Spatial-temporal distribution of phytophagous and predatory mites in the canopy of Jatropha curcas L / Distribuição espaço-temporal de ácaros fitófagos e predadores no dossel de plantas de pinhão-manso

The aim of the present study was to evaluate the spatial-temporal distribution of phytophagous and predatory mites in the canopy of Jatropha curcas L. Mite richness, diversity, and abundance were determined, and higher values were observed primarily in the top stratum. Mite population in J. curcas was higher during the rainy season. Phytophagous mites were mostly concentrated in the top stratum, and Brevipalpus sp. was the most abundant. Predatory mites from the family Phytoseiidae presented the highest richness and diversity, and Amblydromalus zannoui was the most abundant species. The present results indicate seasonal population dynamics for both predatory and phytophagous mites on J. curcas.(AU)

O presente estudo teve por objetivo avaliar a distribuição espaço-temporal de ácaros fitófagos e predadores no dossel de plantas de pinhão-manso. Parâmetros de riqueza, diversidade e abundância de ácaros foram determinados. Os resultados deste estudo demonstram que maiores valores de riqueza, diversidade e abundância de ácaros foram observados principalmente no estrato apical e que os níveis populacionais desses artrópodes em plantas de pinhão-manso são mais expressivos na estação chuvosa. Os ácaros fitófagos concentram-se distribuídos principalmente no estrato apical, sendo Brevipalpus sp. a espécie mais abundante. Ácaros predadores da família Phytoseiidae foram aqueles de maior riqueza e diversidade, sendo o ácaro predador Amblydromalus zannoui o mais abundante. Os resultados obtidos neste trabalho sugerem uma dinâmica sazonal tanto para populações de ácaros predadores quanto para ácaros fitófagos em pinhão-manso.(AU)

Glyphosate sub-lethal toxicity to non-target organisms occurring in Jatropha curcas plantations in Brazil.

Weed management in physic nut plantations has generally been performed by spraying the herbicide glyphosate. However, the effects of glyphosate on non-target organisms present in the crop system are unknown. Here, we evaluated the toxicity of glyphosate (Roundup Transorb(®)) against the pest species Polyphagotarsonemus latus (Acari: Tarsonemidae) and Tetranychus bastosi (Acari: Tetranychidae) which can be exposed by drift. These mites are considered pests of the physic nut; however, they can also feed and reside on weeds associated with the crop, serving as food sources for predatory mites. When subjected to residue (by ingestion of sap of treated plants), and direct contact to glyphosate, P. latus reproduction was affected but T. bastosi was affected only by the residual effect. Although the herbicide caused a reduction in the number of eggs laid by the females of both pest mites, it is suggested that sublethal effects of glyphosate stimulates oviposition of P. latus and T. bastosi: both species displayed higher reproductive rates when exposed to 0.36 kg ha(-1) of the herbicide. We conclude that glyphosate negatively affects the arthropod herbivores studied and we discuss possible implications on their biological control in Jatropha curcas plantations.

Callus Growth Kinetics of Physic Nut (Jatropha curcas L.) and Content of Fatty Acids from Crude Oil Obtained In Vitro.

The callus growth kinetics allows identifying the appropriate moment for callus pealing and monitoring the accumulation of primary and secondary metabolites. The physic nut (Jatropha curcas L.) is a plant species used for biofuel production due to its high oil content; however, this plant presents a great amount of bioactive compounds which can be useful for industry. The aim of this research was to establish a calli growth curve and to evaluate the fatty acid profile of crude oil extracted from callus. The callus growth kinetics presented a sigmoid standard curve with six distinct phases: lag, exponential, linear, deceleration, stationary, and decline. Total soluble sugars were higher at the inoculation day. Reducing sugars were higher at the inoculation day and at the 80th day. The highest percentage of ethereal extract (oil content) was obtained at the 120th day of culture, reaching 18 % of crude oil from the callus. The calli produced medium-chain and long-chain fatty acids (from 10 to 18 carbon atoms). The palmitic acid was the fatty acid with the highest proportion in oil (55.4 %). The lipid profile obtained in callus oil was different from the seed oil profile.