In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as surviv... more In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as survival strategy during the winter (May-August). In our study, we evaluated the effect of diapause on biological characteristics of the species for 4 months in laboratory. Newly hatched larvae of G. molesta were induced to diapause changing the photoperiod and temperature (T) (12 ± 1°C), relative humidity (RH) (70 ± 10%), and a photophase of 12 h and, when they started diapause in the prepupal stage, the conditions were kept for 4 months. Afterwards, the insects were induced to finalize the diapause process at T 25 ± 1°C, RH 70 ± 10%, and a photophase of 16 h. We evaluated the duration and viability of the larval stages and pupae, pupae weight at 24 h and sex ratio (sr), periods of preoviposition, oviposition, and postoviposition; adult life span (males and females); fecundity (daily and total); embryonic period duration and eggs viability, comparing the data with insects nondiapause. The res...
Laboratory, greenhouse, and field experiments were performed with the objective of selecting effi... more Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD(90) of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm(2), respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm(2) of either nematode. In the field, H. bacteriop...
Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a m... more Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a major pest in temperate fruit trees, such as peach and apple. Entomopathogenic nematodes (EPNs) are regarded as viable for pest management control due to their efficiency against tortricid in these trees. The objective of this study was to evaluate the effectiveness of native EPNs from Rio Grande do Sul state against pre-pupae of G. molesta under laboratory and field conditions. In the laboratory, pre-pupae of G. molesta were placed in corrugated cardboard sheets inside glass tubes and exposed to 17 different EPNs strains at concentrations of 6, 12, 24, 48 and 60 IJs/cm(2) and maintained at 25 ° C, 70 ± 10% RH and photophase of 16 hours. Insect mortality was recorded 72 hours after inoculation of EPNs. Steinernema rarum RS69 and Heterorhabditis bacteriophora RS33 were the most virulent strains and selected for field application (LC95 of 70.5 and 53.8 IJs/cm(2), respectively). Both strains...
Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in... more Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25 ± 1°C, UR 60 ± 10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, S. feltiae, S. riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (S. carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was Heterorhabditis bacteriophora RS33 (from 69.0 to 92.2% of mortality), native of Rio Grande do ...
An understanding of the genetic basis of insect resistance to insecticides is important for the e... more An understanding of the genetic basis of insect resistance to insecticides is important for the establishment of Insect Resistance Management (IRM) strategies. In this study we evaluated the inheritance pattern of resistance to the chitin synthesis inhibitor lufenuron in Spodoptera frugiperda. The LC50 values (95% CI) were 0.23 µg of lufenuron mL(-1) of water (ppm) (0.18 - 0.28) for the susceptible strain (SUS) and 210.6 µg mL(-1) (175.90 - 258.10) for the lufenuron-resistant strain (LUF-R) based on diet-overlay bioassay. The resistance ratio was ≈ 915-fold. The LC50 values for reciprocal crosses were 4.89 µg mL(-1) (3.79 - 5.97) for female LUF-R and male SUS and 5.74 µg mL(-1) (4.70 - 6.91) for female SUS and male LUF-R, indicating that the inheritance of S. frugiperda resistance to lufenuron is autosomal incompletely recessive. Backcrosses of the progeny of reciprocal crosses with the parental LUF-R showed polygenic effect. The estimated minimum number of independent segregations ...
Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian... more Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell), Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley), Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso), Pseudococcus viburni (Signoret), Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn) and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret). Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species.
Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that at... more Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that attacks the crops during both larval and adult phase. The occurrence of E. humilis was observed in a forest area with Eucalyptus saligna Smith, from Votorantim Celulose & Papel (Fazenda Aroeira), in the Municipality of Candiota, Rio Grande do Sul State. Plants approximately 1m high were damaged by E. humilis adult insects near the stem base, what unraveled its cortex and led some of them to death. The attack was verified in about 10% of the eucalypts plants, in an area of approximately 30 ha.
The objective of the work was to determine the minimum diet quantity in glass containers for Heli... more The objective of the work was to determine the minimum diet quantity in glass containers for Helicoverpa zea rearing. Adults of H. zea were collected in corn farms from Pelotas (RS). Seventy carterpillars were individualized in glass tubes of flat bottom (2.5 cm of diameter x 8.5 cm of height) containing different quantities of Modified Greene artificial diet (4, 5,
Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that at... more Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that attacks the crops during both larval and adult phase. The occurrence of E. humilis was observed in a forest area with Eucalyptus saligna Smith, from Votorantim Celulose & Papel (Fazenda Aroeira), in the Municipality of Candiota, Rio Grande do Sul State. Plants approximately 1m high were damaged by E. humilis adult insects near the stem base, what unraveled its cortex and led some of them to death. The attack was verified in about 10% of the eucalypts plants, in an area of approximately 30 ha.
The efficacy of three entomopathogenic nematode (EPN) species, Heterorhabditis indica, Steinernem... more The efficacy of three entomopathogenic nematode (EPN) species, Heterorhabditis indica, Steinernema thermophilum, and S. glaseri, from Meghalaya, India was studied against the larvae of taro leaf beetle, Aplosonyx chalybaeus (Hope) (Coleoptera: Chrysomelidae), under the laboratory conditions. The beetle larvae (grubs) were exposed to 25, 50, 75, 100 and 200 infective juveniles (IJs) of each nematode species for different time periods and they were found to be susceptible to all the EPNs tested. However, the susceptibility of grubs to nematode infection varied according to the dosages of IJs and their exposure periods. Appreciably good performance was achieved by S. glaseri, which showed 100 % mortality of insect larvae in 48 h exposure time. At 48 h of incubation, its LC50 value was 90.3 IJs/larva, which was lower than that of S. thermophilum (115.0 IJs/larva) and H. indica (186.0 IJs/larva), at the same exposure time. All the tested nematode species were also found to reproduce within the host and produced infective juveniles. H. indica, however, showed comparatively more production of IJs per cadaver of infected host (168.9 × 10(3) IJs/larva), as compared to the other two tested nematode species. The production of IJs per cadaver of infected host by S. thermophilum was recorded to be 82.0 × 10(3) IJs/larva. In case of S. glaseri, while production of IJs increased initially to 18.9 × 10(3) IJs/larva at concentration of 100 IJs/larva, it declined thereafter to 14.7 × 10(3) IJs/larva at the dose of 200 IJs/larva. In conclusion, the evidence obtained in this study suggests that all the three indigenous EPN species are virulent enough to produce 100 % mortality in the last instar larvae of A. chalybaeus. These EPN species thus have potential scope for the management of A. chalybaeus in taro crops.
The greenbug Chaetosiphon fragaefolli is the main insect pest of strawberry. This study evaluated... more The greenbug Chaetosiphon fragaefolli is the main insect pest of strawberry. This study evaluated the effect of azadirachtin for the control of the insect in the laboratory and in the greenhouse. The treatments were azadirachtin (Azamax® 100, 200 and 300 ml.100L-1), compared with thiamethoxam (Actara 250 WG®, 10 g. 100L-1), lambda-cyhalothrin (Karate Zeon CS 50®, 80 ml .100 L-1) and control (water). The insecticides products were sprayed on strawberry plants infested artificially in the greenhouse. Azadirachtin was equivalent to lambda-cyhalothrin and thiamethoxam to control C. fragaefolli since a second spray is made seven days after the first. The biological persistence of the insecticides lambda-cyhalothrin and thiamethoxam was more than 28 days with a control of 75% of the population of aphids while azadirachtin was less persistent controlling 70% of the population for seven days.
In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as surviv... more In southern Brazil, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) uses diapause as survival strategy during the winter (May-August). In our study, we evaluated the effect of diapause on biological characteristics of the species for 4 months in laboratory. Newly hatched larvae of G. molesta were induced to diapause changing the photoperiod and temperature (T) (12 ± 1°C), relative humidity (RH) (70 ± 10%), and a photophase of 12 h and, when they started diapause in the prepupal stage, the conditions were kept for 4 months. Afterwards, the insects were induced to finalize the diapause process at T 25 ± 1°C, RH 70 ± 10%, and a photophase of 16 h. We evaluated the duration and viability of the larval stages and pupae, pupae weight at 24 h and sex ratio (sr), periods of preoviposition, oviposition, and postoviposition; adult life span (males and females); fecundity (daily and total); embryonic period duration and eggs viability, comparing the data with insects nondiapause. The res...
Laboratory, greenhouse, and field experiments were performed with the objective of selecting effi... more Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD(90) of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm(2), respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm(2) of either nematode. In the field, H. bacteriop...
Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a m... more Oriental fruit moth Grapholita molesta (Busck, 1916) (Lepidoptera: Tortricidae) is considered a major pest in temperate fruit trees, such as peach and apple. Entomopathogenic nematodes (EPNs) are regarded as viable for pest management control due to their efficiency against tortricid in these trees. The objective of this study was to evaluate the effectiveness of native EPNs from Rio Grande do Sul state against pre-pupae of G. molesta under laboratory and field conditions. In the laboratory, pre-pupae of G. molesta were placed in corrugated cardboard sheets inside glass tubes and exposed to 17 different EPNs strains at concentrations of 6, 12, 24, 48 and 60 IJs/cm(2) and maintained at 25 ° C, 70 ± 10% RH and photophase of 16 hours. Insect mortality was recorded 72 hours after inoculation of EPNs. Steinernema rarum RS69 and Heterorhabditis bacteriophora RS33 were the most virulent strains and selected for field application (LC95 of 70.5 and 53.8 IJs/cm(2), respectively). Both strains...
Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in... more Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25 ± 1°C, UR 60 ± 10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, S. feltiae, S. riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (S. carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was Heterorhabditis bacteriophora RS33 (from 69.0 to 92.2% of mortality), native of Rio Grande do ...
An understanding of the genetic basis of insect resistance to insecticides is important for the e... more An understanding of the genetic basis of insect resistance to insecticides is important for the establishment of Insect Resistance Management (IRM) strategies. In this study we evaluated the inheritance pattern of resistance to the chitin synthesis inhibitor lufenuron in Spodoptera frugiperda. The LC50 values (95% CI) were 0.23 µg of lufenuron mL(-1) of water (ppm) (0.18 - 0.28) for the susceptible strain (SUS) and 210.6 µg mL(-1) (175.90 - 258.10) for the lufenuron-resistant strain (LUF-R) based on diet-overlay bioassay. The resistance ratio was ≈ 915-fold. The LC50 values for reciprocal crosses were 4.89 µg mL(-1) (3.79 - 5.97) for female LUF-R and male SUS and 5.74 µg mL(-1) (4.70 - 6.91) for female SUS and male LUF-R, indicating that the inheritance of S. frugiperda resistance to lufenuron is autosomal incompletely recessive. Backcrosses of the progeny of reciprocal crosses with the parental LUF-R showed polygenic effect. The estimated minimum number of independent segregations ...
Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian... more Mealybugs (Hemiptera: Pseudococcidae) are pests constraining the international trade of Brazilian table grapes. They damage grapes by transmitting viruses and toxins, causing defoliation, chlorosis, and vigor losses and favoring the development of sooty mold. Difficulties in mealybug identification remain an obstacle to the adequate management of these pests. In this study, our primary aim was to identify the principal mealybug species infesting the major table grape-producing regions in Brazil, by morphological and molecular characterization. Our secondary aim was to develop a rapid identification kit based on species-specific Polymerase Chain Reactions, to facilitate the routine identification of the most common pest species. We surveyed 40 sites infested with mealybugs and identified 17 species: Dysmicoccus brevipes (Cockerell), Dysmicoccus sylvarum Williams and Granara de Willink, Dysmicoccus texensis (Tinsley), Ferrisia cristinae Kaydan and Gullan, Ferrisia meridionalis Williams, Ferrisia terani Williams and Granara de Willink, Phenacoccus baccharidis Williams, Phenacoccus parvus Morrison, Phenacoccus solenopsis Tinsley, Planococcus citri (Risso), Pseudococcus viburni (Signoret), Pseudococcus cryptus Hempel, four taxa closely related each of to Pseudococcus viburni, Pseudococcus sociabilis Hambleton, Pseudococcus maritimus (Ehrhorn) and Pseudococcus meridionalis Prado, and one specimen from the genus Pseudococcus Westwood. The PCR method developed effectively identified five mealybug species of economic interest on grape in Brazil: D. brevipes, Pl. citri, Ps. viburni, Ph. solenopsis and Planococcus ficus (Signoret). Nevertheless, it is not possible to assure that this procedure is reliable for taxa that have not been sampled already and might be very closely related to the target species.
Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that at... more Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that attacks the crops during both larval and adult phase. The occurrence of E. humilis was observed in a forest area with Eucalyptus saligna Smith, from Votorantim Celulose & Papel (Fazenda Aroeira), in the Municipality of Candiota, Rio Grande do Sul State. Plants approximately 1m high were damaged by E. humilis adult insects near the stem base, what unraveled its cortex and led some of them to death. The attack was verified in about 10% of the eucalypts plants, in an area of approximately 30 ha.
The objective of the work was to determine the minimum diet quantity in glass containers for Heli... more The objective of the work was to determine the minimum diet quantity in glass containers for Helicoverpa zea rearing. Adults of H. zea were collected in corn farms from Pelotas (RS). Seventy carterpillars were individualized in glass tubes of flat bottom (2.5 cm of diameter x 8.5 cm of height) containing different quantities of Modified Greene artificial diet (4, 5,
Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that at... more Euetheola humilis (Burmeister) is a scarabaeid pest of rice, sugarcane and corn cultures, that attacks the crops during both larval and adult phase. The occurrence of E. humilis was observed in a forest area with Eucalyptus saligna Smith, from Votorantim Celulose & Papel (Fazenda Aroeira), in the Municipality of Candiota, Rio Grande do Sul State. Plants approximately 1m high were damaged by E. humilis adult insects near the stem base, what unraveled its cortex and led some of them to death. The attack was verified in about 10% of the eucalypts plants, in an area of approximately 30 ha.
The efficacy of three entomopathogenic nematode (EPN) species, Heterorhabditis indica, Steinernem... more The efficacy of three entomopathogenic nematode (EPN) species, Heterorhabditis indica, Steinernema thermophilum, and S. glaseri, from Meghalaya, India was studied against the larvae of taro leaf beetle, Aplosonyx chalybaeus (Hope) (Coleoptera: Chrysomelidae), under the laboratory conditions. The beetle larvae (grubs) were exposed to 25, 50, 75, 100 and 200 infective juveniles (IJs) of each nematode species for different time periods and they were found to be susceptible to all the EPNs tested. However, the susceptibility of grubs to nematode infection varied according to the dosages of IJs and their exposure periods. Appreciably good performance was achieved by S. glaseri, which showed 100 % mortality of insect larvae in 48 h exposure time. At 48 h of incubation, its LC50 value was 90.3 IJs/larva, which was lower than that of S. thermophilum (115.0 IJs/larva) and H. indica (186.0 IJs/larva), at the same exposure time. All the tested nematode species were also found to reproduce within the host and produced infective juveniles. H. indica, however, showed comparatively more production of IJs per cadaver of infected host (168.9 × 10(3) IJs/larva), as compared to the other two tested nematode species. The production of IJs per cadaver of infected host by S. thermophilum was recorded to be 82.0 × 10(3) IJs/larva. In case of S. glaseri, while production of IJs increased initially to 18.9 × 10(3) IJs/larva at concentration of 100 IJs/larva, it declined thereafter to 14.7 × 10(3) IJs/larva at the dose of 200 IJs/larva. In conclusion, the evidence obtained in this study suggests that all the three indigenous EPN species are virulent enough to produce 100 % mortality in the last instar larvae of A. chalybaeus. These EPN species thus have potential scope for the management of A. chalybaeus in taro crops.
The greenbug Chaetosiphon fragaefolli is the main insect pest of strawberry. This study evaluated... more The greenbug Chaetosiphon fragaefolli is the main insect pest of strawberry. This study evaluated the effect of azadirachtin for the control of the insect in the laboratory and in the greenhouse. The treatments were azadirachtin (Azamax® 100, 200 and 300 ml.100L-1), compared with thiamethoxam (Actara 250 WG®, 10 g. 100L-1), lambda-cyhalothrin (Karate Zeon CS 50®, 80 ml .100 L-1) and control (water). The insecticides products were sprayed on strawberry plants infested artificially in the greenhouse. Azadirachtin was equivalent to lambda-cyhalothrin and thiamethoxam to control C. fragaefolli since a second spray is made seven days after the first. The biological persistence of the insecticides lambda-cyhalothrin and thiamethoxam was more than 28 days with a control of 75% of the population of aphids while azadirachtin was less persistent controlling 70% of the population for seven days.
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