Coccidophilus citricola es un depredador importante de Diaspis echinocacti, un insecto escama, la principal plaga del nopal forrajero, Opuntia ficus-indica, cultivado en el noreste de Brasil. La eficacia de un programa de manejo que implica el enemigo natural de una plaga agrícola se puede aumentar mediante la adopción de técnicas de conservación. El objetivo del presente estudio fue evaluar la selectividad de cinco productos fitosanitarios: querobão, aceite mineral, NatuneemTM, extracto acuoso de hojas de neem y conidios de Beauveria bassiana y Metarhizium anisopliae hacia el depredador. Las alícuotas de los productos se pulverizaron en secciones (5 x 5 cm) de raquetas de cactos infestados con D. echinocacti obtenidos a partir de cactus forrajero cultivado bajo condiciones de invernadero. Las secciones se secaron y se ofrecieron a la segunda generación de adultos C. citricola que habían sido criados en laboratorio. Fue evaluada la mortalidad del depredador a las 24, 48 y 72 h después de la aplicación de los productos o el control (agua). Querobão y NatuneemTM fueron más tóxicos para el depredador, con altos niveles de mortalidad registrados a las 24 y 48 h. Los conidios de B. bassiana y M. anisopliae (1 x 10(8) conidios mL-1) fueron menos tóxicos y de más lenta acción, alcanzando sus más altas mortalidades entre 48 y 72 h. Las toxicidades de aceite mineral, extracto de hoja de neem y M. anisopliae (1 x 10(7) conidios mL-1) hacia C. citricola no fueron significativamente diferentes al control. Se concluye que estos agentes pueden ser selectivos para el enemigo natural de D. echinocacti y podrían utilizarse en combinación con el depredador para controlar esta plaga en cultivos de nopal forrajero.

Coccidophilus citricola is an important predator of Diaspis echinocacti, a scale insect that is the main pest of the forage cactus Opuntia ficus-indica cultivated in northeastern Brazil. The efficiency of a management program involving the natural enemy of an agricultural pest can be increased by adopting conservation techniques. The aim of the present study was to evaluate the selectivity of querobão, mineral oil, NatuneemTM, aqueous extract of neem leaves, and conidia of Beauveria bassiana and Metarhizium anisopliae towards the predator. Aliquots of phytosanitary products were sprayed on sections (5 x 5 cm) of cactus rackets infested with D. echinocacti obtained from forage cactus grown under greenhouse conditions. Sections were dried and offered to second-generation C. citricola adults that had been reared under laboratory conditions. Predator mortalities were assessed at 24, 48 and 72 h after application of the products or water control. Querobão and NatuneemTM were most toxic to the predator, with high levels of mortality recorded at 24 and 48 h. Conidia of B. bassiana and M. anisopliae (1 x 10(8) conidia mL-1) were less toxic and slower acting, with highest mortalities occurring between 48 and 72 h. The toxicities of mineral oil, neem leaf extract and M. anisopliae (1 x 10(7) conidia mL-1) towards C. citricola were not significantly different from the control. It is concluded that these agents may be selective to the natural enemy of D. echinocacti and could be used in combination with the predator to control this pest in forage cactus cultures.

Thermal hygrometric requirements for the rearing and release of Tamarixia radiata (Waterston) (Hymenoptera, Eulophidae). Tamarixia radiata is the main agent for the biological control of Diaphorina citri in Brazil with a parasitism rate ranging from 20 to 80%. This study investigated the influence of temperature on the development, fecundity and longevity of adults of T. radiata and the effect of relative humidity (RH) on their parasitism capacity and survival rate in the pre-imaginal period. The effect of temperature was assessed in the range between 15 and 35 ± 1ºC, 70 ± 10% RH, and a 14-h photophase. The RH effect was evaluated in the range from 30 to 90 ± 10%, temperature at 25 ± 1ºC, and photophase of 14-h. At 25ºC, circa 166.7 nymphs were parasitized, the highest parasitism capacity observed compared to other treatments. The longest longevity of females was observed at 25ºC, although the rate did not differ in the 20-30ºC temperature range. The threshold temperature (TT) was 7.2ºC, and 188.7 degrees-day were required for the development (egg-to-adult period). The parasitism rate and longevity were higher at 50 and 70% of RH. This shows that temperature and RH may affect the parasitism capacity of T. radiata on nymphs of D. citri, which can explain the great parasitism variation for D. citri observed in citrus groves in São Paulo State, Brazil.

The aim of this study was to evaluate in the laboratory different isolates and concentrations of conidia of Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 and Beauveria bassiana (Balsamo) Vuillemim, 1912 for control of the cattle tick. The conidial suspensions were prepared from fungi grown in rice medium in polypropylene bags. The tests were performed by immersion of engorged females collected from animals not treated with acaricides. The experimental design was completely randomized with 20 treatments and 5 repetitions, each consisting of 5 females. The mortality rate caused by the fungus M. anisopliae ranged from 92 to 100%, while for B. bassiana it was 44 to 100%; mortality was greater at concentrations of 10(8) and 10(9) conidia mL-1 suspension. The isolates B. bassiana Fitossan 1 and M. anisopliae PL 43 (both at 10(9) conidia mL-1) and Fitossan 4 (10(8) conidia mL-1) within 14 days of treatment killed 100%, 92% and 88% of the engorged females, respectively. In general there was no difference in the weight of eggs from females treated with the same isolate at concentrations of 10(7), 10(8) and 10(9) conidia mL-1, although isolates of M. anisopliae had lower weight. The efficiency of control ranged from 0% (control with water) to 31.30% (M. anisopliae Fitossan 4, 10(8) conidia mL-1).

El objetivo de este trabajo fue evaluar diferentes colonias aisladas en concentraciones de Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 y de Beauveria bassiana (Balsamo) Vuillemim, 1912 para el control de la garrapata común del vacuno. La multiplicación de conidias fue realizada a partir de hongos inoculados en arroz precocido estéril. Los ensayos de inmersión fueron realizados sobre garrapatas adultas ingurgitadas o teleoginas colectadas de bovinos no tratados con acaricidas. El diseño experimental fue completamente al azar con 20 tratamientos y cinco repeticiones, siendo cada una de estas constituidas por cinco hembras. La mortalidad de las teleoginas ocasionada por M. anisopliae fue variable entre 92 a 100% y para B. bassiana este parámetro varió entre 44 a 100%, observándose que la mortalidad fue superior en las concentraciones de 10(8) y 10(9) conidias mL-1, destacándose las cepas de B. bassiana Fitossan 1 e M. anisopliae PL 43 (ambos 10(9) conidias mL-1) y Fitossan 4 (10(8) conidias mL-1), que a los 14 días de tratamiento habían eliminado el 100, 92 y 88 % de las teleoginas, respectivamente. En general, no existió diferencia en relación al peso de los huevos provenientes de hembras tratadas con el mismo aislado en las concentraciones de 10(7), 10(8) y 10(9) conidia .mL-1, aunque se obtuvieron pesos inferiores para las cepas de M. anisopliae. La eficiencia del control varió de 0% (control) a 31,30% (M. anisopliae Fitossan 4, 108 conidias.mL-1).