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 32 o C to 167 days at 18 o C 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 METHODS General 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, O 2 and CO 2 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 PLAN Activity JFMAMJJASON D JFMA 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

BUDGET ItemDescriptionQuantityUnit Cost (Ksh)Total Cost (Ksh) Grain16 bags+16 bags32 bags3000 per 90 kg bag96,000 Metal silos165,00080,000 Wooden pallets ,000 Farmer’s bagspolypropylene Insecticides Phostoxin8 tablets5,000 Fare to Kiboko Experiment set up and data collection 2 x 3 trips50010,000 Laboratory analysisAflatoxin45 samples3,500157,500 Daily Subsistence Allowance503,500175,000 Stationeries,10,000 Thesis printing & binding services 10,000 Printing and Publishing Services20,000 Transport: Motor vehicle fuel & maintenance 25,000 Local conferences & seminars10,000 Casual laborMan days ,000 TOTAL640,500