Download Steinernema sp - Stellenbosch University

Fighting Nature with Nature – a case study of biological warfare
Jeanne Y. de Waal, A. P. Malan, M. F. Addison & P. Addison
University of Stellenbosch

Chemicals

Mating Disruption

Parasitoids

Attract and Kill

Sterile Insect Release

Virus

Insect Growth Regulators

Entomopathogenic Nematodes
Entomopathogenic Nematodes (EPNs)
Nematodes
Insect
2 mm
 Lethal pathogens of insects
 Use as microbial agents for the biological control of codling moth
1mm
1mm
EPN Life Cycle
(Commercial Agriculture)
CO2
CO2
STEP 3: Select the most promising isolate for codling moth control
 Heterorhabditis bacteriophora (6 isolates)
 Heterorhabditis zealandica (6 isolates)
 Heterorhabditis safricana (1 isolates)
 Steinernema khoisanae (5 isolates)
 Steinernema sp. 1
 Steinernema sp. 2
 Steinernema sp. 3
?
2-3 generations/ growing season
 Effective against CM larvae
 Active at lower temperatures (cold)
 Desiccation-tolerant (above-ground application)
 Active searching behaviour (cryptic habitats)
Alive, not infected
Dead, infected
Results…
100%
% Kill (epn)
80%
60%
40%
20%
0%
0.5 mil IJs
1 mil IJs
Treatment
1.5 mil IJs
100%
Mortaliteit
% Mortality
80%
a
a
1 mil
1.5 mil
60%
40%
20%
b
0%
0.5 mil
EPNs/boom
Treatment
Wind speed (m/s)
>2 m/s
% RH
Temperature (°C)
55 % RH
14°C
STEP 5: Application Technology
COMPILATION OF A PRACTICAL APPLICATION PROTOCOL
MANIPULATION OF
ORCHARD ENVIRONMENT
FORMULATION
50%
c
40%
% CM Mortality
bc
30%
ab
20%
a
10%
0%
EPN + Water
EPN + Water + Zeba
Treatment
60% RH
80% RH

Insecticides

Mating Disruption

Parasitoids

Lure-and-kill-method

Sterile Insect Technique

Virus

Insect Growth Regulators

Entomopathogenic Nematodes
Summer Population
Winter Population
New ideas pass through three stages:
1. “It can’t be done…”
2. “It probably can be done, but it’s not worth doing...”
3. “I knew it was a good idea all along!”
Acknowledgements
 Dr. A. P. Malan, Dr. P. Addison and M. F. Addison (supervisors)
 Friends and family for support throughout
University of Stellenbosch
South African Apple
and Pear Producers’
Association