Insects Associated with Underutilized Crop: Grain, Leafy and Ornamental Amaranth in Ibadan, Nigeria

摘要

Aim: Staple crops face major challenges in the near future and a diversification away from over-reliance on staples is important towards the achievement of global food security, this stimulate the retrieving and field evaluation of underutilized amaranth accessions for pest infestation before recommendation for wider adoption in Nigeria. Study Design: Field experiments were laid out in a randomized complete block design while the laboratory experiments were laid out in a completely randomized design. Place and Duration of Study: Experiments were conducted at the vegetable field and entomology laboratory of the National Horticultural Research Institute, Ibadan, Nigeria, during the rainy and dry seasons of 2008–2009. Methodology: The 91 accessions of amaranth which comprised of 28 grain amaranth type (26 introduced and 2 indigenous accessions), 54 leafy amaranth type (2 introduced and 52 indigenous accessions) and 9 ornamental amaranth type (6 introduced and 3 indigenous accessions), were planted in the field. All the plants were observed daily in the morning, a week after transplanting through grain maturity and all insects were collected with sweep nets and aspirators. Results: The most abundant insect pests on all the 3 amaranth types were from the orders Coleoptera, Lepidoptera and Hemiptera. Among the natural enemies, the heteropterans were the most abundant belonging to the Reduviidae. All the twelve (12) major pests from the families: Curculionidae, Coreidae, Pentatomidae and Pyralidae were observed on all the 3 amaranth types planted. The major leaf eating larvae were Hymenia recurvalis Fabricius, Psara bipunctalis Fabricius and Psara palpalis Hampson all from Pyralidae. The major stem borers were Baris circumscutellata Hustache, Gasteroclisus rhomboidalis Boheman, Leucogrammus paykulli Boheman, Lixus camerunus Kolbe, Hypolixus nubilosus Boheman and Hadromerus sagittarius Olivier all belonging to Curculionidae. The major grains sucking bugs were the coreids Cletus fuscescens Walker and Cletomorpha unifasciata Blote and the pentatomid Aspavia armigera Fabricius. Conclusion: The introduced underutilized grain amaranth accessions could be cultivated alongside the indigenous leafy amaranth with the application of the same pest control methods.