Two full-length cDNA sequences encoding digestive serine proteases (designated asSmPROT-1 and SmPROT-2) were recovered from the midgut of the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), in an ongoing expressed sequence tag project. The deduced amino acid sequences shared homology with digestive serine proteases from insect and non-insect species, including conserved regions such as the catalytic triad, active pocket, and conserved structural motifs. Secretory signal peptides in both proteases at the N-terminals indicate that these proteins could function as midgut digestive serine proteases. A phylogenetic analysis grouped SmPROT-1 and SmPROT-2 with trypsin-like and chymotrysin-like serine proteases, respectively. Quantitative real-time PCR analysis showed that SmPROT-1 and SmPROT-2 were expressed predominantly in the midgut rather than in other tissues (fat body and salivary glands). Expression analyses revealed high mRNA levels for the feeding instars (1st-and 2nd-instar larvae) compared with other stages (neonate, 3rd instar, pupa, and adult). These results provide new insights into the biology of S. mosellana and are discussed in the context of developing alternative control strategies.

Growing annual crops such as corn (Zea mays L.) can lead to considerable nutrient losses through subsurface drainage in agricultural fields, posing a serious threat to surface water quality in the midwestern United States. Perennial crops have the potential to reduce these nutrient losses. However, more comprehensive data are needed on the nutrient loss effect of perennial crops. We examined the effect of alfalfa (Medicago sativa L.) on nitrate-nitrogen (NO 3 − -N), total nitrogen (TN), dissolved reactive phosphorus (DRP), and total phosphorus (TP) in subsurface drainage using a beforeafter-control-impact (BACI) experimental design with one control field (with annual crops) and one impact field (with alfalfa) each on two farms (Sites A and B) located in northwestern Ohio. The "Before" period (prior to planting alfalfa at the impact field) extended for 4 yr (2013-2017) at Site A and 6 yr (2011-2017) at Site B; the "After" period extended for an additional 2 yr at both sites. Reductions in the mean monthly discharge and loads of NO 3 − -N, TN, DRP, and TP were significant at Site A, whereas the only significant change at site B was a reduction in the mean monthly TP load. Significant reductions in NO 3 − -N loads were observed during spring and winter at Site A. In addition, alfalfa reduced the variability of discharge and nutrient loads through subsurface drainage at both sites. Our findings suggest that introducing alfalfa into annual crop rotations has the potential to reduce subsurface nutrient loads and increase the resiliency of agricultural systems.