Effect of different thermal conditions on biology and number of generations of Palpita forficifera (Lepidoptera: Crambidae)
Abstract
Palpita forficifera Munroe (Lepidoptera: Crambidae) is the principal pest in olive groves in Brazil and Uruguay, damaging buds and fruits. Therefore, this work was undertaken to understand the biology of P. forficifera at different temperatures, to determine thermal requirements, and to estimate the number of annual generations in different olive groves located in Brazil and Uruguay. The study was performed at 10, 15, 20, 25, 30, and 35 °C, 60 ± 10% RH, and a 14:10 h (L:D) photoperiod. The duration and survival stages of development, sex ratio, fecundity, and fertility were determined, and we elaborated the fertility life table at different temperatures. We also determined the thermal requirements, and the number of annual generations in olive producing areas were estimated. All immature stages of P. forficifera were affected negatively by the temperature at 10 and 35 °C, whereas 25 and 30 °C provided the shortest egg-to-adult periods. However, larval viability was affected at 30 °C (48.7%). Highest fecundity (325.5 eggs) was found for P. forficifera females kept at 25 °C. Additionally, the highest net reproduction rates (Ro) and intrinsic population growth rates (Rm) were verified at 25 and 30 °C. Lower thermal threshold (Tb) and thermal constant (K) for the egg-to-adult period were 10.7 °C and 549.45 degree-d, respectively. Based on the thermal requirements, P. forficifera can produce 4.0 to 6.3 generations per yr in the olive producing regions of Brazil and Uruguay. Results of the present study are important for understanding the occurrence of P. forficifera under field conditions and to aid strategic management designs.
Resumo
Palpita forficifera Munroe (Lepidoptera: Crambidae) é a principal praga da oliveira no Brasil e Uruguai, causando danos nas brotações e nos frutos. Assim, o trabalho compreenderá a biologia de P. forficifera em diferentes temperaturas, determinar as exigências térmicas e estimar o número de gerações anuais para diferentes locais de cultivo de oliveira no Brasil e no Uruguai. O estudo foi realizado nas temperaturas de 10, 15, 20, 25, 30, e 35 °C, umidade relativa do ar de 60 ± 10% e fotoperíodo de 14:10 h (L:D). Foram avaliados parâmetros biológicos das fases imaturas e adulta e com esses dados foi elaborada a tabela de vida de fertilidade, estimado as exigências térmicas e o número de gerações anuais em áreas produtoras de oliveira. As temperaturas de 10 e 35 °C afetaram negativamente todas as fases imaturas de P. forficifera e as temperaturas de 25 e 30 °C proporcionaram as menores durações do período ovo-adulto. Porém, a viabilidade larval foi afetada na temperatura de 30 °C (48,7%). Fêmeas de P. forficifera mantidas a 25 °C resultaram na maior fecundidade (325,5 ovos). Em adição, as maiores taxas liquidas de reprodução (Ro) e a taxa intrínseca de aumento populacional (Rm) foram verificadas nas temperaturas de 25 e 30 °C. A temperatura base (Tb) e a constante térmica (K) para o período ovo-adulto foi de 10,7 °C e 549,45 graus-dia, respectivamente. Com base nas exigências térmicas P. forficifera pode ter de 4,0 a 6,3 gerações anuais em regiões produtoras de oliveira do Brasil e Uruguai. Os resultados do presente estudo são importantes para a compreensão da ocorrência de P. forficifera nas condições de campo e auxiliar no delineamento de estratégias para o seu manejo.
Key Words: thermal requirements; lower thermal threshold; biology; caterpillar of the olive tree; life cycle
View this article in BioOne https://doi.org/10.1653/024.104.0405
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