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Varikou K.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Birouraki A.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Kontodimas D.C.,Benaki Phytopathological Institute
Annals of the Entomological Society of America | Year: 2010

The developmental biology of Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) on table grape (Vitis spp.) leaves ('Soultanina') was studied at seven constant temperatures15, 17.5, 20, 25, 30, 32.5, and 35°Cunder laboratory conditions. Developmental time and adult longevity were inversely related to temperature. No nymphs hatched from eggs when incubated at 15 and 35°C, whereas no nymphs survived at 32.5°C. The highest egg-to-adult survival (72.09%) was found at 30°C and the lowest (48.80%) at 25°C. The mean total developmental time from egg to adults for females ranged from 39.87 d at 30°C to 112.62 d at 17.5°C. The recorded sex ratio of the offspring was strongly female biased. Adult females lived from 27.64 d at 30°C to 63.70 d at 20°C, whereas males lived 1.667.55 d, respectively. Both linear and nonlinear models adequately described the relationship between temperature and developmental rates for immature stages of P. ficus. Thus, P. ficus required 555.56 degree-days to complete development from egg to adult stage, above a minimum threshold of 11.11°C as estimated by linear regression. The temperature thresholds for all nymph instars of P. ficus, estimated by the linear model, were lower than values that were estimated by the non linear model. The predicted upper lethal temperature was 32.5°C, with a minimum threshold for total development occurring at 14.20°C, as estimated by a nonlinear model. These results may lead to better management of P. ficus by improving predictions of its seasonal appearance. © 2010 Entomological Society of America. Source


Varikou K.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Birouraki A.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Tsitsipis I.,University of Thessaly | Sergentani Chr.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref
Annals of the Entomological Society of America | Year: 2012

The reproductive biology of a citrus pest Pezothrips kellyanus (Bagnall) was studied at four constant temperatures (15, 20, 25, and 30°C) on lemon leaf discs, under laboratory conditions. Lifetime fecundity of mated P. kellyanus was twofold higher at 20 and 25°C than at 15°C. Temperature had no significant effect on fecundity but daily oviposition rate increased as temperature increased. At 15°C, a female of P. kellyanus oviposited 1.13 offspring and at 30°C 5.35 offspring in average per day. Adult longevity was inversely related to temperature. Specifically, female longevity was longest at 15°C (53.90 d) and shortest at 30°C (13.64 d). Preoviposition, oviposition, and postoviposition periods decreased inversely to temperature. Sex ratio was strongly female biased (>60%) at 15 and 25°C. The net reproductive rate (Ro was highest at 15°C and lowest at 30°C. The intrinsic rate of natural increase (rm) as well as the finite rate of increase (λ) were related to temperature and were highest at 30°C. The mean generation time (T) and population doubling time (DT) were inversely related to temperature and were longest at the lowest studied temperature, 15°C. Almost all biological parameters (except preoviposition period) differed significantly between mated and unmated females when were tested at 25°C. The offspring sex ratio was significantly higher at mated than unmated females. Unmated females produced only a few female offspring confirming arrhenotoky in P. kellyanus. © 2012 Entomological Society of America. Source


Varikou K.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Alexandrakis V.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Gika V.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | Birouraki A.,Institute Of Olive Tree And Subtropical Plants Of Chania Nagref | And 2 more authors.
Phytoparasitica | Year: 2013

Population density of adults of Bactrocera oleae (Gmelin) (Diptera: Tephritidae) was obtained from olive trees during a two-year study by means of two different methods, namely, knock down by an insecticide applied as a fog ('sondage') and trap captures (of yellow sticky panels and McPhail traps baited with ammonium). First it was concluded that yellow sticky panel traps give a poor representation of the olive fruit fly population density of the olive grove. Yellow panel trap captures were significantly lower than McPhail's (September) and than the actual population of B. oleae as recorded in olive tree canopy (August of 2008). When only McPhail captures were compared to the olive fruit fly population in the tree canopy, B. oleae captures in McPhail traps represented only a small percentage of the population that was recorded in the olive tree canopy (July and August of 2009). It was estimated that traps captured only 0. 5% of the flies present within a radius of 20 m in the studied field (which consists of approximately 25 trees). However, during autumn (September), low trap captures of B. oleae can occur even when the fly population in the field is near zero. © 2012 Springer Science+Business Media Dordrecht. Source

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