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The invasive brown marmorated stink bug, Halyomorpha halys, poses significant risk to organic farming systems because they rely on biological control, nonsynthetic inputs, and cultural tactics for pest management. This study evaluated the potential of five crop plants (sorghum, admiral pea, millet, okra, and sunflower) to be used as trap crops under organic production in four mid-Atlantic states. Stink bug (H. halys and endemic species) densities and host plant phenologies were recorded weekly (mid-June through September). Sorghum attracted significantly more H. halys than the other crops evaluated, followed by sunflower and okra. Seasonal average H. halys density was 1.5-4× higher on sorghum than the other crops (P < 0.05), depending on site. Endemic stink bugs were equally attracted to all crops except admiral pea. A significant effect of time was detected (P < 0.0001), with H. halys densities initially higher on sunflower; as the sunflower senesced, sorghum supported significantly higher average H. halys densities. While sunflower and sorghum phenologies differed, these crops together provided a 5-wk attraction period coinciding with peak H. halys activity. The efficacies of pheromone-baited traps, flaming, applying OMRI-approved insecticides (Azera and Venerate), and vacuuming to removing stink bugs were evaluated as a management tactic. Flaming was the most effective treatment against H. halys and endemic stink bugs. Our results suggest that a trap crop composed of sorghum and sunflower may be an effective management tool for the mid-Atlantic stink bug complex, including H. halys. Future research should address the appropriate size and placement of trap crop within the farm.

A field experiment was conducted at the Tropical Research and Education Center, University of Florida, Homestead, to determine the effects on plant morphology, biomass yield, and flower production. of cutting the main stem of sunn hemp (Crotalaria juncea Aref A. Abdul-Baki is Plant Physiologist with the United States L.) plants at different heights. Seeds treated with cowpea (Vigua unguicalata)-type rhizobium were sown on 15 April 1999. The main stems were cut at 30, 60, and 90 cm above soil surface 100 days after seeding when the plants were about 1.5 m tall. Control plants were left uncut. Biomass that had been cut from plants was included in the total biomass yield. Seventy days following stem cutting, individual plants were evaluated for: plant height; main stem diameter; fresh and dry weights of roots, main stems, primary branches, secondary branches, leaves, open flowers, and unopened flowers. Leaf area and nutritional analyses of the plant parts were determined. Cutting the main stem at 30 and 60 cm above soil surface reduced total plant biomass, whereas cutting at 90 cm height increased biomass yield. Cutting at 30 cm produced the highest quality of biomass by increasing the leaf yield and reducing the weights of root and main stem both of which are low in N and high in C/N. Cutting the main stem at 90 cm produced the highest biomass yield, increased the number and weight of primary and secondary branches and, consequently, increased the number of flowers per plant. Nitrogen was highest in flowers and lowest in roots and main stems. Flowers were highest in K, P, Zn and Cu, whereas roots were highest in Fe content. We conclude that cutting the main stem at 30 cm height and allowing the plants to grow for an additional 70 d result in the highest quality biomass for use as green manure, windbreaks, and mulch. Cutting at 90 cm produced the largest biomass yield and increased flower production.

Compared to upland forests, riparian forest soils have greater potential to remove nitrate (NO 3 ) from agricultural runoff through denitrification. It is unclear, however, whether prolonged exposure of riparian soils to nitrogen (N) loading will affect the rate of denitrification and its end products. This research assesses the rate of denitrification and nitrous oxide (N 2 O) emissions from riparian forest soils exposed to prolonged nutrient runoff from plant nurseries and compares these to similar forest soils not exposed to nutrient runoff. Nursery runoff also contains high levels of phosphate (PO 4 ). Since there are conflicting reports on the impact of PO 4 on the activity of denitrifying microbes, the impact of PO 4 on such activity was also investigated. Bulk and intact soil cores were collected from N-exposed and non-exposed forests to determine denitrification and N 2 O emission rates, whereas denitrification potential was determined using soil slurries. Compared to the non-amended treatment, denitrification rate increased 2.7-and 3.4-fold when soil cores collected from both N-exposed and non-exposed sites were amended with 30 and 60 lg NO 3 -N g -1 soil, respectively. Net N 2 O emissions were 1.5 and 1.7 times higher from the N-exposed sites compared to the non-exposed sites at 30 and 60 lg NO 3 -N g -1 soil amendment rates, respectively. Similarly, denitrification potential increased 17 times in response to addition of 15 lg NO 3 -N g -1 in soil slurries. The addition of PO 4 (5 lg PO 4 -P g -1 ) to soil slurries and intact cores did not affect denitrification rates. These observations suggest that prolonged N loading did not affect the denitrification potential of the riparian forest soils; however, it did result in higher N 2 O emissions compared to emission rates from non-exposed forest soils.

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