Monitoring Feeding Performance and Effectiveness of Ladybird Beetles for the Control of Aphids

Monitoring feeding performance and effectiveness of ladybird beetles (Coleoptera: Coccinellidae) for the

control of aphids (Homoptera: Aphididae).

ByD.K Murahwi

Supervisors: Mr. Matsiga Dr Mvumi

BACKGROUND

Many farmers in Zimbabwe are relying more 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).

Biological control of crop pests by the use of natural enemies is a fundamental component of integrated pest management (IPM), (Bajwa and Kogan, 1997).

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.

RESEARCH PROBLEM

Organic farming advocates for farming practice that excludes or minimises the use of synthetic pesticides among others.

Use of natural enemies of pests is harmonious with organic farming, hence there is need to enhance biological control as an alternative to chemical control.

JUSTIFICATION

Pests will always be a threat to agricultural productivity due to their phytophagous tendencies thus, insect pest related issues have to be dealt with to boost the agricultural sector productivity.

The beneficial aspects of insects outweigh the detrimental effects.

JUSTIFICATION CONT’

Chemical control of phytophagous pests has proven to be the most viable method of dealing with problem pest.

Berlandier et al, (1998) lupin plants. Biological control of aphids using native ladybird beetles is therefore being investigated as an alternative to chemical control.

OBJECTIVES

MainTo monitor feeding performance and effectiveness of ladybird beetles for the control of aphids.

SpecificTo evaluate the feeding rates of ladybird beetles on aphids.

To evaluate the feeding rates of ladybird beetles on pollen.

To identify the native ladybird species most suited to effectively control aphids.

HYPOTHESIS

H1: Ladybird beetles are heavy consumers of aphids.H1: Ladybird beetles are heavy consumers of pollen.H1: Different ladybird beetle species have different consumption rates of aphids.

PILOT STUDY

ADJUSTMENTS

Aphid cultureBond paper baseGrind bee pollenDamp cotton wool

MATERIALS AND METHODS

TRIAL SITE

1. UZ Crop Science Dept. Greenhouse (18o12’S, and 31o 05’E)

2. UZ Crop Science Dept. Entomology laboratory

MATERIALS AND METHODS CONT’

In the greenhouse 5 planting pots will be filled with soil and rape seed planted and watered at 2 day intervals.

Aphids collected from Crop Science plots will then be inoculated onto the rape plants at 6 weeks after emergence

Two experiments will be carried out in the lab, for aphids (experiment 1) and for pollen (experiment 2).

The study design is a Completely Randomised Design (CRD) with 6 treatments for both the experiments.

Treatments will be replicated 3 times.

MATERIALS AND METHODS CONT’

Adult, pupating and larval stage Coccinellids will be handpicked from the Crop Science Department fields and placed in 500g peanut butter bottles.

Brassica leaves infested with aphids will then be placed in the bottles as food for the beetles and the bottles will be taken into the laboratory to start the Coccinellidae cultures.

Mating pairs will be identified and isolated for the experiment.

TREATMENTS

EXPRERIMENT 1

EXPERIMENT 2

Treatments Aphids (mg) Pollen (mg)

1 0 0

2 5 5

3 10 10

4 15 15

5 20 20

6 25 25

DATA COLLECTION AND ANALYSIS

Data will be collected at 4 hour intervals.The responses of the experiment will be the measured weight of the ladybird beetle after each period and the measured changes in pollen or aphid mass at each 4 hour period.

Statistical packages Minitab16 and Genstat14 will be used for analysis of variance for the data collected and graphs will be plotted in Excel2013 and Sigma Plot10.0.

The relationship between variables will be evaluated using linear regression.

SKELETAL ANOVA

SOURCE OF VARIATION

DF SS MS F P

Treatment 5

Error 12

Total 17

WORK PLANActivity Sept Oct Nov Dec Jan Feb Mar Apr May Jun

Proposal_Development

Literature review

Study design

Data collection

Data analysis

Dissertation development

Submission of dissertation

MAIN BUDGET

COST ($)Rape seed 1.50Fine Artist camel hair brushes *2

5.00

Bond paper rim 6.00Sweep net 10.00Bee pollen *3 60.00Cages- adult rearing *4 100.00TOTAL 182.50

Thank you