Effects of mixtures of arrestants, dislodgers, and phagostimulants with synthetic insecticides on green-belly stink bug: walking behavior assessments, physicochemical interactions, and laboratory and field trials.

The green-belly stink bug (Diceraeus melacanthus Dallas (Hemiptera: Pentatomidae)) is a key pest of corn-soybean crop systems and the management of this pest is difficult due to behavioral characteristics. However, products that alter its behavior, such as arrestants, dislodgers, and phagostimulants, have been used in an attempt to improve the effectiveness of chemical control. In this study, the effect of these products on the walking behavior of nymphs and adults of D. melacanthus was initially evaluated through computational behavioral tracking (Ethovision system). Adults of D. melacanthus exposed to the dislodgers Creolin Pearson and Quimifol S450 (sulfur) significantly increased the distance covered and the walking speed. On the other hand, the only treatment that significantly affected the walking behavior of nymphs was the treatment with soy milk (phagostimulant). The physical-chemical analyses indicated considerable changes in the pH and electrical conductivity of mixtures of such products with insecticides from different chemical groups, as well as lack of homogeneity (physical incompatibility). Nevertheless, none of the products tested improved the control efficacy of an insecticide based on imidacloprid + beta-cyfluthrin, either in laboratory tests (contact bioassay) or in tests conducted in corn crops during 2 crop harvests. Thus, the association of these products in a tank mixture does not increase the control levels of D. melacanthus in post-emergence of maize and may have an antagonistic effect in some associations.

Essential Oils as a Source of Ecofriendly Insecticides for Drosophila suzukii (Diptera: Drosophilidae) and Their Potential Non-Target Effects.

The spotted wing drosophila (Drosophila suzukii) is one of the main invasive pests of small fruits in the world. Thus, 19 essential oils (EOs) were selected to analyze the effects through toxicity and repellency on oviposition and D. suzukii adults. In addition, their lethal and sublethal effects on the pupal endoparasitoid Trichopria anastrephae were evaluated. The EOs of C. flexuosus and Mentha spp. had the highest toxicity observed in the topical application bioassay for D. suzukii. In contrast, the EOs of C. verum, C. citratus QT citratus, and C. winterianus showed the highest toxicity in the ingestion bioassay for D. suzukii. The dry residues of C. verum and C. citratus QT citratus reduced the oviposition of D. suzukii. In the repellency bioassays, the 19 EOs analyzed repelled ≅ 90% of the D. suzukii females. All EOs evaluated using the LC90 values of the products provided mortality of less than 20% of T. anastrephae adults and did not cause a reduction in the parasitism of surviving T. anastrephae females. We conclude that the EOs evaluated have the potential to be used in the management of D. suzukii. They can also serve as selective active ingredients for the formulation and synthesis of new biopesticides.

Toxicity and Transgenerational Effects of Insecticides on Trichopria anastrephae (Hymenoptera: Diapriidae).

Trichopria anastrephae Costa Lima, 1940 (Hymenoptera: Diapriidae) is a pupal endoparasitoid of Drosophila suzukii Matsumura, 1931 (Diptera: Drosophilidae) in Brazil. This species is of great agricultural importance and is almost exclusively managed by organophosphate, spinosyn, pyrethroid, neonicotinoid, and avermectin insecticides. However, frequent application of insecticides can have negative effects on the parasitoid. The objective of this study was to evaluate the lethal and transgenerational toxicity of five insecticides on T. anastrephae adults during the F0, F1, and F2 generations. Drosophila suzukii puparia were sprayed prior to their exposure to T. anastrephae for 24 h. Parameters evaluated in generation F0 were mortality and rate of parasitism. After the emergence of the F1 generation, the emergence rate and sex ratio were analyzed. Then, pairs of parasitoids were selected from F1 and pupae; the host was offered to evaluate parasitism, emergence, and sex ratio of the F2 generation. In the F0 generation, malathion was the only insecticide that caused 100% mortality of adults of T. anastrephae. However, all insecticides tested affected the parasitism rate, being classified as moderately to slightly harmful. In F1, the emergence of T. anastrephae was also affected, making the insecticides moderately to slightly harmful. However, there were no significant differences in the sex ratio and parasitism rate or the parameters evaluated in F2, which means that all products were classified as harmless. These results are important for the development of Integrated Management programs for D. suzukii and for the conservation of natural populations of T. anastrephae in the field.

Essential Oil of Rosmarinus officinalis Ecotypes and Their Major Compounds: Insecticidal and Histological Assessment Against Drosophila suzukii and Their Impact on a Nontarget Parasitoid.

Essential oils (EOs) produced by plants in the Lamiaceae family may provide new insecticidal molecules. Novel control compounds are needed to control Drosophila suzukii (Matsumura), a severe economic invasive pest of thin-skinned fruit crops. Thus, we characterized the main compounds of EOs from three rosemary Rosmarinus officinalis ecotypes (ECOs) and evaluated their toxicity to D. suzukii adults, deterrence of oviposition behavior, and histological alterations in larvae. Additionally, we analyzed the lethal and sublethal effect on the pupal parasitoid Trichopria anastrephae. The main compounds identified in the R. officinalis ECOs were α-pinene, camphor and 1,8-cineole. In bioassays via topical application or ingestion, ECOs and their major compounds showed high toxicity on D. suzukii adults and a lower concentration could kill 50% and 90% of flies compared to spinetoram. The dry residues of a-pinene, 1,8-cineole, and camphor provided a repellent effect by reducing D. suzukii oviposition by ~47% compared to untreated fruit. Histological sections of 3rd instar larval D. suzukii posttreatment revealed damage to the fat body, Malpighian tubules, brain, salivary gland, and midgut, which contributed to high larval and pupal mortality. Survival and parasitism by adult T. anastrephae were not affected. Thus, R. officinalis EO and their compounds have potential for developing novel insecticides to manage D. suzukii.

Pesticide selectivity to the parasitoid Trichogramma pretiosum: A pattern 10-year database and its implications for Integrated Pest Management.

Trichogramma pretiosum is one of the main egg parasitoids used in the control of lepidopteran pests in Brazil. This natural enemy can be negatively affected by the use of insecticides, herbicides, and fungicides. The present work used a systematic review and meta-analysis to group information from multiple studies on the selectivity of pesticides (279 commercial products) in rice, corn, soybean, apple and peach crops for immature stages (egg-larva, pre-pupa, and pupa) and adult parasitoids. The selected studies used the International Organization for Biological and Integrated Control (IOBC) methodology with the same adaptations for T. pretiosum. The meta-analysis found that corn crops had the highest frequency of tests (2 0 7). The most frequently tested active ingredients (a.i.) were glyphosate, glyphosate isopropylamine salt, and sulfur at frequencies of 41, 32 and 24 tests, respectively. The pesticides registered for rice crops showed the greatest sublethal effects on T. pretiosum, with an approximately 47% reduction in parasitism (RP) or emergence (RE). The adult stage of the parasitoid showed greater sensitivity to the tested pesticides (65% RP), in comparison to the immature stages. In general, insecticides showed superior toxicity for all development stages of T. pretiosum, compared to herbicides and fungicides, regardless of the recommended dosage for the crop. The present study aggregates information related to selectivity for the four life stages of T. pretiosum, contributing significantly to the integration of biological control and chemical control in rice, corn, soybean, apple and peach crops in Brazil.

Effects of insecticides used in strawberries on stingless bees Melipona quadrifasciata and Tetragonisca fiebrigi (Hymenoptera: Apidae).

The use of pesticides is considered one of the most important threats to pollinators, especially since they are widely used in agriculture for pest control. In the last years, several studies have reported severe secondary effects on various bee species, including exotic and native bees. In this study, lethal (mortality) and sublethal (locomotor activity) effects of insecticides and acaricides used in strawberries in Brazil (abamectin, novaluron, spinetoram, and thiamethoxam) were evaluated on the native stingless bees Melipona quadrifasciata and Tetragonisca fiebrigi. The results showed that the effects varied significantly according to the pesticide, type of exposure (oral or topical), and bee species. Through oral exposure, M. quadrifasciata was more susceptible to all insecticides except for abamectin, while in topical exposure, T. fiebrigi was more sensitive. Thiamethoxam followed by spinetoram and abamectin were the most lethal, regardless of species or exposure route; novaluron was not harmful at the highest tested dose. The locomotor activity of bees was altered in the presence of sublethal doses (LC10 and LC50) of all insecticides. Spinetoram and abamectin can be as much as toxic as thiamethoxam against M. quadrifasciata and T. fiebrigi in laboratory experiments. These findings should be confirmed in field experiments to define possibilities to combine pest control and pollinator management. In crops like strawberries, the selectivity of native pollinators should be considered.

Some Aspects of the Biology of Trichopria anastrephae (Hymenoptera: Diapriidae), a Resident Parasitoid Attacking Drosophila suzukii (Diptera: Drosophilidae) in Brazil.

Spotted-wing Drosophila, Drosophila suzukii (Matsumura, 1931), is an economic pest of thin-skinned fruit crops. Its control has commonly been carried out through chemical methods. However, given the need to develop safer and environmentally friendly management alternatives, the pupal endoparasitoid Trichopria anastrephae Lima stands out as a potential biological control agent. However, the lack of information on the mass rearing of this parasitoid limits its use. Thus, the objective of our study was to provide information that is useful for rearing T. anastrephae using D. suzukii as a host. The effects of pupal age, exposure time, and pupal density on the parasitism rate were examined, as was the effect of honey provision for extending adult parasitoid longevity. Exposing 15 12-h-old pupae per female for 24 h resulted in higher parasitism rates and a greater number of emerged parasitoids. Males and females of T. anastrephae fed with pure honey (100%) or honey diluted to 50% in water lived longer compared to those fed 10% honey, no food, or only water.

Toxicity, attraction, and repellency of toxic baits to stingless bees Plebeia emerina (Friese) and Tetragonisca fiebrigi (Schwarz) (Hymenoptera: Apidae: Meliponini).

Toxic bait formulations have been one of the main strategies used in apple orchards in southern Brazil for the control of South American fruit fly. However, its effects on the stingless bees Plebeia emerina (Friese) and Tetragonisca fiebrigi (Schwarz) are unknown. This study aimed to assess the toxicity, attraction and repellency of food lures and toxic baits on P. emerina and T. fiebrigi. We evaluated the food lures Anamed® (pure), Biofruit® (3%), Flyral® (1.25%), Sugarcane molasses (7%) and Samaritá Tradicional® (3%), in toxic baits formulations associated with spinosad (Tracer® 480SC) and malathion (Malathion® 1000EC), and the ready-to-use toxic baits Success® 0.02CB and Gelsura®. We obtained the mean lethal concentration (LC50) and the mean survival of workers after exposure to toxic bait formulations. In the field, we carried out attraction and repellency tests of toxic baits to foraging. The food lures associated with malathion and spinosad showed different levels of toxicity to P. emerina and T. fiebrigi. Sugarcane molasses and Samaritá Tradicional® associated with spinosad showed high toxicity, with LC50 values of 6.92 and 10.61 ng/µL diet to P. emerina, and of 4.37 and 15.48 ng/µL diet to T. fiebrigi, respectively. Gelsura® and food lures with malathion caused rapid workers mortality, with mean survival less than 3 h after exposure. No toxic bait formulation was attractive to P. emerina foragers in the field. Anamed®, Gelsura®, and Success® were repellent to P. emerina foragers.