Swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), causes severe economic losses in Brassica Linnaeus (Brassicaceae) crops in its invasive range in North America. Larvae feed within the meristem of their host plants, causing deformed heads, stems, and leaves. Pheromone-mediated mating disruption is particularly promising for swede midge management in high-value vegetable crops because its use is allowed in organic production. However, a major challenge to developing economically viable mating disruption is that the stereospecific three-component swede midge pheromone is costly to synthesise. In broccoli (Brassica oleracea Linnaeus var. italica) field plots, we tested whether stereospecific, lower-cost racemic, and single-component pheromone blends resulted in trap shutdown and reduced crop damage compared to nontreated controls. We found a significant reduction in males caught in three-component stereospecific and racemic pheromone–treated plots but not in the single-component treatments. Although marketable broccoli yields were not higher overall in the pheromone-treated plots compared with those in the controls, yields were significantly higher in the three-component stereospecific treatment in year 2. Therefore, the three-component stereospecific blend shows promise as a pheromone blend for swede midge mating disruption. However, due to high cost and levels of crop damage across all treatments, additional research is necessary to optimise swede midge mating disruption.

Biofuel crops such as napiergrass possess traits characteristic of invasive plant species, raising concern that biofuels might escape cultivation and invade surrounding agricultural and natural areas. Napiergrass biofuel types are being developed to have reduced invasion risk, but these might be cultivated in areas where naturalized populations of this species are already present. The successful management of napiergrass biofuel plantations will therefore require techniques to monitor for escaped biofuels as distinguished from existing naturalized populations. Here we used 20 microsatellite DNA markers developed for pearl millet to genotype 16 entries of napiergrass, including naturalized populations and accessions selected for biofuel traits. Use of the markers showed a clear genetic separation between the biofuel types and naturalized entries and revealed naturalized populations undergoing genetic isolation by distance. These findings demonstrated the utility of microsatellite marker transfer in the development of an important tool for managing the invasion risk of a potential biofuel crop.

Hepatitis C virus (HCV) nonstructural protein 3 (NS3) has been shown to possess protease and helicase activities and has also been demonstrated to spontaneously associate with nonstructural protein NS4A (NS4A) to form a stable complex. Previous attempts to produce the NS3/NS4A complex in recombinant baculovirus resulted in a protein complex that aggregated and precipitated in the absence of nonionic detergent and high salt. A single-chain form of the NS3/NS4A complex (His-NS4A21–32–GSGS-NS33–631) was constructed in which the NS4A core peptide is fused to the N-terminus of the NS3 protease domain as previously described (Taremi et al., 1998). This protein contains a histidine tagged NS4A peptide (a.a. 21–32) fused to the full-length NS3 (a.a. 3–631) through a flexible tetra amino acid linker. The recombinant protein was expressed to high levels in Escherichia coli, purified to homogeneity, and examined for NTPase, nucleic acid unwinding, and proteolytic activities. The single-chain recombinant NS3-NS4A protein possesses physiological properties equivalent to those of the NS3/NS4A complex except that this novel construct is stable, soluble and sixfold to sevenfold more active in unwinding duplex RNA. Comparison of the helicase activity of the single-chain recombinant NS3-NS4A with that of the full-length NS3 (without NS4A) and that of the helicase domain alone suggested that the presence of the protease domain and at least the NS4A core peptide are required for optimal unwinding activity.