Prostephanus truncatus （Horn） is a notorious stored grain insect pest established in Tanzania in late 1970s and currently threatening the maize industry of Zimbabwe. The devastating effects of the pest attack, deman...Prostephanus truncatus （Horn） is a notorious stored grain insect pest established in Tanzania in late 1970s and currently threatening the maize industry of Zimbabwe. The devastating effects of the pest attack, demands adequate preparation including identification of the potential invasion areas for more focused planning towards its effective management. In the current study, the potential P. truncatus invasion areas in Zimbabwe were identified based on climatic data with reference to the Tanzania situation using the geographical information system （GIS） Almanac Characterization Tool （AWhere-ACT 3.5 software）. Areas identified to be at greatest risk of invasion includes the northern part of the country, the southern-east region and a few areas in the east （Manicaland province）. Alternative host plants for P. truncatus similar to those identified in Kenya, where the pest is already endemic, were found to occur throughout Zimbabwe which could support initial colonization and subsequent perpetuation of the pest in the country. In Zimbabwe, chances that P. truncatus may spread throughout the country, should it invade the country, are high because of unregulated grain trade and the fact that most of the potential invasion areas identified in this study, are located in the major maize producing areas. Measures to delay the occurrence of the pest in Zimbabwe should focus on the high-risk areas identified.展开更多
Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under amb...Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.展开更多
文摘Prostephanus truncatus （Horn） is a notorious stored grain insect pest established in Tanzania in late 1970s and currently threatening the maize industry of Zimbabwe. The devastating effects of the pest attack, demands adequate preparation including identification of the potential invasion areas for more focused planning towards its effective management. In the current study, the potential P. truncatus invasion areas in Zimbabwe were identified based on climatic data with reference to the Tanzania situation using the geographical information system （GIS） Almanac Characterization Tool （AWhere-ACT 3.5 software）. Areas identified to be at greatest risk of invasion includes the northern part of the country, the southern-east region and a few areas in the east （Manicaland province）. Alternative host plants for P. truncatus similar to those identified in Kenya, where the pest is already endemic, were found to occur throughout Zimbabwe which could support initial colonization and subsequent perpetuation of the pest in the country. In Zimbabwe, chances that P. truncatus may spread throughout the country, should it invade the country, are high because of unregulated grain trade and the fact that most of the potential invasion areas identified in this study, are located in the major maize producing areas. Measures to delay the occurrence of the pest in Zimbabwe should focus on the high-risk areas identified.
文摘Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.
