International Journal of Plant Research 2013, 3(3): 17-22 DOI: 10.5923/j.plant.20130303.01 Screening of Stored Maize (Zea mays L.) Varieties Grain for Tolerance Against Maize Weevil, Sitophilus zeamais (Motsch.) Simbaras he Muze mu 1,* , James Chitamba 2 , Sipiwe Goto 1 1 Department of Horticulture, Faculty of Natural Resources Management and Agriculture, Midlands State University, P. Bag 9055, Gweru, Zimbabwe 2 Department of Agronomy, Faculty of Natural Resources Management and Agriculture, Midlands State University, P. Bag 9055, Gweru, Zimbabwe Abstract Insect pests cause major damage to stored maize grain thereby reducing its weight, quality and germination vigour. Five open pollinated maize varieties (ZM401, ZM309, ZM521, ZM421 and Hickory King) and one hybrid maize variety (SC709) were evaluated for tolerance and their effects on progeny development against the maize weevil, Sitophilus zeamais (Motsch.). The experiment was laid in a randomised complete block design, with 6 treatments replicated 5 times. 100g maize grain was infested with 100 three week old unsexed pure culture adult weevils in 750 ml jars. After 14 days oviposition period, adult weevils were sieved out and parent weevil mortality determined. After a further 45 days, number of weevils emerged, percentage grain weight loss and number of damaged kernels were determined. Percentage kernel germination was determined through a germination test after 45 days of weevil attack. There were significant differences (p<0.05) in number of parent weevil mortality, number of weevils emerged, grain weight loss, kernel damaged and germination percentage among varieties. ZM421 and ZM521 varieties showed potential to S. zeamais progeny suppression and tolerance as evidenced by high parent weevil mortality, low weevil emergence, less grain weight loss, low grain damage and high germination percentage. Keywords Stored Maize Grain, Sitophilus Zeamais, Maize Varieties, Progeny Suppression 1. Introduction Maize ( Zea mays L.) is the most important crop in Zimbabwe and Southern Africa since it is a staple food crop which is widely grown by most smallholder farmers who significantly contribute to national production[1,2]. The necessity to increase maize production cannot be over emphasized; in Zimbabwe it ranks first in terms of total cereal production, number of producers and area grown[3]. It has been reported that the crop accounts for 70% of the total of the total hectarage under cereals with 60% of the whole production coming from the small-scale farmers[4]. Sitophilus zeamais Motschulsky is a serious pest of economic importance in stored products worldwide[5]. The pest is so devastating and is capable of multiplying to large populations causing tremendous damage to the grain[6]. It is estimated that about 10–40% of the total damage to stored grains worldwide is caused by insect pests[7] of * Corresponding author: smuzemu@gmail.com (Simbarashe Muzemu) Published online at http://journal.sapub.org/plant Copyright © 2013 Scientific & Academic Publishing. All Rights Reserved which they account for approximately 5–10% of maize grain loss in Southern Africa[8]. Under severe infestations, maize weevils can cause up to 90% loss of stored grain[9]. Grain weight loss of 12–20% and 80% caused by the maize weevil is common in untreated maize grain stored in traditional structures in tropical countries[10,11]. It has been reported that much of the maize produced by the smallholder farmers in Zimbabwe is lost to weevil attack and very little research has been done on the development of affordable alternatives which offer same control levels to weevils as pesticides[6]. Although synthetic pesticides can control it, majority of communal farmers are resource-poor and have no means and proper skills to acquire and handle them. Moreover, pesticides are expensive, not readily available and pose health problems to consumers due to their toxicity since many have some residual effect. Evidence from different African countries illustrates that improper use of chemicals is causing loss of life and negative repercussions on human health[2]; and other problems associated with their use are loss of efficacy, regulatory restrictions as a result of adverse effect on non-targeted organisms and eco-toxicity[12,13]. The status quo is exacerbated by the development of resistance to