Effect of Burning Candle and Grain Volume on Rate of Oxygen Depletion and Carbon

Dioxide Build-up in Metal Silos for Control of Larger Grain Borer (Prostephanus truncatus)

MSc. Crop Protection Proposal Presentation

Anne Kimani

INTRODUCTION•Maize (Zea mays L) is the third most important cereal after wheat and rice in the world (FAO, 1993).•It constitutes 3% of Kenya’s GDP and12% agricultural GDP (Government of Kenya, 1998).•Post harvest losses is estimated to be 20 – 30%(Babangida and Yong 2011). •Losses due to insect pests are 5-8% in both cobs and shelled grain (de Lima, 1979).•Infestation may commence in the field but most damage is done during storage (Yuya et al., 2009).

Introduction con’t

• Larger Grain Borer, Prostephanus truncatus (Horn) is a Coleoptera:Bostrichidae native to meso-America (Hodges 1994).

• Has a deflexed head, strong mandibles and cylindrical body shape with a large pronotum that protects the head during tunneling (Li 1988).

• On average 5−8 eggs are laid in small clutches protected by tightly packed frass in tunnels.

• Takes 25 days at 32oC to 167 days at 18oC to develop from egg to adult at 70% RH.

• LGB has three larval instar stages and the average larval period is 16 days.

Problem Statement and Justification• LGB a serious storage pest causes a weight loss of 67.1%

and 52.8 % flour production in a period of 90 days (Tefera et al., 2011b ).

• Metal silos are effective in control of Maize weevils and LGB (CIMMYT, 2011).

• Oxygen level should be reduced to 3% or less to kill all insects and 1% to stop fungal development in silos (Quezada et at., 2006).

• Aim of the study is to determine effective method of sealing the silos and the rate of oxygen depletion in metal silos to effectively control LGB.

Objectives

Broad Objective • To contribute to the effective management of Larger

Grain Borer, Prostephanus truncatus for reduced post harvest losses in stored maize grain.

Specific Objectives• To determine the most effective method of sealing

the metal silos for control of Prostephanus truncatus.

• To determine the rate of oxygen depletion and carbon dioxide build up using burning candle and grain volume in the metal silo.

MATERIALS AND METHODSGeneral methodology

• Site: KARI-Kiboko Research Centre.• LGB culture will be from Cimmyt at KARI, Kiboko post

harvest pest laboratory.• Clean maize will be fumigated using Phostoxin and dried to

12-13% moisture content. Aflatoxin levels and grain quality will be analyzed prior to start of experiment.

Objective 1: Determine the most effective method of sealing the metal silos for control of LGB.

• 90 kgs silos will be used. • 100 LGB will be introduced into a 2-liter glass jar and in

each silo.

Methodology con’t

• One silo per treatment will be fitted with a rubber cork for measuring gas composition

• A lighted candle will be put in each silo before closing and sealing it.

• Experimental design -CRD with four replicates per treatment for 3 months.

Summary of the treatments• T1 = Metal silo fully-filled with grain + grease• T2 =Metal silo fully-filled with grain + rubber band • T3 =Metal silo fully-filled with grain + grease + rubber

band• T4 = Metal silo fully-filled with grain + no grease + no

rubber band (control)

Objective 2: Determine rate of oxygen depletion and carbon dioxide build-up in metal silos using burning

candle and different grain volumes.

• Silos (90kg) and a polypropylene bag (90kg) will be used.

• 100 LGB will be introduced into a 2-liter glass jar and in each silo.

• One silo per treatment will be fitted with a rubber cork for measuring gas composition.

• The most effective sealing method determined in objective 1 will be used to seal silos.

• Experimental design-CRD replicated three times for 6 months.

Summary of the treatments

• T1 = Metal silo(90kgs) full+ burning candle• T 2 = Metal silo (90kgs) full+ no candle• T3 = Metal silo (45kgs) half- filled + burning candle• T 4 = Metal silo (45kgs) half- filled + no candle• T 5 = 90kg polypropylene bag filled with maize.

Data collection• Moisture content, Aflatoxin levels, chemical analysis,

O2 and CO2 levels will be measured prior to start of the experiment and every two weeks for 3 and 6 months.

• Kernel damage and weight loss : A sample (450g) will be collected using double-tube spear, sieved using 4.7 and 1.0mm sieves (Tefera et al., 2011b).

Data collection con’t • No. of damaged kernels, undamaged grains and the

number of live and dead insects will be recorded. • Weight of undamaged grain, damaged kernels and

flour produced will be weighed and recorded. • Grain weight loss will be determined using the count

and weight method of Gwinner et al., 1996: Weight loss % = (Wu x Nd)-Wd x Nu) X 100

Wu x (Nd + Nu)Where :Wu = weight of undamaged grain, Wd = Weight of

damaged kernel, Nu= number of undamaged grain, and Nd = Number of damaged kernels.

Data collection con’t

Data analysis• Data collected will be subjected to analysis of

variance using the statistical analysis software (SAS).EXPECTED OUTPUT

• Reduced post harvest losses resulting in food security.

• MSc. Thesis

WORK PLANActivity 2013 2014

J F M A M J J A S O N D

J F M A

Procurement of experiment

requirements e.g. maize,

metal silos, insecticides etc

Initiate research – Set up of

experiment 1

Data collection and entry

Set up of experiment 2

Data collection and entry

Data analysis and writing of

thesis

BUDGETItem Description Quantity Unit Cost (Ksh) Total Cost (Ksh)Grain 16 bags+16 bags 32 bags 3000 per 90 kg bag 96,000Metal silos 16 5,000 80,000Wooden pallets 16 1000 16,000Farmer’s bags polypropylene 5 200 1000Insecticides Phostoxin 8 tablets 5,000

Fare to Kiboko Experiment set up and data collection

2 x 3 trips 500 10,000

Laboratory analysis Aflatoxin 45 samples 3,500 157,500

Daily Subsistence Allowance 50 3,500 175,000

Stationeries, 10,000Thesis printing & binding services

10,000

Printing and Publishing Services 20,000

Transport: Motor vehicle fuel & maintenance

25,000

Local conferences & seminars 10,000

Casual labor Man days 50 300 25,000TOTAL 640,500