Use of entomopathogenic fungi combined with biorational insecticides to controlDichroplus maculipennis(Orthoptera: Acrididae: Melanoplinae) under semi-field conditions

Abstract

Grasshoppers are among the invertebrate herbivores that cause most economic losses in grasslands throughout Argentina's Pampas and parts of Patagonia. Chemical insecticides remain the sole option for grasshopper control in this area, despite being of significant environmental concern. Our aim was to evaluate the efficacy of combinations between three entomopathogenic fungi strains (Beauveria bassiana LPSc 1067 and LPSc1082), and Metarhizium anisopliae (LPSc 907), two biorational insecticides (luphenuron and methoxyfenozide), and a new synthetic chemical pesticide (rynaxypyr) in the control of the pest grasshopper Dichroplus maculipennis under field cage conditions. Fungal strains used were adjusted to 1 × 10 8 , 1 × 10 6 and 1 × 10 4 conidia/ml. Insecticides were tested at three concentrations: the average concentration recommended for application in the field (100%), 50% of that level and finally 25%. Combinations of the insecticides with B. bassiana (LPSc 1067, LPSc 1082) and M. anisopliae (LPSc 907) caused higher mortality to D. maculipennis nymphs than any of the individual agents used alone. The three insecticides tested did not negatively affect the isolates of the two species of entomopathogenic fungi employed.

Toxin-Pathogen Synergy Reshaping Detoxification and Antioxidant Defense Mechanism of Oligonychus afrasiaticus (McGregor)

“…Interaction of entomopathogenic fungal spores with chemicals can have antagonistic, neutral or synergistic mortality response against target pest population [ 28 , 42 ]. Increased mortality of O. afrasiaticus with the use of phytol and entomopathogenic fungus B. bassiana in combinations was recorded in the current study.…”

Analysis of the management of grasshopper species (Orthoptera: Acrididae), agricultural pest in Laprida county, Buenos Aires, Argentina

“…Teniendo como base tanto el registro documental como la información proporcionada por los entrevistados, es posible afirmar que desde mediados del siglo pasado hasta la actualidad el control de estos insectos se lleva a cabo mediante insecticidas químicos de alta toxicidad. Esto se corresponde con los datos obtenidos de las encuestas, en los que el 43,1% de los consultados manifestaron realizar control químico en situaciones de explosiones poblacionales de tucuras, y el 56,5% de los mismos realizan las aplicaciones sobre Mariottini & Lange, 2014;Pelizza et al, 2015Pelizza et al, , 2017Pelizza et al, , 2018Lange et al, 2020a, b). A fines del año 2019 comenzaron a realizarse experiencias piloto con la aplicación del microsporidio Paranosema locustae, sobre pastizales naturales de los partidos de Tandil, Olavarría y Laprida, con el objetivo de establecer a este microsporidio como una medida de control alternativa a largo plazo.…”

The Effect of Herbicide Use on the Occurrence of Entomopathogenic Fungi in the Soil of Blackcurrant Plantations

“…Reports by many authors (Vänninen and Hokkanen, 1988;Miętkiewski et al, 1997;Tkaczuk, 2008;Tkaczuk et. al., 2012;Pelizza et al, 2015;Fiedler and Sosnowska, 2017) indicate that chemical substances in plant protection products can affect EPF and their natural occurrence, species composition, sporulation, colony growth, and infectiousness potential. With a wide range of pesticides used in chemical plant protection, fungicides and herbicides have the most negative effect on the population of fungi and their impact largely depends on the amount of the active substance and on the species of fungus (Andalo et al, 2004;Tkaczuk et al, 2012).…”