Biology and Control of the Currant-Lettuce Aphid (Nasonovia ribisnigri)
Gemma Hough (G.L.Hough@warwick.ac.uk)
Supervisor: Dr Rosemary Collier
School of Life Sciences, The University of Warwick, Wellesbourne, Warwick CV35 9EF
Introduction
Spring
Winter
• N. ribisnigri prefers to feed in lettuce hearts where it is
protected from certain insecticide sprays and natural
enemies.
Males and
females
produce
eggs
• Insecticide resistance has been detected in some
populations and whilst several new insecticides are
available to growers, they may still not provide a complete
solution.
Life cycle
• During summer N. ribisnigri reproduces asexually on lettuce and
related species.
• In autumn, males are produced and both sexes migrate to the winter
host (Ribes species). Males mate with females who lay overwintering
cold-resistant eggs.
• In the spring the eggs hatch and nymphs colonise shoots of the
winter host before migrating to lettuce once again.
• Some N. ribisnigri have overcome the resistance provided
by resistant lettuce cultivars. We call them resistancebreaking (Rb) clones.
• Some clones have lost their sexual phase and overwinter as live
insects on other herbaceous hosts (see below).
Summer
Autumn
Results
What’s next?
Development time from nymph to adult for resistance-breaking
(Rb) and wild-type (WT) N. ribisnigri on susceptible and
resistant (Nr) lettuce cultivars
18.00
16.00
14.00
10 °C
12.00
15 °C
10.00
20 °C
8.00
25 °C
6.00
4.00
Mean percentage of aphids surviving at day 9
of development from nymph (%)
Development time to adult (days)
20.00
Percentage of aphids surviving on
day 7 of development from nymph (%)
Percentage survival of resistance-breaking (Rb) and wildtype (WT) N. ribisnigri on alternative hosts to lettuce
120
100
80
60
40
20
0
2.00
0.00
Percentage survival of resistance-breaking (Rb) and
wild-type (WT) N. ribisnigri on Butterhead cultivars
from different plant breeding companies
100
80
60
2.Determine whether
predators and fungi play a
role in the mid-summer
crash
40
20
0
Rb Saladin Rb Eluarde Rb Rotary WT Saladin WT Eluarde WT Rotary
(Sus)
(Nr)
(Nr)
(Sus)
(Nr)
(Nr)
Aphid type and lettuce cultivar
1. N. ribisnigri develops faster at higher temperatures.
2. Rb aphids develop at the same rate as WT aphids at
each temperature.
3. Some WT aphids survived to adulthood on resistant
lettuce but had longer development times and earlier
mortality.
Aphid type and host plant
Aphid type and lettuce cultivar
All alternative host plant species screened supported
development and reproduction of WT and Rb N.
ribisnigri, except for Prickly Sowthistle.
Orange
Hawkweed
(Hieracium
aurantiacum)
Prickly
Sowthistle
(Sonchus
asper)
Chicory
Smooth
Spiked
(Chichorium
Hawksbeard
Speedwell
intybus)
(Crepis capillaris) (Veronica
spicata)
Wall
speedwell
(Veronica
arvensis)
1.Determine how well N.
ribisnigri can overwinter on
alternative hosts.
Rb N. ribisnigri can survive equally well on
different resistant and susceptible Butterhead
cultivars.
3.Quantify the effects of day
length on development of
both WT and Rb N.
ribisnigri on lettuce.
4.Quantify temperature and
day length requirements for
key overwintering stages on
Ribes species.