Los insectos plaga representan los mayores problemas en plantaciones forestales, principalmente, en monocultivos del género Eucalyptus, debido a los relevantes daños y su persistencia durante todo el ciclo de cultivo. Supputius cincticeps presenta potencial para ser usado en el control biológico de larvas defoliadoras de eucalipto. El objetivo de este trabajo fue estudiar la morfología e histología de los órganos reproductivos de S. cincticeps, con el fin de contribuir en el conocimiento de su reproducción, para ser aplicado en programas de cría masiva. Los ovarios y los testículos de ese depredador fueron extraídos y se realizaron cortes de 5mm, en un micrótomo automático, los cuales, fueon descritos y registrados fotográficamente.

Insect pests represent the most remarkable problems in forest plantations. This scenario is present mainly in monocultures of the genus Eucalyptus, due to significant damage that occurs throughout the growing season. Supputius cincticeps might be used biological control agent of eucalyptus defoliating larvae. The aim of this work was to study the morphology and histology of the reproductive organs of S. cincticeps to contribute to the knowledge of their reproduction to be applied in mass rearing programs. Ovaries and testicles of the predator were extracted and sectioned by using a microtome up to obtain tissue sections of 5mm which were described and recorded photographically.

Tetranychus urticae es una importante plaga asociada al cultivo de fresa debido a las altas densidades poblacionales alcanzadas y a los daños ocasionados a las plantas. Los productores utilizan acaricidas en grandes volúmenes sin cumplir los periodos de carencia, ocasionando residuos tóxicos en los frutos, desarrollo de poblaciones resistentes a los productos, destrucción de organismos benéficos, intoxicación de mamíferos y contaminación del medio ambiente. Por lo tanto, es necesario generar otras alternativas de manejo de este ácaro plaga. El objetivo de este trabajo fue evaluar, mediante el análisis conjunto de la concentración letal y subletal, la acción tóxica de productos comerciales a base de nim sobre los ácaros T. urticae y Phytoseiulus macropilis. Fueron controladas poblaciones de T. urticae en plantas de fresa cuando se emplearon concentraciones correspondientes a CL95 de los productos alternativos a base de nim, y también cuando se utilizaron concentraciones inferiores. La aplicación de los productos a base de nim, Neem Pro, Organic Neem y Natuneem en la CL95 y cuando la tasa instantánea de crecimiento poblacional ri=0,1 para el predador representan una alternativa viable para el control del ácaro fitófago T. urticae.

Tetranychus urticae is an important pest associated with strawberry, due to its high densities and plant damage. Farmers use acaricides in large volumes without complying with the window between the last application and harvest, resulting on toxic residues in fruits, as well as pest populations resistant to pesticides, decrement of beneficial organisms, mammalian toxicity and environmental pollution. Therefore, it is necessary to generate new alternatives for the control of this mite. The aim of this work was to evaluate the toxic effect of commercial neem-based products on the mites T. urticae and Phytoseiulus macropilis, through a combined analysis using both, lethal and sublethal concentrations. Tetranychus urticae populations were controlled in strawberry plants when neem was used at or below LC95 concentrations. The application of the neem-based products, Neem Pro, Organic Neem and Natuneem at CL95, and when the instantaneous predator’s rate of population increase ri = 0.1, represents a viable alternative to be considered for the control of the phytophagous mite T. urticae.

Tetranychus evansi Baker & Pritchard is an important pest of solanaceous plants, including tomatoes. This mite is characterized by a high reproductive rate, which leads to high population growth in a short period of time causing important economic damage. Control of T. evansi is mainly through synthetic acaricides. In searching for environmentally friendly control measures, we evaluated the efficiency of alternative products to control T. evansi on tomato plants under greenhouse conditions. The products tested were lime sulphur and neem based products. We first estimated the lethal concentration (LC) and instantaneous rate of increase (r i) of T. evansi exposed to different product concentrations in laboratory conditions, and later tested the efficacy of LC95 and the concentrations that restrained mite population growth (r i = 0) in greenhouse conditions. The following treatments were repeated three times: NeemPro (81.0 and 71.6 mg a.i./l), Natuneem (31.1 and 20.4 mg ai/l), Organic Neem (39.1 and 30.4 mg a.i./l), lime sulphur (1.0 and 0.6%) and water (control). For all products, control provided by LC95 was higher than provided for lower concentrations (r i = 0) one day after spraying. However, after five days, for both concentrations, the percentage of T. evansi population reduction was superior to 95% and increased over time. Only plants sprayed with Natuneem (31.1 mg a.i./l) showed symptoms of phytotoxicity. Lime sulphur and neem based products, applied in appropriate concentrations and formulations, bear out as a viable alternative to control T. evansi on tomato plants.

O morangueiro, Fragaria x ananassa, pode ser atacado por diferentes espécies de ácaros fitófagos, dentre elas o ácaro-vermelho, Oligonychus ilicis McGregor, e o ácaro-rajado, Tetranychus urticae Kock. Essas espécies são encontradas juntas, alimentando-se, com maior freqüência, sobre a epiderme adaxial e abaxial das folhas, respectivamente. Neste trabalho estudou-se o padrão de escolha de O. ilicis e T. urticae por sítio de alimentação em plantas de morangueiro. Duas hipóteses foram formuladas: a primeira, que a escolha por sítios de alimentação estaria relacionada à aptidão das espécies; a segunda, que esta escolha seria determinada pela presença do heteroespecífico. Com o objetivo de testar tais hipóteses, avaliou-se a preferência, biologia e sucesso reprodutivo de O. ilicis e T. urticae sobre a face abaxial e adaxial de folhas de morangueiro infestadas ou não pelo heteroespecífico. O. ilicis preferiu permanecer sobre a face adaxial enquanto T. urticae preferiu permanecer sobre a face abaxial de folhas de morangueiro. A preferência pelas faces foliares correlacionou-se com o sucesso reprodutivo das espécies, avaliado pela taxa intrínseca de crescimento populacional (r m). O padrão de escolha não se alterou quando as espécies foram submetidas ao teste de escolha entre as faces foliares previamente infestadas pelo heteroespecífico. É discutida a possibilidade de T. urticae induzir defesas da planta capazes de reduzir a aptidão de O. ilicis e vice-versa. A possibilidade dessas espécies permanecerem juntas sobre plantas de morangueiro aumenta a capacidade de dano à cultura.

Many phytophagous mites can attack strawberry plants, Fragaria x ananassa, among them the southern red mite, Oligonychus ilicis McGregor, and the two-spotted spider mite, Tetranychus urticae Koch. They are found together feeding on the same plant on the upper and underside of the leaves, respectively. Here we studied the choice for feeding sites of O. ilicis and T. urticae on strawberry plants. The first hypothesis tested whether the feeding site choice would be related to the fitness of the species. The second hypothesis dealt whether the feeding site would be determined by the presence of a heterospecific mite. We evaluated the preference, biology and reproductive success of O. ilicis and T. urticae on the under and upper side surface of strawberry leaves infested or not by the heterospecific. O. ilicis preferred to stay on the upper side surface while T. urticae preferred the underside. The preference for the leaf surface correlated with the reproductive success of the species (measured by the intrinsic growth rate). The choice pattern of feeding sites did not alter when the choice test was applied using sites previously infested by heterospecific. Although O. ilicis and T. urticae, apparently, do not interact directly for feeding sites, there is a chance that the first species induces defenses in strawberry plant enabling to reduce the fitness of the second species. The possibility of those species stay together on strawberry plant increases the damage capacity to the culture.

As plantas podem desenvolver mecanismos de defesa que reduzem o efeito do ataque de herbívoros. Em resposta, os insetos herbívoros evoluem de forma a quebrar os mecanismos de defesa das plantas. Uma das formas que os insetos têm de escapar do sistema de defesa das plantas é migrar para outros hospedeiros cujo sistema de defesa não seja eficiente a seu ataque. No Brasil, em plantios de Eucalyptus spp., observam-se surtos freqüentes da lagarta desfolhadora Thyrinteina arnobia Stoll, cujo hospedeiro nativo é a goiaba. A não ocorrência de surtos populacionais em goiaba pode estar relacionada ao desenvolvimento de mecanismos de defesa, nessa espécie de Myrtaceae, o que aparentemente ainda não ocorreu com o eucalipto. Por isso, investigou-se neste trabalho se o desempenho de T. arnobia criada em seu hospedeiro de origem, plantas de goiaba, difere do seu desempenho em hospedeiro exótico, o eucalipto. A taxa intrínseca de crescimento populacional de T. arnobia (r m) foi maior em eucalipto do que em plantas de goiaba. O pior desempenho de T. arnobia em plantas de goiaba possivelmente se deu por atuação do sistema de defesa constitutiva dessas plantas. Barreiras químicas das plantas de goiaba podem estar atuando principalmente na redução da digestibilidade do inseto, afetando o desenvolvimento da população atual e, por conseguinte, o das próximas gerações.

Plants can develop mechanisms of defense that reduces the effects of herbivore attacks. In response, the herbivores evolve to breaking the defense mechanisms of plants. Herbivores may also escape from the plant defense system by migrating to other host whose defense is not effective against them. In Brazil, outbreaks of the defoliator caterpillar Thyrinteina arnobia Stoll in Eucalyptus sp. are frequently observed. However, the native host of this insect is guava, Psidium guajava where outbreaks are not registered. The absence of outbreaks in P. guajava may be related to the development of defense mechanisms in that specie of Myrtaceae, which has apparently not yet occurred on eucalyptus. Here we investigated the performance of T. arnobia reared on its origin host plant, in comparison with those reared on its exotic host, Eucalyptus sp. The intrinsic growth rate of T. arnobia was higher on eucalyptus than on P. guajava. It is possible that the defense mechanism on guava plants acts as a chemical barrier, probably reducing the digestibility of the insect, which could affect the development of the current population and the next generations.