Anastrepha fraterculus es la principal plaga de la producción de frutas en el sur de Brasil. El objetivo de este estudio fue identificar los daños causados por esta especie, evaluar su desarrollo y correlacionar el índice de infestación con las características físicas y químicas de los cultivares de pera Williams y Packhams en cinco distintas etapas de desarrollo. En el campo, se instalaron jaulas en las ramas de los perales para aislar frutas en las que se colocó dos parejas de A. fraterculus durante 48 horas. Se evaluó, en intervalos de 15 días, el daño provocado por la oviposición a través del recuento de los frutos caídos y deformes y de la presencia de larvas en su interior desde el inicio del experimento y hasta el momento de la cosecha. La evaluación de los daños consistió en la observación visual de frutas podridas y deformes y la presencia de larvas. En el laboratorio, se separó cada uno de los frutos de pera en potes de 750 mL y se los dejó con dos parejas de moscas durante 48 horas. La evaluación consistió en contar el número de larvas de tercer instar vivas, pupas y adultos emergentes. El análisis físicoquímico de las frutas determinó la textura de su piel y pulpa, el color, los sólidos solubles totales y su diámetro transversal. Se observó la incidencia de moscas en los cultivares Packhams y Williams cuando las frutas midieron 54,9 y 52,86 mm respectivamente. El desarrollo de A. fraterculus en frutos de pera de ambos cultivares está relacionado principalmente con la textura de la piel y pulpa de las frutas.

Anastrepha fraterculus is the main horticultural pest for food crops in southern Brazil. This study aimed to identify the damage caused by this species, evaluate its development, and correlate its infestation rate with physical and chemical characteristics of Packhams and Williams pear fruit cultivars at five different stages of development. In the field, cages were installed on branches of the pear plants in which two couples of A. fraterculus were released for a period of 48 hours. The damage resulting from oviposition was evaluated at fifteen-day intervals from the day the insects were released until harvest. The evaluation of damage consisted of visual observation of decayed and deformed fruits and the presence of larvae. In the laboratory, two couples were individualized with one fruit in a 750 mL pot for 48 hours. The evaluations consisted of counting the number of living third-instar larvae, pupae and adults. The physical and chemical analyses consisted of the determination of fruit peel and pulp texture, color, soluble solid content and transversal diameter. The incidence of the fruit fly on Packhams and Williams fruits occurred when fruits measured 54.9 and 52.8 mm respectively. The development of A. fraterculus in pear fruits of both cultivars is related mainly to fruit peel and pulp hardness.

Acaricidas inibidores da respiração celular são importantes para o controle de Brevipalpus phoenicis (Geijskes) na cultura dos citros no Brasil. Foram conduzidos estudos para avaliar: (a) a variabilidade na suscetibilidade de populações de B. phoenicis coletadas em pomares de citros para cihexatim, azociclotim, propargite e enxofre; (b) relações de resistência cruzada entre propargite e os acaricidas azociclotim, cihexatim, dinocape, piridabem e enxofre; e (c) o custo adaptativo associado à resistência de B. phoenicis a propargite em condições de laboratório. O método de bioensaio adotado foi o contato residual. A suscetibilidade foi estimada com concentrações diagnósticas baseadas na CL95 de cada acaricida. A resistência cruzada foi avaliada pela caracterização da curva de concentração-mortalidade das linhagens suscetível (S) e resistente a propargite (Propargite-R). O custo adaptativo foi avaliado mediante comparação de parâmetros biológicos das linhagens S e Propargite-R em frutos de laranja a 25 ± 1ºC e fotofase de 14h. Diferenças significativas na sobrevivência de B. phoenicis foram verificadas aos acaricidas cihexatim (de 16,3% a 80,5%), azociclotim (de 3,0% a 15,0%), propargite (de 1,0% a 71,6%) e enxofre (de 9,0% a 82,6%). Baixa intensidade de resistência cruzada foi verificada entre propargite e os acaricidas azociclotim (1,8 vezes), cihexatim (4,6 vezes), dinocape (3,5 vezes) e piridabem (3,5 vezes). Por outro lado, a intensidade de resistência cruzada a enxofre (> 111 vezes) foi bastante alta. Não foi verificada presença de custo adaptativo associado à resistência de B. phoenicis a propargite. Portanto, o uso desses acaricidas também deve ser feito de maneira criteriosa no manejo da resistência de B. phoenicis a acaricidas.

Acaricides that inhibit cellular respiration play an important role in the control of Brevipalpus phoenicis (Geijskes) in citrus groves in Brazil. Studies were conducted to evaluate: (a) the variability in the susceptibility among B. phoenicis populations collected from citrus groves to cyhexatin, azocyclotin, propargite and sulphur; (b) cross-resistance relationships between propargite and azocyclotin, cyhexatin, dinocap, pyridaben and sulphur; and (c) the fitness cost associated with propargite resistance in B. phoenicis under laboratory conditions. A residual-type contact bioassay was used to characterize the susceptibility. The susceptibility was estimated with diagnostic concentrations based LC95 of each acaricide. The cross-resistance was evaluated by characterizing the concentration-mortality responses of susceptible (S) and propargite-resistant (Propargite-R) strains. The fitness cost was evaluated by measuring the biological parameters of S and Propargite-R strains on citrus fruits at 25 ± 1ºC and fotophase of 14h. Significant differences in the susceptibility of B. phoenicis were detected at diagnostic concentration of cyhexatin (survivorship from 16.3% to 80.5%), azocyclotin (from 3.0% to 15.0%), propargite (from 1.0% a 71.6%) and sulphur (from 9.0% to 82.6%). A low intensity of cross-resistance was detected between propargite and the acaricides azocyclotin (1.8-fold), cyhexatin (4.6-fold), dinocap (3.5-fold) and pyridaben (3.5-fold). On the other hand, the intensity of cross-resistance to sulphur (> 111-fold) was very high. There was no fitness cost associated with B. phoenicis resistance to propargite, based on biological parameters evaluated. Therefore, the use of these acaricides should also be done very carefully in resistance management of B. phoenicis to acaricides.