Evaluation of AgroZ Hermetic Storage Bag against insect pests on stored maize

Abstract

A study on AgroZ airtight bag was conducted against two major storage insects under simulated farmers' storage practice. Two (2) lots of 50kg white maize of Pioneer variety were put into AgroZ bag and polypropylene woven bag to serve as a control. Four replications of each bag type were used. In each bag, 50 adults of unsexed larger grain borer, Prostephanus truncatus, and maize weevil, Sitophilus zeamais, each were introduced. AgroZ bag had one liner placed inside polypropylene bag to provide support and handling convenience. Each liner had been tested for air tightness before use. The AgroZ bags were securely tied to ensure airtightness thus leading to a hermetic environment. The bags were then randomly placed in a barn on pallets in a randomised complete design (RCD). Sampling was done every 4 weeks up to 24 weeks. A 500g sample was initially taken using a compartmented long spear probe from each bag for baseline data, and subsequent ones at 4, 8, 12, 20 and 24 weeks. Repeated sampling from the same storage device reflected farmer practices of opening the device at regular intervals to draw grain for use as household food. Gas analysis in AgroZ bags showed oxygen level dropping rapidly to 7% within 4 weeks and later increased gradually to 10% at 12 weeks. Conversely, carbon dioxide level increased sharply to 10% and declined gradually to 9% over the same period. The number of insects and percentage damaged grains between AgroZ bag and polypropylene bag significantly differed from 12th week to 24th week. AgroZ bag outperformed the polypropylene bag commonly used by farmers and conveniently protected maize from insect infestation within the 6-month storage period.