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

5.
Predator
 Free living species that consume a large number of prey
during its lifetime

6.
Parasitoid
 Lays its eggs on or in the body of an insect which is then
used as a food for developing larvae. The host is ultimately
killed.

7.
Pathogens
Nematodes
Fungi
Viruses
Bacteria

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

15.
Biological control agents recovered
Eretmocerus sp.
Parasitised nymph (2nd instar)Adult (0.6 mm)

16.
Micromus timidus
Biological control agents recovered
Larva Adult (9mm)

17.
Biological control agents recovered
Exochomus sp.
Larva Adult (3.2 mm)

18.
Biological control agents recovered
Larva Adult (1.8 mm)
Scymnus constrictus

19.
Anthocorid bug
Biological control agents recovered
Immature stages Adult (3-4 mm)

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

23.
Biological control agents recovered
Predatory mites (0.5 mm)

24.
Biological control agents recovered
Stethorus sp.
Larva Adult (1mm)

25.
Biological control agents recovered
Nymph
Adult (1 mm)
Scolothrips sp.

26.
Biological control agents recovered
Franklinothrips vespiformis
Nymph Adult (2.5-3.0 mm)

27.
Biological control agents recovered
Chrysoperla sp.
Larva
Adult (10-20 mm)

28.
Biological control agents recovered
Feltiella sp.
Larva feeding on adult mites
Adult (2 mm)
Larva feeding on mite eggs

29.
Biological control agents recovered
Oligota sp.
Larva Adult (1-2 mm)

30.
Biological control agents recovered
Wollastoniella sp.
Nymph Adult (1.2-1.5 mm)

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

33.
Biological control agents recovered
Cheilomenes sulphurea
Larva Adult (6.2 mm)

34.
Biological control agents recovered
Brumus suturalis
Larva Adult (3.2 mm)

35.
Biological control agents recovered
Scymnus sp.
Larva Adult (1.5-2.0 mm)

36.
Micromus timidus
Biological control agents recovered
Adult (9 mm)Larva

37.
Paragus borbonicus
Biological control agents recovered
Larva Adult (3-4.5 mm)

38.
Biological control agents recovered
Larva
Allograpta nasuta
Adult (6-7 mm)

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

41.
Biological control agents recovered
Jumping spider (4 mm)

42.
Biological control agents recovered
Triphobius sp. (0.7 mm)

43.
Biological control agents recovered
Franklinothrips vespiformis
Nymph Adult (2.5-3.0 mm)

44.
5. Biological control of fruit flies
Zeugodacus cucurbitae female (8mm)Bactrocera dorsalis female (8mm)
Oriental fruit fly Melon fly

45.
(1-20/fruit)

46.
100 fruits = 1000
emerging female
fruit flies
1 female lays
1000 eggs
Potentially
1000 females =
1.0 M fruit flies
20 eggs/fruit
10 females
20 adults emerging

47.
 Management of fruit flies is difficult
 Investigate on biological control of fruit flies
5. Biological control of fruit flies

48.
Psytallia fletcheri
Biological control agents recovered

49.
Biological control agents recovered
Fopius arisanus (4 mm) Tetrastichus giffardianus

50.
Augmentorium
Multiplication of parasitoids at field level

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

56.
THANK YOU