Comparative Efficacy of Four Hermetic Bag Brands Against Prostephanus truncatus (Coleoptera: Bostrichidae) in Stored Maize Grain

Abstract

Hermetic storage technology using plastic liners is threatened by the boring action of Prostephanus truncatus Horn. (Coleoptera: Bostrichidae), a major insect pest of stored maize in sub-Saharan Africa. We investigated the performance of four brands of hermetic storage bags against adult P. truncatus in maize stored for 90 d under simulated resident and incoming infestation. Five treatments were used: four hermetic bag brands; SuperGrain Bag (SGB) IV-R, SGB Farm, Purdue Improved Crop Storage (PICS) bag, and Kuraray bag; and an ordinary plastic bag; each containing 50 kg of shelled maize. Two modes of insect infestation were used whereby 50 adult insects were introduced inside and outside the hermetic bags to simulate resident and incoming insect infestations, respectively. Parameters measured included carbon dioxide-oxygen levels, live adult P. truncatus numbers, grain moisture content, grain damage and weight loss, germination, and number of insect-induced perforations on plastic liners. Externally infested bags had no insect activity; all the introduced insects died of starvation. Internally infested bags were all perforated. The ordinary plastic liner was severely perforated with 151 insect-induced holes compared to hermetic plastic liners (<40 holes). There was no live adult insect infestation in grain samples collected using double-tube multi-slotted sampling probes inserted vertically several times. However, live adult insects were present in the bottom grain layer (0.05 m) of all plastic liners. There were no significant differences between hermetic bags regardless of mode of infestation for all parameters assessed. The results show that the tested hermetic bags are equally susceptible to perforations by resident P. truncatus.

Comparative Study of Cowpea Storage Technologies in the Sahel Region of Niger

“…The increase in insect populations and damages to grain stored in ZeroFly ® and control woven bags observed here corroborates findings of previous studies in which maize was stored in several different countries in sub-Saharan Africa [ 19 , 25 , 27 , 28 , 29 ]. The present study further confirmed that C. maculatus is the only insect species that attacks cowpea during storage in West Africa.…”

“…Our results are corroborated by findings from other studies on maize in several regions of sub-Saharan Africa. These studies showed weigh losses ranging from 3% to 35% [ 19 , 20 , 22 , 25 , 27 , 28 , 29 ]. Our results contradict laboratory studies conducted in both Ghana and Nigeria that claimed 100% insect mortality and no weight loss of cowpea stored in 5 and 10 kg ZeroFly ® storage bags for 21 to 25 days [ 41 ].…”

“…Storing grain in hermetic bags has shown to maintain or minimally reduce its germination [ 40 ]. Significant losses of germination in grain stored in ZeroFly ® storage bags and woven bags described here are likely due to grain damage due to insects [ 13 , 28 , 47 ].…”

“…Wide dissemination of PICS TM bags led to the development and commercialization of several alternative hermetic bags as well as other storage technologies in sub-Saharan Africa, especially in East and Southern Africa [ 18 ]. In addition to PICS TM bags, other storage technologies that have been tested for maize storage in sub-Saharan Africa include SuperGrainbag TM , AgroZ ® , EVAL™, and ZeroFly ® bags [ 15 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ]. These studies have provided evidence that hermetic bags are effective at protecting grain during storage, while the ZeroFly ® bag has limited success.…”

Performance of Five Postharvest Storage Methods for Maize Preservation in Northern Benin

“…A side-by-side experiment comparing PICS™ and SuperGrainbag™ for storing cowpea in Niger found no difference in effectiveness between the two hermetic bags [ 30 ]. Additional studies comparing several hermetic bags for controlling Prostephanus truncatus (Horn, Coleoptera: Bostrichidae) on stored maize in Malawi, Tanzania, and Zimbabwe found no difference among these technologies [ 22 , 28 , 31 ]. These hermetic bags are as effective as and often better than insecticides in protecting grains against insect attacks during storage [ 24 , 27 , 32 ].…”