Tabaci Females Research Articles

The Preference of Thrips tabaci for Allium cepa, Allium fistulosum, and Allium roylei

Thrips tabaci Lind. (Thysanoptera: Thripidae) is a key pest of onions worldwide. It causes both direct and indirect damage to onion crops, resulting in high yield losses. Today, the Integrated System of Production and Plant Protection requires onion growers to use onion- thrips-resistant cultivars. It has become apparent that the improvement of existing onion cultivars may not be a sufficient, so it is necessary to search for desirable plant traits related to disease and pest resistance among existing and wild cultivars. For this purpose, we conducted bioassays on the possible preference of T. tabaci for three different cultivars of Allium cepa L., namely, Alibaba, Bila, Tęcza, one cultivar Kroll of Welsh onion, Allium fistulosum L., and the wild species Allium roylei Stearn. The settling preference and the oviposition rate of female onion thrips were evaluated using choice and no-choice laboratory tests, respectively. During the bioassay, on leaf sections of the A. roylei species, a significantly higher number of T. tabaci females was recorded compared to the cv. Tęcza of the A. cepa species and the cv. Kroll of the A. fistulosum species in each observation period. Significantly more thrips settled on cv. Kroll compared to Alibaba and Bila. Regarding the results obtained on A. cepa, significantly fewer females were found on cv. Bila compared to cv. Tęcza. Opposite results were observed in a combination of cvs. Tęcza–Alibaba, where significantly more insects settled on the leaves of cv. Alibaba. Statistically significant differences between cultivars/species were found in the number of hatched larvae on the leaves of the tested cultivars/species of onion. The lowest number of larvae hatched from eggs laid on A. roylei, as compared to A. fistulosum and the cultivars of A. cepa, except for Bila.

Sub-Lethal Effects of Lecanicillium lecanii (Zimmermann)-Derived Partially Purified Protein and Its Potential Implication in Cotton (Gossypium hirsutum L.) Defense against Bemisia tabaci Gennadius (Aleyrodidae: Hemiptera)

Whiteflies, Bemisia tabaci Gennadius (Aleyrodidae: Hemiptera), are a polyphagous economically destructive pest of several solanaceous crops around the world. Many secondary metabolites are synthesized by different biotrophic and necrotrophic fungi which are capable of inducing systemic resistance in plants against various phytophagous pests. The present laboratory work demonstrated the anti-insect impact of a protein extracted and purified partially from an entomopathogenic fungus (EPF) Lecanicillium lecanii (Zimmermann) against B. tabaci. Three different concentrations (i.e., 7.43, 11.15, and 22.31 μg mL−1) of this protein were bioassayed to assess its effect on the fecundity rate of B. tabaci on cotton (Gossypium hirsutum L.) plants. Furthermore, the possible implication of this fungal protein in defense pathways of cotton plants was evaluated by determining the expression profiles of salicylic acid (SA) and jasmonic acid (JA) pathways related to major genes through reverse transcription qPCR (RT-qPCR). According to the results, all protein concentrations exerted a significant (F3, 252 = 62.51; p ≤ 0.001) and negative impact on the fecundity rate of B. tabaci females. At the highest protein concentration (22.31 μg mL−1), the minimum rate of fecundity (i.e., 2.46 eggs female−1day−1) of B. tabaci was noted on the seventh day, whereas fecundity rates for the other two protein concentrations (i.e., 11.15 and 7.43 μg mL−1) were, respectively, 3.06 and 3.90 eggs day−1 female−1. The maximum rate of fecundity (6.01 eggs female−1day−1) was recorded in untreated (control) treatments. In addition, the foliar application of L. lecanii derived protein significantly upregulated all SA linked genes (OPR3, PPO1 and COI1) and slightly triggered up the JA linked genes (LOX1, UBQ7 and AOS) in the cotton plants. These findings revealed that this L. lecanii extracted partially purified protein triggered systemic resistance against B. tabaci in the cotton plants, proposing its putative effectiveness as an innovative biological control technique against B. tabaci and other phloem-feeding hemipteran pests. Nevertheless, further investigations such as purification and molecular and functional characterization of this L. lecanii-derived partially purified protein are required.

Changes in plant responses induced by an arthropod influence the colonization behavior of a subsequent herbivore

Plants in nature can be sequentially attacked by different arthropod herbivores. Feeding by one arthropod species may induce plant-defense responses that might affect the performance of a later-arriving herbivorous species. Understanding these interactions can help in developing pest-management strategies. In tomato, the sweet-potato whitefly Bemisia tabaci and the two-spotted spider mite Tetranychus urticae are key pests that frequently cohabit on the same plant. We studied whether colonization by one species can either facilitate or impede later colonization of tomato plants by conspecific or heterospecific individuals. B. tabaci females showed a strong preference for and increased oviposition on plants previously colonized by conspecifics. In contrast, plants infested with T. urticae repelled B. tabaci females and reduced their oviposition rate by 86%. Although females of T. urticae showed no preference between conspecific-infested or uninfested plants, we observed a 50% reduction in the number of eggs laid on conspecific-infested plants. Both herbivorous arthropods up-regulated the expression of genes involving the jasmonic acid and abscisic acid pathways, increasing emissions of fatty-acid derivatives, but only B. tabaci increased the expression of genes related to the salicylic acid pathway and the total amount of phenylpropanoids released. Terpenoids were the most abundant compounds in the volatile blends; many terpenoids were emitted at different rates, which might have influenced the arthropods' host selection. Our results indicate that B. tabaci infestation facilitated subsequent infestations by conspecifics and mites, while T. urticae infestation promoted herbivore-induced resistance. Based on both the molecular and behavioral findings, a novel sustainable pest-management strategy is discussed.

A Chemosensory Protein BtabCSP11 Mediates Reproduction in Bemisia tabaci.

The olfactory system serves a vital role in the evolution and survival of insects, being involved in behaviors such as host seeking, foraging, mating, and oviposition. Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are involved in the olfactory recognition process. In this study, BtabCSP11, a CSP11 gene from the whitefly Bemisia tabaci, was cloned and characterized. The open reading frame of BtabCSP11 encodes 136 amino acids, with four highly conserved cysteine residues. The temporal and spatial expression profiles showed that BtabCSP11 was highly expressed in the abdomens of B. tabaci females. Dietary RNA interference (RNAi)-based functional analysis showed substantially reduced fecundity in parthenogenetically reproduced females, suggesting a potential role of BtabCSP11 in B. tabaci reproduction. These combined results expand the function of CSPs beyond chemosensation.

Transcriptomic Analysis of Mating Responses in Bemisia tabaci MED Females.

Mating triggers substantial changes in gene expression and leads to subsequent physiological and behavioral modifications. However, postmating transcriptomic changes responding to mating have not yet been fully understood. Here, we carried out RNA sequencing (RNAseq) analysis in the sweet potato whitefly, Bemisia tabaci MED, to identify genes in females in response to mating. We compared mRNA expression in virgin and mated females at 24 h. As a result, 434 differentially expressed gene transcripts (DEGs) were identified between the mated and unmated groups, including 331 up- and 103 down-regulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that many of these DEGs encode binding-related proteins and genes associated with longevity. An RT-qPCR validation study was consistent with our transcriptomic analysis (14/15). Specifically, expression of P450s (Cyp18a1 and Cyp4g68), ubiquitin-protein ligases (UBR5 and RNF123), Hsps (Hsp68 and Hsf), carboxylase (ACC-2), facilitated trehalose transporters (Tret1-2), transcription factor (phtf), and serine-protein kinase (TLK2) were significantly elevated in mated females throughout seven assay days. These combined results offer a glimpe of postmating molecular modifications to facilitate reproduction in B. tabaci females.

Induced Tomato Resistance Against Bemisia tabaci Triggered by Salicylic Acid, β-Aminobutyric Acid, and Trichoderma.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype B is a key pest of Solanum lycopersicum L. (Solanaceae) throughout the world. In this study, we examined the induction of resistance on tomato plants treated with SA, BABA, and Trichoderma either individually or in combination against B. tabaci biotype B through the assessment of some biological and behavioral aspects of this insect pest. Also, to understand the mode of action of these inducers, we correlated and analyzed the biochemical basis of plant resistance, by measuring levels of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia lyase (PAL), and phenolic content in leaves of treated tomato plants. The longest development time of whitefly immature stages was recorded for plants treated with root β-aminobutyric acid application (RBABA) + root Trichoderma application (RT), root salicylic acid application (RSA) + RT, and RT. In a free-choice assay, B. tabaci adults showed a significantly lower preference for settling and oviposition in RBABA + RT, RSA + RT, and RT in comparison with control. In a no-choice assay, B. tabaci females laid significantly fewer eggs on treatments than those in control, with better results observed in RBABA + RT. Plants responded to different treatments and showed higher induction of PPO, POD, and PAL activities, besides the higher accumulation of phenols in RBABA + RT, RSA + RT, and RT treatments. These results suggest that RBABA + RT, RSA + RT, and RT could be utilized for the induction of effective plant defense against B. tabaci.

Effect of a novel repellent, acetylated glyceride, on courtship behaviours and acoustic signals of Bemisia tabaci

AbstractThe sweet potato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), attacks a wide range of vegetables and ornamental plants in the tropics and subtropics. This study involved observations of adult whitefly courtship behaviours to determine the impact of acetylated glyceride treatment, which is currently being developed as a repellent for adults, on their progeny. In addition, the effect of acetylated glyceride treatment on acoustic‐based communication was evaluated, as this type of communication is known to play a pivotal role in the search for mating partners on host‐plant leaves in adult whiteflies. Adults were able to land on grape tomato leaves a few days after treatment, when the residual repellency had dissipated. Almost no male courtship behaviour in terms of searching for sexually mature females was observed throughout the observation period (60 min) under conditions in which adults of both sexes remained on a treated leaf or those in which an adult of either sex remained on a non‐treated leaf. By contrast, these behaviours accounted for 26.5% of the observation time under conditions in which both sexes remained on a non‐treated leaf. In cross‐tests performed for 4 days using one non‐mated female and two non‐mated males, the sex ratio (male/female) of the newly emerged adults on treated leaves (2.4) was 63.6% lower than that of the non‐treated controls (0.9). During courtship, acoustic signals produced by both sexes were exchanged rhythmically on non‐treated leaves, whereas the signals on treated leaves were irregular. The frequency of the vibratory sound produced by males was 66–81% lower on the treated leaves than on the non‐treated leaves. A large reduction in the acoustic signals produced by males on treated leaves caused a decrease in courting pair formation, leading to a significant reduction in the number of female progeny due to arrhenotokous parthenogenesis in virgin B. tabaci females.

Does a multi‐plant diet benefit a polyphagous herbivore? A case study with Bemisia tabaci

AbstractBemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a highly polyphagous herbivore. This research was conducted to compare the development of B. tabaci reared in a multi‐plant treatment (polyculture) with those in single‐plant treatments (monocultures). Adult B. tabaci females fed on a mixture of tomato, cabbage, cotton, cucumber, and kidney bean survived longer and laid more eggs than those fed exclusively on one of these plant species. Egg numbers per plant laid in the polyculture treatment were positively correlated with those laid on the same plant species in the monoculture treatments, and egg numbers per plant laid on tomato, cotton, and cucumber in the polyculture were significantly higher than those laid on the same plants in the monocultures. Concentrations of total protein and trehalose in B. tabaci were not significantly different after 7 days of feeding in the respective treatments, but activities of superoxide dismutases (SOD) and alkaline phosphatase (AKP) of B. tabaci in polyculture were lower than those in monoculture. Conversely, activities of trehalase, sucrase, and amylase in B. tabaci kept in polyculture were higher than those of insects from the monoculture. In each of the monoculture treatments, there was a negative correlation between AKP in B. tabaci and oviposition, and also between AKP and amylase. SOD and sucrase activities in B. tabaci were positively correlated with polyphenol oxidase (PPO) and peroxidase (POD) activities in plants. In the plants damaged by whiteflies in the polyculture treatment, activities of SOD in cucumber, PPO in cotton and kidney bean, and POD in tomato and cucumber were lower than those in the monoculture treatments, whereas SOD in cabbage and catalase (CAT) in tomato in the polyculture treatment were higher than those in the monoculture treatments.

Bemisia tabaci females from the Mediterranean (Q) species detect and avoid laying eggs in the presence of pyriproxyfen, a juvenile hormone analogue

Pyriproxyfen, a juvenile hormone analogue, disrupts embryogenesis, metamorphosis and adult formation in Bemisia tabaci, but does not directly affect adult females. The effect of pyriproxyfen on egg-laying preference and performance of B. tabaci females and the influence of resistance to pyriproxyfen on these reproductive behaviours were studied. Choice experiments utilising cotton plants treated and not treated with pyriproxyfen revealed a significant preference for egg laying on non-treated plants both by resistant and susceptible females. No-choice assays indicated a reduction of ∼60% in the number of eggs laid on pyriproxyfen-treated plants by both resistant and susceptible females. The reduction in oviposition on treated plants was not accompanied with reduced expression of the vitellogenin gene or a delay in oocyte maturation, but significant accumulation of mature oocytes in the ovaries was observed, and could be reversed by transferring the females to non-treated plants. Pyriproxyfen caused reduced oviposition and enhanced mature oocyte accumulation in pyriproxyfen-resistant and pyriproxyfen-susceptible females. These findings can be explained by two alternative mechanisms: pyriproxyfen-regulated physiological arrest of oviposition, involving hormonal regulation of myotrophic factors, or the hierarchy-threshold behavioural theory of host choice, in which pyriproxyfen-treated plants are defined as low-quality hosts. Aspects of application are discussed.

Effect of geomagnetic field on whitefly Bemisia tabaci (Gennadius) flight to the cardinal and halfway directions and their attraction to different colors in Jeddah of Saudi Arabia

Whitefly Bemisia tabaci (Gennadius) is well-known as serious pest on economic plants all over the world. In this study we examine the effect of geomagnetic field on the whitefly B. tabaci flight to the cardinal (north, south, west and east) and halfway (north-east, south-east, north-west and southwest) directions in Jeddah of Saudi Arabia. Also, we studied the effect of geomagnetic field on the attraction of B. tabaci adults to five colors (yellow, orange, green, blue and violet). We found that , B. tabaci females oriented to the cardinal and halfway directions significantly more than males. Also, there were no significant differences in the total numbers of B. tabaci adults attracted to the four main directions. South east was significantly the most halfway direction which B. tabaci attracted to. Statistically, yellow color was significantly the most attractive color, while blue and violet were the least colors preferred by B. tabaci

Odour masking of tomato volatiles by coriander volatiles in host plant selection of Bemisia tabaci biotype B

AbstractThe silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pest insects in tomato crop systems worldwide. It has been previously demonstrated that intercropping tomato [Solanum lycopersicum L. Mill. (Solanaceae)] with coriander [Coriandrum sativum L. (Apiaceae)] reduces the incidence and severity of damage caused by B. tabaci. However, it is not yet known how coriander affects the insect′s behaviour. We evaluated the attractiveness of tomato constitutive volatiles to B. tabaci and what effect coriander constitutive volatiles have on the insect′s behaviour. To this end, we conducted three bioassays in a multiple‐choice four‐arm olfactometer (‘×’ type), measuring B. tabaci behaviour when offered tomato and coriander constitutive volatiles presented alone as well as together. We also evaluated the colonisation and establishment of B. tabaci in experimental plots with only single tomato plants and tomatoes intercropped with coriander in a greenhouse. Bemisia tabaci males and females recognised tomato constitutive volatiles as a positive stimulus (kairomonal effect), indicating that semiochemicals from this plant can play an important role in the insect’s host plant selection. Coriander constitutive volatiles reduced the attractiveness of tomato volatiles but no repellency to these volatiles was observed. Greater numbers of adults and nymphs of B. tabaci per plant were observed in tomato monoculture plots than in tomato intercropped with coriander. We suggest that coriander constitutive volatiles have an odour masking effect on tomato volatiles, thus interfering in the host plant selection of B. tabaci.

Effects of plant essential oils on immature and adult sweetpotato whitefly, Bemisia tabaci biotype B

Effects of essential oils derived from garden thyme, Thymus vulgaris L., patchouli, Pogostemon cablin (Blanco) Benth., and lemon-scent gum, Corymbia citriodora (Hook.) K. D. Hill & L. A. S. Johnson, on mortality of eggs, first-instar nymphs, and pupae, and on adult oviposition, of Bemisia tabaci (Gennadius) biotype B were determined under laboratory conditions. Three concentrations of essential oils, 0.125%, 0.25% and 0.5% (v/v), were applied in contact toxicity experiments. In separate experiments, 0.5% essential oil treatment was tested for repellency. Greater mortality was observed with increasing dose of essential oils. No phytotoxicity was observed on plants treated with these essential oils. First-instar nymphs were more sensitive to essential oil treatments, compared with eggs and pupae. The greatest effect was found with essential oil extracted from T. vulgaris, which reduced the survival rate of B. tabaci by 73.4%, 79.0% and 58.2% after treatment of eggs, nymphs and pupae, respectively, as compared with controls. In no-choice tests, the cumulative survival rates of B. tabaci females treated with T. vulgaris, P. cablin and C. citriodora were 46.4%, 38.8% and 26.8% lower, respectively, as compared with controls. In choice tests, the mean numbers of eggs laid on P. cablin, T. vulgaris and C. citriodora oil-treated plants were 74.5%, 59.0% and 48.0% fewer, respectively, than on control plants. Based on this study, essential oil derived from T. vulgaris possessed the greatest contact toxicity, while P. cablin oil exerted the strongest repellency to B. tabaci. Hence, these two oils could be used as effective and environmentally sustainable bio-insecticides for the control of B. tabaci.

Comportamento de oviposição da mosca-branca Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae) biótipo B em tomateiro

The objective of this work was to evaluate the influence of the leaf surface, the insect geotropic behavior and the type of foliar trichome on Bemisia tabaci (Genn.) biotype B oviposition on tomato leaves. Bemisia tabaci females were confined in acrylic boxes in which tomato leaflets were fixed at the bottom and top part of the boxes to allow insects to access the leaf surface to be tested (adaxial and/or abaxial) in both no-choice and free choice tests. Oviposition was always higher when the leaf was offered at the top of the box and preferably at the abaxial leaf surface. The effects of leaf trichomes (glandular and non glandular) on B. tabaci oviposition was evaluated by offering the abaxial surface of tomato leaflets to females after a 70% ethanol wash to remove glandular exsudates against a control treatment (without a ethanol wash). Oviposition was concentrated mostly near to non glandular trichomes, showing whitefly females can discriminate among the trichomes.

Behaviour-modifying activity of eugenol on Thrips tabaci Lindeman

A series of observational bioassays were conducted to investigate the behavioural responses of the onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), to an application of a secondary plant compound to two different host plants with dissimilar leaf surface characteristics. Eugenol, a phenylpropanoid compound known to deter feeding and oviposition of the onion thrips, was applied to leek (Allium porrum L.) and cucumber (Cucumis sativus L.) at 1% concentration. Using a video system and special software for computing observational data, influences of this plant compound on the behaviour of T. tabaci females were evaluated. Eugenol treatment significantly prolonged the time periods thrips spent being inactive and moving across the treated leek or cucumber surface. The feeding periods on leek leaves treated with eugenol were clearly shorter compared to periods on untreated leek. The behaviours related to oviposition on leaves from both host species treated with eugenol were slightly reduced. T. tabaci females avoided direct contact with eugenol particularly when applied to leek, showing significantly lower contact duration compared to an untreated surface. This shows that behaviour-modifying secondary compounds such as eugenol may be used in various strategies and may contribute to the enhancement of current biological control measures and/or form novel components of Integrated Pest Management strategies.

Twelve new polymorphic microsatellite loci and PCR multiplexing in the whitefly, Bemisia tabaci

Twelve new dinucleotide microsatellite loci of the whitefly, Bemisia tabaci, were obtained from enriched genomic libraries. Three polymerase chain reaction multiplex sets comprising three, five and four loci were optimized and characterized across 133 B. tabaci females from Israeli rearings and natural populations collected in four Mediterranean countries (Tunisia, France, Spain and Morocco). There were three to 24 alleles per locus and the observed heterozygosity was from 0.084 to 0.420. Deviation from Hardy-Weinberg equilibrium was detected at four loci associated with significant heterozygote deficiencies due to null alleles and presence of subpopulations that were mostly in the Tunisian sample. The 12 loci carried independent information.

Differential gene expression in whitefly ( Bemisia tabaci) B-biotype females and males under heat-shock condition

Bemisia tabaci (Insecta, Hemiptera, Aleyrodidae) females are more heat resistant than males, which has important ecological significance in adaptation and expansion of B. tabaci populations. Differentially expressed genes between 25 °C and 44 °C were identified by Suppression Subtractive Hybridization (SSH) in B. tabaci sexes. 50 and 83 differentially expressed Expression Sequence Tags (ESTs) were obtained from female and male libraries, respectively. The ESTs have four functional categories. The frequency of heat stress-related ESTs, metabolism-related ESTs and new ESTs was higher in males than females. However, the percentage of ESTs with unclassified functions was higher in females than males. Furthermore, three differentially expressed genes were further examined by real-time PCR. The results suggested that difference of heat-resistance under heat-shock condition was associated with differentially expressed genes in B. tabaci sexes, which might enable us to better understand the mechanism behind this ecologically important trait.

EFFECT OF TEMPERATURE ON THE DEVELOPMENT AND REPRODUCTION OF BEMISIA TABACI B BIOTYPE (HOMOPTERA: ALEYRODIDAE)

The development, survivorship and reproduction of Bemisia tabaci B bi otype on eggplant at seven constant temperatures (17, 20, 23, 26, 29, 32 and 35℃) were studied. The developmental periods from egg to adult varied from 48.7 days at 17℃ to 13.9 days at 29℃ and the develo pmental threshold estimated for a generation by linear regression was 12.4℃. The optimum temperature for B. tabaci population growth was 26℃, both extremely low (17℃) and high temperature (32℃) delayed the de velopment. Survivorships from egg to adult was 67.3 % at 26℃, 27.6 % and 29.0 % at 35℃ and 17℃ resp ectively. The average longevity of females ranged from 39.6 days at 20℃ to 12.8 days at 35℃. Ovipo sition per female varied from 164.8 eggs at 20℃ to 78.5 eggs at 32℃. Both the longevity and oviposition of B. tabaci females at different temperatures were significantly different ( P 0.05), and the intrinsic rate of natural increase ( r m ) for B. tabaci at 29℃ was the highest.

A differential interaction study of Bemisia tabaci Q‐biotype on commercial tomato varieties with or without the Mi resistance gene, and comparative host responses with the B‐biotype

AbstractThree tomato varieties (Motelle, Ronita, and VFN8) bearing the Mi‐1.2 gene providing resistance to nematodes Meloidogyne spp. and to the potato aphid Macrosiphum euphorbiae Thomas, and three varieties not bearing this gene (Moneymaker, Roma, and Río Fuego), were compared by choice assay for host preference using the Q‐biotype of Bemisia tabaci (Gennadius). The most preferred hosts, determined by infestation levels and numbers of feeding adults were Moneymaker, Río Fuego and Roma, all of which were not carrying the Mi gene. Ronita and Motelle, both of which bore the Mi gene, were the least preferred hosts. In a no‐choice assay, B. tabaci females laid a significantly lower number of eggs on the varieties that carried the Mi gene than on those lacking the gene. Differences were more dramatic when plants carrying the Mi gene were pooled together and compared with pooled plants without this gene. Significantly greater values were obtained for the Mi‐lacking group for all parameters tested. Comparing these results with those from a previous study on the B‐biotype of B. tabaci, Q‐biotypes were found to produce higher daily infestation rates on most of the tomato varieties. When results from plants carrying Mi were pooled, they showed lower infestation levels of Q‐biotypes than B‐biotypes. The Q‐biotype infested less Mi‐plants and more non‐Mi plants than B‐biotype. Q‐biotype females produced significantly less pupae than the B‐biotype females on both groups of plants. These results suggest the existence of an antixenosis and antibiosis‐based resistance to the Q‐biotype of B. tabaci in Mi‐bearing commercial tomato varieties, which is greater than that previously reported for the B‐biotype.

Host species and plant part specificity of the polyphagous onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), in an Australian cotton‐growing area

We determined the pattern of host plant use of Thrips tabaci by surveying wheat and five weed species growing near cotton crops in the area centred on the Namoi Valley, northern New South Wales. Highest densities of T. tabaci females and larvae were found on inflorescences and vegetative parts of turnip weed, Rapistrum rugosum, and lowest on wheat, Triticum aestivum. The other plant species (Paterson’s curse, Echium plantagineum, curled dock, Rumex crispus, Mayne’s pest, Verbena tenuisecta and sowthistle, Sonchus oleraceus) hosted intermediate densities of T. tabaci. The presence of high densities of reproductive T. tabaci on flowering and vegetative parts of turnip weed suggests that this species is a primary host of T. tabaci in the study area.

Host species and plant part specificity of the polyphagous onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), in an Australian cottongrowing area

AbstractWe determined the pattern of host plant use of Thrips tabaci by surveying wheat and five weed species growing near cotton crops in the area centred on the Namoi Valley, northern New South Wales. Highest densities of T. tabaci females and larvae were found on inflorescences and vegetative parts of turnip weed, Rapistrum rugosum, and lowest on wheat, Triticum aestivum. the other plant species (Paterson's curse, Echium plantagineum, curled dock, Rumex crispus, Mayne's pest, Verbena tenuisecta and sowthistle, Sonchus oleraceus) hosted intermediate densities of T. tabaci. the presence of high densities of reproductive T. tabaci on flowering and vegetative parts of turnip weed suggests that this species is a primary host of T. tabaci in the study area.