Volatile organic compounds (VOCs) of essential oils for the control of Fusarium oxysporum in cherry tomato seeds.

Fusarium oxysporum is the causal agent of Fusarium wilt in tomato plants. The most common form of control of this disease is through seed chemical treatment. However, the present work presents an alternative method, through the fumigation technique with essential oils. The pathogen F. oxysporum was inoculated on organic cherry tomato seeds through contact with sporulated Petri® plates. Thereafter, seeds were placed in stainless steel crucibles containing a 1.0 x 1.0 cm filter paper adhered to the lid and kept for 24 hours. This paper received 20 µL of each essential oil: tea tree, chia, citronella, lavender, anise basil, clove basil, and deionized water as control. This process was called "seed fumigation by essential oil". After this process, a germination test was carried out in germ boxes with Germitest® paper to verify the variables Germination Speed Index (GSI), Germination (G%), and Mean time to germination (MGT). Mycelial growth was verified in Petri® plates containing PDA medium. The plates containing mycelial growth were observed through scanning electron microscopy to verify possible morphological damage in the hyphae of the pathogen. Tea tree essential oil was the one that allowed the greatest suppression of the phytopathogen. Therefore, new tests were carried out with this specific oil. In germ boxes, tests of germination (G%), Abnormal seedlings count (ASC), and percentage of seedlings with mycelial growth were carried out. In addition, plant elicitation tests were performed in tomato seedlings through the analysis of chitinase, glucanase, and total proteins. All tests were carried out in completely randomized designs with four replications. All data were submitted to the Lilliefors normality test, followed by the analysis of variance, and Tukey's HSD (5% significance) for mean comparison. It was found that tea tree essential oil inhibited the mycelial growth of F. oxysporum without affecting the germination of cherry tomato seeds. Subsequent tests with this oil also demonstrated that there is a reduction in mycelia present in the seeds and a reduction in abnormal seedlings compared to the control. There was no significant difference between the variables tested for plant elicitation.

Occurrence of Metacaligus rufus (Wilson, 1908) (Copepoda, Caligidae) parasitizing the cownose ray Rhinoptera bonasus (Mitchill, 1815) (Elasmobranchii, Myliobatidae) in Brazil

The family Caligidae are predominantly external parasites of fishes, inhabiting the outer surface, the mouth, the gills and opercular cavity of their hosts (Boxshall and Halsey, 2004). This family comprises one of the most speciose group within the Copepoda, currently encompassing 31 genera, including Metacaligus (Thomsen, 1949) which consistis of five nominal species (Walter and Boxshall, 2008). Members of Metacaligus have been associated with actinopterygian fishes or obtained from plankton, particularly from American and Asian waters (Ho and Bashirullah, 1977; Suárez-Morales et al., 2012). In the seaboard of Brazil, two species have been hitherto recorded, i.e., Metacaligus rufus (Wilson, 1908) from the gills of Merluccius sp., Oligoplites palometa (Cuvier, 1832), O. saliens (Bloch, 1793), Scomberomorus sp., Selene vomer (Linnaeus, 1758), Trichiurus lepturus (Linnaeus, 1758) and Umbrina sp.; and M. trichiuri (Krøyer, 1863) from the gills of T. lepturus (Luque and Tavares, 2007; Luque et al., 2013). The Cownose ray Rhinoptera bonasus (Mitchill, 1815) (Myliobatidae) is an oceanic species found occasionally in sandy bottoms near the coast, feeding a variety number of bivalve mollusks and other benthic prey (Figueiredo, 1977; Froese and Pauly, 2016). This species is widely distributed in the Atlantic Ocean, found in the Western Atlantic: northern Florida (USA), throughout the Gulf of Mexico to south Brazil; and in the Eastern Atlantic: Mauritania, Senegal and Guinea (Froese and Pauly, 2016). Among the species of genus Rhinoptera, The International Union for Conservation of Nature (IUCN) listed this species as Near Threatened (NT) in relation to the state of conservation (Froese and Pauly, 2016; International Union for Conservation of Nature and Natural Resources, 2016).(AU)