40 research outputs found
Evaluation of non-linear models to describe development and fertility of codling moth at constant temperatures
Μελετήθηκε η ανάπτυξη των ατελών σταδίων και η γονιμότητα των θηλέων της καρπόκαψας της μηλιάς Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) σε σταθερές θερμοκρασίες. Για την καλύτερη περιγραφή των δύο αυτών βιολογικών παραμέτρων ακολούθησε αξιολόγηση μη γραμμικών μαθηματικών υποδειγμάτων η οποία, εκτός από τον συντελεστή προσδιορισμού (R2) και το άθροισμα τετραγώνων του υπολοίπου (RSS), βασίστηκε επιπλέον και στον προσαρμοσμένο συντελεστή προσδιορισμού (R2adj) και στο πληροφοριακό κριτήριο του Akaike (Akaike information criterion - AIC). Δοκιμάστηκαν οι εξισώσεις των Enkegaard, Αναλυτή, Bieri 1 και Bieri 2, οι οποίες έδειξαν καλή προσαρμογή στα δεδομένα, ιδιαίτερα της ανάπτυξης των ατελών σταδίων [R2, R2adj, RSS και AIC κυμάνθηκαν από 0,9673-0,9917, 0,8601-0,9861, 0,08-6,7x10-4 και (-75,29) – (-46,26) αντίστοιχα]. Η ιδανική θερμοκρασία ανάπτυξης (Topt) και το ανώτερο θερμοκρασιακό όριο (Tmax) υπολογίστηκαν ικανοποιητικά από όλα τα πρότυπα (Topt: 29,9-31,2oC και Tmax: 35,9-36,7oC). Το κατώτερο θερμοκρασιακό όριο (Tmin) υπολογίστηκε ικανοποιητικά από την εξίσωση Bieri-1 (9,9-10,8oC) ενώ υποεκτιμήθηκε από την εξίσωση Αναλυτή (7,0-8,4oC). Στα δεδομένα της γονιμότητας υπήρξε καλύτερη προσαρμογή στους 30oC, (δηλαδή κοντά στην ιδανική θερμοκρασία) [R2 ,R2adj, RSS και AIC κυμάνθηκαν από 0,6966-0,7744, 0,5756-0,6455, 2,44-3,33 x10-4 και (-9,15)-7,15 αντίστοιχα].Developmental rate of immature stages and age-specific fertility of females of codling moth at constant temperatures was modeled using non-linear models. The equations of Enkegaard, Analytis, and Bieri 1 and 2 were evaluated based on the value of adjusted R2 (R2adj) and Akaike information criterion (AIC) besides coefficient of determination (R2) and residual sum of squares (RSS). All models have goodness of fit to data especially for development [R2, R2adj, RSS and AIC ranged 0.9673-0.9917, 0.8601-0.9861, 0.08-6.7x10-4 and (-75.29) – (-46.26) respectively]. Optimum temperature (Topt) and upper threshold (Tmax) were calculated accurately (Topt and Tmax ranged 29.9-31.2oC and 35.9-36.7oC) by all models. Lower temperature threshold (Tmin) was calculated accurately by Bieri-1 model (9,9-10,8oC) whereas Analytis model (7,0-8,4oC) underestimated it. As far as fertility is concerned the respective values were better fitted near the optimum temperature (in 30oC) [R2 ,R2adj, RSS and AIC ranged 0,6966-0,7744, 0,5756-0,6455, 2,44-3,33 x10-4 and (-9,15)-7,15 respectively]
The effect of temperature on the development of Nephus includens (Kirsch) and Nephus bisignatus (Boheman) (Coleoptera: Coccinellidae), predators of Planococcus citri Risso (Hemiptera: Pseudococcidae)
The effect of temperature οη the development of the predators Nephus includens (Kirsch) and Ν. bisignatus (Boheman) (Coleoptera: Coccinellidae), was studied. The development time of immature stages and the pre-oviposition period of adult females for the two predators was recorded at eight constant temperatures (10, 15, 20, 25, 30, 32.5, 35 and 37.5°C). The beetles were reared on eggs, nymphs and female adults of Planococcus citri (Risso) (Homoptera: Pseudococcidae) that had developed on squash (Cucurbita pepo) and on sour orange leaves (CΊtrus aurantium). Using the linear model for the biological cycle of Ν. includens on squash and on sour orange leaves, the developmental zeros (lower temperature thresholds) were estimated to be 10.9 and 11.0°C respectively and the thermal constants, 490.5 and 472.8 day-degrees respectively. Using the Lactin model the lower thresholds were estimated to be 11.1 and 11.2°C respectively and the upper thresholds 36.1 and 36.0°C respectively. For the biological cycle of Ν. bisignatus, using the linear model, the lower thresholds were estimated to be 9.4°C on squash and 9.3°C on sour orange leaves and the thermal constants were 614.3 and 647.9 day-degrees respectively. Using the Lactin model the lower thresholds were estimated to be 9.9 and 1O.0°C respectively and the upper thresholds, 34.7 and 35.0°C respectively. The survival rate of Ν. includens instars at 10, 15, 20, 25, 30, 32.5, 35 and 37.5°C on squash and on sour orange leaves was respectively 0.0, 34.9, 63.2, 70.6, 63.3, 54.5, 19.8, 0.0, and 0.0, 32.2, 61.0, 68.0, 68.3, 56.6, 17.6, 0.0%. The survival rate of Ν. bisignatus instars at 10, 15, 20, 25, 30, 32.5 and 35°C on squash and on sour orange leaves was respectively, 0.0, 39.9, 61.1, 60.7, 47.2, 26.4, 0.0 and 0.0, 35.7, 65.7, 68.0, 44.2, 29.1, 0.0%. The results show that Ν. includens has a shorter biological cycle than Ν. bisignatus, whereas the latter species has lower temperature thresholds
Predicting the Potential Worldwide Distribution of the Red Palm Weevil Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) using Ecological Niche Modeling
This is the publisher's version, also available electronically from http://www.bioone.org/doi/abs/10.1653/024.095.0317.The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae), ranks among the most important pests of various palm species. The pest originates from South and Southeast Asia, but has expanded its range dramatically since the 1980s. We used ecological niche modeling (ENM) approaches to explore its likely geographic potential. Two techniques, the Genetic Algorithm for Rule-set Prediction (GARP) and a maximum entropy approach (MaxEnt), were used. However, MaxEnt provided more significant results, with all 5 random replicate subsamples having P < 0.002 while GARP models failed to achieve statistical significance in 3 of 5 cases, in which predictions achieved probabilities of 0.07 < P < 0.10. The MaxEnt models predicted successfully the known distribution, including the single North American occurrence point of Laguna Beach, California, and various areas where the pest has been reported in North Africa, southern Europe, Middle East and South and Southeastern Asia. In addition, areas where the pest has not been yet reported were found to be suitable for invasion by RPW in sub-Saharan Africa, southern, central and northern America, Asia, Europe, and Oceania. Highly suitable areas in the United States of America were limited mostly to coastal California and southern Florida, while all Caribbean islands were found highly suitable for establishment and spread of the pest
Comunicación corta. Susceptibilidad de Phoenix theophrasti frente a Rhynchophorus ferrugineus y su control mediante el uso de Steinernema carpocapsae en una formulación con quitosano
The invasive red palm weevil, Rhynchophorus ferrugineus Oliv. (Coleoptera: Curculionidae) is the most destructive pest of palms in the world. It has been reported on 19 palm species belonging to 15 different genera. The host status of theCretan Date Palm, Phoenix theophrasti, remains unclear. Therefore, the present study was carried out to ascertain the host status of this protected palm species. Additionally, the efficacy of entomopathogenic nematodes in a chitosan formulation to control this pest in P. theophrasti was assessed. Our results showed that healthy 4-yr-old P. theophrasti palms were not infested by adult females after 9 days exposure in a population density of 3 adults per plant. However, infestation was successful when neonate larvae were artificially introduced in palms. Therefore, natural populations of P. theophrasti could be at risk. Gummy secretion was observed in both naturally and forced infested palms indicating the existence of antibiosis in this species. Curative applications with the entomopathogenic nematode Steinernema carpocapsae in a chitosan formulation in early infested P. theophrasti palms managed to reduce insect’s activity and could help the palms to recover.El picudo rojo de las palmeras, Rhynchophorus ferrugineus Oliv. (Coleoptera, Curculionidae) es la plaga de palmerasmás destructiva del mundo. Se ha citado en 19 especies de palmeras pertenecientes a 15 géneros diferentes. El estatus de la palmera datilera de Creta, Phoenix theophrasti como huésped del picudo rojo no está claro. Este estudio se llevó a cabo para determinar la respuesta de la palmera datilera de Creta frente al ataque de este curculiónido. Además se evaluó la eficacia de una formulación del nematodo entomopatógeno Steinernema carpocapsae con quitosano para su control. Fue imposible infestar palmeras de 4 años de edad con hembras adultas tras 9 días de exposición con 3 hembras por planta. Sin embargo, la infestación fue exitosa cuando las larvas neonatas se introdujeron artificialmente en las palmeras. Por lo tanto, las poblaciones naturales de P. theophrasti podrían estar en riesgo. Se observó una secreción de goma, tanto en las palmeras infestadas de forma natural, como en las forzadas, que indica la existencia de antibiosis. Las aplicaciones curativas con los nematodos entomopatógenos en P. theophrasti redujeron la actividad de los insectos y podrían ayudar a esta especie de palmera en su recuperación
Evaluation of the Entomopathogenic Fungi Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosorosea for Control of Sitophilus oryzae
The entomopathogenic fungi Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosorosea were tested against the stored-grain pest Sitophilus myzae. The fungi were isolated from the soil (from three locations in Attica, Greece: B. bassiana from Tatoion, M. anisopliae from Marathon, and I. fumosorosea from Aghios Stefanos) using larvae of Galleria mellonella as bait. Suspensions of 2.11 x 10(7) and 2.11 x 10(8), 1.77 x 10(7) and 1.77 x 10(8), and 1.81 x 10(7) and 1.81 x 10(8) conidia per ml of B. bassiana, M. anisopliae, and I.fumosorosea, respectively, were applied by three treatments: (i) sprayed on food and set in petri dishes with adults of S. myzae, (ii) sprayed on adults of S. oryzae and set in petri dishes without food, and (iii) sprayed on adults of S. myzae and set in petri dishes with food. The observed mortality of S. oryzae adults during the overall exposure period for the lowest, as well as for the highest, concentrations of B. bassiana, M. anisopliae, and I. fumosorosea ranged from 0 to 100%. Concentration was, in most of the cases tested, a critical parameter that determined the "speed of kill" of the exposed insect species for B. bassiana and M. anisopliae. Conversely, concentration was not that critical for I. fumosorosea, and survival was high in some of the combinations tested, even after 14 days of exposure. Both in the highest and the lowest concentrations of fungi, the mortality of S. oryzae adults was higher when the fungi were applied on adults than when they were applied on food. Higher mortality was observed when food was absent than when food was present, in most of the cases tested. The high efficacy levels recorded in the current study indicate that the tested fungi could be effective biocontrol agents against S. oryzae
Efficacy of alpha-cypermethrin and thiamethoxam against Trogoderma granarium Everts (Coleoptera: Dermestidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae) on concrete
Laboratory bioassays were conducted to evaluate alpha-cypermethrin and thiamethoxam for the control of adults, small larvae and large larvae of the khapra beetle Trogoderma granarium, and the yellow mealworm beetle Tenebrio molitor, on concrete. Factors such as dose (0.025 and 0.1 mg alpha-cypermethrin or thiamethoxam/cm(2)), exposure interval (1, 3 and 7 d), and formulation (alpha-cypermethrin SC and thiamethoxam WG) were evaluated. Apart from immediate assessment at end of exposure, an assessment of delayed mortality was performed with the survivors of the 7-d exposure by removing them from the treated substrate and keeping them on untreated surfaces for 7 more days. After the 7-d exposure, more T. granarium adults were dead on dishes treated with alpha-cypermethrin than with thiamethoxam. Small larvae were generally less susceptible than adults. After 7 d, small larval mortality reached 64.4% for alpha-cypermethrin, while for thiamethoxam it was <6%. Large T. granarium larvae were more tolerant than the small ones. Delayed mortality of T. granarium adults was generally high for both insecticides and doses, and ranged between 43.3 and 63.3% of those that were still alive immediately after the 7-d treatment. For both larval categories, delayed mortality was higher for larvae that had been previously exposed to alpha-cypermethrin, than with thiamethoxam. For T. molitor, after the 7-d exposure, significantly more adults were dead on dishes treated with alpha-cypermethrin than with thiamethoxam. For small larvae mortality was 38.9% at the lowest thiamethoxam dose, but in the other cases ranged between 88.9 and 95.6%. In the case of large larvae, the overall mortality was low in all tested combinations. Regarding delayed mortality of this species, it remained at low levels, for both adults and small larvae. Our results indicate that 7: molitor was more susceptible than T. granarium in both insecticides tested, but alpha-cypermethrin was more effective than thiamethoxam. (C) 2015 Elsevier Ltd. All rights reserved
Short communication. Susceptibility of Phoenix theophrasti (Palmae: Coryphoideae) to Rhynchophorus ferrugineus (Coleoptera: Curculionidae) and its control using Steinernema carpocapsae in a chitosan formulation
The invasive red palm weevil, Rhynchophorus ferrugineus Oliv. (Coleoptera: Curculionidae) is the most destructive pest of palms in the world. It has been reported on 19 palm species belonging to 15 different genera. The host status of theCretan Date Palm, Phoenix theophrasti, remains unclear. Therefore, the present study was carried out to ascertain the host status of this protected palm species. Additionally, the efficacy of entomopathogenic nematodes in a chitosan formulation to control this pest in P. theophrasti was assessed. Our results showed that healthy 4-yr-old P. theophrasti palms were not infested by adult females after 9 days exposure in a population density of 3 adults per plant. However, infestation was successful when neonate larvae were artificially introduced in palms. Therefore, natural populations of P. theophrasti could be at risk. Gummy secretion was observed in both naturally and forced infested palms indicating the existence of antibiosis in this species. Curative applications with the entomopathogenic nematode Steinernema carpocapsae in a chitosan formulation in early infested P. theophrasti palms managed to reduce insect’s activity and could help the palms to recover.El picudo rojo de las palmeras, Rhynchophorus ferrugineus Oliv. (Coleoptera, Curculionidae) es la plaga de palmerasmás destructiva del mundo. Se ha citado en 19 especies de palmeras pertenecientes a 15 géneros diferentes. El estatus de la palmera datilera de Creta, Phoenix theophrasti como huésped del picudo rojo no está claro. Este estudio se llevó a cabo para determinar la respuesta de la palmera datilera de Creta frente al ataque de este curculiónido. Además se evaluó la eficacia de una formulación del nematodo entomopatógeno Steinernema carpocapsae con quitosano para su control. Fue imposible infestar palmeras de 4 años de edad con hembras adultas tras 9 días de exposición con 3 hembras por planta. Sin embargo, la infestación fue exitosa cuando las larvas neonatas se introdujeron artificialmente en las palmeras. Por lo tanto, las poblaciones naturales de P. theophrasti podrían estar en riesgo. Se observó una secreción de goma, tanto en las palmeras infestadas de forma natural, como en las forzadas, que indica la existencia de antibiosis. Las aplicaciones curativas con los nematodos entomopatógenos en P. theophrasti redujeron la actividad de los insectos y podrían ayudar a esta especie de palmera en su recuperación
Susceptibility of "Phoenix theophrasti" (Palmae: Coryphoideae) to "Rhynchophorus ferrugineus" (Coleoptera: Curculionidae) and its control using "Steinernema carpocapsae" in a chitosan formulation: short comunication
The invasive red palm weevil, Rhynchophorus ferrugineus Oliv. (Coleoptera: Curculionidae) is the most destructive
pest of palms in the world. It has been reported on 19 palm species belonging to 15 different genera. The host status of the
Cretan Date Palm, Phoenix theophrasti, remains unclear. Therefore, the present study was carried out to ascertain the host
status of this protected palm species. Additionally, the efficacy of entomopathogenic nematodes in a chitosan formulation
to control this pest in P. theophrasti was assessed. Our results showed that healthy 4-yr-old P. theophrasti palms were not
infested by adult females after 9 days exposure in a population density of 3 adults per plant. However, infestation was
successful when neonate larvae were artificially introduced in palms. Therefore, natural populations of P. theophrasti could
be at risk. Gummy secretion was observed in both naturally and forced infested palms indicating the existence of antibiosis
in this species. Curative applications with the entomopathogenic nematode Steinernema carpocapsae in a chitosan
formulation in early infested P. theophrasti palms managed to reduce insect�s activity and could help the palms to recover.El picudo rojo de las palmeras, Rhynchophorus ferrugineus Oliv. (Coleoptera, Curculionidae) es la plaga de palmeras
más destructiva del mundo. Se ha citado en 19 especies de palmeras pertenecientes a 15 géneros diferentes. El
estatus de la palmera datilera de Creta, Phoenix theophrasti como huésped del picudo rojo no está claro. Este estudio
se llevó a cabo para determinar la respuesta de la palmera datilera de Creta frente al ataque de este curculiónido. Además
se evaluó la eficacia de una formulación del nematodo entomopatógeno Steinernema carpocapsae con quitosano
para su control. Fue imposible infestar palmeras de 4 años de edad con hembras adultas tras 9 días de exposición
con 3 hembras por planta. Sin embargo, la infestación fue exitosa cuando las larvas neonatas se introdujeron artificialmente
en las palmeras. Por lo tanto, las poblaciones naturales de P. theophrasti podrían estar en riesgo. Se observó
una secreción de goma, tanto en las palmeras infestadas de forma natural, como en las forzadas, que indica la existencia
de antibiosis. Las aplicaciones curativas con los nematodos entomopatógenos e
DATA ON PHENOLOGY, PARASITISM AND CONTROL OF CITRUS LEAF MINER, PHYLLOCNISTIS CITRELLA STAINTON (LEPIDOPTERA, GRACILLARIIDAE), IN GREECE
Abstract – Research was conducted to determine whether Phyllocnistis citrella Stainton (Lepidoptera, Gracillariidae) has any preference in attacking either the upper or the lower surface of the leaves of citrus trees. This investigation took place during the year 1999 at Marathon (Attica, Central Greece) while studying the dispersal of P. citrella on the leaves of three different types of citrus trees. Data on the overwintering and parasitism of P. citrella from different areas in Greece are also presented during the years 1999-2002. In addition, the effect of P. citrella infestationon imidacloprid-treated and untreated tangerine trees was comparatively studied. The parasitoids collected were Pnigalio sp. (Hymenoptera, Eulophidae)