Herbivoria de Tetranychus urticae Koch (Acari: tetranychidae) induz defesa direta em morangueiro?

Plantas de morangueiro Fragaria x ananassa podem apresentar mecanismos de defesa direta e indireta contra herbívoros. Tais defesas podem alterar o comportamento e o desenvolvimento dos ácaros fitófagos e seus inimigos naturais, reduzindo a taxa de herbivoria. Testou-se o efeito da préinfestação de plantas de morangueiro por Tetranychus urticae Koch sobre o seu desenvolvimento e reprodução. Plantas de morangueiro cultivar IAC Campinas foram divididas em dois grupos: plantas limpas e plantas pré-infestadas por T. urticae. A infestação prévia de plantas de morangueiro por T. urticae não alterou a duração das fases imaturas, a fecundidade e a sobrevivência das fêmeas do ácaro. Tais resultados podem estar associados à inexistência ou baixo nível de resistência induzida da cultivar IAC Campinas, ou ainda, ao fato de a pré-infestação ter sido insuficiente para induzir defesa. Assim, a resistência relatada na cultivar IAC Campinas a T. urticae pode estar relacionada às defesas indiretas

Dinâmica populacional de Catarhinus tricholaenae keifer (diptilomiopidae: acari) sobre cultivares de milho Bt.

SIBA

Os ácaros são pragas do milho no Brasil?

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Natural control of Helicoverpa armigera (Lepidoptera: Noctuidae) pupae in organic and conventional maize crops.

The natural biological control of soil pests is poorly studied. Notably, the control of Helicoverpa armigera in the pupae stage is unknown. To increase knowledge about the control of this pest in organic and conventional maize crop, tests were conducted to verify if the duration of pupae availability in days, the type of crop treatment (organic and conventional), the stage of crop development, and the depth of the soil significantly affect predation by natural enemies. The pupae availability time (days) in the soil did not affect their removal by natural enemies. However, in the fallow stage, on the surface and in the reproductive phase, the predation was higher. In organic maize, predation was 15% higher when compared to conventional maize. The rupture of the soil and the possible losses associated with beneficial fauna were the main factors responsible for higher predation during fallow, so conservationist practices usually used in organic treatment are the main reason for higher predation in this type of crop. There is a significant decrease in the control of H. armigera pests by natural enemies when maize is grown using conventional practices, what reinforces the importance of the conservation techniques used in maize crop

Interações em teias alimentares de ácaros fitófagos no milho Bt.

Resumo

Preferência alimentar de Tetranychus urticae Koch (Acari: Tetranychidae) por milho Bt.

Resumo

Riqueza e abundância de espécies de ácaros fitófagos em milho Bt.

Resumo

Effects of the SGLT2 inhibitor dapagliflozin on cardiac function evaluated by impedance cardiography in patients with type 2 diabetes. Secondary analysis of a randomized placebo-controlled trial

Cardiovascular outcome trials have documented a strong benefit of sodium glucose cotransporter-2 inhibitors (SGLT2i) on the risk of hospitalization for heart failure (HF) in patients with type 2 diabetes (T2D) with or without established cardiovascular disease or prior history of HF. The mechanisms, however, are not entirely clear. We aimed to evaluate whether treatment with SGLT2i affected cardiac function using impedance cardiography (ICG) in a randomized placebo-controlled trial

Maize plants produce direct resistance elicited by Tetranychus urticae Koch (Acari: Tetranychidae).

Plants can be attacked by a wide variety of herbivores. Thus, developing protective mechanisms for resistance against these agents is an advantage for survival and reproduction. Over the course of evolution, many resistance mechanisms against herbivory have been developed by the plants. Induced direct and indirect resistance mechanisms can manifest in plants after herbivore attack. The two-spotted spider mite Tetranychus urticae is not a pest of maize crops (Zea mays), despite being reported infesting plants that may have resistances against this herbivore. We tested the hypothesis that maize plants would be able to induce direct resistance against T. urticae after, evaluating the effect of T. urticae infestation in maize plants on the development and reproduction of conspecifics. We tested induced direct resistance performing infestation and measuring biological parameters upon a second infestation. Maize plants, 40 days after sowing, were divided into two groups: 30 not infested by T. urticae (clean plants clean) and, 30 infested by the spider mite. Infestation of maize plants by T. urticae reduced the conspecific female adult survival. However, no change in the survival of immature or reproduction was observed. These results suggest the induction of induced direct resistances in maize by T. urticae. This is first report of direct resistance induction in Z. mays by the two-spotted spider mite T. urticae