José V. Oliveira

Efeito de extratos aquosos de plantas no desenvolvimento de Plutella xylostella (L. ) (Lepidoptera: Plutellidae)

The effects of aqueous extracts of different plant species on the development of Plutella xylostella (L.) were studied. Leaf discs of kale cultivar Portuguesa, Brassica oleracea var. acephala, were dipped in each plant extract per 30 seconds. Twelve neonate P. xylostela larvae (<12h) were fed on treated leaf discs and kept in petri dishes. The leaf discs were replaced at two-day intervals by fresh leaf discs treated with the plant extracts. Larvae of P. xylostella which fed on leaf discs treated with Melia. azedarach L. and Cissampelos aff. glaberrima St. Hil. delayed their development by 3.5 and 1.7 days, respectively. However, the other plant extracts studied did not affect larva development. Extracts of Aspidosperma pyrifolium Mart., Azadirachta indica A. Juss., and A. indica oil formulation caused 100% mortality of P. xylostella larvae, while, the extracts of M. azedarach, C. aff.glaberrima, Laurus nobillis L., Prosopis juliflora DC, Croton sp. and Eugenia uniflora L. caused larval mortality of 96.7, 93.3, 83.3, 66.7, 63.3 and 60%, respectively. The other studied extracts did not cause significant larval mortality. Duration of pupae stage was not affected by the studied plant extracts, however, the extracts of M. azedarach, L. nobillis, C. aff. Glaberrima and Croton sp. caused 100, 90, 66.7 and 65% of pupae mortality, respectively.

Biologia comparada e comportamento de Tetranychus urticae Koch (Acari: Tetranychidae) e Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae) em algodoeiro bollgardTM e Isolinha não-Transgênica

The two spotted spider mite, Tetranychus urticae Koch, is a nontarget herbivore of Bt-cotton, but acquires and accumulates higher levels of Cry toxin than that expressed by transgenic plants. This work investigated the development and reproduction of T. urticae and of the predator Phytoseiulus macropilis Banks, during three successive generations looking for potential nontarget effect. In addition, behavioral studies on feeding preference, oviposition, and predation were carried out on Bt and non-Bt cottons. The development and reproduction of T. urticae and P. macropilis was conducted using leaf discs of Bt and non-Bt cottons. Arena containing leaf discs from both cotton types connected by a slide coverslip were also used in the behavioral studies. Averages of the three generations showed that the Bt-cotton does not affect the development, survival of immature stages, and reproductive output of T. urticae and of the predator P. macropilis. Furthermore, the preference for feeding and oviposition of T. urticae and P. macropilis were similar on both cotton types. In addition, P. macropilis exhibited similar predatory behavior on T. urticae fed on both cotton types. Levels of Cry1Ac toxin in T. urticae was 3.97 times greater than that found in the Bt-cotton plants as determined using a ELISA test. Despite of the amount of toxin acquired by the prey (T. urticae), no detectable levels of Cry1Ac were found in the predatory mite P. macropilis.

Morphology of the alimentary canal of Spodoptera frugiperda (J E Smith) Larvae (Lepidoptera: Noctuidae) fed on neem-treated leaves

Research involving plants with insecticide activity evolved significantly in the last decades. Among these plants, the neem tree, Azadirachta indica, is commonly used against several insects, mainly Lepidoptera. The neem efficiency depends on the target insect and on the concentration used. A barrier against potential toxic agents ingested together with the food is the alimentary canal. Thus, this research aimed to describe the histology of the alimentary canal of Spodoptera frugiperda (J E Smith) larvae fed on leaves treated with neem (Neemseto) at a concentration of 0.5% and 1.0% and non treated, at different intervals (48, 96, 144, 192 and 240 h), by quantifying the regenerative cells and analyzing the secretion of the mesenteron histochemically. Larvae were immobilized at low temperatures (-4 degrees C), the alimentary canal was removed, fixed in Boüin s aqueous, embedded in paraplast and historesin, sectioned and stained with hematoxilin-eosin and periodic acid- Schiff. The histology of the alimentary canal of S. frugiperda was similar to other lepidopterans. Neem effects on morphology were seen only in the mesenteron, depending on the time and concentration used, such as: epithelium, reduction on regenerative cells and on the secretory activity in this region, confirmed by the histochemistry in both neem concentrations. These alterations were observed after 96 h at 1.0%, and 144 h at 0.5%. These results indicate that neem (Neemseto), at the concentrations studied, may be effective to control S. frugiperda because it promotes meaningful morphological alterations in the mesenteron.

Repelência de óleos essenciais e pós vegetais sobre adultos de Zabrotes subfasciatus (Boh.) (Coleoptera: Bruchidae) em sementes de feijoeiro

The repellent effect of essential oils and powders from plants on Zabrotes subfasciatus (Boh.) (Coleoptera: Bruchidae) was studied on bean seeds. The number of attracted insects was reduced, and the repellency percentages increased directly with the doses and concentrations of the products used. Cinnamon leaf oil (Cinnamomum zeylanicum Ness) showed repellency percentages of 63.5; 85.4, and 96.2% at 0.5; 2.5, and 5.0 ml/kg of seeds, respectively; the repellency percentages of neem seed oil (Azadirachta indica A. Juss) were 29.6; 76.7, and 89.4%, respectively at the same doses. At 0.5 and 2.5 ml/kg, the repellency percentages of laurel leaf oil (Laurus nobilis L.) were 62.0 and 74.6, respectively. The powders were less repellent than the oils, except for laurel leaf powder at 2.5 and 5.0% with 93.7 and 92.9% of repellency, respectively, followed by cinnamon (51.0; 62.3%), and black peper, Piper nigrum L., (35.9; 45.4). The results showed that the cinnamon, laurel, and neem oils, as well as the laurel leaf powder are promising products for alternative control of Z. subfasciatus in stored bean.

Toxicidade de formulações de nim (Azadirachta indica A. Juss.) ao ácaro-rajado e a Euseius alatus De Leon e Phytoseiulus macropilis (Banks) (Acari: Phytoseiidae)

The toxicity of selected commercial formulations of neem on Tetranychus urticae Koch (Acari: Tetranychidae) and two predatory mites Euseius alatus De Leon and Phytoseiulus macropilis (Banks) was studied. Topical toxicity was tested with the commercial formulations (Natuneem, Neemseto and Callneem) and extract of neems seeds at concentration 1%, compared to the standard acaricide abamectin at concentration of 0.3 ml/L and the control treatment (distilled water). Based on the best performance against T. urticae through topical contact, the formulation Neemseto was selected to be evaluated using different concentrations against eggs, and residual and repellent effects on adults of the mites. Egg treatment consisted of dipping eggs into Neemseto dilutions and control treatment for five seconds. In addition, residual and repellent effects of Neemseto for adult mites consisted of using leaf discs dipped into the dilutions for five seconds. The toxicity of Neemseto on eggs and adults was greater for T. urticae compared to the toxicity observed for the predatory mites. Neemseto was repellent for T. urticae and E. alatus when tested at the concentrations of 0.25, 0.50 and 1.0%, and did not affect P. macropilis. Neemseto using all concentrations, while for the predatory mites significant reduction of mite fecundity was only observed at the largest concentrations reduced the fecundity of T. urticae significantly. So Neemseto, among tested neem formulations, performed better against the twospotted spider mite and exhibited relatively low impact against the predatory mites studied.

Biologia de Amblyseius largoensis (Muma) (Acari: Phytoseiidae), um potencial predador de Aceria guerreronis Keifer (Acari: Eriophyidae) em coqueiro

Aceria guerreronis Keifer is considered one of the main pests of coconuts around the world. Amongst the Phytoseiidae recorded on this crop, Amblyseius largoensis (Muma) has been reported in association with A. guerreronis. In order to verify whether A. largoensis feeds on A. guerreronis, the biology of this predator was evaluated on different food sources, including A. guerreronis. Three types of diet were tested [Tetranychus urticae Koch + castor bean (Ricinus communis L.) pollen + honey at 10%, A. guerreronis + pollen + honey, and only A. guerreronis], determining its development, survivorship, oviposition, sex ratio and longevity at 27oC, 60 ± 5% RH 12 h photophase. Fertility life tables were constructed. The duration of the immature phase was lower when feeding only on A. guerreronis, while fecundity was higher when feeding on a prey + pollen + honey. There was no difference in relation to survivorship of the immature stages between the three diets. Parameters of fertility life tables were higher when the diet included A. guerreronis or T. urticae + pollen + honey, although the predator was able to complete its life cycle and reproduce when feeding exclusively on A. guerreronis. The results suggest that A. largoensis preys upon A. guerreronis under natural condition and that it might play some role in the control of the latter.

Seleção de isolados de fungos entomopatogênicos para o controle de Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) e sua compatibilidade com alguns inseticidas usados na cultura do tomateiro

The activity of Metarhizium anisopliae and Beauveria bassiana towards eggs and larvae of Tuta absoluta (Meyrick) was evaluated. Our data showed that the isolates were pathogenic to both developmental stages tested and the eggs were more susceptible than the 1st instars. The isolates URPE-6 and URPE-19 of M. anisopliae were more pathogenic to eggs and larvae, respectively. The compatibility of these two isolates with the insecticides chlorfenapyr, spinosad, indoxacarb, abamectin, and neem were evaluated. Spinosad and indoxacarb were compatible with the two M. anisopliae isolates in all tested concentrations. At the average recommended concentration, chlorfenapyr was compatible to URPE-6 and abamectin to UFPE-19. The use of entomopathogenic fungi associated with compatible insecticides may be a useful alternative to control T. absoluta.

Potencial de isolados de Metarhizium anisopliae e Beauveria bassiana e do óleo de Nim no controle do pulgão Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae)

This work aimed to determine the efficiency of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana to control the aphid Lipaphis erysimi (Kalt.) (Hemiptera: Aphididae) in kale Brassica oleracea var acephala D.C., as well as their compatibility with a neem oil formulation (Neemseto). Ten isolates of both fungi were tested and the most pathogenic ones were B. bassiana CG001 and M. anisopliae CG30 with 90% and 4.4 days, and 64% and 3.8 days of mortality and median lethal time, respectively. Bioassays with neem at concentrations of 0.5, 1.0 and 2.0% were done either by leaf discs dipping or spraying the aphids on the leaf discs. The neem spraying treatment at 2.0% provided 90% mortality. The use of B. bassiana isolate CG001 or M. anisopliae isolate CG30 with neem at 0.125, 0.25, and 0.5%, demonstrated that these isolates could have their spore viability or colony growth affected when exposed to neem concentrations higher than 0.25%. In absolute values, the isolates B. bassiana CG001 and M. anisopliae CG30 are the most virulent to L. erysimi, and could be utilized in the management of this pest.

Biologia, exigências térmicas e tabela de vida de fertilidade do ácaro-branco Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) em videira (Vitis vinifera L.) cv. Itália

The mite Polyphagotarsonemus latus (Banks) constitutes one of the main pest of grape crop at the Submedio Sao Francisco Valley. The objective of this work was to study the biology of the broad mite Polyphagotarsonemus latus (Banks), to determine its thermal requirements and its fertility life table in grape (Vitis vinifera L.) cv. Italy. Acclimatized chambers (BOD) were used, adjusted to the temperatures of 18, 22, 25, 28 and 32°C, relative humidity of 65 ± 10% and alternated light of 12h. Egg-adult period was 3.4 and 6.8 days for males and 3.5 and 7.4 days for females, respectively at 32oC and 18oC. At the temperatures of 18, 25 and 32oC, each female deposited, respectively, 16.5, 44.3 and 13.3 eggs. The stages of egg, larva and pupa and egg-adult period presented, respectively, thermal thresholds of 11.23, 9.45, 12.19, and 9.71°C and thermal constant of 28.51, 14.59, 8.33, and 62.73 degrees-day. The mean duration of one generation (T) was 25.6, 10.8 and 8.2 days, respectively, at the temperatures of 18, 25 and 32°C. The net reproductive rate (R0) at the temperature of 25°C was the highest, corresponding to an increase of 30.12 times at each generation. The intrinsic rate of population increase (rm) was 0.10 (18°C), 0.31 (25°C) and 0.12 (32°C) and the finite ratio of population increase (l) was 1.10 (18°C), 1.36 (25°C) and 1.13 (32°C). According to the mean temperature values, P. latus can have 95 and 99 generations/year, respectively, for the municipal districts of Petrolina, PE and Juazeiro, BA.

Microscopic Analysis of Spodoptera frugiperda (Lepidoptera: Noctuidae) Embryonic Development Before and After Treatment with Azadirachtin, Lufenuron, and Deltamethrin

ABSTRACT The botanical insecticides, growth regulators, and pyrethroids have an effect on the biology of Spodoptera frugiperda (Smith). However, no emphasis has been given to the effect of these insecticides on embryonic development of insects, in histological level. Thus, this research aimed to examine by light and scanning electron microscopy S. frugiperda eggs and to describe the embryonic development, before and after immersion treatment, using commercial concentrations and lower concentrations than commercial ones, of the compounds lufenuron (Match), azadirachtin (AzaMax), and deltamethrin (Decis-positive control). For light microscopy semithin sections of eggs were used, and for scanning electron microscopy, images of the surface of eggs, treated and untreated with insecticides. The morphological characteristics of S. frugiperda eggs, in general, were similar to those described in the literature for most of the insects in the order Lepidoptera. Spherical eggs slightly flattened at the poles, with chorion, yolk, vitelline membrane, and embryo formation. In both microscopic analysis, we observed that insecticides acted immediately and independent of concentration, resulting absence, or incomplete embryo, presented yolk granules widely dispersed, without vitellophage formation, chorion disintegration, disorganized blastoderm, presenting vacuoles, yolk region with amorphous cells, and formation of completely uncharacterized appendages. Thus, we conclude that the compounds lufenuron and azadirachtin interfere on S. frugiperda embryonic development.