Extratos de plantas no controle de Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) em laboratório Plant extracts in control of Rhipicephalus (Boophilus) microplus (Canestrini, 1887) (Acari: Ixodidae) in laboratory

Extratos vegetais foram estudados com o objetivo de avaliar suas eficiências no controle de Rhipicephalus (Boophilus) microplus (Canestrini, 1887) em laboratório. Fêmeas ingurgitadas de carrapato foram coletadas de bovinos e mantidas em placas de Petri. Foram utilizados extratos orgânicos alcoólicos 2% (peso/volume) de sementes de Annona muricata L. (Annonaceae) (graviola); flores de Syzygium malaccensis (L.) (Myrtaceae) (jambo); folhas de Cymbopogon citratus (DC.) Stapf (Poaceae) (capim-santo); folhas de Azadirachta indica A. Juss (Meliaceae) (nim); e extrato hexânico na mesma concentração de A. indica (sementes). Os grupos-controle foram compostos por fêmeas sem tratamento e fêmeas tratadas com água destilada e esterilizada e dimetilsulfóxido (DMSO) a uma concentração de 1%. O extrato de A. muricata apresentou o maior poder acaricida, com eficácia de 100%, seguido dos extratos de S. malaccensis (75 e 59,24%) e A. indica (65 e 38,49%). Houve 100% de redução na eclosão das larvas quando se utilizou o extrato de sementes de A. muricata.Plant extracts were studied to evaluate its efficiency in the control of Rhipicephalus (Boophilus) microplus (Canestrini, 1887) in laboratory. Engorged female ticks were collected from the cattle, kept in Petri dishes. Organic alcoholic extracts 2% (weight/volume) were used: seeds of Annona muricata L. (Annonaceae) (soursop); flowers of Syzygium malaccensis (L.) (Myrtaceae) (iamb), leaves of Cymbopogon citratus (DC.) Stapf (Poaceae) (holy grass), leaves of Azadirachta indica A. Juss (Meliaceae) (neem) and hexane extract 2% (weight/volume) of A. indica (seeds). The control groups consisted of untreated females and females treated with distilled water and sterile and dimethylsulfoxide (DMSO) a concentration of 1%. The extract of A. muricata (seed) had the highest mortality with acaricide activity and 100% efficacy followed by extracts of S. malaccensis (75 and 59.24%) and A. indica (65 and 38.49%). The seed extract of A. muricata reduced 100% larvae hatch

Stingless bees damage broccoli inflorescences when collecting fibers for nest building

The stingless bee Trigona spinipes (Fabricius, 1793) (Hymenoptera: Apidae) is an important pollinator for various crops, but constitutes an occasional pest of other plant species since it causes injury to leaves, stems, flowers and fruits while collecting nest materials. The aim of the present study was to determine the damage caused by T. spinipes to a broccoli (Brassica oleracea L. var. italica, Brassicaceae) growing on an organic farm. A significant number of plants (72.5 %) presented damaged inflorescences, while 39% of all of the inflorescences suffered some degree of injury. The activities of T. spinipes caused scarifications on the stems of the inflorescences, and these typically evolved to epidermal cicatrices up to 10 mm wide. In some cases, the lesions were sufficiently deep to cause partial destruction of the vascular tissues, and this lead to thinner (< 5 mm diameter) floral stems that may collapse. To the best of our knowledge, this is the first report concerning the attack of broccoli plants by T. spinipes. The results obtained should serve to highlight the possibility that stingless bees could be responsible for direct and/or indirect damage to vegetable crops, and to stimulate the development of control strategies for these incidental pests