Pathogenicity and virulence of entomopathogenic nematodes against Dichelops melacanthus Dallas (Hemiptera: Pentatomidae)

Abstract

Infestations of Dichelops melacanthus (Dallas; Hemiptera: Pentatomidae) in corn and wheat in Brazil, and the subsequent damage, have increased in recent years, mainly owing to this insect’s ability to survive the off-season. The control of this insect is mainly carried out with chemical insecticides, but the development of alternative methods, such as biological control, can contribute to a more sustainable management. Thus, the objective of this study was to evaluate the potential of entomopathogenic nematodes (EPNs) for the control of D. melacanthus. A selection test was performed with 15 isolates of genera Steinernema and Heterorhabditis regarding their pathogenicity and virulence on adults of D. melacanthus. Concentration (10, 20, 40, 50, and 100 infective juveniles (IJs)/cm2) and greenhouse tests were carried out only with the Steinernema feltiae isolate (IBCB-n 47). All experiments were conducted in a completely randomized design. The selection test data were submitted to the Scott-Knott averages test (P ? 0.05), and those from the greenhouse test to the Student's t-test. The results of the concentration assay were subjected to regression analysis. All isolates showed pathogenicity and virulence in adults of D. melacanthus. The isolates GL (Heterorhabditis amazonensis), IBCB-n27 (Steinernema sp.), and RSC05 (H. amazonensis) were the most virulent (80.0, 82.0, and 88.0% mortality, respectively). The higher concentrations of S. feltiae (50 and 100 IJs/cm²) were responsible for the highest mortality rates of green belly stink bug (88.0 and 86.0%, respectively). In the greenhouse test, S. feltiae caused higher mortality (38%) than the control.

Assessment of entomopathogenic nematodes and their symbiotic bacteria to control the stink bugs Euschistus heros and Dichelops melacanthus (Heteroptera: Pentatomidae) in the soybean-corn succession system

“…Testing S. diaprepesi and S. carpocapsae on D. melacanthus, Guide et al (2019) obtained higher mortality rates (78 and 64% respectively), however using higher rate ( 100IJs/cm 2 ) and holding the insects inside Petri dishes (9 cm) containing filter paper lied on the bottom. The nematode S. feltiae selected by Guide et al (2019) as one of the most virulent, caused 72% mortality inside the Petri dishes (over filter paper), and less than 40% in the greenhouse (over straw), with more than 25% mortality in the control. In the present study, the use of straw to screen EPNs against E. heros allowed the selection of species that may display a better performance over this substrate, explaining the similar results (> 70%) obtained in both lab and greenhouse tests, where the same substrate was used, treated with the rate of 88.4 IJs/cm 2 .…”

“…In fact, D. melacanthus was equally more resistant to both nematodes S. diaprepesi AM163 and S. carpocapsae IP1, which differ in their "cruiser" and "ambusher" behaviors, respectively, according to Koppenhöfer and Kaya (1996) and Del Valle et al (2014). Testing S. diaprepesi and S. carpocapsae on D. melacanthus, Guide et al (2019) obtained higher mortality rates (78 and 64% respectively), however using higher rate ( 100IJs/cm 2 ) and holding the insects inside Petri dishes (9 cm) containing filter paper lied on the bottom. The nematode S. feltiae selected by Guide et al (2019) as one of the most virulent, caused 72% mortality inside the Petri dishes (over filter paper), and less than 40% in the greenhouse (over straw), with more than 25% mortality in the control.…”

“…There have been some reports of EPNs serving as biological control agents against Hemiptera species on the leaves (Martínez-Córdoba et al, 2011;Naranjo et al, 2013;Niekerk and Malan, 2013;Platt et al, 2020), trunks/stems/shoots (Shapiro-Ilan and Mizell, 2012;Marrero et al, 2015;Guide et al, 2015;Guide et al, 2019) and soil (Leite et al, 2005;Melo et al 2006;Batista and Auad, 2010;Vieux and Malan, 2013;Mbata and Shapiro-Ilan, 2013;Batista et al, 2014;Alves et al, 2009;Guerrero & Pardey, 2019;Moussa et al, 2021;Zart et al, 2021). Susceptibilities of these insects range widely, with some species being more resistant than other usually tested insect hosts, requiring high rate of EPNs (100 IJs/cm 2 ) to provide > 70% mortality (Guide et al, 2015;Guide et al, 2019). Correspondences: samanta.nanzer@gmail.com and garrigos.leite@gmail.com The present study is the first to assess EPNs and their symbiotic bacteria against.…”

“…In studies conducted by Marrero et al (2015), H. bacteriophora (Poinar, 1975) caused 100% mortality of P. guildinii (Westwood) and N. viridula (Linnaeus), while in study conducted by Guide et al (2019), H. amazonensis (Andaló, Nguyen and Moino. 2006) caused 88% mortality of D. melacanthus, when both nematodes were tested in Petri dishes (9 cm) containing a filter paper lied on the bottom plate.…”

Potencial de nematoides entomopatogênicos e suas bactérias simbióticas para o controle dos percevejos Euschistus heros e Dichelops melacanthus (Heteroptera: Pentatomidae) no sistema de sucessão soja-milho

“…O percevejo D. melacanthus apresentou-se igualmente resistente para ambos os nematoides S. diaprepesi AM163 e S. carpocapsae IP1, os quais diferem nos seus comportamentos "cruiser" e "ambush", respectivamente (DEL VALLE et al, 2014;KAYA, 1996). Testando S. diaprepesi e S. carpocapsae sobre D. melacanthus, Guide et al (2019) obtiveram maiores índices de mortalidade (78 e 64% respectivamente), porém usando concentração maior (100 JIs/cm²) e acondicionando os insetos dentro de placas de Petri (9 cm), sobre papel de filtro no fundo. O nematoide S. feltiae selecionado por Guide et al (2019) como um dos mais virulentos causou 72% de mortalidade em placa de Petri, e menos de 40% em casa de vegetação, ocorrendo mais de 25% de mortalidade no controle.…”