Cotesia flavipes in borer control

An update on performance of
Cotesia flavipes in borer control
in Jamaica
Trevor Falloon
SIRI
Kendal Road
Mandeville
Introduction
Sugar cane borer: Diatraea saccharalis
 Borer of the mature cane stalk
 Native to the Americas
 Prime pest throughout the region
 Secondary to the canefly in Jamaica and
froghopper in Trinidad
 In Jamaica, from 1950s to 1970s, prime focus
on canefly
 With canefly contained by IPM, attention given
to borer
Diatraea saccharalis larvae
Introduction
Damage by D. saccharalis
 Bores into stalk
 Allows entry of red rot fungus
 Reduces sucrose by 0.5 – 1.6% (various
studies)
 Occasionally leads to snapping of stalks,
sometimes death of growing point
 In extreme conditions, yield loss
Introduction
Damage
 In Jamaica – avg. 7% internodes bored
 Range typically 2-12%
 In individual fields up to 34% recorded
 Rain-fed areas <5% internodes damage
 Irrigated areas typically 10-12% damage
 Economic damage threshold – 5%
Introduction
Control
 Primarily by biological control agents
throughout region
 In USA – combination of biological and
chemical methods
Introduction
Native biological control agents
 Trichogramma spp. (egg parasites)
 Larval parasites:
 The Cuban fly – Lixophaga diatraeae
 Agathis stigmaterus (a wasp)
 Miscellaneous predators – ants, earwigs
etc
Introduction
Biological control agents imported to
Jamaica since 1970s
 The Amazon fly - Lidella (Metagonistylum)
minense

A fly from the Orinoco region - Paratheresia

A parasite of the rice stem borer – Allorhogas


claripalpis
pyralophagus
A pupal parasite – Pediobius furvus
The wasp – Cotesia (Apanteles) flavipes
Introduction
Field establishment
 Cotesia flavipes - only successful field
establishment
 Others reared in lab
 Failed to adapt to the field
Cotesia adults in test tubes
Introduction
Cotesia flavipes






First imported early 1970s
Mass reared & released primarily at Innswood,
Caymanas and Monymusk
Failed to gain field establishment
Programme discontinued in 1974, resumed in
1980
Temporary establishment – Monymusk, 1980
Real establishment achieved – Rowington, 1983
Introduction
Cotesia flavipes, Braconidae, Hymenoptera




Tiny wasp (size of a small ant)
Mated females produce 3-5 times more females
than males
Unmated females produce all-male progeny
Within lab, at 73-77 ˚F, and 82-91% relative
humidity, life cycle completed in 28 days, 20 of
which are spent as maggots in the borer and 7
as a cocoon mass
Introduction
Establishment & Spread
 Cotesia spread rapidly after establishment
 Swiftly colonised irrigated plains
 Rowington - 1983
 Innswood - 1985
 Bernard Lodge - 1986
Introduction
Effect
 Avg. parasitism before Cotesia colonisation
(1980) 21.6%
 Avg. after colonisation (1988), 37.4%
 Programme therefore deemed a success
 Internodes Bored: 1980 – 10.5%
 Internodes Bored: 1988 – 12.9%
 Programme appears unsuccessful
Introduction
Dynamic Equilibrium
 Spot check at Rowington in 1999, 12
years after last release, showed Cotesia
almost non-existent
 At the same time, Springfield, Monymusk,
20% parasitism found
 In 2000 lab rearing resumed for
augmentative release of Cotesia
Introduction

This paper updates progress and
evaluates success in enhancing field
populations of Cotesia and assesses its
impact on stalk damage
Materials & Methods




In 2000 SIRI obtained a strain of Cotesia from
Barbados to resume lab rearing
This was augmented by Cotesia collected from
fields primarily at Monymusk
In 2004 gene pool was further diversified by
samples obtained from batches of Cotesia
imported by New Yarmouth from Guatemala
Lab rearing was by procedures developed in the
1980s
Lab rearing borers
Lab-rearing Diatraea
Cotesia flavipes, laboratory Rearing
Cotesia maggots emerging from
borer
Materials & Methods
Field Assessment
 Difficult to sample for Cotesia directly
 Borers were collected primarily from New
Yarmouth and reared singly under observation in
the lab
 Records kept of various parasites emerging
 Annual borer damage survey data used as the
ultimate measure of effectiveness
Results & Discussions
Cotesia cocoon, borer carcass
Lab production, Jul-Aug 2010
Cotesia flavipes
Month
No.
Borers
stung
Males
Females
July
166
711
4082
4793
Aug
296
1408
6347
8355
Total
462
2119
11029
13148
Total
Cotesia Released







Location
Westmoreland
New Yarmouth
Caymanas
Worthy Park
Appleton
Total
Number released
420
5150
2020
610
520
8720
Results & Discussions
Field Parasitism, Monymusk:
 Cotesia - 14.9%
 Native parasites: Lixophaga - 10% and
Agathis - 0%
 Total parasitism, 25% - marginally above
levels before the start of the programme
Results & Discussion
New Yarmouth
 Cotesia parasitism increased to 7.4% in
2009 (up from near 0% in 1999)
 Lixophaga – 10.2%
 Agathis – 0.4%
 Total parasitism - 18% or slightly below
pre-programme level of 22%
Results & Discussions


Both Monymusk & New Yarmouth register
a reduction in percent parasitism by native
parasite, Lixophaga, from pre-programme
levels of 20-22%
There is no net increase in total parasitism
even with the addition of a new parasite
to the ecosystem
Percent Internodes Bored, New
Yarmouth
25
20
15
10
5
0
2002 2003 2004 2005 2006 2007 2008 2009 2010
Conclusions


Despite some 3 decades of field
colonisation by imported parasite, Cotesia,
in the industry, there has been no net gain
in total parasitism
Gains in population levels of Cotesia seem
to be at the expense of native parasite,
the Cuban fly
Conclusions



Similar finding in Venezuela: After 6 years
of Cotesia colonisation, no net increase in
parasitism
Stalk damage levels remained the same as
in previous 45 years
Cotesia considered competitor to native
Amazon fly
Conclusions




Barbados, the only success with classical
approach to Cotesia use, did not have a native
parasite like the Cuban or Amazon flies
Nonetheless, many industries, e.g. Brazil, claim
success with use of Cotesia
They apply Cotesia by the millions – more like a
biological insecticide
Perhaps this approach might eventually have to
taken by Jamaica
The End