Resistência varietal de morangueiro aos pulgões Cerosipha forbesi (Weed) e Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae)

Resumo. A identificacao de picos populacionais de pragas e a selecao de genotipos resistentes ajudam a definir o momento do controle e reduzir a aplicacao de inseticidas. O objetivo deste estudo foi avaliar aresistencia varietal de seis cultivares de morangueiro (Aromas, Campinas, Dover, Festival, Oso Grande e Toyonoka) ao ataque de Cerosipha forbesi (Weed)e Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae). A presenca dos pulgoes nas plantas foi avaliada semanalmente por contagem direta em tres foliolos por planta, durante cinco meses (Fevereiro a Junho de 2012). Marco apresentou a maior densidade de ambas especies de pulgoes, com reducao populacional nos meses proximos ao inverno. As cultivares Campinas, Toyonoka e Dover tiveram maior incidencia de C. forbesi , e Campinas e Toyonoka foram tambem mais atacadas por C. fragaefolii . As cultivares Festival, Aromas e Oso Grande apresentaram menores infestacoes de ambas as especies, tendo potencial para serem utilizadas em programas de melhoramento visando a resistencia ao ataque de C. forbesi e C. fragaefolii . Varietal resistance of strawberry to aphids Cerosipha forbesi (Weed) and Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) Abstract. The identification of peak populations of pests and the selection of resistant genotypes help to define the timing of control and to reduce the frequency of insecticide application. The objective of this study was to evaluate varietal resistance of six strawberry cultivars (Aromas, Campinas, Dover, Oso Grande and Toyonoka) to the attack of Cerosipha forbesi (Weed) and Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae). Attack of the aphids was evaluated on a weekly basis by direct counting in three leaflets per plant for five months (February to June 2012). March presented higher densities of both aphids species, with population reductions in months closer to the winter. The cultivars Campinas, Toyonoka, and Dover had higher incidence of C. forbesi , and Campinas and Toyonoka were also more attacked by C. fragaefolii . The cultivars Festival, Aromas, and Oso Grande presented lower infestation of both aphids species, and hold potential to be used in breeding programs aiming resistance to attack of C. forbesi and C. fragaefolli .