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ARS Home » Pacific West Area » Hilo, Hawaii » Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center » Tropical Plant Genetic Resources and Disease Research » Research » Publications at this Location » Publication #415450
Research Project: Crop Health and Genetic Improvement of Sub-Tropical and Tropical Crops in the Pacific

Location: Tropical Plant Genetic Resources and Disease Research

Title: Effects of entomopathogenic nematodes and entomopathogenic fungi on nontarget soil surface arthopods and nematodes

Author
item WONG, LANDON - University Of Hawaii
item WANG, KOON-HUI - University Of Hawaii
item SIPES, BRENT - University Of Hawaii
item Myers, Roxana

Submitted to: Nematropica
Publication Type: Abstract Only
Publication Acceptance Date: 6/18/2024
Publication Date: 2/9/2025
Citation: Wong, L.G., Wang, K., Sipes, B.S., Myers, R.Y. 2025. Effects of entomopathogenic nematodes and entomopathogenic fungi on nontarget soil surface arthopods and nematodes. Nematropica. 54:185.

Interpretive Summary:

Technical Abstract: Entomopathogenic nematodes (EPN) and entomopathogenic fungi (EPF) are regarded as sustainable and organic insect management options that have reduced environmental impacts compared to conventional insecticides and may be useful in managing the sweetpotato weevil, Cylas formicarius. However, EPN and EPF tend to have wide host ranges and may infect non-target and beneficial insects. EPN have effects on plant-parasitic nematodes and may serve as a food source for nematophagous fungi or predatory nematodes. A sustainable integrated pest management approach could employ EPN and EPF. Oschieus tipulae and Beauveria bassiana were evaluated for non-target effects on soil surface arthropods and nematodes. A sweetpotato field was divided into ten 3-m long plots and a 2×2 factorial experiment established. O. tipulae was applied at 125,000 IJs/plot and B. bassiana applied as the commercial product Botanigard® was applied at label rates. The two remaining plots were treated with carbaryl at farmer practice rates. For arthropods, 17×17×5.5 cm pitfall traps were placed in the middle of each plot. A 100 ml aliquot of 1% liquid detergent solution (Dawn®, Procter & Gin amble, Cincinnati, OH) was placed in each trap to capture arthropods. Traps were monitored weekly by sorting arthropods to order and recording their numbers. To determine effects on the nematode community, 350 g soil samples were taken before sweetpotato planting and at crop harvest 17 weeks later. The soil samples were sifted to remove large particles and then a 250 cm3 subsample was subjected to elutriation and centrifugation. Nematodes were identified to trophic level and counted. The experiment was repeated once. Populations of C. formicarius were reduced by 100% in carbaryl treated plots. Botanigard® application increased populations of C. formicarius by 50% whereas applications of O. tipulae reduced populations of C. formicarius by 50%. Ten arthropod orders were recorded over the 17-week crop growth including Arachnida, Blattodea, Coleoptera, Diptera, Dermaptera, Hymenoptera, Isopoda, Lepidoptera, Orthoptera, and Thysanoptera. No differences were observed in detection of any arthropod order except Isopoda in plots treated with carbaryl and Botanigard®. Application of O. tipulae did not affect soil surface arthropods in any order. The soil nematode community was also not affected by cabaryl, Botanigard®, nor introduction of O. tipulae. Isopods are a particular group of soil arthropods which are indicated to be keystone species that react quickly to changes in the environment. The isopod group and the soil nematode community is an indicator of soil health. Isopod reduction indicated that carbaryl and Botanigard® had nontarget effects on the arthropod community. O. tipulae reduced the target pest, C. formicarius, while having the least effect on non-target organisms.