1) Native ladybird beetles were found to be effective predators of cowpea aphids, though they could not be reared on alternative diets tested. 2) C. lunata consumed the most aphids on average, followed by H. variegata, and was considered best for controlling cowpea aphid populations. 3) Further research on maize and cowpea pollen as well as artificial diets is recommended to mass produce C. lunata as a biological control agent.

1. Feeding Performance and Effectiveness of Ladybird
Beetles (Coleoptera: Coccinellidae) for Cowpea Aphid
(Aphis craccivora Koch) Control.
By
D.K Murahwi
Supervisors: Mr. Matsiga
Prof. Mvumi

2. BACKGROUND
Many farmers in Zimbabwe are relying on pesticides for
control of crop pests, (Mudimu et al. 1995).
Pesticides tend to have a non-selective effect on insects,
(Ali et al. 2011).
There is a global shift towards organic and sustainable
agriculture.

3. BACKGROUND CONT’
Ladybird beetles are the perfect candidate as
biological control agents, since they are voracious
predators (in both larval and adult stage), (Brewer &
Oswald II 1995).
Can supplement their diet with pollen, nectar, or
honeydew, (Cranshaw, 2014).
Although slow this method is effective in both
curative and preventative measures of dealing with
phytophagous insects.

4. RESEARCH PROBLEM and
JUSTIFICATION
Research Problem
Aphids are a major crop pest and tend to develop
resistance to pesticides.
There are side effects associated with chemical
pesticides
Thus chemical control being pushed out especially in
the wake of organic farming
Justification
Berlandier et al, (1998) research on aphid effect on
lupin plants.
The beneficial aspects of insects outweigh the
detrimental effects, (Goodwin 2014).

5. OBJECTIVES
Broad Determine
To determine feeding performance and effectiveness of
ladybird beetles for the control of cowpea aphids.
Specific
1. To evaluate the feeding of native ladybird beetles on
cowpea aphids.
2. To evaluate the feeding of native ladybird beetles
possible alternative diets.
3. To identify the native ladybird species most suited to
effectively control cowpea aphids.

6. HYPOTHESES
1. H1: Native ladybird beetles are effective
consumers of cowpea aphids.
2. H1: Ladybird beetles can survive on possible
alternative food sources.
3. H1: Different native ladybird beetle species have
different consumption rates of cowpea aphid.

7. MATERIALS AND METHODS
GENERAL
UZ Crop Science Dept. cowpea plot in Natural Region
2a (18o12’S, and 31o 05’E) for the aphid and ladybird
beetle source.
UZ Crop Science Dept. Entomology Laboratory
averaging 26oC and 42% RH for food source
experiments 1, 2, 3 and 4.
Study design had 3 treatments (Cheilonomes geisha,
Hippodamia variegata and Cheilonomes lunata) and
blocking by day for all 4 experiments.
Feeding samples were taken for each treatment and the
weight changes averaged for the specific day to the
particular treatment.

8. MATERIALS AND METHODS
30mg of food source was presented to the test subjects
and after a 2 hour period the weight change of the food
source was measured and recorded.
This was repeated for each day the experiment was run.

9. MATERIALS AND METHODS
OBJECTIVE 1
Experiment 4 using cowpea aphid as the food source was
done (02/03/15).
OBJECTIVE 2
Experiment 1, 2 and 3 using Bee Pollen (07/01/15),
Dried Ground Chicken Liver(13/03/15) and Shredded
Tuna (18/03/15) respectively as the alternative diets.
OBJECTIVE 3
Experiment 4 on cowpea aphid as the food source
(02/03/15).

10. DATA COLLECTION AND ANALYSIS
Weight changes were measured at 2 hour intervals
for the feeding samples which were ranging from 3
to 20 and averaged for each particular species.
This was done each day the experiment was run.
Statistical package Minitab16 was used for analysis
of the generated data.
Friedman’s test was carried out for test of
significance and box plots used for graphical display
of significance.

11. RESULTS
Figure 4.1: C. geisha, H. variegata and C. lunata

12. EXPERIMENT 1
Table 4.2: Friedman’s Test on Bee Pollen Data
Species Weight
Changes
(mg)
C. geisha 29.1
H. variegata 29.3
C. lunata 29
Grand median 29.1
P value 0.202

13. EXPERIMENT 2
Table 4.4: Friedman’s Test on Dried Ground Chicken Liver
Species Weight
Changes
(mg)
H. variegata 29.25
C. lunata 28.35
Grand median 28.8
P value 0.564

14. EXPERIMENT 3
Table 4.6: Friedman’s Test on Shredded Tuna
Treatments Weight
Changes
(mg)
Control 5.8667
H. variegata 6
C. lunata 5.2333
Grand median 5.7
P value 0.529

15. EXPERIMENT 4
C.lunataH.variegataC.geisha
30
28
26
24
22
20
18
16
Species
WeightChange(mg)
Boxplot of Weight Change
Figure 4.3: Box Plot of Aphid Consumption.

16. EXPERIMENT 4
Figure 4.4: Line graph of Ladybird Beetle Field Population

17. DISCUSSION
In this study, the ladybird beetles could not be reared
on the possible alternative food sources Bee Pollen,
Dried Ground Chicken Liver and Shredded Tuna.
Smith (1960) successfully reared ladybird beetles on
corn pollen.
Kariluoto et al. (1976) and Kariluoto (1980) in Da
Silva et al. (2010; pg 15) reveal diets based on pig
liver have been developed.

18. DISCUSSION
The ladybird beetles were effective feeders of
aphids.
C. lunata was the heavier aphid feeder among the
three species followed by H. variegata and C.
geisha was the least.
Ladybird beetles are voracious feeders of aphids
influenced prey and predator attributes, (Ferran &
Dixon 1993).
In North Dakota in the period June and July of 1949
successful control of aphid infestation in wheat
(Munroi & Somsen 1949).

19. CONCLUSION
The native ladybird beetle were found to be effective
cowpea aphid feeders.
Although an alternative diet for rearing was not
found in the current study, C. lunata was observed to
be most suitable for control of Aphis craccivora
Koch.

20. RECOMMENDATION
Maize pollen and cowpea pollen should be
considered for research as alternative diet.
Research on possible artificial diets for the mass
laboratory production of C. lunata would be
important for cost effective production of the
biological control agent for successful control of
Aphis craccivora Koch

21. ACKNOWLEDGEMENTS
Peace Mujuru for the source of aphids
Mrs Mutisi and Mr Vengai from Entomology
Department of DR&SS for species identification
Dr David Icishahayo for statistical aid
Dr Mabasa for technical and technological
assistance
Department of Crop Science Staff for their time and
dedication
My Colleagues for moral and academic support

22. Thank you