The control of Lepidoptera pests should be carried out before hatching of their caterpillars to avoid damage to the crops. The aim of this work was to assess the activity of neem (trade name: Natuneem ® , producer: Base Fértil, Chapadão do Sul, Brazil) and pyroligneous extracts (trade name: Biopirol 7M ® , producer: Biocarbo, Itabirito, Brazil) at 10 mL/L (1%) and 20 mL/L (2%) contents on egg masses of different ages of Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) and of Diatraea saccharalis F. (Lepidoptera: Pyralidae) at Embrapa Corn and Sorghum in Sete Lagoas, Minas Gerais State, Brazil. The tests took place in an unbiased casualized design with 12 treatments and four replications. The insecticides were diluted in water, and 0.04 mL of the solution was applied to recently laid and one-and two-day-old eggs of S. frugiperda and D. saccharalis. Caterpillars hatching from recently laid egg masses of S. frugiperda was lower with 2% pyroligneous extract [(0.02 ± 0.00)%]. Recently laid eggs and one-or two-day-old eggs of D. saccharalis presented lower caterpillar hatching with 1% neem extract [(0.00 ± 0.00)%, (0.00 ± 0.00)%, and (1.00 ± 0.01)%] and 2% neem extract [(0.00 ± 0.00)%], compared to 1% pyroligneous extract [(27.30 ± 3.22)%, (28.40 ± 3.32)%, and (37.80 ± 4.14)%] and 2% pyroligneous extract [(42.20 ± 4.49)%, (48.70 ± 4.97)%, and (56.60 ± 5.52)%], respectively. Neem and pyroligneous extracts had impact on hatching of S. frugiperda and D. saccharalis caterpillars.
The forage grasses are explored for the phytoremediation of heavy metals from contaminated areas. The present study evaluates the tolerance of forages grasses to Pb and the availability of Pb for the Mehlich 1, DTPA, and USEPA 3051 and 3052 extraction methods. The forage grasses cultivars Panicum maximum cultivars Aruana and Tanzânia, Brachiaria decumbens cultivar Basilisk, Brachiaria brizantha cultivar Xaraés and Marandu were assessed. Each cultivar was grown in a greenhouse in Diamantina, Brazil, in Typic Hapludox (Oxisol). The Pb was applied to the soil at doses of 0, 45, 90 and 270 mg kg-1 soil in a randomized design with four replications. The experiment was conducted over a 90-day trial period. Increasing Pb doses in the soil caused a reduction of growth in all varieties studied, and the "Basilisk" forage was generally more tolerant to Pb, while the Xaraés forage was generally more susceptible to the addition of Pb. The lower transfer coefficient of the cultivar "Basilisk", due to the high Pb content and accumulation in its roots, makes it the most suitable for phytoremediation programs, with possible uses in pasture areas. None of the varieties can be considered a Pb hyperaccumulator. The Mehlich 1, DTPA, USEPA 3051 and USEPA 3052 extraction methods indicated different doses of Pb in the soil, and the Mehlich 1 method demonstrated the lowest level of metal extraction from the soil. No correlation was observed between the forage grasses growth and the measurement of Pb in soil by the studied extraction methods, especially for the Mehlich 1 and DTPA methods, suggesting the inefficiency of these techniques for determining the phytoavailability of Pb.
Abstract.-Development of secondary attachment structures (SAS) was evaluated in apical fragments of pinnules, and basal and lateral branches in the carrageenophyte Chondracanthus chamissoi. When no dissolved calcium was added to the culture medium, most basal and lateral branches initiated SAS formation, while most pinnules remained unchanged. Calcium addition greatly increased the proportion of fragments developing SAS, and also increased the stage of development achieved by SAS in all branch types. We suggest that SAS formation by basal branches contributes to a complex attachment system. SAS formation by lateral branches and pinnules may contribute to vegetative propagation following fragmentation of thalli.
It is important to know the mechanisms for forage development, especially those related to the tolerance of potentially toxic elements, when considering their use in phytoremediation in heavy metal contaminated areas. In this study, we evaluated plant growth, concentration, and the availability of cadmium (Cd) for forage grasses (Panicum maximum Jacq. cv. Aruana and cv. Tanzânia; Brachiaria decumbens cv. Basilisk; Brachiaria brizantha cv. Xaraés and cv. Marandu) cultivated in Cd contaminated soils. The experiments were performed under greenhouse conditions over a 90-day evaluation period, and the Cd rates were 2, 4, and 12 mg/kg of soil. The relative growth rate of the forage grasses decreased as Cd rates increased, and the following descending order of susceptibility was observed: Marandu > Xaraés > Aruana > Tanzânia > Basilisk, with regard to phytotoxicity in these plants. The forage Cd concentration increased in line with increases in the Cd rates. Cd contents extracted by Mehlich-1 and by diethylenetriaminepentaacetic acid presented high positive correlation with forage relative growth. The forage plants did not block Cd entry into the food chain because they were not capable of limiting Cd absorption.
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