Diapause and population ecology of the stem borer, Coniesta ignefusalis (Hampson) in Northern Ghana

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Effects of photoperiod and temperature on the development of Bonagota cranaodes

The Brazilian apple leafroller, Bonagota cranaodes (Meyrick) (Lepidoptera: Tortricidae) is reared in the laboratory under a long-day (LD 14 : 10 h) and a short-day (LD 7 : 17 h) photoperiod at 22 degrees C, and under two different temperatures (10-13 degrees C and 21-22 degrees C). The development time from larval to adult eclosion do not differ between the two photoperiods, but did between the two temperature regimes. However, the larvae do not enter diapause, even under short day conditions and low temperatures. The number of adults obtained does not differ with temperature and light conditions. Field captures with pheromone traps show that Brazilian apple leafroller occurs in apple orchards throughout the year and the population densities are lower in winter. Accordingly, control measures should be taken during the off-season

Desenvolvimento de Spodoptera frugiperda (J. E. Smith) em genótipos de milho tratados com extrato acetato de etila de Trichilia pallida (Swartz) Development of Spodoptera frugiperda (J. E. Smith) on corn genotypes treated with ethyl acetade extract from Trichilia pallida (Swartz)

Avaliou-se o efeito do extrato acetato de etila obtido de folhas e ramos de Trichillia pallida, (a 0,001%), sobre o desenvolvimento de Spodoptera frugiperda alimentada com folhas de quatro genótipos de milho, um suscetível, 'Piranão', e três resistentes, 'CMS 14C', 'Zapalote Chico', 'ESALQ-PB-4', à referida praga. Os parâmetros biológicos avaliados foram peso, duração e viabilidade das fases larval e pupal. Verificou-se que o extrato provocou alongamento da fase larval e redução dos pesos larval e pupal e que os genótipos resistentes não confirmaram esse comportamento pois quando comparados ao genótipo suscetível, apenas reduziram o peso pupal. Não houve interação significativa entre os fatores genótipo e extrato.<br>The effect of the ethyl acetate extract of leaves and branches of Trichilia pallida was evaluated (at 0.001%) on larvae of S. frugiperda, fed on leaves of the corn genotypes 'Zapalote Chico', 'CMS 14C' and 'ESALQ-PB-4', considered resistant to this pest, and the susceptible genotype 'Piranão'. The parameters evaluated were length, weight and viability of larval and pupal stages. The extract increased the length of the larval stage, and larval and pupal weight, while resistant genotypes only reduced the pupal weight, did however not confirm the resistant behaviour. There was no interaction between genotype and extract

Efeito de extratos aquosos de Azadirachta indica, Melia azedarach e Aspidosperma pyrifolium no desenvolvimento e oviposição de Plutella xylostella Effect of aqueous extracts of Azadirachta indica (A. Juss), Melia azedarach (L.) and Aspidosperma pyrifolium (Mart.) on the development and oviposition of Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Foram avaliados a CL50 e o efeito de extratos aquosos de plantas na biologia, oviposição e período embrionário de Plutella xylostella L. (Lepidoptera: Plutellidae). Para determinação da CL50 foram utilizadas concentrações entre 0,03 e 0,8 % para amêndoas de Azadirachta indica (A. Juss.) 0,5 e 7,0 % para casca de Aspidosperma pyrifolium (Mart.) e 0,5 e 12,5 % para frutos de Melia azedarach (L.), obtendo-se as CL50 de 0,06; 2,17 e 2,90%, respectivamente. Verificou-se que os extratos aquosos de todas as espécies vegetais afetaram o desenvolvimento do inseto, principalmente na fase larval. Na fase de pupa, os extratos reduziram a massa e a viabilidade. Houve deformação de adultos para os extratos de A. pyrifolium e M. azedarach e o de A. indica causou maior porcentagem. Todos os extratos possuem efeito tóxico para ovos de P. xylostella, sendo dependente do aumento da concentração. Nos extratos da casca de A. pyrifolium, do fruto de M. azedarach e da amêndoa de A. indica observa-se ação ovicida quando usados na concentração letal de lagartas de primeiro ínstar da praga. Em observações do ovo de P. xylostella com auxílio de um microscópio eletrônico de varredura, verificou-se a existência de microporos onde pode ocorrer a penetração do produto ovicida, além da constatação da textura rugosa da casca do ovo que pode reter ou fixar os extratos.<br>The effects of aqueous extracts of plants on the biology, preference for oviposition and embryonic period of Plutella xylostella were evaluated. Concentrations between 0.03 and 0.8 % for kernel of Azadirachta indica, 0.5 and 7.0% for peel of Aspidosperma pyrifolium and 0.5 and 12.5% for fruits of Melia azedarach were used, with LC50 values of 0.06; 2.17 and 2.90%, respectively, being obtained. It was verified that the aqueous extracts of all of the appraised vegetable species affected the development of the insect, mainly in the larval phase. In the pupae phase, the extracts reduced the weight and the viability. There was adults' deformation for the extracts of A. pyrifolium and M. azedarach, being it of A. indica what caused larger percentage. Toxics effects on the eggs of P. xylostella were observed for all extracts. The extracts from A. pyrifolium (peel); M. azedarach (fruit) and A. indica (kernel) presented ovicide action in the lethal concentration of caterpillars at first instar of the pest. Observations of P. xylostella eggs with the aid of an electronic microscope showed presence of microspore, revealing ovicide action, besides wrinkled texture of the eggs peel retaining the extracts