Running head: Mating disruption of Tuta absoluta using sex pheromoneO potencial do componente principal sintético do feromônio sexual de T. absoluta (Meyrick) para a interrupção dos acasalamentos foi estudado em parcelas (0,01 hectares) cultivadas com tomate estaqueado. Os efeitos de doses do 3E,8Z,11Z-14:Ac (0 a 80 g i.a./ha) aplicadas nas parcelas foram determinados considerando a orientação dos machos às armadilhas contendo feromônio sexual, os acasalamentos em gaiolas e os danos no tomateiro. Os mais altos níveis de interrupção na orientação dos machos (60-90%) foram obtidos com 35 a 50 g/ha de feromônio sexual. Nenhum tratamento com feromônio foi hábil para reduzir significativamente a percentagem de folíolos minados e de frutos broqueados ou a freqüência de acasalamentos em relação às parcelas não-tratadas. A falha na técnica de interrupção dos acasalamentos pode ser atribuída à composição do feromônio sintético e às doses usadas, à alta densidade populacional da praga e à imigração de fêmeas acasaladas para dentro da área tratada.The potential of the synthetic major component of T. absoluta (Meyrick) sex pheromone for mating disruption was studied in small plots (0.01 hectares) with fresh-market tomato crop. The effects of the application of the sex pheromone 3E,8Z,11Z-14:Ac (from 0 to 80 g a.i./ha) were assessed on male orientation to pheromone baited traps, mating in cages and plant damage. The highest levels of interruption in male orientation (60-90%) were found in plots treated with 35 to 50 g/ha of sex pheromone. However, no treatment with pheromone was capable of significantly reducing the percentage of mined leaflets or bored fruits or the frequency of mating in cages compared to the control plots. The failure in mating disruption technique may be attributed to the composition of the synthetic pheromone, doses used, high pest population density, and mated female migration to the area treated.

Plutella xylostella is a recurring pest on cruciferous crops around the world. In Brazil, it typically requires large number of insecticide sprays, which may lead to fast evolution of resistance. The aim of this study was to assess the susceptibility of Brazilian diamondback moth populations to the insecticides abamectin, deltamethrin, and spinosad. Leaf dip bioassays were used to determine mortality data obtained after 48 h of exposure to insecticides and subjected to Probit analysis. The population from Bonito, state of Pernambuco, Brazil, had the highest toxicity ratio (20.2 -fold) to abamectin compared to the reference population. The LC 50 values for deltamethrin ranged from 85.2 to 360.1 mg L -1 , demonstrating a high survival of populations in relation to this insecticide field dose rate (7.5 mg L -1). The toxicity ratios of the estimated LC 50 s, however, were very low (varying from 2.2 -to 4.2 -fold). Most populations exhibited toxicity ratios for spinosad, ranging from 2.3 -to 5.1 -fold, while both the LC 50 and LC 95 values reflected a high susceptibility to the spinosad field dosage (120 mg L -1).Only the Bonito -PE population resisted to abamectin, while all P. xylostella populations were resistant to deltamethrin, but particularly susceptible to spinosad because of the absence of selection pressure with it in these areas.

1 Despite the importance of Leucoptera coffeella (Gue´rin-Me`neville) in coffee production worldwide, there is a lack of information on its reproduction. This knowledge will help in mass rearing, and support the development of behavioural control techniques for this insect. The present study determined the effects of delayed mating and previous matings of male L. coffeella on fecundity, egg viability and frequency of female remating. 2 The highest levels of fecundity and egg viability were obtained from matings of 1-3-day-old females. When females mated at 5 days of age, there were reductions of 40% in oviposition and of 43% in egg viability. 3 Females mated with 2-day-old virgin males were more fecund than those mated with older males; egg viability was also low (18%) from females mated with older males. 4 Virgin females that mated with virgin males laid a greater number of eggs than those mated with previously copulated males. Egg viability decreased with the increase in the number of previous male matings. 5 Five-day-old females remated in greater proportion than 2-3-day-old females.Females that copulated with males that had previously mated three times had higher rates of remating than those that copulated with virgin males. 6 The results obtained indicate that 1-3 days after emergence is the optimum age for mating. The implications of these findings for the control of L. coffeella by synthetic sex pheromone are discussed.

Begomoviruses are the most important viruses affecting tomato (Solanum lycopersicum) crops in Brazil. Tomato severe rugose virus (ToSRV) is the most predominant species, followed by Tomato golden vein virus (TGVV). We evaluated the putative effect of host range and whitefly transmission efficiency on the predominance of ToSRV. Whitefly (Bemisia tabaci, B biotype or MEAM 1) vectors carrying the two viruses were allowed to freely inoculate plants of 27 species, maintained in cages. Visual and PCR detection indicated that ToSRV could infect five plant species and TGVV could infect six species. Transmission studies were performed in single or double infections in tomato plants. ToSRV infected a higher percentage of plants than TGVV (single or mixed inoculation) in all trials. The rates of acquisition of ToSRV and TGVV, however, did not differ significantly between insects fed on tomato leaves with single or mixed infections. A higher transmission efficiency of ToSRV by whiteflies under the agricultural conditions of tomato cultivation in Brazil may thus contribute to the predominance of ToSRV in the field.

The association of resistant crop varieties and biological pest control has great potential for pest management, as resistant cultivars may affect herbivore population dynamics by interfering with their biology and search behaviour for host plants. In addition, resistant varieties can also affect the efficiency of natural enemies. The aims of this work were to evaluate the influence of the soybean cultivars Dowling (resistant), IAC 100 (resistant) and Silvânia (susceptible) under field conditions on: (i) the abundance of parasitoids in the Platygastridae family and the stink bug Euschistus heros and (ii) the parasitism of stink bug eggs by these natural enemies. There was no difference between cultivars in stink bug distribution in the field. The parasitoids Telenomus podisi, Trissolcus teretis, Tr. urichi and Tr. brochymenae emerged from the sentinel eggs of E. heros, and T. podisi was the most abundant species observed during the reproductive stage R6. The cultivars Dowling and IAC 100 attracted a higher number of Platygastridae parasitoids, T. podisi and Tr. teretis, and the abundance of these parasitoids during the period from R1 to R7 might have being sufficient to control the stink bug population. These results suggest that the cultivars Dowling and IAC 100 have important attributes that should be taken into account in the implementation and development of new cultivars in breeding programmes that aim to obtain plants more resistant to stink bugs and more attractive to natural enemies.

Costa(6) , Ary Teixeira de Oliveira-Filho (7) & Nilton Curi RESUMOEm solos de restinga de constituição areno-quartzosa aumenta a influência da fração orgânica e da atividade biológica em funções-chave dos solos, como a capacidade de reciclar e armazenar nutrientes. A análise de atributos do solo e da fauna edáfica em sítios sob diferentes coberturas vegetais é importante para entender o comportamento desses ambientes. Neste estudo, avaliaram-se atributos químicos, físicos e microbiológicos do solo e suas relações com a população de formigas de sítios de restinga sob diferentes coberturas vegetais no Estado de Sergipe. Foram coletadas amostras em seis coberturas vegetais (três sítios por cobertura), sendo quatro na área Caju (mata, capim-gengibre, coqueiral e capoeira) e duas na área Pirambu (mata de topo de duna e mata de sopé de duna). As análises químicas foram feitas em amostras coletadas nas camadas de 0-5 e 5-20 cm, e a atividade microbiana, avaliada por meio da hidrólise do diacetato de fluoresceína, foi determinada em amostras coletadas a 0-10 cm. A massa de fragmentos orgânicos foi avaliada em diferentes profundidades. Na avaliação das comunidades de formigas foram consideradas aquelas com atividade na superfície do solo. Na comparação entre os sítios foi utilizada a análise de componentes principais. Os atributos de compartimentos orgânicos (C orgânico, C orgânico dissolvido e fragmentos orgânicos) foram muito sensíveis à modificação da cobertura vegetal nos sítios do Caju, isolando os sítios sob mata dos alterados e os sítios sob capim-

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-Despite the importance of Leucoptera coffeella (Guérin-Mèneville) in coffee production worldwide, there is a lack of information on its reproductive biology. This knowledge will help in mass rearing, as well as support the development of behavioral control techniques for this insect. The purpose of the study was to determine the periodicity of mating and male capture and describe the mating behavior L. coffeella. In laboratory, we observed the periodicity of mating with virgin couples of different ages, zero to five days after emergence. Male activity was studied in a 0.7 ha coffee plantation, cv. Catuaí, where Delta traps were installed at 0.5 m above ground, using either virgin females or rubber septa lured with the synthetic sex pheromone. The sequence of mating behavior was studied by making visual observations and recorded of pairs placed on individual plastic tubes. Mating occurred between 4h and 6h of photophase, when the highest frequencies involved pairs with ages of one and three days after emergence, with peak of mating occurring in 5 th hour of photophase. The young or old pairs showed significantly copulation frequency and the peak of matings advance in 1h. The highest male capture occurred at 12p.m. and 13 p.m. by traps with virgin females or traps with synthetic sex pheromone lures, respectively. L. coffeella is one insect with diurnal mating and the mating behavior was not different from what is know for other Lepidoptera species.KEY WORDS: Reproduction, calling behavior, courtship, pheromone trap RESUMO -Leucoptera coffeella (Guérin-Mèneville) é praga-chave na cafeicultura; contudo, faltam informações sobre sua reprodução para o desenvolvimento de táticas de controle por comportamento. Este trabalho teve como objetivos determinar a periodicidade de cópulas; a periodicidade de captura dos machos e caracterizar o comportamento de acasalamento de L. coffeella. A periodicidade de acasalamento foi avaliada em laboratório com casais virgens de diferentes idades, zero a cinco dias após a emergência, individualizados em tubos transparentes. A periodicidade de captura foi avaliada em café cv. Catuaí, onde foram instaladas armadilhas Delta com dois atraentes: fêmeas virgens e septos de borracha impregnados com o feromônio sexual sintético. As etapas do comportamento de acasalamento foram descritas a partir de observação direta e de filmagens de casais virgens individualizados em tubos transparentes. Os acasalamentos ocorreram entre 4h e 6h da fotofase, onde as maiores freqüências envolveram casais com idades entre um e três dias da emergência, com pico de acasalamentos na quinta hora da fotofase. Os casais recém-emergidos ou velhos mostraram significativamente menor freqüência de cópulas e o pico dos acasalamentos antecipado em 1h. A maior captura ocorreu às 12:00h e 13:00h, nas armadilhas com fêmeas virgens e feromônio sexual sintético, respectivamente. Pelos resultados, L. coffeella é um inseto com acasalamento diurno e os comportamentos de chamamento e corte seguem o padrão encontrado em outr...