Location: Fruit and Tree Nut ResearchTitle: Potential use of entomopathogenic nematodes against the soil dwelling stages of onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) under laboratory, greenhouse and field conditions
|GULZAR, SEHRISH - University Of Agriculture - Pakistan|
|WAKIL, WAQAS - University Of Agriculture - Pakistan|
|Shapiro Ilan, David|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2021
Publication Date: 8/1/2021
Citation: Gulzar, S., Wakil, W., Shapiro Ilan, D.I. 2021. Potential use of entomopathogenic nematodes against the soil dwelling stages of onion thrips Thrips tabaci Lindeman (Thysanoptera: Thripidae) under laboratory, greenhouse and field conditions. Biological Control. 161/104677. https://doi.org/10.1016/j.biocontrol.2021.104677.
Interpretive Summary: Onion thrips is a major pest of onions. Chemical insecticides are often used to control this serious pest. However, due to environmental and regulatory concerns, alternative control measures are needed. Entomopathogenic nematodes, also known as beneficial nematodes, are small round worms that are used as environmentally-friendly natural insecticides. Beneficial nematodes are used to control a wide variety of economically important insect pests. In this study, we tested the potential of beneficial nematodes to control onion thrips. We measured the virulence (killing power) of ten different nematode species against different developmental stages of the onion thrips. Overall, the nematodes called Heterorhabditis bacteriophora and Steinernema feltiae were most efficacious followed by S. carpocapsae. Our results revealed that EPNs could be included in integrated pest management programs for onion thrips in onion production systems.
Technical Abstract: Onion thrips Thrips tabaci is one of the most damaging insect pests of onion Allium cepa, which is an economically important agriculture crop cultivated worldwide. This is first comprehensive study in which we have tested a broad range of entomopathogenic nematodes (EPN) species against different developmental stages of T. tabaci under laboratory, greenhouse and field conditions. In screening bioassays, at 100 infective juveniles (IJs) cm-2 mortality ranged from 8.5-74.2% and 5.0-62.7% among all the tested EPNs (Steinernema carpocapsae (ALL strain), S. glaseri (NC), S. riobrave (355), S. feltiae (SN strain), S. rarum (17 C&E), Heterorhabditis bacteriophora (VS), H. georgiana (Kesha), H. indica (HOM1), H. floridensis (K22) and H. megidis (UK211 strain)) in pre-pupae and pupae, respectively. The pre-pupal stage was the most susceptible (87.9% mortality) followed by pupae (78.1% mortality) and late second instar larvae (59.4% mortality) when exposed to H. bacteriophora at highest dose tested (200 IJs cm-2). Among the different temperatures tested, maximum efficacy was observed by all the tested EPNs at 25oC and 30oC followed by 35oC and 20oC with H. bacteriophora and S. feltiae being most virulent among all species at all the tested temperatures. In a potted soil bioassay, the lowest adult emergences were observed in the H. bacteriophora treatment for both pre-pupae and pupae. Under field conditions, the lowest number of larvae (4.9 per plant in 2017-18 and 9.6 per plant in 2018-19) and adult (0.1 per plant in 2017-18 and 5.2 per plant in 2018-19) were observed in H. bacteriophora treated plots as compared to control larvae (29.4 per plant in 2017-18 and 44.1 per plant in 2018-19) and adults (20.0 per plant in 2017-18 and 28.1 in 2018-19). Our results revealed that EPNs could be included in integrated pest management programs for T. tabaci in onion production systems.