Jose Francisco Arruda e Silva

Mycoacaricides represent a promising alternative for managing resistant tick populations. This study evaluated the efficacy of corn oil–based Cordyceps javanica formulations against non-parasitic stages the southern cattle tick Rhipicephalus microplus under laboratory and semi-field conditions. Additionally, fungal persistence in soil and possible alterations in soil composition were assessed using ATR-FTIR spectroscopy combined with chemometric analysis. Corn oil (1%, 3%, and 5%) combined with 0.01% silicone oil did not affect conidial germination (> 98.4%). Corn oil and C. javanica suspensions alone yielded larval average mortality of 20.1% and 18.8%, respectively, 15 days after the treatment. When formulated in corn oil, averages of larval mortality ranging from 64.1% on day 5 to 100% on day 15, indicating a synergistic effect between fungus and oil. Corn oil alone resulted in a female tick control percent ranged from 20.5 to 73.3%, while the fungus alone achieved 28.2% and 14.9% control at 10⁷ and 10⁸ conidia/mL, respectively. All fungus–oil formulations significantly reduced female reproductive efficiency, achieving 90–100% tick control. Under semi-field conditions, the 10⁸ conidia/mL + 3% corn oil formulation reduced larval recovery from Urochloa decumbens pots by 98.6% compared to the oil and silicone control. Thirty days after application, C. javanica persisted in soil at 2.1 ± 0.3 × 10⁵ CFU/g (39.4% recovery). ATR-FTIR analysis showed no detectable alterations in the soil’s chemical profile following application of any formulation. These results highlight the potential of oil-based C. javanica formulations as an effective and sustainable tool for integrated tick management in livestock systems.

Entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana and the egg parasitoid Telenomus podisi are complementary strategies for managing the brown stink bug, Euschistus heros. This study evaluated fungal virulence against E. heros and selectivity to T. podisi in two experiments: (1) virulence assessment of M. anisopliae (CG 168; IBCB 425) and B. bassiana (LPP 129; LPP S1) applied at 1×10⁸ viable conidia mL⁻¹; and (2) selectivity tests in which eggs were immersed in fungal suspensions before (pre-parasitism) and after (post-parasitism) oviposition by T. podisi. Isolates CG 168 and IBCB 425 prolonged egg incubation and significantly reduced egg viability, with CG 168 showing hatching below 5%. At the nymphal stage, all isolates were pathogenic, and CG 168 and LPP 129 were the most virulent, causing higher mortality and shorter lethal times. In adults, CG 168 was the most effective, reducing survival to 8% by day seven, whereas IBCB 425, LPP 129, and LPP S1 caused intermediate effects, with 30–32% survival. Control treatments and Tween 80 maintained high survival. Fertility varied among isolates, increasing under LPP S1 and decreasing under LPP 129. Regarding selectivity, CG 168 reduced parasitism and emergence of T. podisi when applied after parasitism, whereas IBCB 425 showed performance similar to the control. Overall, CG 168 is highly effective against E. heros but shows low selectivity to T. podisi, while IBCB 425 combines efficacy and compatibility with the parasitoid, supporting its use in integrated management of the brown stink bug in soybean crops under agricultural production systems conditions.

The fungus Metarhizium anisopliae is under development as a bioinsecticide for Euschistus heros. To further elucidate the effect of this fungus on E. heros behavior, we monitored the feeding activities of adults treated with the fungus at 1 × 10⁸ conidia mL⁻¹ on soybean in the pod-filling stage (R5) through electropenetrography (EPG) AC-DC. We also determined the virulence of M. anisopliae to adults and its damage to soybean seeds. M. anisopliae displayed high levels of virulence to adults even at low concentrations of 5 × 10⁶ conidia mL⁻¹ (98% mortality). E. heros females were more susceptible to M. anisopliae than males, exhibiting a lower LT₅₀ for mycosed adults (7.1 and 9.7 days, respectively). The EPG experiment showed that fungus-treated adults spent significantly less time on probing activities (reduced by 86% at day four and ceased at day five) than untreated insects, and the number of waveform events per insect significantly decreased. This information is valuable for managing stink bugs at the field level, as it shows that even though the insect is alive, its feeding is compromised, consequently minimizing the damage inflicted to the crop. This study paves the way for further research employing entomopathogenic fungi in pest control.

Lalguard C99 WP, based on the Cordyceps javanica BRM 27666 strain, is registered in Brazil for whitefly control. Spatial prediction is crucial for optimizing its field use and efficacy. In this study, the optimal temperature for mycelial growth and conidial production of C. javanica is 25–30 °C, with no growth at 33–35 °C. The highest nymphal mortality occurred at 25 and 30 °C, showing lower LT₅₀ values at 30 °C. Mycelial growth was similar at 15, 20, 25, 30, and 35 °C when the fungus was exposed for 6 h and then transferred to a 27.4 °C environment; however, growth was slower at 35 °C with daily 6 h exposure alternating over 18 h at room temperature (mean of 28.5 °C). When the second instar whitefly nymphs were exposed for 6 h or 6 h daily at 15, 20, 25, 30, and 35 °C, followed by 7 days at fluctuating temperatures (mean of 28.4–30.2 °C), nymphal mortality was similar across temperatures. Although other abiotic factors (solar radiation, humidity, rainfall, etc.) must be considered for fungal efficacy, spatial predictions based on fluctuating temperatures indicated that C. javanica is suitable for use throughout Brazil, though its performance varied at constant temperatures in different locations.

No Brasil, o Cowpea mild mottle virus transmitido pela Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), é uma ameaça emergente ao feijão comum (Phaseolus vulgaris L.; Fabaceae), incluindo as linhas elites de feijão geneticamente modificadas desenvolvidas para resistência ao Bean golden mosaic virus. Para investigar essa interação, quantificamos a suscetibilidade de dez linhas geneticamente modificadas resistentes ao Bean golden mosaic virus à infecção pelo Cowpea mild mottle virus em duas regiões do Brasil com incidência natural de B. tabaci virulíferas. Em dois ensaios de campo, B. tabaci estabeleceu em todas as variedades, mas mostrou preferência pelas cultivares convencionais ‘Pérola’ e ‘BRS Pontal’ quando comparadas com as linhas elite geneticamente modificadas (média > 400 ninfas por folíolo e > 97% taxa de infecção por virus em um dos estudos). No entanto, embora as linhas elite foram resistentes ao Bean golden mosaic virus, todas foram infectadas pelo Cowpea mild mottle virus. As maiores taxas de infecção (19 a 99% de plantas infectadas) ocorreram nas linhas elite geneticamente modificadas derivadas da BRS Pontal versus Pérola (12 a 16%). Ao comparar a produtividade, a maioria das linhas elite superou seu pai convencional recorrente. Os aumentos relativos de rendimento foi de 199 a 1.045% sendo as variedades CNFCT 16205 e CNFCT 16210 as mais produtivas. Nossos resultados mostraram que o uso de cultivares de feijão resistentes ao mosaico dourado é uma ferramenta importante dentro das estratégias integradas de manejo para moscas-brancas e vírus. No entanto, mais estudos são necessários para elucidar à ameaça do Cowpea mild mottle virus e a natureza das interações da mosca-branca com estes diferentes vírus.

A inoculação e coinoculação do arroz de terras altas com rizobactérias multifuncionais pode promover o crescimento das plantas, especialmente do sistema radicular. Assim, este estudo teve como objetivo avaliar o efeito da inoculação e coinoculação com Azospirillum sp. e Bacillus sp. no desenvolvimento inicial do arroz de terras altas. O experimento foi conduzido em delineamento inteiramente casualizado com 4 tratamentos e 10 repetições, totalizando 40 parcelas. Os tratamentos foram: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) coinoculação de Ab-V5 + BRM 63573 e 4) controle (sem rizobactérias). A inoculação e coinoculação com as rizobactérias multifuncionais Ab-V5 e BRM 63573 proporcionaram efeitos positivos no desenvolvimento inicial do arroz de terras altas. A inoculação com o isolado BRM 63573 teve efeitos significativos no comprimento da raiz, parte aérea e biomassa total, enquanto a inoculação com o isolado Ab-V5 teve efeitos significativos no comprimento da raiz e produção de raiz e biomassa total. O tratamento com coinoculação teve efeitos significativos em variáveis como diâmetro, volume e superfície total de raiz e biomassa de raiz e total. O tratamento controle (sem rizobactérias multifuncionais) apresentou os piores resultados para a maioria das variáveis analisadas.

Entomopathogenic fungi stand out in the biological control of several agriculturally important insects. Six isolates of Metarhizium anisopliae, Cordyceps javanica, Beauveria sp. and B. bassiana were screened to control Anthonomus grandis, Euschistus heros, Oebalus poecilus, O. ypsilongriseus and Thyanta perditor, important insect pests of soybean, cotton and rice. The bioassays were conducted in a completely randomized design, with four replications (10 insects/replication). Significant differences for virulence were observed between the tested fungal species and isolates. For A. grandis, the most virulent isolate was M. anisopliae BRM 2335, followed by Beauveria BRM 14527 and BRM 67744 [82.5 to 97.5 % of mortality; average lethal time (LT₅₀) of 5.9 to 7.8 days]. M. anisopliae BRM 2335 was also highly virulent to the four stink bug species (75 to 97.5 % of mortality; LT₅₀ of 5.2 to 9.7 days). For the stink bugs, Beauveria sp. BRM 67744 was infectious to O. poecilus (75 % of mortality), but failed to control E. heros (16.9 % of mortality). C. javanica BRM 27666 and BRM 14526 showed average virulence to the stink bugs and A. grandis (17.5 to 57.3 % of mortality; LT₅₀ of 6.0 to 9.7 days). M. anisopliae was consistently more virulent to the stink bugs than the other fungi. Therefore, M. anisopliae BRM 2335 was selected for further studies under screenhouse and field conditions to control A. grandis and other stink bug species, especially E. heros.

Encapsulation via nanotechnology offers a potential method to overcome limited thermal and photo-stability of botanical pesticides. In this study, nanospheres of essential oils (NSEO) derived from Zanthoxylum rhoifolium Lam. fruit were characterized and evaluated for their photostability and insecticidal activity against Bemisia tabaci. Three major compounds of Z. rhoifolium fruits were detected by CG-MS: β-phellandrene (76.8%), β-myrcene (9.6%), and germacrene D (8.3%). The nanoprecipitation method was used to obtain homogeneous spherical NSEO, with ≥98% encapsulation efficiency. Tests with UV/Vis spectrophotometry showed significantly reduced photodegradation from exposed NSEO samples when compared with essential oil (EO) controls. Whitefly screenhouses bioassays with bean plants treated with 0.25, 0.5, 1 and 1.5% suspensions showed EO treatments in both free and nanoencapsulated forms reduced adult whitefly oviposition by up to 71%. In further tests, applications at 1.5% caused ≥64% mortality of second instar nymphs. When the test was conducted under high temperature and light radiation conditions, the insecticidal effect of NSEO treatments was improved (i.e., 84.3% mortality) when compared to the free form (64.8%). Our results indicate the insecticidal potential of EO-derived from Z. rhoifolium fruits with further formulation as nanospheres providing greater photostability and enhanced insecticidal activity against B. tabaci under adverse environmental conditions.

The use of beneficial microorganisms in crop systems can contribute to sustainable agriculture by promoting improvements in crop development and grain yield without damaging the environment. However, there is much uncertainty surrounding the effects of using a combination of microorganisms to promote plant development. The objective of this work was to determine the effects of microorganism species individually and in combination on the biomass production, gas exchange and nutrient contents in the shoots and roots of soybean plants. The experimental design was completely randomized, with 30 treatments and three replicates. The treatments consisted of the application of the rhizobacteria BRM 32109, BRM 32110 and 1301 (Bacillussp.); BRM 32111 and BRM 32112 (Pseudomonas sp.); BRM 32113 (Burkholderia sp.); BRM 32114 (Serratia sp.); Ab-V5 (Azospirillum bras ilense) and 1381 (Azospirillum sp.); the fungus Trichoderma asperellum (a mixture of the isolates UFRA. T06, UFRA. T09, UFRA. T12 and UFRA. T52); 19 combinations of these microorganisms, and a control (no microorganisms). At sowing, the soil was treated with Bradyrhizobium, and then the soybean seeds were inoculated. The microorganism suspension was applied in each treatment at 7 days after planting (DAP) in the soil and at 21 DAP on the seedlings. The Trichoderma pool, Ab-V5, 1301 + 32110, 1301 + 32114, 1301 + Ab-V5 and 32110 + Ab-V5 treatments resulted in significantly higher total biomass accumulation in the soybean plants, with values that were, on average, 25% higher than that in the control treatment. Our results suggest that the use of beneficial microorganisms in cropping systems is a promising technique.