Granary Trial of Protein-Enriched Pea Flour for the Control of Three Stored-Product Insects in Barley

Abstract

A granary trial was conducted to evaluate the efficacy of protein-enriched pea flour against three common stored-grain insects, Sitophilus oryzae (L.), Tribolium castaneum (Herbst), and Cryptolestes ferrugineus (Stephens). Six 30-t farm granaries were filled with approximately 11 t of barley. The barley was either not treated, treated with protein-enriched pea flour at 0.1% throughout the entire grain mass, or treated at 0.5% throughout the top half of the grain mass. Adult insects were released in screened boxes (two insects per kilogram barley for S. oryzae and T. castaneum 1.4 insects per kilogram barley for C. ferrugineus). Barley was sampled four times during the 70-d trial. The number and mortality of adults and emerged adults in the samples were noted. Four kinds of traps, flight, surface-pitfall, probe-pitfall, and sticky-bar, were placed at different locations in the granaries to estimate the movement of insects. The 0.1% protein-enriched pea flour treatment reduced adult numbers of S. oryzae by 93%, T. castaneum by 66%, and C. ferrugineus by 58%, and reduced the emerged adults by 87, 77, and 77%, respectively. Treating the top half of the barley with 0.5% protein-enriched pea flour had similar effects as treating the entire grain mass with 0.1% pea-protein flour. However, the top-half treatment failed to prevent insects from penetrating into the untreated lower layer. Differences between traps are discussed.

Simple technique to increase the sensitivity of probe traps in detecting Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) in stored wheat

“…As the concentration of protein-enriched pea flour increased, the number of insects caught in the traps also increased. The results of our investigation are in accordance with those of the field experiment conducted by Hou and Fields (2003). However, we used higher pea flour concentrations than Hou and Fields (they used 0.5%) in an effort to increase the sensitivity of the traps in detecting the beetles.…”

“…We believe that the presence and multiplication of C. ferrugineus in grain storage bins are a result of entry through the top inlet of storage structures (bin head space) as well as the aeration duct beneath the perforated floor of the granary (see also Toews et al 2003). Entry through the aeration duct can be prevented by the application of sticky material at the hopper bottom beneath the floor (Hou and Fields 2003), leaving the top inlet as the only point of entry of migrant beetles. It is very important to detect these potential migrants early so that further multiplication in storage (Flinn et al 1977) can be prevented.…”

“…The higher the concentration of protein-enriched pea flour, the better the results. Practical studies by Hou and Fields (2003) clearly demonstrate the difficulty of applying the powdered protectant to an entire 30 tonne bin for control of stored-grain insects. Thus, we propose the application of proteinenriched pea flour to the top 6 inches of the trapping area to increase the efficacy of the probe trap.…”

Protein-enriched pea flour extract protects stored milled rice against the rice weevil, Sitophilus oryzae

“…Barley treated with pea flour extract at 0.1% reduced adult numbers of S. oryzae by 93% (Hou and Fields 2003). …”

Biorational Approaches to Managing Stored-Product Insects

“…Crude pea flour, and the protein-rich fraction of field peas, Pisum spp., as well as that of other food legumes (e.g., species of Pissum, Phaseolus, and Vignia), are toxic and repellent to stored-product insects (13,30). Direct application of protein-enriched pea flour to bulk grain at 0.1% by weight resulted in substantial reductions in stored-grain beetle populations (44), and broadscale application of pea flour to the inside of mills reportedly resulted in insect control, but such control was not at commercially acceptable levels like those achieved with synthetic fumigants.…”