Do Some Green Manures Used for Soil Enrichment Also Attract Beneficial Insects?
Recently, NAI researchers Bob Bugg and Tracy Ellis investigated ten green manure crops to assess the beneficial (predatory or parasitic) insects visiting them. In one study (presently completed) five cultivars were compared. These were Fava Bean (Vicia fabae), Buckwheat (Fagopyrum esculentum), Hairy vetch (Vicia villosa), sorghum (Sorghum bicolor) and Annual White Sweet Clover (Melilotus alba). In the second study (not yet completed) five other cultivars were compared. These were Austrian Winter and Canadian Field Peas (Pisum sativum), Cowpea (Vigna uniguiculata), Maximiliani sunflower (Helianthus maximiliani) and Rapeseed (Brassica napus). (Figure 1.) The researchers made observations weekly during the season by visual inspection and shake sampling of the vegetation. A reference collection of insects visiting the green manures was also made. They observed parasites of lepidopteran pest larvae such as vespid, sphecid, ichneumonid, and chalcid wasps and tachinid flies. These parasites f
