Wireworm (Coleoptera: Elateridae) Species Composition and Management in Sweet Potato Grown in North Florida Using Chemical Insecticides and Entomopathogenic Nematodes

Abstract

Wireworms are immature stages of click beetles (Coleoptera: Elateridae) and are considered a serious threat to sweet potato production in the southern United States. The major wireworm species collected in North Florida sweet potato fields in 2017 and 2018 were Conoderus scissus, C. rudis, C. amplicollis, and C. falli. These species vary in their behavior and biology. During a 2-yr study period, we conducted two insecticide field trials using eleven insecticides belonging to organophosphates, neonicotinoids, pyrethroids, and botanical classes, and three field trials using entomopathogenic nematode (EPN) species to control wireworms. In 2017, all insecticide treatments significantly reduced new feeding holes and total holes (old + new + other) as compared to the untreated control. In 2018, the result was similar with a few variations. In both years, all insecticides showed a percentage reduction in wireworm damage holes (2017: 34.88–96.19%; 2018: 12.38–97.02%) with the highest by Regent. In the EPN field study, one application of EPN near planting significantly reduced soil insects. In a laboratory study conducted at the Tropical Research and Education Center, UF-IFAS, chlorpyrifos caused higher percentage mortality of C. rudis (55.5%) than C. scissus (22.2%). At the present experiment rates, none of the insecticides caused the mortality of C. amplicollis. Heterorhabditids strain ‘FL-2122’ was more susceptible to chlorpyrifos than other strains of EPN.

Meloidogyne incognita Management Using Fumigant and Non-fumigant Nematicides on Sweet Potato

“…Other factors, namely wireworms ( Conoderus spp. ), serious pests in north Florida sweet potato production ( Seal et al ., 2020 ), which were present in this study, could have also contributed to yield response. Wireworms feed on sweet potato tubers causing scars and holes, primarily affecting tuber quality ( Seal et al ., 2020 ), although it is suggested they reduce bulk tuber quality under high pressure ( Chalfant et al ., 1992 ).…”

“…), serious pests in north Florida sweet potato production ( Seal et al ., 2020 ), which were present in this study, could have also contributed to yield response. Wireworms feed on sweet potato tubers causing scars and holes, primarily affecting tuber quality ( Seal et al ., 2020 ), although it is suggested they reduce bulk tuber quality under high pressure ( Chalfant et al ., 1992 ). Both 1,3-D and oxamyl are reported to have activity against wireworms ( Chalfant et al ., 1992 ; Arrington et al ., 2016 ), but neither fluopyram nor fluazaindolizine are known to have any insecticidal activity.…”

Influence of Asafoetida Extract on the Virulence of the Entomopathogenic Nematode Steinernema carpocapsae and Its Symbiotic Bacterium Xenorhabdus nematophila in the Host Pyrrhocoris apterus

“…This may be beneficial in line with the underlying essential parameters influencing the metabolic functionality of both biological agents. According to recent studies, administering insecticides to nematodes either reduced or impacted their virulence [ 16 , 17 , 18 ]. Most of the ASF/nematode co-interaction research has been conducted on plant or alimentary parasite nematodes, with no reports on EPNs [ 19 , 20 ].…”

Plastic Mulch and In-row Spacing Effects on Sweetpotato Yield in Northwest Washington

“…and Plectris aliena), sugarcane beetle (Euetheola rugicepes), and sweetpotato weevil (Cylas formicarius) (Cuthbert, 1967;Smith, 2006;Sorensen, 2009). Sweetpotato weevils and wireworms are reported as the most damaging insect pests worldwide, and of all reported beetle pests, only Agriotes and Limonius species of wireworm have been reported in northwest Washington (Seal et al, 2020).…”