New approaches to improve the livelihoods of poor farmers and pastoralists through monitoring and control of African armyworm, Spodoptera exempta.

Transcription

1 New approaches to improve the livelihoods of poor farmers and pastoralists through monitoring and control of African armyworm, Spodoptera exempta. WILFRED L MUSHOBOZI, 1 DAVID GRZYWACZ 2, RICHARD MUSEBE 3, MARTIN KIMANI 3 and KEN WILSON 4 1 Pest control Services, Ministry of Agriculture and Food security, Arusha, Tanzania 2 Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK 3 CAB International Africa Regional Centre P O Box , Nairobi, Kenya 4 Department of Biological Sciences, Lancaster Environment Centre, Lancaster University, LA1 4YQ, UK United Republic of Tanzania Ministry of Agriculture and Food LANCASTER U N I V E R S I T Y Division of Biological Sciences Institute of Environmental and Natural Sciences Lancaster LA1 4YQ United Kingdom

2 The African Armyworm Spodoptera exempta) Armyworm is a serious outbreak pest of cereal crops and grasslands in eastern and southern Africa

3 Armyworm is especially damaging when it attacks the cereal crops like maize, rice and sorghum and grassland which provide much of the food and pastures for poorer households

4 Armyworm Outbreaks in Tanzania occurs frequently Armyworm can reach densities in excess of 1000 caterpillars per m 2 African armyworm outbreak in Arusha, Tanzania March 04

5 Reported armyworm outbreaks in Tanzania during the period Number of Districts Seasonal Area Infested affected Year (Hectares) (out of total of 113) 1989/90 28, /91 15, /92 517, /93 34, /94 45, /95 4, /96 3, / /98 35, /99 311, / / , / , / ,414 32

6 Migration of Africa Armyworm moths Outbreaks start in central Tanzania then adult moths spread to other parts of the country starting new outbreaks The adult moths from these outbreaks move on to other east African countries including Kenya, Ethiopia, Uganda, Sudan Eritrea and Yemen. Also may move southward to Malawi, Mozambique, Zambia and South Africa

7 Life-cycle of African armyworm MOTHS (5-16 d) PUPAE (7-10 d) EGGS (2-4 d) Moths migrate 100s km Larvae pupate in the soil LARVAE (11-22 d) 1 st instars eat egg shell Larvae damage crops

8 The impact of armyworm outbreaks on cereal and livestock production Armyworm outbreaks impact primarily on cereal production, maize, sorghum, wheat and rice, thus effecting the food security Large outbreaks of armyworms can have devastating effects on the quality and quantity of pasture available to livestock Armyworms have been linked with the lethal poisoning of cattle due to a phenomenon known as Armyworm Related Cattle Poisoning (ARCP).

9 Management of African armyworm Monitoring through pheromone trap Weekly forecast and early warning Timely control

10 Existing armyworm management The management of African armyworm has been to rely on centralised forecasting and decision-making. Armyworm control has been dependant upon the use of chemical insecticides to control outbreaks These are chemicals often given free to Tanzania as part of aid projects and distributed to farmers in outbreak areas

11 Problems with centralized forecasting and decision-making. Less than 25% of intended farmers are receiving the forecasts Larval outbreaks are catching farmers unawares and unprepared. Farmers are getting too late warning to plan and implement control.

12 Chemical control of armyworm also has significant problems Imported insecticides are expensive for Tanzania This results in limited availability: in most cases only 10-30% of insecticide needed can be provided to farmers Increasing concerns about the negative environmental effects of broad spectrum chemicals Increasing donor objections for provision of chemical insecticides or funding their use. Many poor farmers are unable to afford the $10 ha-1 chemical costs.

13 Reliance on chemical control has also created a serious problems in Tanzania disposing of 1200MT of obsolete insecticide Disposal to cost 8.0 Million $ Disposal to cost 8 million $

14 New approaches to control armyworm for the benefit of poor farmers and pastoralist in Tanzania Not rely on expensive imported Chemicals Have less negative environment- -al effects Be locally produced & cheaper Managed by local Community Community Based Armyworm Forecasting (CBAF) Utilization of armyworm natural disease (SepxNPV)

15 Community Based Armyworm Forecasting (Piloted in 20 villages) Each village democratically elect two farmers 2 day training workshop Trained community forecasters take home forecasting park (Pheromone trap, rain gauge, operator's manual & recording sheet) Forecasters run the trap & issue weekly forecast Mid and end of season evaluation

16 Mid season & end of season evaluation Check the performance of community forecast Assess the forecast information flow among the stakeholders Assess the farmer s response to the forecast

17 Evaluation indicators forecasters making correct forecasts positive forecasts with outbreaks negative forecasts without outbreak proportion of farmers monitoring and controlling

18 Forecast Information Flow COMMUNITY FORECASTER Extension officer Village Government Village runner Village school Church & Mosque Farmers

19 Analysis of Forecasting efficiency Outbreaks Farmer forecast Yes No Positive (Occurred) 23 (74%) 8 (26%) Negative 2 52 (4%) (96%)

20 A comparison of before and after CBAF Attribute Moths are precursor of armyworm outbreaks Knowledge of armyworm forecast Before (%) After (%) Change (%) Access of forecast information Farmers monitoring their fields Farmers attempting to control with various methods Control at instars I &II

21 Why use Baculoviruses (NPV) as Bio control Agents against armyworms? Baculoviruses are natural pathogens Usually highly host-specific (incl. SpexNPV) Very safe to humans and non-target organisms

22 African armyworm nucleopolyhedrovirus (SpexNPV) control SpexNPV has been known since 1965 SpexNPV is a natural disease of armyworm that can destroy 98% of armyworm outbreaks in the later part of the season. By introducing it artificially we can destroy armyworm outbreaks before they can cause to damage to crops.

23 How does NPV work as a bio control agent against armyworms? 2004 Ground spray trials 2004 Aerial spray trials

24 NPV ground spray trial 160 NPV acts slower than chemicals NPV as effective as chemicals after 3-4 days Population size relative to pre-spraying (%) DAY -1 DAY +1 DAY +3 DAY +5 DAY +7 DAY +9 A = CONTROL E = NPV F = CHEMICAL Control Chemical insecticide NPV Days post-spraying SPRAY

25 Proportion of larvae counted dead/dying of NPV Aerial spray trials Proportion of armyworm larvae counted in quadrats dead or dying SPRAY of NPV in trials at M'ringa 2004 NPV Control Days pre/post application NPV Aerially-sprayed NPV effective >80% kill after 3-4 days NPV-sprayed area Control area

26 NPV aerial trials,2004. Treated and untreated plots Dead and dying larvae in NPV sprayed plot, no grass damage Larvae swarming from untreated pasture, damaging pasture

27 Harvesting NPV Total yield of NPV in OB harvested per man hour (mean ± 95% confidence limits) 600x x x x x x Harvesting grass with NPV dead larvae Harvesting grass with dead and live larvae NPV can be easily harvested Harvesting NPV-infected larvae difficult It would take just 2.5 man-hours to harvest enough NPV to treat 1 ha Harvesting time in days post inoculation All larvae collected NPV-killed larvae only

28 Field Production of SpexNPV Direct harvesting of SpexNPV by handpicking is not viable as the cadavers are too fragile. Collecting grass on which dead or dying larvae are hanging is a feasible method of harvesting significant quantities of SpexNPV. Identifying a mechanical cutting and collecting system is the key to economical field production. Collaboration with Dr Flavio Moscardi of EMBRAPA (Brazil) have identified that their production technology could be used for NPV production in Tanzania

29 Benefits of new approaches Armyworm outbreaks are detected early by farmers and pastoralists Armyworm forecasting process is in the hand of people who use it Farmers are doing timely control Crop loss due to armyworm is now reduced

30 Lessons learned That poor rural farmers should be true partners in any research activity that is meant to improve their livelihoods. Strengthening the link between North and South scientists will benefit the poor farmers and improve their livelihoods. New innovations made in Tanzania is now benefiting other farmers in Kenya and Ethiopia.

31 Challenges Scaling-up and implement CBAF in 21 armyworm high risk districts. Develop NPV mass harvesting system Establish production facilities to produce SpexNPV formulation Determine effectiveness of NPV in Armyworm strategic control

32 The End