Abundance and diversity of arthropod pests infesting stored maize in smallholder farmers and traders systems highlight critical points for pest management in Uganda

Vortrag

Abstract

Knowledge of the diversity of arthropod pests infesting stored maize value chain in Uganda is very scanty to guide the development and implementation of management strategies. From a cross-sectional study conducted in north western, eastern and central regions of Uganda during 2017/2018, the diversity and economic importance of storage arthropod pests of maize in farmer storage, trader/retailer stores in villages and townships, and in milling and processing facilities is presented. A total of 11 insect pests were recorded feeding internally and externally on stored maize. Rhyzopertha dominica, Sitophilus zeamais and Sitophilus oryzae were the primary insect pests followed by Tribolium spp., Cryptolestes spp., Sitotroga cerealella, and Oryzaephilus mercator. The highest insect diversity and damage was recorded when maize was stored with husked cobs in farmers’ houses, a practice farmers use to store seed for next planting. Meanwhile the distribution pattern of the pests in trader/retailer stores in villages and townships, and in milling facilities indicate waves of insect infestation occurring with stocks of grain being brought in storage. The maize grain at the peak of harvesting was in excellent quality but later stocks brought in several months after harvest were infested with diverse insects. Re-drying at farm level and use of chemical dusts at trader/retailer stores in villages and townships were the most common pest management practice. However, the lack of a differentiated market, whereby better quality would fetch premium price, discourages investment to reduce postharvest losses. Subsequently, most farmers sold their grains immediately after harvest and most traders sold their stocks as soon as there was the next bulk buyer. The critical point for pest management is at farm level where pest diversity and damage is greatest, and at the village/ township stores where the grain may be held in anticipation of improvement in price.