sure that you will put them to good use.

It was a pleasure to have you participate in NEEM 99 and to have the opportunity to meet your family. I wish the Foundation every success in the future.

With best regards,
Murray B. Isman


In The Wake of NEEM FOUNDATION's Campaign ...

GOVERNMENT URGED TO DECLARE NATIONAL TREES:

Referring to the longstanding debate and indecision within the government on adopting a National Tree, WWF - India has urged the Ministry of Environment and Forests to declare the Banyan (Ficus bengalensis), Peepal (Ficus religiosa) and Neem (Azadirachta indica) as National Trees.

If we could declare a national animal - the tiger and a national bird - the peacock - long ago, there is no reason why we should indefinitely delay on such an important concept for conservation as National Trees, feels WWF - India.