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Indutores de resistência à mosca-branca Bemisia tabaci Biótipo B (GENN., 1889) (Hemiptera: Aleyrodidae) em soja
Moraes, Jair Campos;Ferreira, Ronara Souza;Costa, Rosane Rodrigues;
Ciência e Agrotecnologia , 2009, DOI: 10.1590/S1413-70542009000500009
Abstract: the objective of this paper was to evaluate the effect of the application of inducers on the resistance of two soybean cultivars to the whitefly b. tabaci biotype b. the experiment was carried out at the entomology department - ufla. the soybean seeds of cultivars iac-19 and monsoy-8001 were previously treated with captan fungicide. the following treatments were tested: t1- irrigating the soil around the plants of each pot with 250 ml of solution of 1% silicic acid; t2- spraying of the plants, to the 'point of dripping', with a solution of 0.3% acibenzolar-s-methyl; t3- spraying of the plants, to the 'point of dripping', with a solution of 0.24% pyraclostrobin+epoxiconazole, and t4- control. the plants were infested with 100 adult whiteflies that were released eight days after applying the treatments. the number of eggs on the abaxial face of each leaf, which was marked for further evaluation of nymphs, tannin and lignin contents, dry weight of the aerial parts and roots, was evaluated. there was no difference for the number of eggs and nymphs among the soybean cultivars. nevertheless, the average survival rate of b. tabaci was lower on cultivar iac-19. the application of silicon or acibenzolar-s-methyl induces an increase in lignin content in the soybean cultivar iac-19.
Genetic diversity of Bemisia tabaci (Genn.) Populations in Brazil revealed by RAPD markers
Lima, L.H.C.;Campos, L.;Moretzsohn, M.C.;Návia, D.;Oliveira, M.R.V. de;
Genetics and Molecular Biology , 2002, DOI: 10.1590/S1415-47572002000200016
Abstract: bemisia tabaci (genn.) was considered a secondary pest in brazil until 1990, despite being an efficient geminivirus vector in beans and soybean. in 1991, a new biotype, known as b. tabaci b biotype (=b. argentifolii) was detected attacking weed plants and causing phytotoxic problems in cucurbitaceae. nowadays, b. tabaci is considered one of the most damaging whitefly pests in agricultural systems worldwide that transmits more than 60 different plant viruses. little is known about the genetic variability of these populations in brazil. knowledge of the genetic variation within whitefly populations is necessary for their efficient control and management. the objectives of the present study were to use rapd markers (1) to estimate the genetic diversity of b. tabaci populations, (2) to study the genetic relationships among b. tabaci biotypes and two other whitefly species and (3) to discriminate between b. tabaci biotypes. a sample of 109 b. tabaci female individuals obtained from 12 populations in brazil were analyzed and compared to the a biotype from arizona (usa) and b biotype from california (usa) and paraguay. trialeurodes vaporariorum and aleurodicus cocois samples were also included. a total of 72 markers were generated by five rapd primers and used in the analysis. all primers produced rapd patterns that clearly distinguished the bemisia biotypes and the two other whitefly species. results also showed that populations of the b biotype have considerable genetic variability. an average jaccard similarity of 0.73 was observed among the b biotype individuals analyzed. cluster analysis demonstrated that, in general, brazilian biotype b individuals are scattered independently in the localities where samples were collected. nevertheless, some clusters were evident, joining individuals according to the host plants. amova showed that most of the total genetic variation is found within populations (56.70%), but a significant portion of the variation is found between crop
Genetic diversity of Bemisia tabaci (Genn.) Populations in Brazil revealed by RAPD markers  [cached]
Lima L.H.C.,Campos L.,Moretzsohn M.C.,Návia D.
Genetics and Molecular Biology , 2002,
Abstract: Bemisia tabaci (Genn.) was considered a secondary pest in Brazil until 1990, despite being an efficient geminivirus vector in beans and soybean. In 1991, a new biotype, known as B. tabaci B biotype (=B. argentifolii) was detected attacking weed plants and causing phytotoxic problems in Cucurbitaceae. Nowadays, B. tabaci is considered one of the most damaging whitefly pests in agricultural systems worldwide that transmits more than 60 different plant viruses. Little is known about the genetic variability of these populations in Brazil. Knowledge of the genetic variation within whitefly populations is necessary for their efficient control and management. The objectives of the present study were to use RAPD markers (1) to estimate the genetic diversity of B. tabaci populations, (2) to study the genetic relationships among B. tabaci biotypes and two other whitefly species and (3) to discriminate between B. tabaci biotypes. A sample of 109 B. tabaci female individuals obtained from 12 populations in Brazil were analyzed and compared to the A biotype from Arizona (USA) and B biotype from California (USA) and Paraguay. Trialeurodes vaporariorum and Aleurodicus cocois samples were also included. A total of 72 markers were generated by five RAPD primers and used in the analysis. All primers produced RAPD patterns that clearly distinguished the Bemisia biotypes and the two other whitefly species. Results also showed that populations of the B biotype have considerable genetic variability. An average Jaccard similarity of 0.73 was observed among the B biotype individuals analyzed. Cluster analysis demonstrated that, in general, Brazilian biotype B individuals are scattered independently in the localities where samples were collected. Nevertheless, some clusters were evident, joining individuals according to the host plants. AMOVA showed that most of the total genetic variation is found within populations (56.70%), but a significant portion of the variation is found between crops (22.73%). The present study showed that the B biotype is disseminated throughout the sampled areas, infesting several host plants and predominates over the A biotype.
Resistance of Soybean Genotypes to Bemisia tabaci (Genn.) Biotype B (Hemiptera: Aleyrodidae)
Vieira, SS;Bueno, AF;Boff, MIC;Bueno, RCOF;Hoffman-Campo, CB;
Neotropical Entomology , 2011, DOI: 10.1590/S1519-566X2011000100018
Abstract: the silverleaf whitefly bemisia tabaci (genn.) biotype b has become a serious problem for soybean cultivation because it can significantly reduce soybean productivity. the use of soybean cultivars resistant to whitefly attack is an important strategy in an integrated pest management (ipm) program. this study evaluated the preference for oviposition and colonization by b. tabaci biotype b on different soybean genotypes. in the free-choice test, the genotypes studied were 'iac 17' and 'iac 19' as the standards for resistance and 'iac holambra stwart' as the standard for susceptibility, as well as babr01-0492, babr01-0173, babr01-1259, babr01-1576, babr99-4021hc, babr99-4021hp, 'barreiras', 'conquista', 'corisco', 'brs gralha', pi274454, pi227687, and pi171451. in the no-choice test, the four best genotypes selected in the free-choice test, in addition to the susceptible and resistant standards were evaluated. our data indicated 'barreiras' as the most resistant genotype against b. tabaci biotype b. 'brs gralha', which was the least attractive to whitefly adults in the free-choice test, did not show resistance to insect attack when they were confined in cages in the no-choice test. despite the high number of eggs observed, babr01-1576 and babr99-4021hc showed a reduced number of nymphs, indicating antibiosis. the genotypes with a high level of resistance can be used as a tool against b. tabaci in ipm or as a source of resistance in plant-breeding programs.
Biology of Bemisia tabaci (Genn.) B biotype (Hemiptera, Aleyrodidae) on tomato genotypes
Oriani, Maria Auxiliadora de Godoy;Vendramim, José Djair;Vasconcelos, Cristina Jensen;
Scientia Agricola , 2011, DOI: 10.1590/S0103-90162011000100006
Abstract: brazil is one of the main tomato (solanum lycopersicum) producers worldwide. nevertheless, considerable part of the production is lost due to bemisia tabaci (genn.) b biotype attacks. resistant plants can be an important method for controlling this pest in an integrated pest management. tests for evaluating some biological aspects of b. tabaci were carried out on 18 tomato genotypes, in controlled laboratory greenhouse conditions. thirty-day-old plants placed in plastic cages were infested with 20 whitefly pairs each, for 24 h. the development of at least 30 eggs in three leaflets per plant (repetition) was observed until adult emergence. the development period of insects grown in la1335, pi365928 and la722 genotypes took three days longer when compared to the ones grown in pi134418 (20.3 days). the highest mortality rate of whitefly nymphs occurred in pi365928, la1335 and la722 genotypes (63.8, 54.5 and 53.3%, respectively), and the smallest ones in iac294 and iac68f-22-2 genotypes (4.9 e 6.2%, respectively). la1335, pi365928 and la722 genotypes presented moderate feeding nonpreference and/or antibiosis-based resistance to b. tabaci b biotype.
Development of Bemisia tabaci (Gennadius,1889) biotype B on Lycopersicon spp. genotypes
Marilene, Fancelli;Vendramim, José Djair;
Scientia Agricola , 2002, DOI: 10.1590/S0103-90162002000400007
Abstract: whiteflies are phytophagous insects, whose nymphs and adults suck the phloem sap, causing direct damage due to host plant weakness. in tomato (lycopersicon spp.) crops, they are important vectors of limiting fitoviruses. the objective of this study was to determine the effects of lycopersicon spp. genotypes on bemisia tabaci (gennadius, 1889) biotype b development under greenhouse conditions. the evaluated genotypes were la462 (l. peruvianum), la716 (l. pennellii), la1584 (l. pimpinellifolium), la1609 (l. peruvianum), la1739 (l. hirsutum), p25 (l. esculentum), pi134417 (l. hirsutum f. glabratum) and santa clara (l. esculentum). la716 was non-preferred for oviposition by the whitefly, which suggests an antixenotic effect. la1584 showed an antibiotic resistance because nymphal survival was reduced and nymphal developmental time was increased. antixenotic resistance was observed in la1739 and pi134417, based on a reduction of oviposition. pi134417 also reduced nymphal survival, which suggests an antibiotic effect, but la1739 was suitable for insect development. la1609 was highly preferred for oviposition, however it reduced insect survival. p25 and santa clara (l. esculentum) were highly preferred for oviposition.
Development of Bemisia tabaci (Gennadius,1889) biotype B on Lycopersicon spp. genotypes  [cached]
Marilene Fancelli,Vendramim José Djair
Scientia Agricola , 2002,
Abstract: Whiteflies are phytophagous insects, whose nymphs and adults suck the phloem sap, causing direct damage due to host plant weakness. In tomato (Lycopersicon spp.) crops, they are important vectors of limiting fitoviruses. The objective of this study was to determine the effects of Lycopersicon spp. genotypes on Bemisia tabaci (Gennadius, 1889) biotype B development under greenhouse conditions. The evaluated genotypes were LA462 (L. peruvianum), LA716 (L. pennellii), LA1584 (L. pimpinellifolium), LA1609 (L. peruvianum), LA1739 (L. hirsutum), P25 (L. esculentum), PI134417 (L. hirsutum f. glabratum) and Santa Clara (L. esculentum). LA716 was non-preferred for oviposition by the whitefly, which suggests an antixenotic effect. LA1584 showed an antibiotic resistance because nymphal survival was reduced and nymphal developmental time was increased. Antixenotic resistance was observed in LA1739 and PI134417, based on a reduction of oviposition. PI134417 also reduced nymphal survival, which suggests an antibiotic effect, but LA1739 was suitable for insect development. LA1609 was highly preferred for oviposition, however it reduced insect survival. P25 and Santa Clara (L. esculentum) were highly preferred for oviposition.
Biology of Bemisia tabaci (Genn.) B-biotype and parasitism by Encarsia formosa (Gahan) on collard, soybean and tomato plants
Takahashi, Karina Manami;Berti Filho, Evoneo;Louren??o, André Luiz;
Scientia Agricola , 2008, DOI: 10.1590/S0103-90162008000600011
Abstract: the silverleaf whitefly bemisia tabaci (genn.) b-biotype (= b. argentifolii) (hemiptera: aleyrodidae) is a polyphagous insect attacking many plant species of economic importance. a comparison study was conducted on the duration of the egg-to-adult period, and the percentage of hatching eggs of bemisia tabaci (genn.) b-biotype on collard (brassica oleracea l. var. acephala d.c.), soybean(glycine max (l.) merr.) and tomato (lycopersicon esculentum mill.) plants, as well as the egg-to-adult period of encarsia formosa (gahan) on the 1st, 2nd, 3rd and 4th whitefly nymphal instars on these three plant species. the experiments were conducted in a laboratory (25oc, 70 ± 10% rh, 14-hour photophase). the duration of the egg-to-adult period of b. tabaci was 19.8 days on collard, 21.2 days on soybean and 22.0 days on tomato. the number of hatched eggs was higher on collard when compared to soybean and tomato plants. concerning e. formosa regardless of plant species, the duration for the egg-to-adult period was shorter for the 3rd and 4th instar nymphs as compared with the other instars.
Resistência de genótipos de abobrinha a Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae)
Baldin, Edson L L;Beneduzzi, Ronaldo A;Souza, Douglas R;Souza, Efrain S;
Neotropical Entomology , 2009, DOI: 10.1590/S1519-566X2009000400015
Abstract: field assays were performed to evaluate the attractiveness and the non-preference of whitefly bemisia tabaci (genn.) biotype b for oviposition on squash genotypes (cucurbita pepo) and to observe the susceptibility of genotypes (novita, sandy, caserta cac melhorada, novita plus, samira, bianca, af-2858 and caserta ts) to silverleaf symptoms. the sandy genotype was the least attractive to whitefly, while novita plus, af-2858 and samira were the most attractive. the caserta cac melhorada genotype was the least preferred for oviposition. the sandy and af-2858 genotypes were the most productive, with the highest mean of fruits produced. the lowest silverleaf symptoms index was observed for the sandy and caserta cac melhorada genotypes.
Exigências Térmicas de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae)
ALBERGARIA, NUNO M.M.S.;CIVIDANES, FRANCISCO J.;
Neotropical Entomology , 2002, DOI: 10.1590/S1519-566X2002000300003
Abstract: the development (egg-adult) of bemisia tabaci (genn.) b-biotype (=bemisia argentifolii, bellows & perring), was studied in field conditions and in incubators at constant temperatures (15, 20, 25, 30 and 35±1oc), using soybean, glycine max (l.) merrill, msoy 8001, as host plant. the temperatures threshold (tb) and the thermal constant (k) for egg, nymph and life cycle (egg-adult) were 11.1oc / 98.8 degree-days; 6.8oc / 383.8 degree-days and 8.3oc / 472.6 degree-days, respectively. at the temperatures of 15oc and 35oc, insect viability was smaller. in the field, 70% of the adults emerged after 413,2 degree-day were accumulated. the degree-day pattern used was adequate for the previewing bemisia tabaci b-biotype adult occurrence in field, and it can also be used to determine the number of generations in different areas of the country.
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