Manejo integrado da mosca-branca Bemisia argentifolii.

Historico; Classificacao sistematica, descricao morfologica, biologia e danos; Ecologia; Hospedeiras e febologia; Metodos de controle de pragas; Manejo integrado.

Producción de Paecilomyces fumosoroseus Brown & Smith y evaluación de su efectividad biólogica contra Bemisia argentifolii Bellows & Perring en cultivo de algodón Gossypium hirsutum L.

Tesis (Doctorado en Ciencias con especialidad en Biotecnología) U.A.N.L., Facultad de Ciencias Biológicas, 2007.

Efectos de micotoxicidad de fungicidas sobre formulados de los entomopatogenos Paecilomyces fumosoroseus y Beauveria bassiana utilizados contra la mosquita blanca (Bemisia argentifolii).

Tesis (Doctor en Ciencias con Especialidad en Biotecnología) UANL, 2011.

Preferência para oviposição de Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae) em genótipos de soja, sob condições de campo

Dez genótipos de soja: IAC 100, IAC 74-2832, IAC 90-2971, IAC 78-2318, PI 227687, PI 229358, PI 274454, BR-82 12547, MG/BRS-68 (Vencedora) e FT-5 (Formosa), foram avaliados quanto a resistência, do tipo não-preferência para oviposição, à mosca-branca, Bemisia tabaci (Genn.) biótipo B. O ensaio foi realizado no campo experimental da FCAV/UNESP, Jaboticabal-SP, de outubro de 1999 a janeiro de 2000. Pretendeu-se, ainda, verificar a preferência de oviposição da referida espécie em relação às folhas unifolioladas e trifolioladas, e quanto à posição do folíolo na folha trifoliolada, e estabelecer o número mínimo de folíolos necessários para amostrar adequadamente a oviposição da mosca branca. Constatou-se que a oviposição foi menor nos genótipos BR-82 12547 e IAC 74-2832 em todas as avaliações (15, 30, 45, 65 e 85 dias após a emergência das plantas). As maiores taxas de oviposição ocorreram em IAC 90-2971, IAC 100, PI 227687 e PI 274454. O número médio de ovos depositados por seção de folha pelas fêmeas de B. tabaci biótipo B nas folhas trifolioladas não diferiu significativamente dos obtidos nas unifolioladas, 15 dias após a emergência das plantas (estádios de desenvolvimento entre V3 e V5), em 70% dos genótipos. Quanto à posição dos folíolos, a mosca-branca ovipositou indistintamente sobre os folíolos mediano e laterais. Também o número médio de ovos depositados por área foliar, pela mosca-branca, nos três folíolos da folha trifoliolada não diferiu significativamente da média obtida para dois ou um folíolo desta, o que sugere ser, um folíolo, uma unidade amostral representativa da oviposição de B. tabaci biótipo B em soja.

Resistência de genótipos de soja à mosca branca Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Exigências Térmicas de Bemisia tabaci (Genn.) Biótipo B (Hemiptera: Aleyrodidae)

O desenvolvimento (ovo-adulto) da mosca-branca, Bemisia tabaci (Genn.) biótipo B (=Bemisia argentifolii, Bellows & Perring), foi estudado em condições de campo e em câmaras climatizadas, reguladas nas temperaturas constantes de 15, 20, 25, 30 e 35±1ºC, usando soja, Glycine max (L.) Merrill, cultivar Msoy 8001, como planta hospedeira. O limite térmico inferior de desenvolvimento (Tb) e a constante térmica (K) das fases de ovo, ninfa e ciclo biológico (ovo-adulto) foram 11,1ºC / 98,8 graus-dia, 6,8ºC / 383,8 graus-dia e 8,3ºC / 472,6 graus-dia, respectivamente. Nas temperaturas extremas (15ºC e 35ºC), a viabilidade dos insetos mostrou-se menor. No campo, a emergência de 70% dos adultos ocorreu depois de terem sido acumulados 413,2 graus-dia. O modelo de graus-dia utilizado mostrou-se adequado para a previsão de ocorrência de adultos de Bemisia tabaci biótipo B no campo, podendo também ser utilizado para determinação do número de gerações nas diferentes regiões do País.

Fatores que afetam a oviposição de Bemisia tabaci (Genn.) biótipo B (Hemiptera: Aleyrodidae) em tomateiro

The aim of the present work was to determine the oviposition preference of the silverleaf whitefly on tomato (Lycopersicon esculentum). Preferred plant age and leaflet position on the plant were studied and the number of adults per plant necessary for selecting hosts was determined. Bruna VFN hybrid plants at different ages (30-, 45- and 60-days old) were offered to adult whiteflies in free choice test and 30-day old plants in no-choice test. Leaves were collected from upper and lower part of the plant; the leaflets were divided into three categories: basis (those near the steam of plant), middle and apex (terminal leaflet). The 30-day old plants were more preferred for oviposition in free choice test. In the upper part of the plant, whitefly adults preferred to oviposit on the leaflets at the apex and the middle of the leaves. However, in the lower part of the plant, the basal leaflets were preferred in relation to middle and apex. The densities of 100 or 150 adults per tomato plant were considered adequate for genotypes screening, using no-choice test.

Plant-derived essential oils affecting settlement and oviposition of Bemisia tabaci (Genn.) biotype B on tomato

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) is an economically important pest of tomatoes Solanum lycopersicum (L.), causing irregular ripening on fruits and transmitting several plant pathogenic geminiviruses. The management of this pest is commonly based on repetitive spraying with synthetic pesticides, causing serious environmental damages and increase of resistance by insect population. In the present study, essential oils from the leaves of Artemisia camphorata Vill., Ageratum conyzoides L., Foeniculum vulgare Mill., Lippia alba (Mill.) N. E. Br., Plectranthus neochilus Schltr., and Tagetes erecta L. were investigated for their possible repellent and oviposition-deterrent effects against B. tabaci biotype B on tomato. In a multi-choice assay, P. neochilus essential oil was the most active repellent and oviposition deterrent. Essential oils of A. conyzoides and T. erecta significantly deterred the female B. tabaci biotype B from laying eggs on treated tomato leaflets compared with the control. (E)-Caryophyllene (30.67 %) and the monoterpenes α-pinene (15.02 %) and α-thujene (11.70 %) were identified as the major constituents of the essential oil of P. neochilus. Our findings demonstrated the potential of essential oil of P. neochilus and other oils in the reduction of settlement and oviposition of B. tabaci biotype B on tomato. © 2012 Springer-Verlag Berlin Heidelberg.

Manejo integrado de mosca-branca.

2005

INSECTICIDAL AND BEHAVIORAL EFFECTS OF SECONDARY METABOLITES FROM MELIACEAE ON BEMISIA TABACI (HEMIPTERA: ALEYRODIDAE)

We studied the effects of crude extracts and fractions of Azadirachta indica, Melia azedarach, Toona ciliata and Trichilia pallida on both egg and nymph mortality and embryonic development of Bemisia tabaci B biotype, using tomato plants grown in a greenhouse. Next, we studied the host selection behavioral effects on the adult whitefly under laboratory conditions. The dichloromethane extracts from all plant species and fractions of the extract from branches of T. pallida (EBTPD) and of the extract from leaves of T. ciliata (ELTCD) in dichloromethane caused mortality of nymphs, but neither affected egg viability. However, the branches of the ethanolic extract of A. indica increased the period of embryonic development of the B. tabaci. In addition, the tomato leaflets treated with the fraction of ELTCD dichloromethane (0.28%) were the least preferred by adults, reducing the number of insects resting on the tomato leaflets. The ELTCD methanol and EBTPD dichloromethane fractions inhibited B. tabaci oviposition. Thus, Meliaceae derivatives can contribute to the reduction of the B. tabaci population. The susceptibility of the B. tabaci to Meliaceae derivatives and the relevant behavioral changes of this pest are discussed.

ASSESSING Bemisia tabaci (GENN.) BIOTYPE B RESISTANCE IN SOYBEAN GENOTYPES: ANTIXENOSIS AND ANTIBIOSIS

Since it was first reported in Brazil in the 1990s, the B biotype of silverleaf whitefly (Bemisia tabaci [Genn.], Hemiptera: Aleyrodidae) has been recognized as an important pest in soybeans (Glycine max L.), reducing the productivity of this legume species in some areas of the country. As an alternative to chemical control, the use of resistant genotypes represents an important tool for integrated pest management (IPM). This study evaluated the performance of 10 soybean genotypes prior to whitefly infestation, by testing attractiveness and preference for oviposition in the greenhouse and antibiosis in the laboratory. In a multiple-choice test, 'IAC-17' was the least attractive to insects. In a no-choice test, 'IAC-17' was the least attractive for, egg deposition, indicating the occurrence of non-preference for oviposition on this genotype. Trichome density was positively correlated with the oviposition site and may be associated with the resistance of 'IAC-17' to infestation. The genotypes 'IAC-PL1', 'IAC-19', 'Conquista', 'IAC-24' and 'IAC-17' extended the insect's life cycle, indicating the occurrence of a small degree of antibiosis and/or non-preference for feeding.

Floating row covers and pyriproxyfen help control silverleaf whitefly Bemisia tabaci (Gennadius) Biotype B (Homoptera: Aleyrodidae) in zucchini

In zucchini, the use of row covers until flowering and the insect growth regulator (IGR) pyriproxyfen are effective methods of reducing the number of insects, especially silverleaf whitefly (Bemisia tabaci (Gennadius) Biotype B), on plants. We compared floating row covers (FRCs) up until flowering with silverleaf whitefly (SLW) introduced (FRC + SLW), or not introduced (FRC-only), or with introduction of SLW in open plots (SLW-only), or with introduction of SLW in open plots with IGR (SLW + IGR). FRC increased temperature and humidity compared with the uncovered treatments. Average fruit weight was less (P < 0.01) for the FRC + SLW treatment compared with the other treatments and the percentage of marketable fruit was less for the FRC + SLW than for the other three treatments. This result indicates that the use of either row covers or IGR controls whiteflies, reduces fruit damage and increases the size, weight, and quality of fruit, and may also control other sap-sucking insects. However, if SLW are already present on plants, the use of FRC may reduce predation and favour build up of SLW. Thus, FRC and IGR, if used judiciously, may provide an effective alternative to broad-spectrum pesticides in small-scale cucurbit production.

Sampling and management of Bemisia tabaci (Genn.) biotype B in Australian cotton

Data on seasonal population abundance of Bemisia tabaci biotype B (silverleaf whitefly (SLW)) in Australian cotton fields collected over four consecutive growing seasons (2002/2003-2005/2006) were used to develop and validate a multiple-threshold-based management and sampling plan. Non-linear growth trajectories estimated from the field sampling data were used as benchmarks to classify adult SLW field populations into six density-based management zones with associated control recommendations in the context of peak flowering and open boll crop growth stages. Control options based on application of insect growth regulators (IGRs) are recommended for high-density populations (>2 adults/leaf) whereas conventional (non-IGR) products are recommended for the control of low to moderate population densities. A computerised re-sampling program was used to develop and test a binomial sampling plan. Binomial models with thresholds of T=1, 2 and 3 adults/leaf were tested using the field abundance data. A binomial plan based on a tally threshold of T=2 adults/leaf and a minimum sample of 20 leaves at nodes 3, 4 or 5 below the terminal is recommended as the most parsimonious and practical sampling protocol for Australian cotton fields. A decision support guide with management zone boundaries expressed as binomial counts and control options appropriate for various SLW density situations is presented. Appropriate use of chemical insecticides and tactics for successful field control of whiteflies are discussed.

Pyriproxyfen controls silverleaf whitefly, Bemisia tabaci (Gennadius), biotype B (Homoptera: Aleyrodidae) (SLW) better than buprofezin in bitter melons Momordica charantia L. (Cucurbitaceae)

To improve compatibility between chemical and biological controls, the use of selective insecticides such as insect growth regulators (IGRs) is crucial. In cucurbits, the use of pyriproxyfen (an IGR) has been shown by others to be an effective method of reducing the number of sap-sucking insects, especially silverleaf whitefly, Bemisia tabaci (Gennadius) Biotype B (SLW). Therefore, we compared pyriproxyfen and buprofezin (an IGR) with that of no treatment (control) in a bitter melon crop for the control of populations of SLW and for their effects on fruit production. Pyriproxyfen controlled SLW and tended to have heavier fruits than the control treatment and reduced the abundance of nymphs and exuvia. Buprofezin showed no evidence in controlling SLW compared with the pyriproxyfen and control treatments. Neither pyriproxyfen nor buprofezin had any effect on the number of harvested fruit or overall fruit yield, but the average weight per fruit was higher than the control treatment. Pyriproxyfen was effective in controlling whitefly populations in bitter melons, and both pyriproxyfen and buprofezin may have the potential to increase yield. Their longer-term use may increase predation by natural enemies as they are species-specific and could favour build up of natural enemies of SLW. Thus, the judicious use of pyriproxyfen may provide an effective alternative to broad-spectrum insecticides in small-scale cucurbit production.

Inter-seasonal population dynamics and pest status of Bemisia tabaci (Gennadius) biotype B in an Australian cropping system

Bemisia tabaci, biotype B, commonly known as the silverleaf whitefly (SLW) is an alien species that invaded Australia in the mid-90s. This paper reports on the invasion ecology of SLW and the factors that are likely to have contributed to the first outbreak of this major pest in an Australian cotton cropping system, population dynamics of SLW within whitefly-susceptible crop (cotton and cucurbit) and non-crop vegetation (sowthistle, Sonchus spp.) components of the cropping system were investigated over four consecutive growing seasons (September-June) 2001/02-2004/05 in the Emerald Irrigation Area (EIA) of Queensland, Australia. Based on fixed geo-referenced sampling sites, variation in spatial and temporal abundance of SLW within each system component was quantified to provide baseline data for the development of ecologically sustainable pest management strategies. Parasitism of large (3rd and 4th instars) SLW nymphs by native aphelinid wasps was quantified to determine the potential for natural control of SLW populations. Following the initial outbreak in 2001/02, SLW abundance declined and stabilised over the next three seasons. The population dynamics of SLW is characterised by inter-seasonal population cycling between the non-crop (weed) and cotton components of the EIA cropping system. Cotton was the largest sink for and source of SLW during the study period. Over-wintering populations dispersed from weed host plant sources to cotton in spring followed by a reverse dispersal in late summer and autumn to broad-leaved crops and weeds. A basic spatial source-sink analysis showed that SLW adult and nymph densities were higher in cotton fields that were closer to over-wintering weed sources throughout spring than in fields that were further away. Cucurbit fields were not significant sources of SLW and did not appear to contribute significantly to the regional population dynamics of the pest. Substantial parasitism of nymphal stages throughout the study period indicates that native parasitoid species and other natural enemies are important sources of SLW mortality in Australian cotton production systems. Weather conditions and use of broad-spectrum insecticides for pest control are implicated in the initial outbreak and on-going pest status of SLW in the region.