RESUMO

Strawberry is a food rich in bioactive compounds with great antioxidant potential. However, due to the high incidence of pests that affect crop cultivation, phytosanitary management still lacks control methods for agroecological cultivation. Thus, the present research aimed to evaluate the chemical composition and the potential of the essential oil of the leaves of Piper macedoi in the control of Cerosipha forbesi in laboratory and semi-field conditions. The concentration of essential oil in the leaves of P. macedoi that showed the highest mortality was 2.0 ml/L of oil, with a mortality above 91% under laboratory conditions. A mortality rate of 80% for all concentrations tested was observed after 24 h in all conditions tested. Thus, using essential oil from the leaf of P. macedoi can be a highly viable strategy in managing the aphid C. forbesi since it showed high mortality rates with small doses of oil.

Assuntos

RESUMO

Phytosanitary control is essential to ensure agricultural productivity and quality. However, approaches based on scheduled use of pesticides, overuse of harmful molecules produce impacts on different types of living organisms. Integrated Pest and Disease Management (IPM-IDM) may significantly reduce the burden of pesticides in the environment. Plant resistance may also be included in the IPM-IDM and even in conventional management due to little requirement of additional knowledge and changes in agricultural practices. Robust environmental assessments using methodology of universal use, life cycle assessment (LCA), may estimate the impacts of specific pesticides that cause major damages, including remarkable category impacts. Therefore the objective of this study was to determine the impacts and (eco)toxicological effects of phytosanitary strategies (IPM-IDM including or not lepidopteran resistant transgenic cultivars) vs. the scheduled approach. Two inventory modeling methods were also applied to gather information on the use and applicability of these methods. Life cycle assessment (LCA) was applied using two inventory modeling methods: 100%Soil and PestLCI (Consensus) using data from Brazilian croplands under tropical conditions, by combining phytosanitary approaches (IPM-IDM, IPM-IDM + transgenic cultivar, conventional, conventional + transgenic cultivar) and modeling methods. Hence, eight soybean production scenarios were established. The IPM-IDM was efficient to reduce the (eco)toxicity impacts of soybean production mainly for freshwater ecotoxicity category. Due to the dynamic character of IPM-IDM approaches, the inclusion of recently introduced strategies (plant resistant and biological control to stink bugs and plant fungal diseases) may diminish even more the principal impacting substances throughout the Brazilian croplands. The PestLCI Consensus method, although its development is yet in progress, to date can be suggested to estimate the agriculture environmental impacts more properly under tropical conditions.

Assuntos

RESUMO

Palpita forficifera Munroe 1959 is a lepidopteran pest native to the Neotropical region and has been causing damage to olive tree crops in Brazil and Uruguay. The use of egg parasitoids of the genus Trichogramma may be a viable and sustainable alternative to pest management. The objective of the present work was to select species and/or strains of Trichogramma as possible agents of control for P. forficifera. Selections were made from five strains of Trichogramma foersteri Takahashi (R1, R2, R3, R4, and R5) collected in olive orchards of southern Brazil and four strains of Trichogramma pretiosum Riley (AC, PR, MJU, and RVI) from laboratory rearings. The strains of T. foersteri presented the longest periods from egg to adult (≈ 11.5 days) when compared to T. pretiosum (≈ 9.5 days). However, T. foersteri provided, in general, the highest daily percentage of parasitized P. forficifera eggs and, consequently, a higher rate of parasitism (between 50 and 69%) in relation to those of T. pretiosum (variation from 7 to 20%). In addition, T. foersteri provided a higher emergence rate (above 90%), with a sex ratio close to 1.0. However, all strains of T. pretiosum were longer-lived compared to adults of T. foersteri. From the biological parameters evaluated, two distinct groups were formed between T. foersteri and T. pretiosum. In general, T. foersteri has better potential for controlling P. forficifera, demonstrating its potential for use in field multiplication and release programs for the management of the olive larvae.

Assuntos

RESUMO

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), one of the principal pests of brassicas, can reduce productivity and thus cause losses for brassica farmers. Alternative controls, such as biological agents and plant extracts, may be used to reduce insect populations, either alone or in conjunction with pest management programs. The objective was to evaluate the insecticidal activity of Beauveria bassiana (Bals.) Vuill. and castor bean oil and mixtures of both components against the diamondback moth. To do so, we separately used castor bean oil (at 2% concentration), the isolate ESALQ-447 and a commercial formulation (Boveril® WP), and a mixture of castor bean oil with the isolate and the B. bassiana product formulation, totaling six treatments with a control. Assays were carried out under greenhouse with the respective treatments sprayed on cabbage plants infested with four second instar larvae of P. xylostella. The evaluated parameters were larval mortality and pupal and larval viability. All treatments reduced larval viability in relation to the control, however, only the ESALQ-447 isolate or a mixture of the isolate with castor bean oil reduced pupal viability, significantly reducing the pest population levels in the next generation. Castor bean oil mixed with B. bassiana, however, does not augment pest mortality.

A traça-das-crucíferas, Plutella xylostella (L.) (Lepidoptera: Plutellidae), uma das principais pragas das brássicas, pode ocasionar redução na produtividade e consequentemente prejuízos aos produtores rurais destas culturas. A busca por alternativas de controle, como o uso do controle biológico e extratos de plantas são métodos de redução populacional de insetos que podem ser usados isoladamente ou associados em programas de manejo fitossanitário. Dessa forma, o objetivo foi avaliar a atividade inseticida de Beauveria bassiana (Bals.) Vuill., do óleo de mamona e a associação destes, visando ao controle da traça-das-crucíferas. Para isso, foram utilizados isoladamente o óleo de mamona (na concentração de 2%), o isolado ESALQ-447 e um formulado comercial (Boveril® WP) e a mistura do óleo de mamona com o respectivo isolado e com o produto formulado de B. bassiana, totalizando assim seis tratamentos com a testemunha. Os ensaios foram realizados em casa telada, onde plantas de repolho infestadas com quatro larvas de segundo ínstar de P. xylostella foram pulverizadas com os respectivos tratamentos mencionados. Os parâmetros avaliados foram mortalidade larval, viabilidade larval e pupal. Todos os tratamentos reduziram a viabilidade larval em relação à testemunha, no entanto apenas o isolado ESALQ-447 ou a sua associação com o óleo de mamona reduziram a viabilidade pupal, diminuindo significativamente o nível populacional da praga na próxima geração. Contudo, o óleo de mamona misturado com B. bassiana não aumenta a mortalidade da praga.

Assuntos