Recent Advances in Biological Control of Key Pests in Mauritius
1. Sub-Activity 1.1.3.1.1 Integrated Pest Management as a Climate Change
Adaptation in Agriculture
Dr Lalini Unmole
Principal Research Scientist
Entomology Division
19th September 2020
Recent advances in biological control of
key pests in Mauritius
2. Mauritius vulnerable to the effects of climate change
Pest problems likely intensified in the forthcoming years
due to
• Pest resurgence
• Incursions of new pests
Sole reliance on pesticides for pest control is not advisable
Introduction (1)
3. Represents risks of:
Environmental contamination,
Resistance to pesticides,
Decimation of beneficial organisms
Pesticide residues in agricultural produce (10 /498
samples)
FAREI has R&D programme on IPM of which biological
control is key component
Introduction (2)
4. Biological control
The use of living organisms to control pests:
Includes:
• Predators
• Parasitoids
• Pathogens
8. Advantages of biological control
Absence of toxic residues
No development of resistance by the pest
No killing of pollinators & other beneficial insects
No environmental contamination
Long-term solution to a pest problem
9. Aim
Promotion of biological control through production and
releases of bio-control agents
10. Objectives
Search for existing biocontrol agents of five key pests
Rear recovered biocontrol agents for evaluation of
effectiveness
Develop protocols for mass rearing biocontrol agents
Train interested potential entrepreneur on mass rearing
11. Methodology
Island wide survey
Samples examined under microscope
Detect biocontrol agents
Rear to confirm identity
12. Major pest on vegetable crops in
greenhouses.
Extract sap from under leaves & secrete
honey dew.
Honey dew nutrient source for sooty
mould.
Reduces photosynthesis & severely
damages host plants
20-25% yield loss
1. Biological control of whiteflies
Damage
Adult (1.2mm) & nymphs of whiteflies
13. Difficult to control with insecticides
Usually farmers apply insecticides intensively
Previously Encarsia sp. identified as potential biocontrol agent
1. Biological control of whiteflies
Adult Encarsia sp. (0.7 mm) Parasitised nymph (black)
14. Releases in greenhouses led to 77%-80% parasitism in whitefly
nymphs
Biological control a viable option for whitefly control in
greenhouses
Identify biocontrol agents to target different stages of
whiteflies for improved control
1. Biological control of whiteflies
Crop No. of insecticide applications
Farmers’ Practice Release of
parasitoids
English cucumber 16 4
Tomato 24 6
20. 2. Biological control of red spider mites,
Tetranychus spp.
Key pest of vegetables & ornamentals
Through their high reproductive capacity
they can destroy plants rapidly
Cause damage by feeding on plant tissue
& sap
Results in yellow spots on leaves
As damage increases whole leaves turn
yellow & eventually the plant may die
Adult(0.4 mm)
21. The predator Phytoseiulus persimilis effective in greenhouses of
rose, strawberry, English cucumber & sweet pepper
2. Biological control of red spider mites, Tetranychus
spp.
Phytoseiulus persimilis (0.5 mm)
22. Releases of P. persimilis in greenhouses
Not effective on tomato crop
Identify suitable predators of red spider mites on tomato
2. Biological control of red spider mites,
Tetranychus spp.
Crop No. of acaricide applications
Farmers’ practice After release of
predators
Strawberry 24 4
English cucumber 16 4
Sweet pepper 28 8
31. 3. Biological control of yellow sugarcane aphid,
Sipha flava
Key pest on pasture grass - herbe d’argent an
important fodder crop in deer ranches
Has a high reproductive capacity
Sipha flava (2mm)
32. Feeding causes leaves to turn
red & eventually dry out
Not appropriate to apply
insecticides in ranches
Introduction of Diomus
terminatus by Agricultural
Services
3. Biological control of yellow sugarcane aphid, Sipha
flava
Diomus terminatus
39. 4. Biological control of thrips
Key pest of vegetables & ornamentals
Feed by scraping outer layer of host tissue
& sucking out cell contents
Silver-white spots on leaves that turn
brown or rusty-red
Significant leaf damage resulting in
reduction of photosynthetic area
10-50% yield loss
Thrips tabaci (1mm)
40. Thrips difficult to control with pesticides
Intensive use of chemical insecticides has led to thrips
populations developing resistance
Study biological control initiated
4. Biological control of thrips
51. Funding by EU
• Equipments
• Capacity building
• Refurbishment of building
52. Way forward
Pursue survey on natural enemies of key pests
Study effectiveness of biocontrol agents
Promote promising species among farmers
Develop protocols for mass rearing
Train interested parties in rearing of biocontrol agents
53. Outcome
Effective biological control agents of key pests identified
Protocols for mass rearing biocontrol agents developed
Biological control adopted by farmers
Reduction in pesticide use
54. Impact of the project
Food productivity & safety improved
Reduction in imports and use of insecticides
Reduction in environmental and health hazards
Revenue generation – opportunity for agri-business
Creation of employment
55. Conclusion
Rich fauna of biocontrol agents
Opportunity for commercial production of biocontrol agents
Ensure plant biodiversity
Judicious use of pesticides
Favour safer products