Management Strategies for Squash Bug and Cucumber Beetles in Watermelon

Entomolog

Tritrophic Interaction of Parasitoid \u3ci\u3eLysiphlebus testaceipes \u3c/i\u3e(Hymenoptera: Aphidiidae), Greenbug, \u3ci\u3eSchizaphis graminum\u3c/i\u3e (Homoptera: Aphididae), and Greenbug-Resistant Sorghum Hybrids

Interactions of the parasitoid Lysiphlebus testaceipes (Cresson) and the greenbug, Schizaphis graminum (Rondani), on greenbug-resistant ‘Cargill 607E’ (antibiosis), ‘Cargill 797’ (primarily tolerance), and -susceptible ‘Golden Harvest 510B’ sorghum, Sorghum bicolor (L.) Moench, were tested using three levels of biotype I greenbug infestation. The parasitoid infestation rate was 0.5 female and 1.0 male L. testaceipes per plant. For all three greenbug infestation levels, the parasitoid brought the greenbug under control (i.e., prevented the greenbugs from killing the plants) on both resistant hybrids, but it did not prevent heavy leaf damage at the higher greenbug infestation rates. At the low greenbug infestation rate (50 greenbugs per resistant plant when parasitoids were introduced), greenbugs damaged 5 and 18% of the total leaf area on ‘Cargill 797’ and ‘Cargill 607E’, respectively, before greenbugs were eliminated. Leaf damage was higher for the intermediate infestation study (120 greenbugs per plant), 21% and 30% leaf area were damaged on the resistant sorghum hybrids ‘Cargill 797’ and ‘Cargill 607E’, respectively. At the high greenbug infestation rate (300 greenbugs per plant), heavy damage occurred: 61% on ‘Cargill 607E’ and 75% on ‘Cargill 797’. The parasitoids did not control greenbugs on the susceptible sorghum hybrid ’Golden Harvest 510B’. L. testaceipes provided comparable control on both greenbug-resistant hybrids. This study supports previous studies indicating that L. testaceipes is effective in controlling greenbugs on sorghum with antibiosis resistance to greenbugs. Furthermore, new information is provided indicating that L. testaceipes is also effective in controlling greenbugs on a greenbug-tolerant hybrid

Biology and management of the potato tuberworm in the Pacific Northwest

The potato tuberworm, Phthorimaea operculella, is a pest of many solanaceous crops, including potatoes. Commonly found in tropical and subtropical regions throughout the world, potato tuberworm (PTW) is one of the most important constraints to potato production worldwide. Larvae of this species mine leaves, stems, and petioles and excavate tunnels through potato tubers. Adequate control of PTW is critical because larval infestation of tubers renders potatoes unmarketable. There is zero tolerance for the presence of tuberworm larvae in raw processing product because they are classified as foreign material. Additional losses are likely from infested tubers that rot in storage or from spread that may occur early in the storage season.Published April 2007. Reviewed August 2013. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Categories of Resistance, Antibiosis and Tolerance, to Biotype I Greenbug (\u3ci\u3eSchizaphis graminum\u3c/i\u3e (Rondani) Homoptera: Aphididae) in Four Sorghum (\u3ci\u3eSorghum bicolor\u3c/i\u3e (L.) Moench. Poales:Gramineae) Hybrids

Resistance categories (antibiosis and tolerance) of four sorghum (Sorghum bicolor (L.) Moench) hybrids to biotype I greenbug, Schizaphis graminum (Rondani), were determined in environmental growth chamber and field studies. Greenbug weight and fecundity were lower on ‘Cargill 607E’ compared with ‘Cargill 797’. Percentage of leaf damage area was significantly less on two resistant hybrids (Cargill 607E and Cargill 797) after a 14-d greenbug feeding period compared to two susceptible hybrids (‘Golden Harvest 510B’ and Garst 5715). In growth chamber studies on sorghum seedlings, ‘Cargill 607E’ and ‘Cargill 797’ reduced greenbug weight significantly compared with ‘Golden Harvest 510B’ and ‘Garst 5715’. Greenbug weight was 2.9 mg/25 greenbugs on ‘Cargill 607E’, 3.1 mg/25 greenbugs on ‘Cargill 797’, 3.9 mg/25 greenbugs on ‘Golden Harvest 510B’, and 4.8 mg/25 greenbugs on ‘Garst 5715’. On field grown sorghum plants, ‘Cargill 797’ did not reduce greenbug growth compared with ‘Golden Harvest 510B’. ‘Cargill 607E’ had a negative impact on weight of greenbugs. Greenbug weight was 7.9 mg/25 greenbugs on ‘Cargill 607E’, 9.2 mg/25 greenbugs on ‘Cargill 797’, and 10.0 mg/25 greenbugs on ‘Golden Harvest 510B’. ‘Cargill 607E’ and ‘Cargill 797’ were resistant to biotype I greenbugs compared with susceptible ‘Golden Harvest 510B’ and ‘Garst 5715’. Antibiosis was confirmed as the primary category of resistance in ‘Cargill 607E.’ ‘Cargill 797’ was primarily tolerant but may have some level of antibiosis, because smaller greenbugs developed in some of the studies

Does Strand Configuration and Number of Purchase Points Affect the Biomechanical Behavior of a Tendon Repair? A Biomechanical Evaluation Using Different Kessler Methods of Flexor Tendon Repair

This study compares the mechanical properties of modified Kessler and double-modified Kessler flexor tendon repair techniques and evaluates simple modifications on both methods. Forty fresh sheep flexor tendons were divided equally into four groups. A transverse sharp cut was done in the middle of each tendon and then repaired with modified Kessler technique, modified Kessler with additional purchase point in the midpoint of each longitudinal strand, double-modified Kessler technique, or a combination of outer Kessler and inner cruciate configuration based on double-modified Kessler technique. The tendons were tested in a tensile testing machine to assess the mechanical performance of the repairs. Outcome measures included gap formation and ultimate forces. The gap strengths of the double-modified Kessler technique (30.85 N, SD 1.90) and double-modified Kessler technique with inner cruciate configuration (33.60 N, SD 4.64) were statistically significantly greater than that of the two-strand modified Kessler (22.56 N, SD 3.44) and modified Kessler with additional purchase configuration (21.75 N, SD 4.03; Tukey honestly significant difference test, P < 0.000). There were statistically significant differences in failure strengths of the all groups (analysis of variance, P < 0.000). With an identical number of strands, the gap formation and ultimate forces of the repairs were not changed by additional locking purchase point in modified Kessler repair or changing the inner strand configuration in double-modified Kessler repair. The results of this study show that the number of strands across the repair site together with the number of locking loops clearly affects the strength of the repair; meanwhile, the longitudinal strand orientation and number of purchase points in a single loop did not affect its strength