Trichogramma acacioi (Hymenoptera, Trichogrammatidae) parasitism capacity at different temperatures and factitious hosts

It was studied the parasitism capacity of Trichogramma acacioi on Anagasta kuehniella and Sitotroga cerealella eggs at different temperatures (15, 20, 25, 30 and 35 ± 1°C). The parasitism of T. acacioi varied with temperature and host. The highest parasitism (³80%) were observed during the first days after emergence in both hosts, at all tested temperatures. The accumulated parasitism varied with both host and temperature, being higher on A. kuehniella at 20°C, what shows good parasitoid species adaptation to this temperature. Thus, we conclude that the best host and best temperature to be used at mass-rearing of T. acacioi is A. kuehniella and 20ºC, respectively. Moreover, this Trichogramma species has great potential to be used in field releases at regions where average temperature is around 20ºC.

Trichogramma acacioi (Hymenoptera, Trichogrammatidae) parasitism capacity at different temperatures and factitious hosts

It was studied the parasitism capacity of Trichogramma acacioi on Anagasta kuehniella and Sitotroga cerealella eggs at different temperatures (15, 20, 25, 30 and 35 ± 1°C). The parasitism of T. acacioi varied with temperature and host. The highest parasitism (³80%) were observed during the first days after emergence in both hosts, at all tested temperatures. The accumulated parasitism varied with both host and temperature, being higher on A. kuehniella at 20°C, what shows good parasitoid species adaptation to this temperature. Thus, we conclude that the best host and best temperature to be used at mass-rearing of T. acacioi is A. kuehniella and 20ºC, respectively. Moreover, this Trichogramma species has great potential to be used in field releases at regions where average temperature is around 20ºC.

Biological characteristics and parasitism capacity of Trichogramma pretiosum Riley (Hymenoptera, Trichogrammatidae) on eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae)

This study aimed at evaluating the biological characteristics and the capacity of parasitism of a Trichogramma pretiosum Riley, 1869 (Hymenoptera, Trichogrammatidae) strain (T. pretiosum RV) collected in Rio Verde County, State of Goiás, Brazil. The study was carried out on eggs of Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera, Noctuidae) and conducted under controlled environmental conditions at different constant temperatures. The biological parameters determined were: developmental time (egg-adult; days); emergence (%); sex ratio; number of progeny/egg; number of generation/year; thermal constant (K); temperature threshold (Tb); daily number of parasitized eggs; cumulative parasitism (%); total number of eggs parasitized by T. pretiosum; and female longevity. To study the T. pretiosum parasitism capacity, 20 S. frugiperda eggs (< 24 h old) were placed into 8.0 cm x 2.0 cm glass vials containing one female (< 24 h old) each. Trials were carried out in a completely randomized experimental design, with 20 replications at each temperature. The environmental chambers (BOD type) were set at 18ºC, 20ºC, 22ºC, 25ºC, 28ºC and 32ºC ± 1ºC, 70 ±10% relative humidity, and 14/10 h (L:D) photoperiod. The eggs of S. frugiperda were replaced daily until parasitoid death. Results have shown an inverse correlation between developmental time and temperature, with statistically significant differences among means, except at 25ºC and 28ºC (10 days). Parasitoid emergence (%) was also influenced by temperature. The lowest percent emergence was observed at 32ºC, and the highest ones at 18ºC and 20ºC temperatures. The temperature did not affect T. pretiosum sex ratio and number of parasitoids per egg, thus allowing changes in the temperature to control insect mass production in the laboratory to meet the needs for field releases.

Parasitism capacity of Telenomus remus Nixon (Hymenoptera: Scelionidae) on Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) eggs

Este trabalho estudou a capacidade de parasitismo de Telenomus remus Nixon (Hymenoptera: Scelionidae) em ovos de Spodoptera frugiperda (Smith) (Hymenoptera: Scelionidae) nas temperaturas de 15, 20, 25, 28, 31 e 35ºC objetivando usar esse inimigo natural em programas de controle biológico em culturas onde S. frugiperda é considerada praga. O parasitismo ocorrido nas primeiras 24 h foi de 60,90; 81,65; 121,05; 117,55 e 108,55 ovos parasitados por fêmea em massas ovos com aproximadamente 150 ovos, nas temperaturas de 15, 20, 25, 28 e 31ºC. Fêmeas de T. remus causaram mais de 80% do parasitismo dos ovos nas temperaturas de 15, 20, 25, 28 e 31ºC aos 5, 27, 8, 2 e 2 dias, respectivamente. Na temperatura de 35ºC não houve parasitismo. As maiores taxas de parasitismo ocorreram nas temperaturas de 20, 25, 28 e 31ºC. A longevidade média de fêmeas de T. remus nas temperaturas compreendidas entre 15 e 31ºC variou de 15,5 a 7,7 dias. A temperatura máxima testada (35ºC) foi inadequada ao desenvolvimento de T. remus, sendo que nessa temperatura as fêmeas apresentaram longevidade bastante reduzida (1,7±0,02 dia) e não houve emergência de adultos. Todas as curvas de sobrevivência para T. remus foram do tipo I o que mostram que para todas as temperaturas há um aumento da taxa de mortalidade com o tempo.

Telenomus remus (Hymenoptera: Platygastridae) parasitism on eggs of Anticarsia gemmatalis (Lepidoptera: Eribidae) compared with its natural host Spodoptera frugiperda (Lepidoptera: Noctuidae)

The capacity of Telenomus remus to parasitize eggs of Anticarsia gemmatalis, compared with its natural host, Spodoptera frugiperda, was evaluated under different temperatures. The parasitoid T. remus was reared at 25 +/- 1 degrees C for a single generation on both hosts. After reaching the adult stage, they were allowed to parasitize both hosts to study parasitoid biology and parasitism capacity at temperatures between 19 degrees C and 37 +/- 1 degrees C. Egg-to-adult developmental time was similar on both hosts. The number of A. gemmatalis eggs parasitized was lower than that of S. frugiperda eggs at all temperatures. Parental female longevity of parasitoids was greater on A. gemmatalis eggs. This indicated a smaller metabolic expense during parasitism, a common feature observed on nonpreferable hosts. In general, sex ratio was little affected by temperature or hosts. When parental T. remus were reared on A. gemmatalis before the experiment, base temperature (Tb) and the thermal constant (K) were 9.53 degrees C and 209.57 DD on eggs of A. gemmatalis and 9.68 degrees C and 197.79 DD on eggs of S. frugiperda, respectively. When parental T. remus were reared on S. frugiperda eggs, Tb and K were 10.12 degrees C and 188.46 DD and 9.69 degrees C and 190.24 DD for the evaluated host eggs of A. gemmatalis and S. frugiperda, respectively. Therefore, T. remus develops in eggs of A. gemmatalis. This can be beneficial for its use in field crops where outbreaks of both Spodoptera spp. and A. gemmatalis occur. However, A. gemmatalis is a less favorable host for the parasitoid development.

Biological characteristics of Telenomus alecto and Trichogramma galloi reared on eggs of the sugarcane borer Diatraea flavipennella

Diatraea flavipennella (Box) (Lepidoptera, Crambidae) is one of the most destructive pests in sugarcane plantations in the Northeast Region of Brazil. Developmental characteristics and parasitism potential of the egg parasitoids Telenomus alecto Crawford (Hymenoptera, Scelionidae) and Trichogramma galloi Zucchi (Hymenoptera, Trichogrammatidae) were compared with the aim of selecting a suitable species for biological control of D. flavipennella. Both T. alecto and T. galloi developed well and were readily adapted to D. flavipennella eggs as host. Although, T. galloi presented higher viability, with more adults emerging per host egg and higher sex ratio, the developmental period (egg-adult) was shorter in T. alecto and female longevity was extended. In addition, T. alecto exhibited significant higher levels of parasitism during the first three days after emergence than T. galloi. Thus, both parasitoids studied here offer considerable potential for the control of D. flavipennella in sugarcane.

Thermal hygrometric requirements for the rearing and release of Tamarixia radiata (Waterston) (Hymenoptera, Eulophidae)

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.

Fertility life table of Trichogramma pretiosum and Trichogramma acacioi (Hymenoptera : Trichogrammatidae) on Sitotroga cerealella (Lepidoptera : Gelechiidae) eggs at different constant temperatures

Fertility life tables were developed for both Trichogramma pretiosum and Trichogramma acacioi reared on Sitotroga cerealella eggs as an alternative host at five different temperatures. The egg parasitoids were first collected from Nipteria panacea eggs, a lepidopterous pest of avocado. Egg parasitoid females were individualized in small glass vials along with 40 eggs of the host during 24 h for parasitization. For evaluation of the parasitism capacity, a similar procedure was adopted, but cardboards with eggs were replaced every day. The net reproductive rate (Ro), intrinsic rate of increase (rm), finite rate of increase (lambda), and mean generation time (T) were estimated. Temperature affected all parameters for both Trichogramma species. The highest fecundity for both species was observed at 25degreesC. Extreme temperatures such as 15degreesC or 35degreesC negatively affect the development rate of both species.

Subdosages of Bacillus thuringiensis on Plutella xylostella) (Lepepidoptera: plutellidae) and Trichogramma pretiosum (Hymenoptera: trichogrammatidae)

The aim of this paper was to evaluate the biological aspects of Plutella xylostella and Trichogramma pretiosum in eggs of the F2 generation of P. xylostella under the influence of Bacillus thuringiensis in laboratory conditions. The experiment was conducted in the Laboratorio de Biologia and Criacao de Insetos of Faculdade de Ciencias Agrarias e Veterinarias de Jaboticabal - UNESP reen collars contaminated with strains and commercial product based on B. thuringiensis in the laboratory. The eggs obtained from the F2 generation of P. xylostella evaluated the biological parameters of T. pretiosum. It was observed that some biological characteristics of P. xylostella showed changes by the treatment with B. thuringiensis. The viability of the larvae and pupae stages, pupae weight were the biological parameters more influenced by treatments, with values significantly reduced when compared to control. However, the larvae length and pupae stages and sex ratio were similar in all treatments, with no significant biological variations. Thus, this bacterium isolated from this behavior may provide greater exposure of larvae to other natural enemies as well as generation of adults less viable, which makes them potential programs in pest control, since the interaction of the methods of control is one of the main ways to enhance the biological control of insect pests. It was observed sublethal effects on P. xylostella biology, and B. thuringiensis negative influence on the parasitism capacity and emergency of T. pretiosum.

Capacidade de parasitismo de Trichogramma exiguum Pinto & Platner, 1978 (Hymenoptera: Trichogrammatidae) em ovos de Plutella xylostella (L., 1758) (Lepidoptera: Plutellidae) em diferentes temperaturas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Telenomus remus Nixon Egg Parasitization of Three Species of Spodoptera Under Different Temperatures

Telenomus remus Nixon is a promising biocontrol agent as an egg parasitoid of Spodoptera spp., but the lack of information on the host-parasitoid interactions in this system precludes its applied use in agriculture. Therefore, we studied the parasitism capacity of T. remus on eggs of Spodoptera cosmioides (Walker), Spodoptera eridania (Cramer), and Spodoptera frugiperda (Smith) in a range of temperatures (19, 22, 25, 28, 31, and 34 ± 1°C) under controlled conditions (70 ± 10% RH and 12 h photophase). Egg masses of Spodoptera spp. were offered to a single-mated T. remus female on a daily basis. More than 80% lifetime parasitism on eggs of S. cosmioides, S. frugiperda, and S. eridania was reached from 1 to 5, 1 to 7, and 1 to 9 days, respectively, at temperatures from 19 to 34°C. More than 80% parasitization was obtained at extreme temperatures for all hosts studied. Lifetime parasitization of S. frugiperda, S. cosmioides, and S. eridania was affected by temperature, with the lowest values for S. frugiperda (34°C) and S. cosmioides (19 and 34°C). Parasitization of S. eridania eggs was reduced around 18% at 28 and 31°C, but dropped more severely at 34°C. Parasitoid longevity was reduced as temperature increased. Thus, our data indicated that T. remus might be suitable as a biocontrol agent against S. eridania, S. cosmioides, and S. frugiperda in geographical areas that fit the temperature range studied here, even though T. remus parasitism was reduced at 34°C. © 2013 Sociedade Entomológica do Brasil.

Performance de Trichogramma pretiosum Riley, 1879 e T. exiguum Pinto & Platner, 1978 (Hymenoptera: trichogrammatidae) em ovos de populações de Plutella xylostella (LINNAEUS, 1758) (Lepidoptera: Plutellidae) sob ação de Bacillus thuringiensis Berliner, 1915 (Bacillales: Bacillaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da endogamia em Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae) criada em Diatraea saccharalis (Fabricius, 1794) (Lepidoptera Crambidae) ao longo de gerações

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Biocontrole de nematoides com fungos

Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV

Capacidade de parasitismo de Trichogramma pretiosum em ovos de Trichoplusia ni em diferentes temperaturas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)