Campina Grande, Brazil
Campina Grande, Brazil

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Ramalho F.S.,Biological Control Unit | Azeredo T.L.,Biological Control Unit | Fernandes F.S.,Biological Control Unit | Nascimento Jr. J.L.,Biological Control Unit | And 4 more authors.
Journal of Pest Science | Year: 2011

The study investigated the development, survivorship, and food intake of cotton leafworm Alabama argillacea (Hübner) fed on three cotton cultivars with colored fibers. Significantly shorter larval life-span and higher pupal weight as well as higher survival rates were observed in A. argillacea fed on leaves of BRS Safira and BRS Rubí cotton cultivars compared with the BRS 200 cultivar (BRS = Brazil). Weight gain, feces, and food intake were higher in A. argillacea fed on leaves of BRS Safira compared with the BRS 200 cultivar. The cotton cultivar significantly affected all larval food intake and utilization indices for A. argillacea. The larvae of A. argillacea were more efficient (higher efficiency in converting ingested (ECI) and digested (ECD) food) when fed on leaves of the BRS Safira cultivar in comparison to the BRS 200 cultivar, since the larval phase was shortened and food intake was higher, resulting in a higher growth rate (RGR). However, A. argillacea larvae fed on the leaves of the BRS 200 cultivar, with lower ECI and ECD, exhibited a compensatory response, extending the duration of the larval phase and increasing food intake, resulting in a higher relative metabolic rate. We conclude that BRS Safira provides the best food quality for A. argillacea, BRS 200 the worst, and BRS Rubi plants of intermediate quality. © 2010 Springer-Verlag.

De Sousa Ramalho F.,Biological Control Unit | Azeredo T.L.,Biological Control Unit | De Nascimento A.R.B.,Biological Control Unit | Fernandes F.S.,Biological Control Unit | And 4 more authors.
Entomologia Experimentalis et Applicata | Year: 2011

Studies on insect food intake and utilization are important for determining the degree of insect/plant association and host species' resistance, and also for helping design pest management programs by providing estimates of potential economic losses, techniques for mass breeding of insects, and identifying physiological differences between species. We studied the feeding and development of fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), on transgenic (Bt) and non-transgenic (non-Bt) cotton. The larvae of S. frugiperda fed on Bt cotton had a longer development period (23.0days) than those fed on non-Bt cotton (20.2days). Survivorship of S. frugiperda larvae fed on Bt cotton (74.1%) was lower than that of larvae fed on non-Bt cotton (96.7%). Pupal weight of larvae fed on Bt cotton (0.042g) was lower than that of larvae fed on non-Bt cotton (0.061g). The cotton cultivar significantly affected food intake, feces production, metabolization, and food assimilation by S. frugiperda larvae. However, it did not affect their weight gain. Intake of Bt-cotton leaf (0.53g dry weight) per S. frugiperda larva was lower than the intake of non-Bt-cotton leaf (0.61g dry weight). Larvae fed on Bt-cotton leaves produced less feces (0.25g dry weight) than those fed on non-Bt-cotton leaves (0.37g dry weight). Weight gain per S. frugiperda larva fed on Bt-cotton leaves (0.058g dry weight) was similar to the weight gain for larvae fed on non-Bt-cotton leaves (0.056g dry weight). The cotton cultivar significantly affected the relative growth, consumption, and metabolic rates, as well as other nutritional indices: the figures were lower for larvae fed on Bt-cotton leaves than for larvae fed on non-transgenic cotton leaves. © 2011 The Authors. Entomologia Experimentalis et Applicata © 2011 The Netherlands Entomological Society.

Wang X.,University of California at Berkeley | Johnson M.W.,University of California at Riverside | Yokoyama V.Y.,U.S. Department of Agriculture | Pickett C.H.,Biological Control Unit | Daane K.M.,University of California at Berkeley
BioControl | Year: 2011

Psyttalia lounsburyi (Silvestri) and P. humilis (Silvestri) (Hymenoptera: Braconidae) were evaluated in California for their potential to control the invasive olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae). Psyttalia lounsburyi is a specialist on B. oleae while P. humilis also attacks other tephritid species. Field cage trials, conducted from 2006 to 2009, were used to compare P. lounsburyi and two populations of P. humilis (Kenya and Namibia) in California's interior valley and coastal regions. Both parasitoid species reproduced on B. oleae in all trials. Under similar abiotic conditions, offspring production per female was higher in P. humilis than in P. lounsburyi, suggesting that host specificity by P. lounsburyi does not confer a higher efficiency on B. oleae in cultivated olives. Two abiotic factors were shown to impact parasitoid efficiency. First, adult parasitoid survival was poor during periods of high summer temperatures, common to the olive production areas in California's interior valleys. Second, parasitism levels were lower on B. oleae larvae feeding in larger Ascolano cv. fruit than in smaller Manzanillo cv. fruit. Results are discussed relative to biological control of B. oleae in commercial olives and the usefulness of natural enemies specialized to attack fruit flies in wild olives compared with the larger cultivated olive fruit. © 2010 The Author(s).

Malaquias J.B.,Biological Control Unit | Omoto C.,Escola Superior de Agricultura Luiz de Queiroz | Ramalho F.S.,Biological Control Unit | Wesley W.A.C.,Escola Superior de Agricultura Luiz de Queiroz | Silveira R.F.,Escola Superior de Agricultura Luiz de Queiroz
Journal of Pest Science | Year: 2015

This study sought to provide relevant information for developing effective programs to manage Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) resistance to insecticides by quantifying and describing the interactions between cotton Bt and Podisus nigrispinus (Dallas) (Heteroptera; Pentatomidae) in the management of lambda-cyhalothrin resistance in S. frugiperda fed Bt cotton leaves expressing Cry1Ac (Bollgard, Monsanto, St Louis, MO, USA). These effects were assayed by studying functional responses. Third instar S. frugiperda larvae were used for the following treatments: strains resistant (1) or susceptible (2) to lambda-cyhalothrin fed Bollgard cotton leaves and strains resistant (3) or susceptible (4) to lambda-cyhalothrin fed non-Bt cotton leaves. The predatory behavior of P. nigrispinus females was best represented by a sigmoid curve. The type of P. nigrisinus functional response was not affected by the cotton cultivar or S. frugiperda strain used in the trials. P. nigrispinus females invested a greater amount of handling time (Th) in S. frugiperda larvae that were suseptible to insecticides and fed non-Bt cotton (Th = 1.72 h) compared to those from the insecticide-resistant strain fed with Bt cotton (Th = 1.23 h) or even compared to those that were lambda-cyhalothrin resistant and fed Bt (Th = 1.17 h) or non-Bt cotton (Th = 1.17 h). The results in the present study can be applied in the development of management programs targeting S. frugiperda resistance to pyrethroid lambda-cyhalothrin. The integration of Bt cotton concurrent with biological control by the Asopinae P. nigrispinus is important for successfully managing S. frugiperda resistance to lambda-cyhalothrin. © 2014, Springer-Verlag Berlin Heidelberg.

Fernandes F.S.,Biological Control Unit | Ramalho F.S.,Biological Control Unit | Godoy W.A.C.,University of Sao Paulo | Pachu J.K.S.,Biological Control Unit | And 2 more authors.
Florida Entomologist | Year: 2013

Intercropping fennel (Foeniculum vulgare Mill.) with naturally colored cotton (Gossypium hirsutum L.) may provide a beneficial socioeconomic, ecological and environmental alternative for recuperating agribusiness in fennel and cotton cultivations in northeast Brazil because these crops do not compete for nutrients. The objectives of this study were to investigate the vertical and horizontal distribution of Hyadaphis foeniculi (Pass.) within fennel plants and its population dynamics in fennel crops and fennel intercropped with naturally colored cotton as a function of plant age during 2 fennel seasons by examining plants throughout the entire growing seasons. The vertical and horizontal distributions and the dynamics of the fennel aphids on the monocultured fennel and fennel intercropped with cotton were determined at intervals of 7 days, sampling 5 whole plants per plot from 55 days after transplanting the fennel seedlings until the first harvest (195 days after transplanting). The vertical distribution of apterous or alate aphids on the fennel plants evidenced no significant interactions within the cropping system, plant age, or vertical region of the plant, or between the cropping system and the vertical region of the plant. However for the number of fennel aphids per plant, there was an interaction between cropping system and plant age (apterous aphids) and between plant age and vertical region of the plant (apterous or alate aphids). In the fennel system, the apterous aphid population peaked at 153 and 188 days after transplanting, whereas the alate aphid population peaked at 139 and 174 days after transplanting. In the intercropped fennel/cotton system, the apterous aphid population peaked at 188 days after transplanting, and the alate aphid population peaked at 195 days after transplanting. The numbers of apterous aphids found per fennel plant in the monocultured fennel for the entire study were significantly higher than the numbers found in the fennel-cotton intercropped system. The results of our study are extremely important for understanding the vertical and horizontal distribution of H. foeniculi on fennel plants in both monoculture and the fennel-cotton intercropping system and may be useful in decision-making in relation to implementing controls and determining the timing of population peaks of this important fennel pest.

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