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Duponchelia fovealis Zeller, is currently considered one of the most important emergent pests of a range of crops. This pest is common in Europe, but its presence in the Americas, particularly Brazil and Mexico, has been only recently reported in strawberry crops. Since its recent arrival in Mexico interest in the potential of different entomopathogens for the control of D. fovealis has increased. Here we evaluated commercial products of the bacterium Bacillus thuringiensis; three different species of entomopathogenic nematodes; and different isolates of four species of entomopathogenic fungi. All pathogens were evaluated against 3rd instar larvae, except nematodes which were evaluated against both larvae and pupae. Analysis revealed significant differences in virulence amongst B. thuringiensis products, where the most virulent was nine times more virulent than the least virulent product. Amongst nematodes, Heterorhabditis bacteriophora was the most virulent and larvae were more susceptible to nematodes than pupae; larval mortalities at the highest dose evaluated (200 infective juveniles [IJs]) were between 80 and 95%, while for pupae they were between 25 and 40%. Mortality of larvae due to entomopathogenic fungi was lower than for the other entomopathogens; the highest mortality observed was 25% caused by an M. anisopliae isolate, although this was not statistically different to other fungal isolates. Overall, our results showed that biological control products based on B. thuringiensis or the nematode H. bacteriophora have the greatest potential; we consider that H. bacteriophora could be more convenient as it infects larvae and pupae. [ABSTRACT FROM AUTHOR]

The Neotropical brown stink bug Euschistus heros and the green-belly stink bug Dichelops melacanthus are the most important pests today for the succession system of soy-corn in Brazil. Dichelops melacanthus attacks the emerging shoot (epicotyl) of corn plants at the seedling stage of their development, remaining and reproducing on the straw over generations. Euschistus heros, on the other hand, feeds directly on the grains and lodge under fallen leaves after the soybean harvest, due to the absence of another crop host. Entomopathogenic nematodes (EPNs) are capable of killing insects due to their ability to search for the host in the soil and to their associations with symbiotic bacteria that cause pathogenesis. This work aimed to assess strains of EPNs and their symbiotic bacteria regarding their potential to control adults of E. heros and D. melacanthus. Entomopathogenic nematodes could be used to kill the stink bugs adults remaining over the straws, while the symbiotic bacteria could be used to kill these insects above ground, and these bacteria are much easier to produce compared to the EPNs. To assess EPNs and their simbiotic bacteria, tests were conducted in the laboratory and under greenhouse conditions. The nematodes S. diaprepesi AM163, S. carpocapsae All and S. carpocapsae IP1 caused 100% mortality of E. heros on the sand substrate, at the rate of 140 IJs/cm² (1000 IJs/insect). The symbiotic bacteria tested topically provided low mortality of E. heros (<40.3%). In a test with S. diaprepesi AM163 applied on the sand substrate at five different rates, after 7 days, mortality of E. heros remained below 50%, except at the high rates of 24 IJs/cm² (50%) and 256 IJs/cm² (80%), respectively. Higher lethality rates also resulted in the increase of the number of IJs produced per insect, up to 88.4 IJs/cm² (5,400 IJs). The nematode S. diaprepesi AM163 applied to E. heros on two substrates (sand and straw) with two-layer thicknesses, at a rate of 88.4 IJs/cm², caused high insect mortality levels (=69%), regardless of the substrate and its layer thickness. The nematode S. diaprepesi AM163 was twice more virulent to E. heros (69.1% mortality) than to D. melacanthus (28.8%). Dichelops melacanthus was equally resistant to both nematodes S. diaprepesi AM163 and S. carpocapsae IP1. In a greenhouse test, S. diaprepesi AM163 caused again a high mortality level to E. heros (72.5%) at the high rate of 88.4 IJs/cm². Thus, EPNs may turn up an alternative to control E. heros if high rates of production and use become profitable and viable. [ABSTRACT FROM AUTHOR]

The gastropod Pseudosuccinea columella participates in the dissemination of Fasciola hepatica in the environment, acting as the main intermediate host of this parasite in Brazil. The present study sought to elucidate the possible pathogenic effects of the entomopathogenic nematode (EPN) Heterorhabditis bacteriophora on P. columella , by evaluating the influence of infection on alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as the concentrations of total protein, uric acid, and urea in the snail's hemolymph. For this, the snails were exposed to EPNs for 24 and 48 h, and for each exposure time, 20 snails were dissected after 7, 14 and 21 days for hemolymph collection. The primary findings suggest a significant proteolysis alongside elevated levels of uric acid and urea in P. columella infected individuals. These findings reveal that H. bacteriophora HP88 infection induced serious changes in the snail's metabolism, triggering important deleterious effects. • Exposure of the gastropod Pseudosuccinea columella to the nematode Heterorhabditis bacteriophora disrupts mollusk metabolism. • Significantly decreased protein but increased urea and uric acid levels in the hemolymph at different time points. • Infected snails exhibit notable increases in the activities of alanine-and aspartate aminotransferase in the hemolymph compared to those uninfected, indicative of cell injury. [ABSTRACT FROM AUTHOR]

• Exposure by H. bacteriophora changes the levels of galactogen in B. glabrata. • H. bacteriophora induces parasitic castration in B. glabrata. • Infection by H. bacteriophora induces changes in oxidative metabolismo of B. glabrata. • Infection by H. bacteriophora induces alterations in the gonadal tissues of B. glabrata. Heterorhabditis bacteriophora is an entomopathogenic nematode (EPN) that is mutually associated with Photorhabdus luminescens , utilized globally for biological control of numerous organisms. Freshwater snails of the species Biomphalaria glabrata have been incriminated as the main intermediate hosts of Schistosoma mansoni in Brazil, but virtually nothing is known about the susceptibility of these gastropod to EPNs. Information in this respect is relevant for control of these intermediate hosts, and thus of the helminthiases they transmit. This paper for the first time reports the susceptibility of B. glabrata to infective juveniles of H. bacteriophora (isolate HP88) under laboratory conditions. For that purpose, six groups were formed: three Control groups (not exposed) and three Treated groups, in which the snails were exposed to 300 juveniles infecting the nematode over three weeks. The entire experiment was conducted in triplicate, using a total of 270 snails. Significant physiological alterations in B. glabrata were observed in response to the infection by H. bacteriophora HP88, characterized by decreased levels of hemolymphatic glucose as well as reduced contents of glycogen stored in the host's digestive gland. In parallel, the hemolymphatic activity of lactate dehydrogenase increased in the infected snails, indicating that the infection induces breakdown of carbohydrate homeostasis in B. glabrata. Additionally, all the reproductive parameters analyzed were reduced as a consequence of the infection. The results indicate the occurrence of the phenomenon of parasitic castration in the B. glabrata/H. bacteriophora HP88 interface, probably due to the depletion of galactogen in the parasitized organism. Although the infection did not cause lethality in the population of infected snails, H. bacteriophora HP88 compromised the reproductive performance of B. glabrata, suggesting its applicability in programs for biological control of this planorbid. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The Brazilian apple leafroller, Bonagota salubricola (Meyrick, 1937) (Bonagota cranaodes) (Lepidoptera: Tortricidae), is one of the main pest problems in apple orchards is Brazil. The purpose of this work was to evaluate B. salubricola larval and pupal susceptibility to different species of entomopathogenic nematodes, isolated in Rio Grande do Sul state in Brazil, under laboratory and field (apple orchard) conditions. Bioassays for isolates selection and determination of lethal concentration were performed in tubes of 1.5ml (eppendorf), each containing one B. salubricola third instar larvae and filter paper. Field experiments were performed in commercial orchard, with application of 100 infecting juveniles (IJs)/cm2 for each apple plant previously infected with five B. salubricola larvae covered with plastic trays containing thin cloth. Nematodes H. bacteriophora RS107 and H. bacteriophora RS57 had LC50 of 13 and 4.5IJs/larvae (4.3 and 1.5IJs/cm2), respectively. In the field, H. bacteriophora RS107 and H. bacteriophora RS57, applied with sorbitol as an adjuvant, reached 70.2 and 61.1% larval mortality, respectively. The results showed that both isolates had biological activity against B. salubricola under laboratory and field conditions. [Copyright &y& Elsevier]

Abstract: Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD90 of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm2, respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm2 of either nematode. In the field, H. bacteriophora RS88 and S. riobravae RS59 sprayed individually over natural and artificially infested fruit (250IJs/cm2) resulted in A. fraterculus larval mortality of 51.3%, 28.1% and 20%, 24.3%, respectively. There was no significant difference in A. fraterculus pupal mortality sprayed with an aqueous suspension of either nematode; however, when using infected insect cadavers, H. bacteriophora RS88 was more efficient than S. riobrave RS59. Our results showed that H. bacteriophora RS88 was more virulent to insect larvae, with an efficient host search inside the infested fruit and control of pupae in the soil after being applied by aqueous suspension or infected cadavers. [Copyright &y& Elsevier]

In a survey of entomopathogenic nematodes in Brazil, a nematode isolate of the genus Heterorhabditis was found. The nematode was collected from soil by the insect-baiting technique and maintained in the laboratory on last instar Galleria mellonella (L.) larvae. Morphological and molecular studies of the isolate showed that the nematode is a new species. Light and scanning electron microscopy, DNA characterisation and phylogeny were used for this description. Heterorhabditis amazonensis n. sp. is morphologically similar to H. baujardi, H. floridensis, H. mexicana and H. indica, and can be distinguished from these species mainly by male and female characters. Fifty percent of Heterorhabditis amazonensis n. sp. males have two pairs of bursal papillae in the terminal group; 25% with two papillae on one side and one papilla on the other side and 25% with one pair of papillae. Twenty percent of the population has a curved gubernaculum. The percentage of the gubernaculum to spicule length (GS%) is lower than that of H. mexicana (50 vs 56), and the length of the spicule relative to anal body diam. (SW%) is lower than that of H. mexicana (152 vs 167) and H. baujardi (152 vs 182). The female can be differentiated from related species by its unique vulva pattern. In a phylogenetic tree, the new species, H. floridensis, H. baujardi and H. mexicana form a monophyletic group, a sister group to H. indica. The new species has evolved three autapomorphic nucleotide character states, differing from its sister taxa H. mexicana at 22, and H. baujardi at 15, aligned positions. [ABSTRACT FROM AUTHOR]