The following facts become apparent when comparing the various approaches taken for assessing the losses caused by the LGB in farm-level stores, the farm-level and macro-economic impacts of these losses and the benefit of control measures:
· The methodological approaches differ (apart from the determination of dry matter losses).
· The findings of the individual studies diverge considerably,
because:
· _he situation changes from region to region and from season to season.
· The number of available sources drops, as does the accuracy of the statements they make, the broader the level of analysis becomes (from loss assessment, to farm-level analysis to macro-economic assessment).
The GTZ has been working to close the knowledge gaps for a whole decade now, by supporting doctoral theses (Pantenius, 1988; Böye, 1988; Albert, 1992; Henckes, 1992; Helbig, 1995; Mutlu, 1998; and the theses of Schneider and Stumpf that are yet to be completed).
Approaches derived from practice, being based on a number of simplifications and generalizations, (cf. Box 6) only meet scientific demands to a limited extent but can nonetheless provide reference values for practical work in the field. By assuming best-case and worst-case scenarios it is possible to cover the full range of possible outcomes.
The following analysis of the costs and benefits of biological control of the LGB (Table 2) follows a macro-economic calculation for maize production in Togo, Benin and Guinea (Conakry). It is based on the work of Schneider (unpublished) and considers data on the development of real post-harvest maize losses at individual farms, in addition to biological characteristics of the predator-prey dynamics and data on the current spread of both the pest and the beneficial insect. In particular, the external costs of post-harvest protection measures are also valuated, i.e. such costs that are not incurred directly by the individual farmer. External costs can be individual costs, such as expenditure for medical treatment and medicines or opportunity costs of lost labour resulting from improper application of pesticides. Costs can further be public, such as costs for remediating water or food contamination caused by pesticides, or costs incurred by the state plant protection service when a new agent is introduced and farmers must be instructed in its use.
Line 2 gives that part of maize production that is not treated with pesticides (source: FAO). Line 3 states the average market value of a ton of maize in the respective year. Line 4 shows the loss avoided through the use of Tn. This becomes effective for the first time in 1994, with 2.5% of the maize harvest, and rises continuously until reaching a level of 15% in 1999. Line 5 gives the money value of the avoided loss.
Line 6 states the costs of developing and implementing the biological control programme. The costs of rearing, releasing and monitoring Tn are stated separately in Line 7, as these, in contrast to the development costs, will continue to arise in the future if the programme is applied in other countries. Line 8 gives the total costs.
Table 2: Cost-benefit analysis of biological control of the LGB for the maize production of Benin, Togo and Guinea (Conakry) 1980-2010
|
1 Year |
1985-90 |
1991 |
1992 |
1993 |
1994 |
1995 | ||||||||||||||||
2 Maize production (untreated) |
t |
3 420 000 |
596 000 |
664 000 |
789 000 |
685 000 |
740 000 | |||||||||||||||
3 Market value |
DM/t |
355 |
355 |
503 |
296 |
296 |
325 | |||||||||||||||
4 Avoided loss |
% |
0 |
0 |
0 |
0 |
2.5 |
2.5 | |||||||||||||||
5 Benefit |
DM |
0 |
0 |
0 |
0 |
5 070 000 |
6 020 000 | |||||||||||||||
6 Development and implementation of the biological control progr. |
DM |
4 067 000 |
581 000 |
823 000 |
488 000 |
983 000 |
983 000 | |||||||||||||||
7 Mass rearing, release and monitoring of T. nigrescens |
DM |
352 000 |
10 000 |
5 000 |
5 000 |
5 000 |
5 000 | |||||||||||||||
8 Total costs |
DM |
4 419 000 |
591 000 |
828 000 |
493 000 |
988 000 |
988 000 | |||||||||||||||
|
9 Net surplus |
DM |
(4 419 000) |
(591 000) |
(828 000) |
(493 000) |
4 082 000 |
5 032 000 | |||||||||||||||
10 Net surplus
|
DM |
(4 419 000) |
(5 010 000) |
(5 838 000) |
(6 331 000) |
(2 249 000) |
2 783 000 | |||||||||||||||
11 Net surplus
|
DM |
(2 780 000) |
(2 920 000) |
(3 150 000) |
(3 170 000) |
(1 040 000) |
1 190 000 | |||||||||||||||
|
1 Year |
1996 |
1997 |
1998 |
1999 |
2000 |
2001-10 | ||||||||||||||||
2 Maize production (untreated) |
t |
907 000 |
891 000 |
891 000 |
891 000 |
891 000 |
8 910 000 | |||||||||||||||
3 Market value |
DM/t |
355 |
473 |
355 |
355 |
355 |
355 | |||||||||||||||
4 Avoided loss |
% |
5 |
8 |
10 |
15 |
15 |
15 | |||||||||||||||
5 Benefit |
DM |
16 100 000 |
33 740 000 |
31 630 000 |
47 450 000 |
47 450 000 |
474 500 000 | |||||||||||||||
|
6 Development and implementation of the biological control progr. |
DM |
983 000 |
983 000 |
495 000 |
495 000 |
248 000 |
||||||||||||||||
7 Mass rearing, release and monitoring of T. nigrescens |
DM |
5 000 |
98 000 |
41 000 |
|
|
||||||||||||||||
8 Total costs |
DM |
988 000 |
1 081 000 |
536 000 |
495 000 |
248 000 |
||||||||||||||||
|
9 Net surplus |
15 112 000 |
32 659 000 |
31 094 000 |
46 955 000 |
47 202 000 |
474 500 000 | ||||||||||||||||
10 Net surplus cumulative |
DM |
17 895 000 |
50 554 000 |
81 648 000 |
128 603 000 |
175 805 000 |
650 305 000 | |||||||||||||||
11 Net surplus cumulative (8% discount rate) |
DM |
7 110 000 |
18 590 000 |
27 800 000 |
40 540 000 |
51 320 000 |
87 920 000 | |||||||||||||||
12 Internal interest rate (10 years) |
1% |
15 Cost-benefit relation (20 years) |
1 : 57 | |||||||||||||||||||
13 Internal interest rate (20 years) |
68% |
16 Amortization after 9.5 years |
||||||||||||||||||||
14 Cost-benefit relation (10 years) |
1 : 1.3 |
Exchange rate: 1,77 DM = 1 US$ (February 28, 1999) | ||||||||||||||||||||
Line 9 calculates the surplus, which was negative in the first years of the project (figures in parentheses). Line 10 shows the cumulative surplus, i.e. the total of the annual surpluses. Line 11 adjusts (discounts) these figures to their future value. These values form the basis for calculating the economic ratios of the programme, which are given in Lines 12 to 16. For a project duration of 10 years, the internal interest rate, which is comparable to the rate of return of a normal financial investment, figures 1% annually (68% over 20 years), the cost-benefit relation figures 1 : 1.3 (1 : 57 over 20 years). The amortization period of the project funds employed for biological pest control in these three countries is about 9.5 years.
In Togo, Benin and Guinea the annual costs of pesticides used in post-harvest protection amount to approx. 660 000 DM. Estimates indicate that each year some 500 users suffer such severe intoxication that treatment and opportunity costs of approx. 10 000 DM are incurred. However, the largest general external costs have been incurred through the development, testing and introduction of several binary pesticides intended specifically for the control of the LGB. In addition to development costs for stored product protectants running into the millions, which are borne by the manufacturer, high costs were incurred above all in Togo and Benin for extension efforts in connection with the introduction of chemical protection measures. In both Togo and Benin, the national plant protection services received considerable support from the GTZ and BMZ in terms of both financial and human resources for advising farmers. A total sum of approx. 5 million DM can be assumed for the costs that have arisen (and continue to arise) here. The minimal effect of chemical measures in the control of the LGB is due not only to the abovementioned socio-economic conditions, but also to the biology of the pest, which lives for most of the year in inaccessible regions in various shrub and tree species.
If we add the expenditures that can be saved here in the future to the costs avoided by the biological measure, then the benefit of the control programme is considerably increased.
In an overall perspective, the costs and benefits of individual integrated post-harvest protection projects can scarcely be analysed separately. As set out in section 1 above, the BMZ has supported various projects and research efforts whose work has touched and complemented each other in a variety of ways.
Frequently several institutions operate at the same time in the same area (in the case of biological control of the LGB in Africa, these are the NRI and IITA with funding from different sources). In most cases, their contributions to solving the problem can not be analysed in isolation. The participation of various donors, implementing organizations and projects in solving the stored product protection problems of a country are illustrated by the example of the list of post-harvest projects and activities carried out in Benin since the first occurrence of the LGB:
· FAO project for the prevention of post-harvest losses
· Stored product protection component of the GTZ project supporting the national plant protection service
· Post-harvest activities of the GTZ regional development project in the CARDER Atlantique
· Post-harvest activities of the integrated food security project of the GTZ
· Post-harvest activities of the food security project of the World Bank
· Post-harvest activities of the UNDP/World Bank project for decentral storage systems implemented by FAO
· Research by IITA on the biological control of the LGB
· Support for the biological control of the LGB by the TT&TU project of the GTZ and IITA
· Support for the biological control of the LGB by the supraregional GTZ project for the integrated control of the LGB
· Specific post-harvest activities of the supraregional GTZ project "Small Farmers Post-Harvest Protection" (training, extension)
· Training of local specialists by the German Foundation for International Development/Food and Agriculture Development Centre (DSE/ZEL)
· Training of local specialists by other institutions
· Post-harvest activities of Sasakawa Global 2000
· Post-harvest activities of various other non-governmental organizations
This example is typical. The tendency is the same in other countries (e.g. Ghana or Tanzania). An analysis of the cost-effectiveness of programmes, such as that for the biological-integrated control of the LGB, can consequently only then yield meaningful results if the main inputs through research and implementation-oriented projects are considered in an overall perspective. It is clear that the contribution of specific donors can not be ascertained in quantitative terms, as the benefit can not be derived as a function of effort invested.