Integrating <i>Trissolcus japonicus</i> (Ashmead, 1904) (Hymenoptera: Scelionidae) into Management Programs for <i>Halyomorpha halys</i> (Stål, 1855) (Hemiptera: Pentatomidae) in Apple Orchards: Impact of Insecticide Applications and Spray Patterns

• Main Authors: Dalton C. Ludwick, Jessica Patterson, Layne B. Leake, Lee Carper, Tracy C. Leskey
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Insects
• Subjects: parasitoids; chemical control; tree fruit
• Online Access: https://www.mdpi.com/2075-4450/11/12/833

<i>Halyomorpha halys</i> (Stål, 1855) (Hemiptera: Pentatomidae) is an invasive species in the United States, where it has caused significant damage to specialty crops, including apples. While integrated pest management techniques have been developed for <i>H. halys</i> in apple, including spray application techniques, it is unknown how these techniques affect foraging, adventive <i>Trissolcus japonicus</i> (Ashmead, 1904) (Hymenoptera: Scelionidae), and its offspring. In this study, egg masses (unparasitized and 2 and 7 day parasitized pre-treatment) were placed in apple orchards in treated and untreated locations that received full block insecticide applications or reduced application techniques, including border row or alternate row middle applications. Bifenthrin, thiamethoxam + λ-cyhalothrin, clothianidin, and methomyl were evaluated. Egg masses were retrieved 24 h after spray applications. For 2 and 7 day parasitized pre-treatment, adult <i>T. japonicus</i> emergence was recorded from each egg mass. For unparasitized egg masses, <i>T. japonicus</i> females were given 24 h to forage and oviposit on post-treatment egg masses with female survivorship, and adult emergence from egg masses was recorded. Female survivorship was significantly lower on post-treatment egg masses retrieved from areas receiving bifenthrin applications. Emergence from post-treatment egg masses was affected by thiamethoxam + λ-cyhalothrin, bifenthrin, and methomyl in some treated areas, whereas less impact was observed on 2 and 7 day pre-treatment parasitized egg masses in general. These data provide further insights into <i>H. halys</i> management and the potential impact of <i>T. japonicus</i> in sprayed orchard agroecosystems.