Bemisia tabaci (Hemiptera: Aleyrodidae) biotype B is one of the most limiting pests of tomato crops in the world. Tomato yield is currently dependent on the use of pesticides, which are problematic to farmers, consumers and the environment. A promising alternative to reduce the harmful effects caused by the indiscriminated use of synthetic insecticides is the use of insecticides of botanical origin. This study aimed to evaluate the effect of 3% (w/v) aqueous extracts from different structures of thirteen botanical species on the behavior of B. tabaci biotype B adults, as well as insecticidal activity of such aqueous extracts on B. tabaci eggs, nymphs, and adults infesting tomato plants. A distilled water solution was used as a negative control, and thiamethoxam insecticide (18 g/100 L of water) as a positive control. Leaf extract of Toona ciliata was observed to have the most efficient inhibitory effect in tests of extracts on whitefly behavior. Furthermore, the use of leaf extract of Toona ciliata led to the most drastic reduction in the number of adults and eggs on tomato leaflets. Leaf extract of Piper aduncum led to the greatest observed ovicidal effect (78.00% of non-hatched nymphs); however it was not effective against nymphs and adults. The leaf extracts of Trichilia pallida, Trichilia casaretti, and Toona ciliata showed the highest control indexes (67.9, 60.3, and 55.1%, respectively). For adults mortality, T. pallida was the most effective (72.8%). Our results indicate that application of extracts of T. pallida, T. ciliata, and T. casaretti are promising strategies to manage B. tabaci biotype B on tomato.

The current trend toward using natural food additives, cosmetics, and medicines has motivated industries to substitute synthetic compounds for natural products. Essential oils (EOs) from medicinal plants are a well-known source of chemical compounds that display several interesting biological activities, including antimicrobial action. In this study, we investigated the antibacterial activity of EOs extracted from three Piperaceae species collected in the Brazilian Amazon region against a representative panel of cariogenic bacteria. The minimum inhibitory concentration (MIC) of the essential oils extracted from Peperomia pellucida (PP-EO), Piper marginatum (PM-EO), and Piper callosum (PC-EO) was determined against Streptococcus mutans, S. mitis, S. sanguinis, S. salivarius, S. sobrinus, Enterococcus faecalis, and Lactobacillus casei by using the microplate microdilution method. PM-EO, PC-EO, and PP-EO displayed antibacterial activity against all the tested cariogenic bacteria. PM-EO displayed the best inhibitory activity, with MIC values ranging from 50 to 500 µg/mL. The lowest MIC values were obtained for PM-EO against S. mitis (MIC = 75 μg/mL), Lactobacillus casei (MIC = 50 μg/mL), and S. mutans (MIC = 50 μg/mL). Gas chromatography mass spectrometry (GC-MS) analysis allowed the chemical composition of all the EOs to be identified. The main constituents of PM-EO, PC-EO, and PP-EO were 3,4-(methylenedioxy)propiophenone, α-pinene, and dillapiole, respectively. Finally, the compounds that were exclusively detected in PM-EO are highlighted. Our results suggest that PM-EO may be used in products for treating dental caries and periodontal diseases.

The objective of this study was to evaluate the chemical profile and acaricidal activity against the mite Suidasia pontifica of the essential oils from leaves of Piper marginatum Jacq and aerial parts (branches, leaves, and inflorescences) of Piper callosum Ruiz & Pav. From the aerial parts (branches, leaves and inflorescences) of P. callosum, three different essential oils were extracted with variations in the contents of their chemical constituents. The major compounds in the essential oil of P. marginatum were δ-3-carene and (E)-β-ocimene, while safrole was the predominant compound in the essential oils of P. callosum. Concentrations of 4 μL/L of the essential oil of P. marginatum and 2 μL/L of the essential oil of P. callosum killed all the mites tested after 72 h of exposure. The 50% lethal concentration ranged from 1.19 to 2.16 µl/L air for P. marginatum and from 1.22 to 3.44 µl/L air for P. callosum.

The essential oils of Piper marginatum Jacq and Piper callosum Ruiz & Pav were obtained by hydrodistillation and tested in vitro against the adult worms of Schistosoma mansoni species. The chemical constituents were evaluated by Gas chromatography / Mass spectrometry. The main constituents of the essential oil of the leaves of P. marginatum were 3,4- (methylenedioxy) propiophenone (10.41 %), bicyclogermacrene (10.16 %) and germacrene D (9.93 %). The extraction of the aerial parts (branches, leaves and inflorescences) from P. callosum provided two essential oils, one of them being transparent and of greater density than the water presenting safrole (29.32 %), α-pinene (19.23 %) and β-pinene (14.31 %) as major constituents and another yellow oil of smaller density than the water with 92 % safrole. The essential oils exhibited a dose-dependent effect on decreased motor activity and death of parasites. The essential oil of P. marginatum caused death of 100 % of the parasites in the concentration of 50 μg/mL, while the PC+ (denser than water) and PC- (less dense than water) samples obtained from P. callosum caused 100 % death in the concentration of 100 μg/mL.

During grain storage, a considerable amount of product is lost because of insects, such as Zabrotes subfasciatus. Currently, to mitigate these risks, studies are searching for plants with potential for the control of agricultural pests, also known as botanical insecticides. In this study, the fumigant toxicity of the essential oils of Piper callosum (PC-EO), Piper marginatum (PM-EO) and Vitex agnus-castus (VA-EO) against Zabrotes subfasciatus was investigated. The essential oils of PC-EO, PM-EO and VA-EO were analysed by gas chromatography (GC-MS), and the major components were 3,4-methylenedioxypropiophenone (10.4%), bicyclogermacrene (10.1%) and germacrene D (9.9%) for PM-EO; safrol (29.3%) for PC-EO; and 1,8-cineol (23.8%) for VA-EO. In fumigation tests, VA-EO killed 100% Zabrotes subfasciatus at a concentration of 0.004 µL/L air after 24 h of treatment, whereas PC-EO and PM-EO at 0.01 µL/L air caused 100% Z. subfasciatus mortality after 48 h. The VA-EO sample provided the lowest LD50 after 24 h (0.17 µL/L air), followed by PC-EO (0.78 µL/L air) and PM-EO (1.17 µL/L air). These results demonstrate that the essential oils of these species can be an alternative to control pests in stored products. This is the first report of the fumigant potential of these species against Z. subfasciatus.