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This study evaluates the potential of ants as natural biological control agents of the boll weevil (Anthonomus grandis), during the between‐season period, in South‐east Brazil. Active adults of Anthonomus were experimentally distributed on the ground of the cotton field. Results show that 20% of the adult Anthonomus are attacked and removed by foraging ants. The native ant Pheidole oliveirai was by far the most efficient predator, accounting for 94 % of the predation on Anthonomus. Recruited workers of P. oliveirai were usually very fast at transporting the weevils to their nests. The potential benefit of suppressing overwintering adult Anthonomus during the between‐season period is mainly that of reducing the risk of high level infestations during the next cropping cycle.

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Mass trapping was used to control pink bollworm (PBW), Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), populations in cotton fields in Brazil. Oil traps containing lures with a high dose of pheromone, installed at a density of 20 traps per ha soon after the occurrence of the first cotton fruits (or bolls), suppressed PBW populations below detection levels using Delta traps and manual examination of 100 green cotton bolls per ha. Pheromone sources of 0.2 g (approximately 150 NoMate r fibers) were effective in attracting PBW male moths to oil traps for at least three weeks. Trap captures showed that PBW males located the high concentration pheromone plumes, oriented upwind, and landed on or inside the traps. The long life of the pheromone sources and the long lasting viscosity of the oil surface ensured low trap maintenance, thus rendering mass trapping viable as an alternative technique for the control of P. gossypiella populations in commercial cotton fields. We discuss probable mechanisms promoting suppression of PBW populations in fields with mass trapping control.

The endoparasite, Microcharops anticarsiae Gupta, is one of the natural control agents of Anticarsia gemmatalis H/.ibner. The effects of host age on the levels of parasitisation and the sex ratio of the subsequent progeny, together with the functional response of M. anticarsiae at 6 different host densities, were evaluated experimentally. In choice experiments involving two or four consecutive instars, female parasitoids showed no preference for host larvae of a particular age. The sex ratio of the parasitoids was affected by the host instar in which they developed (G3dr = 18.21, p < .001). Parasitoid sex ratio was most skewed towards females in parasitoid larvae that developed in 4th instar hosts.A type II functional response was exhibited by the female parasitoid in response to host density.Information on the sex ratio, indicated the best host instar to parasitize to produce an optimum female: male sex ratio, while the functional response indicated the average rate (38.0 __. 7.5) of parasitism per female. This information is important for mass-rearing of M. anticarsiae, for biological control programs against A. gemmatalis.

In the present work, experimental samples of two products based on Bacillus thuringiensis var. israelensis (H‐14) were evaluated against three aquatic dipterous insects, Culex declarator, Simulium goeldii and S. rorotaense. C. declarator (Culicidae) larvae were more susceptible than those of the simuliid species. Within Simuliidae, S. goeldii larvae were 4 times more susceptible than those of S. rorotaense. The last (4th) instar larvae of C. declarator were apparently more susceptible than those of the first instars. Moreover, within the same instar, these larvae showed different levels of susceptibility. In the beginning of the last instar, they were more susceptible than in the end of the same. Some recommendations, concerning standardization criteria for future commercial products based on B. thuringiensis var. israelensis are given. Utilization of LT50 criterion is suggested. Symptomatology, histopathology and mode of action of this promissing serotype are discussed. Asphixiation could be considered responsible for the death of infected larvae. Zusammenfassung Potential von Bacillus thuringiensis var. israelensis (H‐14) gegen einige Dipteren In der vorliegenden Arbeit wurden Bekämpfungsversuche mit 2 Produkten, die auf Bacillus thuringiensis var. israelensis basieren, gegen drei Dipteren‐Arten ausgewertet. Die Culex declarator (Culicidae‐)Larven waren empfindlicher als jene der Simuliiden‐Species. Innerhalb der Simuliidae waren Simulium goeldii‐Larven viermal empfindlicher als jene von S. rorotaense. Das letzte Larvenstadium (L4) von C. declarator war eindeutig empfindlicher als das erste. Darüber hinaus zeigten diese Larven innerhalb desselben Stadiums verschiedene Grade von Empfindlichkeit. In der Anfangsphase des letzten Stadiums waren sie empfindlicher als in der letzten Phase des gleichen Stadiums. Es werden einige Empfehlungen bezüglich der Standardisierungskriterien für zukünftige Handelsprodukte, die auf B. thuringiensis var. israelensis basieren, gegeben. So wird die Verwendung des LT50‐Kriteriums empfohlen. Symptomatologie, Histopathologic und Abtötungsmechanismus dieses vielversprechenden Agens werden diskutiert. Erstickung könnte als Todesursache der infizierten Larven angesehen werden.

Biological data revealed that the egg stage of Campoletis flavicincta lasted from 2 to 4 days and the larval stage comprised 4 instars. The larval and pupal stages lasted 7.14 ±0.05 and 8.24 ±0.44 days, respectively. The longevity among laboratory culture females was shorter than those originated from field collected pupae. The sex ratio was largely affected by host size. The life cycle averaged approximately 23 days. During the oviposition period, the female was able to deposit an average of 146 eggs. This ichneumonid, normally solitary endoparasite, was able to deposit 2 to 4 eggs/larva when host population densities were low, but without any successful development. Zusammenfassung Beiträge zur Biologie von Campoletis flavicincta (Ashmead, 1890) (Hym., Ichneumonidae), ein Endoparasit von Spodoptera frugiperda (Abbot & Smith, 1797) (Lepid., Noctuidae) Die biologischen Daten zeigen, daß die Eientwicklung von Campoletis flavicincta 2–4 Tage dauerte und die larvale Entwicklung vier Stadien umfaßte. Larven‐ und Puppenstadien dauerten 7.14 ± 0.05 bzw. 8.24 ± 0.44 Tage. Im Labor herangezogene Weibchen hatten eine kürzere Lebensdauer als solche, die von Freilandpuppen stammten. Das Männchen: Weibchen‐Verhältnis wurde hauptsächlich durch die Größe der Wirtsraupen bestimmt. Der Entwicklungszyklus beanspruchte 23 Tage. Das Weibchen legte i. M. 146 Eier. Dieser normalerweise solitäre Ichneumonide Endoparasit legt bei niedriger Wirtspopulation 2–4 Eier pro Spodoptera‐Larve ab, aber die Entwicklung wird dann nicht vollendet.

RESUMO -Devido à falta de informações sobre Urbanus acawoios (Williams, 1926) (Lepidoptera: Hesperiidae), e pelos danos severos por ele causados em árvores de Clitoria racemosa, o presente trabalho foi desenvolvido sob condições de laboratório para verificar a possibilidade de utilizar Bacillus thuringiensis var. kurstaki (H-3a:3b) como agente microbiano para o seu controle. O pH do intestino médio do hesperídeo mostrou ser bastante alcalino, variando de 8,4 a 9,2 (média de 8,7), indicando a possibilidade das larvas serem susceptíveis ao patógeno. Os ensaios confirmaram a alta susceptibilidade a dosagens equivalentes a 110 g / ha, resultando em tempos letais medianos (TL 50 ) de 42,28, 37,18, 28,00 e 51,87 horas para larvas de 3 o , 4°, início e final do 5º ínstares, respectivamente. Três outras dosagens (80, 150 e 280 g/h) foram aplicadas para larvas do 3º ínstar, resultando em TLs50 de 42,62, 30,77 e 30,06 horas, respectivamente. Descrições detalhadas sobre os sintomas externos nas larvas infectadas foram dadas. As alterações histológicas do intestino médio afetado pela d-endotoxina de B. thuringiensis foram descritas. Os resultados obtidos no presente trabalho revelam a grande possibilidade de controlar esta praga utilizando-se produtos e formulados à base desta bactéria. ABSTRACT -Due to the lack of information concerning Urbanus acawoios (Williams, 1926) (Lepidoptera: Hesperiidae), and the severe damage caused by it in Clitoria racemosa trees in Manaus, AM, the present research was conducted. The study was undertaken under laboratory conditions, in order to investigate the possibility of its microbial control, utilizing a commercial formulation, Dipel, based on Bacillus thuringiensis var. kurstaki (H-3a:3b). The larval mid-gut contents of this insect species showed to be highly alkaline, with a pH varying between 8.4 and 9.2, with an average of 8.7, indicating initially, a possible susceptibility of the larval stage to such a pathogen. Posteriorly, Such an indication, was confirmed by bioassays. During the preliminary tests, a dosage, equivalent to 110 g / ha (17.40 IU/cm 2 of leaf-covered area) was utilized and resulted in median lethal times (LTs 50 ) of 42.28, 37.18, 28.00 and 51.87 hours for the 3 rd , 4 th , beginning of the 5 th and end of the 5 th instar, respectively. Giving more attention for the 3 rd instar larvae, three dosages were applied: 80 g/ha (13 IU/cm 2 ), 150 (25 IU/cm 2 ) and 280 g/ha (45 IU/cm 2 ). In this case, the LTs 50 were given. The mid-gut histopathological changes caused by the d-endotoxin of B. thuringiensis are also described. The results obtained during the present work could indicate applications of B. thuringiensis, as a promising method for the microbial control of this urban pest. Palavras-chave -