Biology and host selection stage of Symmetrischema dulce Povolny (Lepidoptera: Gelechiidae) in chili pepper.

The pepper-fruit-borer Symmetrischema dulce Povolny (Lepidoptera: Gelechiidae) is an important chili pepper pest causing significant yield losses. However, chili pepper has insufficient crop protection support and primary information about S. dulce is scarce. In the present study, we aimed to study the biology and ecology of S. dulce in pepper plants (Capsicum frutescens L.) focusing to support integrated pest management programs. In the field, we sampled ripe and unripe chili pepper fruits in three different plant strata. In the laboratory, we established colonies of the S. dulce and we recorded the duration, viability, morphology of each life stage, and number of larval instars. We conducted experiments to evaluate insect reproduction, whereby we registered the pre-oviposition and oviposition period, daily oviposition rate, and sex ratio. From these results, we estimated the reproductive success of S. dulce through the intrinsic population growth rate. The higher occurrence of S. dulce was in unripe fruits with no difference between plant strata. Egg stage lasted 4 days with 94% viability, and larval phase lasted on average 10.72 days and presented four instars with viability of 66.6%. Pupal stage lasted 9.61 days with viability of 94.73%. The adult stage lasted 24.14 days with a pre-oviposition period of 3 days and oviposition period of 13.85 days. The intrinsic growth rate (rm) recorded was 0.0035. Our results suggest that the biology of S. dulce has similarities with other Lepidoptera, but its peculiarities in reproductive parameters are essential for future programs of pest management.

Brazilian Legislation Leaning Towards Fast Registration of Biological Control Agents to Benefit Organic Agriculture.

Brazil is one of the main users of chemical pesticides in the world. These products threaten human and environmental health, and many of them are prohibited in countries other than Brazil. This paradigm exists in contrast with worldwide efforts to make the need for food production compatible with biodiversity conservation, preservation of ecosystem services, and human health. In this scenario, the development of sustainable methods for crop production and pest management such as organic agriculture and biological control are necessary. Herein, we describe how the process of registration of natural enemy-based products in organic agriculture is simpler and faster than the conventional route of chemical insecticides and can favor the development of the biological control market in Brazil. Since the regulatory mechanisms have been established in Brazil for organic agriculture, the number of biological control products registered has increased exponentially. Today, 50 companies and associations are marketing 16 species/isolates and 95 natural enemy-based products. Although this scenario presents a series of new opportunities to increase and stimulate a more sustainable agriculture in the country, biological control is not always aligned with the aims and philosophy of organic agriculture and agroecology. Therefore, we also argue that new research efforts are needed on understanding how conservation biological control strategies can be integrated with augmentation biological control to promote a sustainable agriculture under the concepts of organic agriculture and agroecology.

Survival and preference of cotton boll weevil adults for alternative food sources / Sobrevivência e preferência para exploração de recursos de adultos do bicudo do algodoeiro

Abstract Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus’ flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Resumo Plantas que podem ser uma fonte potencial de recursos alimentares (néctar floral, pólen e tecidos vegetais) para o bicudo do algodoeiro durante a entressafra foram avaliadas, considerando as condições ambientais prevalentes na região de Cerrado do Brasil Central. Primeiro, testamos a adequação nutricional dos recursos (pólen e néctar) fornecidos por oito espécies de plantas (erva-doce, margaridão, mamona, quiabo, hibisco, sorgo, feijão guandu e crotalária) como único recurso alimentar para a sobrevivência do inseto. Posteriormente, nós avaliamos se os recursos fornecidos pelas plantas selecionadas continuaram a serem explorados pelo bicudo na presença do algodoeiro, seu recurso alimentar principal. A longevidade média do bicudo do algodoeiro foi significativamente maior quando eles foram alimentados com flores de hibisco (166,6 ± 74,4) e quiabo (34,7 ± 28,9) do que quando alimentados com flores das outras seis espécies. Em seguida, a preferência do bicudo no uso de recursos foi comparada contrastando o quiabo e o hibisco com o algodão, em experimentos de dupla escolha. Os bicudos preferiram as plantas das três espécies na fase reprodutiva em relação àquelas em estádios vegetativos. Embora a preferência por plantas de algodão na fase reprodutiva tenha sido maior, os bicudos preferiram plantas em floração de quiabo e hibisco quando estas foram contrastadas com o algodão na fase vegetativa.

Survival and preference of cotton boll weevil adults for alternative food sources.

Plants that have potential as alternative food source (floral nectar, pollen and plant tissues) to the boll weevil during the intercropping season were evaluated considering the prevalent conditions of Cerrado in the Central Brazil. Initially, we tested the nutritional adequacy for the survival of the insect of flower resource (pollen and nectar) provided by eight plant species (fennel, mexican sunflower, castor bean, okra, hibiscus, sorghum, pigeonpea and sunn hemp). Subsequently, we tested if the resources provided by the selected plants continued to be exploited by the boll weevil in the presence of cotton plant, its main food source average longevity of boll weevil adults was significantly longer when they were fed on hibiscus' flowers (166.6 ± 74.4) and okra flowers (34.7 ± 28.9) than when they fed on flowers of other six species. Subsequently, the preference of the boll weevil in the use of resources was compared between okra or hibiscus and cotton plants, in dual choice experiments. Boll weevils preferred plants of the three species in the reproductive stages than those in vegetative stages. Although the cotton plant in the reproductive stage was the most preferred plant of all, boll weevils preferred flowering okra and hibiscus than cotton at the vegetative stage.

Coccinellidae Parasitoids in Brazil: Neglected Species in a Mega-Diverse Country.

Current knowledge on coccinellids is primarily focused on their role as natural enemies of soft-bodied insects. However, there is a great diversity of coccinellid parasitoid species that are less studied. Here, we describe new records of coccinellid parasitoids with emphasis on new host-parasitoid interactions in 11 sample sites in Brazil. We collected 122 coccinellid individuals parasitized by six species of parasitoids in the Cerrado and in the Atlantic Rainforest biomes. New records of coccinellid parasitoids and host associations, expansion of habitat ranges and interactions are discussed focusing on the lack of basic information on these interactions in Brazil.

Insecticide survival and behavioral avoidance in the lacewings Chrysoperla externa and Ceraeochrysa cubana.

Insecticide impact on non-target species, such as insect predators and parasitoids, is an ever-growing concern in agriculture and recent studies have been shifting focus from lethal to sub-lethal effects since they may prevail in field conditions, although more difficult to assess. Synthetic insecticides are the main concern, but the recent spread of biopesticide use in agriculture draws attention, particularly the main botanical insecticide currently in use - azadirachtin. Here we assessed the lethal and behavioral sub-lethal response of predatory larvae of the lacewing species Chrysoperla externa and Ceraeochrysa cubana to two frequently used synthetic insecticides, malathion and permethrin, and to the bioinsecticide azadirachtin. The recommended field concentration of the synthetic insecticides led to low survival time of lacewing larvae from both species, in contrast with azadirachtin. However, all three compounds led to 100% mortality of the lacewing larvae from both species. Insecticide repellence (i.e., avoidance without contact) was similar for both synthetic insecticides in both species, but azadirachtin was a stronger repellent for C. externa, but not C. cubana. In addition, insecticide irritability (i.e., avoidance after contact) occurred in both lacewing species to all three insecticides tested. The notion that natural compounds are safer than synthetic compounds to non-target species is refuted in the present study, which also detected significant irritability to all of the insecticides regardless of their origin, and species-specific repellence elicited particularly by azadirachtin. Therefore, bioinsecticides should not be exempted from risk assessment, and non-target sub-lethal effects should not be neglected when considering potential insecticide use in agriculture.

Prey preference, intraguild predation and population dynamics of an arthropod food web on plants.

The theory of intraguild predation (IGP) largely studies effects on equilibrium densities of predators and prey, while experiments mostly concern transient dynamics. We studied the effects of an intraguild (IG) predator, the bug Orius laevigatus, on the population dynamics of IG-prey, the predatory mite Phytoseiulus persimilis, and a shared prey, the phytophagous two-spotted spider mite Tetranychus urticae, as well as on the performance of cucumber plants in a greenhouse. The interaction of the predatory mite and the spider mite is highly unstable, and ends either by herbivores overexploiting the plant or predators exterminating the herbivores. We studied the effect of IGP on the transient dynamics of this system, and compared the dynamics with that predicted by a simple population-dynamical model with IGP added. Behavioural studies showed that the predatory bug and the predatory mite were both attracted to plants infested by spider mites and that the two predators did not avoid plants occupied by the other predator. Observations on foraging behaviour of the predatory bug showed that it attacks and kills large numbers of predatory mites and spider mites. The model predicts strong effects of predation and prey preference by the predatory bugs on the dynamics of predatory mites and spider mites. However, experiments in which the predatory bug was added to populations of predatory mites and spider mites had little or no effect on numbers of both mite species, and cucumber plant and fruit weight.

Diet of a polyphagous arthropod predator affects refuge seeking of its thrips prey.

Antipredator behaviour of prey costs time and energy, at the expense of other activities. However, not all predators are equally dangerous to all prey; some may have switched to feeding on another prey species, making them effectively harmless. To minimize costs, prey should therefore invest in antipredator behaviour only when dangerous predators are around. To distinguish these from harmless predators, prey may use cues related to predation on conspecifics, such as odours released by a predator that has recently eaten conspecific prey or alarm pheromones released by attacked prey. We studied refuge use by a herbivorous/omnivorous thrips, Frankliniella occidentalis, in response to odours associated with a generalist predatory bug, Orius laevigatus, fed either with conspecific thrips or with other prey. The refuge used by thrips larvae is the web produced by its competitor, the two-spotted spider mite, Tetranychus urticae, where thrips larvae experience lower predation risk because the predatory bug is hindered by the web. Thrips larvae moved into this refuge when odours associated with predatory bugs that had previously fed on thrips were present, whereas odours from predatory bugs that had fed on other prey had less effect. We discuss the consequences of this antipredator behaviour for population dynamics. Copyright 2000 The Association for the Study of Animal Behaviour.

Applying psychometric criteria to functional assessment in medical rehabilitation: III. Construct validity and predicting level of care.

A discriminant analysis was performed using Rasch ability estimates derived from four Patient Evaluation and Conference System (PECS) subscales, to distinguish among the functional independence and impairment profiles exhibited by patients admitted into any of three levels of medical rehabilitation delineated by the National Association of Rehabilitation Facilities (NARF): (1) inpatient hospital, (2) atypical nursing home (intermediate), or (3) day program. Two discriminant functions accounted for 91% and 9% of the between-group variance, respectively. Cross-validated classification of patients into one of the three levels of care, based on discriminant function scores, produced 75% correct classification; a 66% improvement over the percentage of correct classification likely by chance alone. Results support the construct validity of the PECS subscales and indicate they may be useful in validating clinically-based admission decisions among three of the levels of care promulgated by NARF.