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The wettable powder was prepared on the basis of aerial conidia of two isolates of the entomopathognic fungus, Beauveria bassiana. Viability and pathogenicity of conidia products were evaluated against the second-instar larva of Thrips tabaci in four cases; Conidial-product Maintained in Refrigerator (CMR), Conidial-product Maintained in Laboratory (CML), New Formulated Conidia (NFC) and New Conidia without formulation (NC). Analysis of corrected seven-day total mortality data revealed that there were significant differences among these product-cases in their pathogenicity to thrips larvae. Recorded mortality rates for CMR, CML, NFC and NC showed that the pathogenicity of CML was lower compared to three other cases for both isolates. In the next step, inorganic salts (MgCl2, NH4PO4, KH2PO4, MgSO4 and NaCl) were added at a rate of 0.1 M into the both CMR and CML products. Bioassay results indicated that caused total mortality of thrips larvae increased with adding of salts. Our results showed that applied carriers and salts have positively effected preserving of conidia viability and pathogenicity to the second-instar larva of the onion thrips.
Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a major pest of greenhouse crops in Iran. It is one of the major limiting factors affecting yield of cucumber. A study on the biology of this pest was carried out in laboratory condition (25±1°C, 70±5% RH and 16:8 h (L: D) photoperiod) on cucumber (var. Soltan) in 2007. This survey showed that T. tabaci completed the life cycle from 18 to 21 days. Duration of life cycle including egg, L1, L2, prepupa, pupa and adult was 2.82±1.33, 1.95±1.42, 4.12±0.92, 1.03±1.44, 1.97±0.91 and 14.4±3.13 days. Females could produce about 26.82±5.56 eggs. Thrips sex ratio progeny revealed no presence of males, since only females emerged. Knowledge on the biology of this insect pest would contribute to a better understanding of the relationships between the crop and the environment, and knowledge on this insect pest biology would allow establishing control strategies in a future integrated pest management program (IPM).
The western flower thrips, Frankliniella occidentalis (Pergande) attacks a large number of crop plants. The current insecticides have caused resistance in insects and have caused outbreaks of thrips. In many instances, alternative methods of insect management and natural products, offer adequate pest control and pose fewer hazards. Several species of minute pirate bugs of the genus Orius play a significant role in the biological control of a large number of thrips species, such as F. occidentalis. In this study, the insecticidal activity of four ethanolic plant extracts (Cercis siliquastrum L., Calendula officinalis L., Peganum harmala L., Melia azedarach L.) in integration with Orius horvathi (Reuter) were evaluated for controlling F. occidentalis. The present research aimed to find plant extracts with a good impact on F. occidentalis but which have fewer side effects on O. horvathi. The results showed that P. harmala extract can be considered compatible with the natural enemy for controlling thrips. When the predatory bugs O. horvathi, were released three days after P. harmala extract spraying, the integration was more effective. While the P. harmala plant extract plays an important role in thrips control, it is necessary to consider the specified time interval between the application of the P. harmala plant extract and the release of the O. horvathi predatory bugs. The ethanolic extract of M. azedarach caused a balance between the pest population and the natural enemy. This result is very important in an Integrated Pest Management (IPM) program because this ethanolic extract of M. azedarach had lower side effects on the natural enemy. This means that an integration of plant derived chemicals and the natural enemy, O. horvathi, can effectively control thrips.
Two species of syrphids were found in aphid colonies on ornamental plants: Episyrphus balteatus (De Geer) under greenhouse conditions and Scaeva pyrastri (L.) in the field. Among ladybirds the most common in aphid colonies on ornamental plants were Coccinella septempunctata and A. bipunctata (L.), whereas Coccinella quinqepunctata L. and Exochomus quadripustulatus L. appeared rarely. Also the invasive lady beetle – Harmonia axyridis (Pallas) was found on dog-wood for the first time in Skierniewice. Larvae of beetle – Anthribus nebulosus Forster from the Anthribidae family were found under the body of Physokermes piceae – pest of white spruce, later adult individuals were also observed on bushes. Predatory thrips – Scolothrips longicornis Priesner were found for the first time in Poland on white spruce infested by Oligonychus ununguis (Jacobi). On ornamental grasses predatory thrips – Aeolothrips fasciatus (L.). were recorded in sweep-net samples. In coniferous nurseries the following spiders occurred with a high frequency: Araneus diadematus Clerck and Agriope bruennichi (Scopoli, 1772) from Araneidae family. Two other spider species Araneus quadratus (Clerck) from Araneidae family and Nigma walckenaeri (Roewer) from Dictynidae family were also present but rare on deciduous bushes.
Thrips nigropilosus Uzel is a polyphagous species occurring mainly in temperate climates. Its life cycle depends on photoperiodic and temperature conditions. T. nigropilosus feeds on different plant species, but it is considered one of the most serious pests of pyrethrum plants causing serious economic problems. However, several additional agricultural host plants have been affected by T. nigropilosus, including spearmint, cucumber, and lettuce, indicating that this insect can significantly widen its habitats and occurs especially frequently in greenhouses. We report that T. nigropilosus massively attacked Mentha × piperita L. cultivated in greenhouses in central Poland and destroyed the entire mint crops within a short time. The study provided insight into the harmful effect of the thrips and showed that the length of the thrips developmental cycle was reduced with temperature increases from 18 to 26.6°C. The lower threshold temperatures were 13.7, 10.2, 5.0, and 10.1 for eggs, larvae, pupae, and total development, respectively, and the thermal constant for the same developmental stages was 65.9, 90, 132.5, and 284.9-degree days. Both parameters were estimated by linear regression analysis. During our experiment, T. nigropilosus developed by thelytokous parthenogenesis. The morphological and anatomical changes in damaged plants were associated with the fact that the insect began feeding on the lower lamina surface close to the leaf midribs, but no damage to vascular bundles and glandular cells was observed.
Doświadczenie polowe prowadzono w Kruszynie Krajeńskim koło Bydgoszczy w latach 2005–2006. Badano wpływ nawadniania kroplowego w uprawie dwóch odmian dyni zwyczajnej: ‘Danka’ i ‘Sweet Dumpling’ na zasiedlenie przez owady. Na podstawie otrzymanych wyników stwierdzono, że na dyni zwyczajnej odmiany ‘Danka’ występowało istotnie więcej owadów szkodliwych. Z entomofauny fitofagicznej najwięcej wystąpiło przedstawicieli rzędu Homoptera, a wśród nich należących do rodziny skoczkowate. Istotnie więcej osobników wystąpiło na roślinach nawadnianych (44 sztuk x poletko-1), w porównaniu do kontrolnych (34 sztuk x poletko-1). Skoczek ziemniaczak stanowił 65 %, skoczek czarnoplamek – 17 %, a skoczek sześciorek – 7 % wszystkich oznaczonych skoczkowatych. Spośród rzędu Heteroptera wystąpiły zmienik lucernowiec i wysmułek paskorogi oraz pożyteczne (dziubałkowate i zażartkowate). Odmiana ‘Sweet Dumpling’ była również w znacznym stopniu zasiedlana przez owady należące do rzędu pluskwiaków równoskrzydłych – Homoptera. Szczególnie licznie wystąpiły tu skoczkowate: skoczek ziemniaczak stanowił 42%, skoczek czarnoplamek – 32%, a skoczek sześciorek i zgłobik smużkowany po 10 % odłowionej fauny Cicadellidae. Heteroptera pożyteczne i szkodliwe zasiedlały analizowaną dynię nielicznie.
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