The Experts below are selected from a list of 1518 Experts worldwide ranked by ideXlab platform
Serge Kreiter - One of the best experts on this subject based on the ideXlab platform.
-
An integrative morphological and molecular diagnostics for Typhlodromus Pyri (Acari: Phytoseiidae)
Zoologica Scripta, 2012Co-Authors: Marie-stéphane Tixier, Mireille Okassa, Serge KreiterAbstract:Phytoseiidae species are predators used in biological control programmes to limit mite pests out-breaks in the world. Specific diagnostic is thus very important to ensure the success of pest management. This study aims to determine the species status of populations within the main species in vineyards and orchards: Typhlodromus (Typhlodromus) Pyri, considering four molecular markers (COI, Cytb mtDNAs, 12SrRNA, ITSS) and 34 morphometrical characters. With the three mitochondrial DNA fragments considered, unexpected high genetic distances were observed between two groups, whereas both nuclear DNA and morphological analyses did not show such distinction. Furthermore, the GYMC and the 4 x rule tests emphasised the existence of a single species. Similarly, cross-breeding experiments between specimens of the two groups showed no reproductive incompatibility. Therefore, despite the great intraspecific variation emphasised by the three mtDNA markers, we conclude that all the specimens considered belong to the same species. The present study clearly underlines the difficulty to conclude on species status using only mt markers and genetic distances, and stresses the necessity to apply multiple approaches for species definition. It also shows the confidence of the morphology for delineating this species.
-
suitability of two laboratory testing methods to evaluate the side effects of pesticides on Typhlodromus Pyri scheuten acari phytoseiidae
Pest Management Science, 2008Co-Authors: Romain Bonafos, Philippe Auger, Sabine Guichou, Serge KreiterAbstract:BACKGROUND: Laboratory results of the French ANPP/CEB guideline No. 167 and IOBC/WPRS Ring Testing Group methods for testing the side effects of pesticides on the predatory mite Typhlodromus Pyri Scheuten were compared with respect to their suitability to evaluate the toxicity of three pesticides. RESULTS: Results obtained with the ANPP/CEB guideline allow the demonstration of significant differences between two slightly toxic products, a dichlofluanid 500 g kg−1 kWP (Euparen® 50WP) and a quinoxyfen 250 g L−1 SCC (Legend®), and a highly toxic cymoxanil 60/mancozeb 200/folpet 275 g kg−1 WP [Remiltine F Pepite® (RFP)], on the basis of bioassays conducted in the laboratory. In contrast, results obtained with the IOBC/WPRS method classified all three as harmful. CONCLUSION: The evaluation of the toxicity of RFP revealed that the concentration, the quantity of the wet deposit and the food source used in the IOBC/WPRS method maximise the toxicity, in comparison with those used in the ANPP/CEB protocol. Valid criteria in controls were all respected in the ANPP/CEB tests but not in the IOBC/WPRS samples. This result revealed difficulties related to the use of the IOBC/WPRS method in laboratories. CoPyright © 2007 Society of Chemical Industry
-
Suitability of tow laboratory testing methods to evaluate the side effects of pesticides on Typhlodromus Pyri Scheuten (Acari: Phytoseiidae)
Pest Management Science, 2008Co-Authors: Romain Bonafos, Philippe Auger, Sabine Guichou, Serge KreiterAbstract:BACKGROUND: Laboratory results of the French ANPP/CEB guideline No. 167 and IOBC/WPRS Ring Testing Group methods for testing the side effects of pesticides on the predatory mite Typhlodromus Pyri Scheuten were compared with respect to their suitability to evaluate the toxicity of three pesticides.RESULTS: Results obtained with the ANPP/CEB guideline allow the demonstration of significant differences between two slightly toxic products, a dichlofluanid 500 g kg-1 kWP (Euparen® 50WP) and a quinoxyfen 250 g L-1 SCC (Legend®), and a highly toxic cymoxanil 60/mancozeb 200/folpet 275 g kg-1 WP [Remiltine F Pepite® (RFP)], on the basis of bioassays conducted in the laboratory. In contrast, results obtained with the IOBC/WPRS method classified all three as harmful.CONCLUSION: The evaluation of the toxicity of RFP revealed that the concentration, the quantity of the wet deposit and the food source used in the IOBC/WPRS method maximise the toxicity, in comparison with those used in the ANPP/CEB protocol. Valid criteria in controls were all respected in the ANPP/CEB tests but not in the IOBC/WPRS samples. This result revealed difficulties related to the use of the IOBC/WPRS method in laboratories
-
A genetic analysis of mancozeb resistance in Typhlodromus Pyri (Acari: Phytoseiidae).
Experimental and Applied Acarology, 2005Co-Authors: Philippe Auger, Serge Kreiter, Romain Bonafos, Robert DelormeAbstract:A field population of Typhlodromus Pyri (Acari: Phytoseiidae) tolerant to mancozeb was selected in the laboratory. After 10 mancozeb selections the LC50 value for mancozeb was 73 times higher in the selected-10 strain compared to the standard susceptible strain. A genetic analysis using reciprocal crosses and backcrosses of female F1 progeny found no maternal effect. Resistance in the selected-10 strain was codominant in expression, dominance value was about −0.1. Backcrosses between F1 females and the susceptible strain indicate that the resistance to mancozeb could be principally conferred by a predominant gene, but additional factors would also be involved.
-
mancozeb resistance patterns among kampimodromus aberrans and Typhlodromus Pyri acari phytoseiidae strains from french vineyards
Canadian Entomologist, 2004Co-Authors: Philippe Auger, Romain Bonafos, Serge KreiterAbstract:Des essais de laboratoire ont ete realises avec deux especes de Phytoseiidae pour evaluer leur resistance a un fongicide, le mancozebe. Des populations sensibles et des populations soupconnees de resistance de Kampimodromus aberrans (Oudemans) et Typhlodromus Pyri Scheuten ont ete testees. Les coefficients de resistance sont faibles a moderes et atteignent 6,3 et 11,7 pour K. aberrans et T Pyri, respectivement. La toxicite intrinseque du mancozebe est 5 a 10 fois plus forte pour les femelles de K. aberrant que pour les femelles de T Pyri. La sensibilite au mancozebe de la population de K. aberrans la plus resistante est comparable a celle de la population de T. Pyri la plus sensible. Les CL 50 des populations les plus resistantes de K. aberrans et de t. Pyri sont obtenues respectivement avec des concentrations 4,6 et 43 fois superieures a la dose maximale recommandee de mancozebe pour lutter contre le mildiou de la vigne. Une enquete realisee sur un nombre limite de parcelles de vigne, en utilisant une concentration diagnostique de mancozebe, tend a montrer que la majorite des populations de K. aberrans testees sont sensibles a ce fongicide, seules quelques unes comportant des individus sensibles et des individus resistants en melange. Toutes les populations de T Pyri echantillonnees en Bourgogne sont sensibles au mancozebe. La moitie des populations echantillonnees dans le Bordelais est sensible, l'autre moitie correspond a des populations resistantes ou composees d'un melange d'individus sensibles et resistants.
B.a. Croft - One of the best experts on this subject based on the ideXlab platform.
-
intra and interspecific predation by adult female metaseiulus occidentalis and Typhlodromus Pyri acari phytoseiidae when provisioned with varying densities and ratios of tetranychus urticae acari tetranychidae and phytoseiid larvae
Experimental and Applied Acarology, 1997Co-Authors: Ian V Macrae, B.a. CroftAbstract:The phytoseiid mites Metaseiulus occidentalis (Nesbitt) and Typhlodromus Pyri Schueten are used together and alone as biological control agents against tetranychid pest mites of apple. Their effectiveness as control agents may be impacted by intraguild predation. The effects of prey species and prey density on the rates of inter- and intraspecific predation and oviposition by these two predators were investigated through a series of experiments. Adult female predators were given prey as mixed populations of phytoseiid larvae and larvae of a more preferred species, the spider mite, Tetranychus urticae Koch, at different densities and ratios. Typhlodromus Pyri, more of a generalist predator, showed higher rates of predation and cannibalism on phytoseiid immatures at most prey densities and ratios. Manly preference indices indicated that T. Pyri switched to feed on phytoseiid larvae at higher prey levels and ratios of T. urticae than M. occidentalis. This greater ability to use phytoseiid larvae as prey may help stabilize T. Pyri populations when more preferred prey is unavailable. This may, in part, explain the observed persistence of T. Pyri populations when M. occidentalis populations were decreasing in orchard test plots.
-
Intra- and interspecific predation on four life stage groups by the adult females of Metaseiulus occidentalis, Typhlodromus Pyri, Neoseiulus fallacis and Amblyseius andersoni
Experimental & Applied Acarology, 1996Co-Authors: B.a. CroftAbstract:Do adult females of oligophagous species such as Neoseiulus fallacis (Garman) and Metaseiulus occidentalis (Nesbitt) show less intra- and interspecific predation on phytoseiids when other foods are scarce than polyphagous species such as Amblyseius andersoni Chant and Typhlodromus Pyri Scheuten? We caged single adult females of each species without food with ten of their own eggs or larvae, with ten eggs or larvae of the other species or with ten nymphs or adult females of M. occidentalis ( T. Pyri for M. occidentalis ). We assessed the ambulatory activity, survival time, egg levels and prey loss in each test. Polyphages (in particular T. Pyri ) lived longer than oligophages (in particular N. fallacis ) without food. The small T. Pyri detected its own stages and benefited most by feeding on small active stages of other species. Amblyseius andersoni , the largest mite, fed and gained the most of any species when held with nymphs and female adults. Metaseiulus occidentalis fed on eggs of all four species to enhance survival. The large hyperactive N. fallacis gained the least from these behaviours. Each mite seemed uniquely adapted to survive conditions of scarce prey and these behaviours may explain their roles in phytoseiid mite complexes. Overall, oligophagous adult females fed less and gained less by feeding on phytoseiids than did polyphagous adult females.
-
differential impact of egg predation by zetzellia mali acari stigmaeidae on metaseiulus occidentalis and Typhlodromus Pyri acari phytoseiidae
Experimental and Applied Acarology, 1996Co-Authors: Ian V Macrae, B.a. CroftAbstract:The differential impact of Zetzellia mali on the phytoseiids Metaseiulus occidentalis and Typhlodromus Pyri was studied in the laboratory and by analysis of population from orchard plots that contained either phytoseiid, similar numbers of prey mites and high or low densities of Z. mali. Five hypotheses were evaluated to explain why Z. mali had more impact on M. occidentalis in the field than on T. Pyri. Given equal opportunity, Z. mali adult females did not consume more M. occidentalis eggs than T. Pyri eggs nor did adult females of either phytoseiid inflict greater mortality on Z. mali eggs or larvae through attack or consumption. There was no difference in the within-tree association of Z. mali adult females with eggs of either phytoseiid species nor were there differences in the way prey mites (all life stages) were spatially partitioned between adult female Z. mali as compared with adults and deutonymphs (combined) of either phytoseiid. The foraging area of adult female Z. mali and the oviposition locations of the two phytoseiids from both field and laboratory data were compared using spatial statistics. Metaseiulus occidentalis laid significantly more eggs in the primary foraging area of adult female Z. mali than T. Pyri. This was the only factor identified which may explain the greater impact of Z. mali on M. occidentalis. The impact of these interspecific effects on the persistence of predatory mite guilds and biological control are discussed.
-
Walking, feeding and intraspecific interaction of larvae of Metaseiulus occidentalis, Typhlodromus Pyri, Neoseiulus fallacis and Amblyseius andersoni held with and without eggs of Tetranychus urticae
Experimental & Applied Acarology, 1994Co-Authors: B.a. Croft, Z Q ZhangAbstract:Larvae of Metaseiulus occidentalis (Nesbitt), Typhlodromus Pyri Scheuten, Neoseiulus fallacis (Garman) and Amblyseius andersoni Chant exhibited different activity levels when held on apple leaf or on tile arenas and given or not given eggs of Tetranychus urticae Koch and water (tiles only). M. occidentalis larvae held without prey exhibited high levels of walking (includes searching) during 24 hours of evaluation, whereas M. occidentalis larvae held with prey fed quickly and then became less active. Fed larvae of M. occidentalis were less active on leaves than tile. Larvae of T. Pyri on leaves had a very low frequency of walking, almost never fed and quickly assumed a resting position during development. While much less active than M. occidentalis , fed and unfed T. Pyri larvae walked more on tiles than leaves before resting. Larvae of N. fallacis and A. andersoni fed at low rates and were similarly active on tiles and leaves. Free water increased walking by M. occidentalis, A. andersoni and T. Pyri on tile but not N. fallacis. M. occidentalis larvae interacted 5–7 times more often than larvae of the other three species. Cannibalism or scavenging was rarely seen and then only for M. occidentalis larvae. Larvae of all four mites walked, fed and interacted much more in the first 12 hours than the second 12 hours of tests, except unfed M. occidentalis . Unfed M. occidentalis larvae did not molt to protonymphs but unfed larvae of the other three species did. Unfed and fed protonymphs of all four species walked more at 4 hours after molting than larvae at 12–24 hours. Unfed and fed protonymphs of T. Pyri or A. andersoni had similar walking frequencies, but unfed protonymphs of N. fallacis were more active than fed ones. Trends in larval activities are discussed relative to the life history of each species.
-
larval survival and feeding by immature metaseiulus occidentalis neoseiulus fallacis amblyseius andersoni and Typhlodromus Pyri on life stage groups of tetranychus urticae koch and phytoseiid larvae
Experimental and Applied Acarology, 1993Co-Authors: B.a. Croft, M B CroftAbstract:When 20 newly hatched larvae either of Metaseiulus occidentalis (Nesbitt), Neoseiulus fallacis (Garman), Amblyseius andersoni Chant or Typhlodromus Pyri Scheuten were held in arenas without food at 95% RH and 20°C, the percentages of mites surviving to protonymphs were 5.0, 81.3, 86.3, and 83.8%, respectively. Unfed M. occidentalis larvae starved within 2–3 days, while immatures of the other three species lived up to 12–14 days, with some becoming adults by cannibalizing and/or scavenging. Phytosciid larvae given eggs, larvae/protochrysalis/protonymphs (L/P), deutochrysalis/deutonymphs (D) or teleiochrysalis/female adult (T/A) of Tetranychus urticae Koch, fed at different incidences during 6 h tests. Larvae of T. Pyri never fed, but almost all larvae of M. occidentalis fed on eggs and L/Ps and 60–70% of M. occidentalis larvae fed on Ds and T/As. N. fallacis and A. andersoni larvae fed at incidences from 20–75% depending on the stage of spider mite given. Larvae fed more commonly on eggs and L/Ps than Ds and T/As for M. occidentalis and N. fallacis but not A. andersoni. Protonymphs and deutonymphs of all four species, readily fed on T/As after 3 h of exposure, but incidences were higher for A. andersoni and T. Pyri. Feeding on phytoseiid larvae by protonymphs and deutonymphs also was more common for A. andersoni and T. Pyri. Except for M. occidentalis, deutonymphs fed more than protonymphs on phytoseiid larvae. Results are discussed in relation to individual species ‘life histories and the value of these traits in predicting a species’ role in a biological control system.
Ian V Macrae - One of the best experts on this subject based on the ideXlab platform.
-
intra and interspecific predation by adult female metaseiulus occidentalis and Typhlodromus Pyri acari phytoseiidae when provisioned with varying densities and ratios of tetranychus urticae acari tetranychidae and phytoseiid larvae
Experimental and Applied Acarology, 1997Co-Authors: Ian V Macrae, B.a. CroftAbstract:The phytoseiid mites Metaseiulus occidentalis (Nesbitt) and Typhlodromus Pyri Schueten are used together and alone as biological control agents against tetranychid pest mites of apple. Their effectiveness as control agents may be impacted by intraguild predation. The effects of prey species and prey density on the rates of inter- and intraspecific predation and oviposition by these two predators were investigated through a series of experiments. Adult female predators were given prey as mixed populations of phytoseiid larvae and larvae of a more preferred species, the spider mite, Tetranychus urticae Koch, at different densities and ratios. Typhlodromus Pyri, more of a generalist predator, showed higher rates of predation and cannibalism on phytoseiid immatures at most prey densities and ratios. Manly preference indices indicated that T. Pyri switched to feed on phytoseiid larvae at higher prey levels and ratios of T. urticae than M. occidentalis. This greater ability to use phytoseiid larvae as prey may help stabilize T. Pyri populations when more preferred prey is unavailable. This may, in part, explain the observed persistence of T. Pyri populations when M. occidentalis populations were decreasing in orchard test plots.
-
differential impact of egg predation by zetzellia mali acari stigmaeidae on metaseiulus occidentalis and Typhlodromus Pyri acari phytoseiidae
Experimental and Applied Acarology, 1996Co-Authors: Ian V Macrae, B.a. CroftAbstract:The differential impact of Zetzellia mali on the phytoseiids Metaseiulus occidentalis and Typhlodromus Pyri was studied in the laboratory and by analysis of population from orchard plots that contained either phytoseiid, similar numbers of prey mites and high or low densities of Z. mali. Five hypotheses were evaluated to explain why Z. mali had more impact on M. occidentalis in the field than on T. Pyri. Given equal opportunity, Z. mali adult females did not consume more M. occidentalis eggs than T. Pyri eggs nor did adult females of either phytoseiid inflict greater mortality on Z. mali eggs or larvae through attack or consumption. There was no difference in the within-tree association of Z. mali adult females with eggs of either phytoseiid species nor were there differences in the way prey mites (all life stages) were spatially partitioned between adult female Z. mali as compared with adults and deutonymphs (combined) of either phytoseiid. The foraging area of adult female Z. mali and the oviposition locations of the two phytoseiids from both field and laboratory data were compared using spatial statistics. Metaseiulus occidentalis laid significantly more eggs in the primary foraging area of adult female Z. mali than T. Pyri. This was the only factor identified which may explain the greater impact of Z. mali on M. occidentalis. The impact of these interspecific effects on the persistence of predatory mite guilds and biological control are discussed.
-
influence of temperature on interspecific predation and cannibalism by metaseiulus occidentalis and Typhlodromus Pyri acarina phytoseiidae
Environmental Entomology, 1993Co-Authors: Ian V Macrae, B.a. CroftAbstract:Interspecific predation and cannibalism and associated rates of oviposition were assessed for adult female Metaseiulus occidentalis (Nesbitt) and Typhlodromus Pyri Scheuten when provided nonlimiting amounts of either eggs, larvae, protonymphs, or deutonymphs. Tests with all four stages of phytoseiids and larvae of Tetranychus urticae Koch were carried out at 25°C. At 15 and 12.5°C, only larvae of phytoseiids and larvae of T. urticae were prey items. Predation by T. Pyri was higher than by M. occidentalis at 12.5 and 15°C but more similar at 25°C. M. occidentalis did not feed appreciably on phytoseiid larvae at 15 and 12.5°C. Neither phytoseiid oviposited at 12.5°C when fed phytoseiid larvae, but T. Pyri did at 15°C. We concluded that T. Pyri was a more active predator at low temperatures. Early-season predation on M. occidentalis immatures by T. Pyri could contribute to displacement of M. occidentalis from apple orchards in western Oregon.
-
biological control of apple mites impact of zetzellia mali acari stigmaeidae on Typhlodromus Pyri and metaseiulus occidentalis acari phytoseiidae
Environmental Entomology, 1993Co-Authors: B.a. Croft, Ian V MacraeAbstract:Zetzellia mali (Ewing) feeds on and is fed upon by Typhlodromus Pyri Scheuten and Metaseiulus occidentalis (Nesbitt), especially when phytophagous mites are scarce on apple foliage. These mites interact indirectly through competition for prey. Probably because of both indirect and direct effects, T. Pyri was less dense and M. occidentalis was much less dense in plots with Z. mali than in plots where Z. mali was suppressed by endosulfan. M. occidentalis also had less effect on Z. mali than T. Pyri . Biological control of Panonychus ulmi (Koch) and Aculus schlechtendali Nalepa was effective where Z. mali occurred alone at high levels or with either or both phytoseiids. Plots that received mixed T. Pyri–M. occidentalis had effective control of pest mites with or without Z. mali. Z. mali displaced M. occidentalis and controlled pest mites in plots with M. occidentalis only. In plots with T. Pyri only, dominance of T. Pyri or Z. mali was mixed—most often near equal levels occurred, but sometimes one or the other dominated. In mixed plots T. Pyri displaced M. occidentalis in 1991, but interactions between T. Pyri and Z. mali in 1992 were like those in plots with T. Pyri only. Releases of 25–50 M. occidentalis and 200–300 P. ulmi into trees with many Z. mali did not allow for establishment of M. occidentalis , but establishment readily occurred where few Z. mali were present. Management of M. occidentalis, T. Pyri, Z. mali , and pest mites is discussed in relation to long-term biological control.
-
persistence of Typhlodromus Pyri and metaseiulus occidentalis acari phytoseiidae on apple after inoculative release and competition with zetzellia mali acari stigmaeidae
Environmental Entomology, 1992Co-Authors: B.a. Croft, Ian V MacraeAbstract:Biological control of European red mite, Panonychus ulmi (Koch), and apple rust mite, Aculus schlechtendali (Nalepa), varied in 1991 in 20 prey-predator treatment plots after Single and mixed releases of Metaseiulus occidentalis (Nesbitt) and Typhlodromus Pyri Scheuten were made in 1990. Control of spider mites in 1991 was better in mixed-species than in single-species release plots. M. occidentalis was the dominant phytoseiid in mixed-species release plots in 1990, but T. Pyri was more common in 1991. In fall, eggs of M. occidentalis disappeared before eggs of T. Pyri did. In spring, eggs of T. Pyri appeared first. Oviposition by M. occidentalis may have been slowed by cool weather and limited use of pollen as food. With few prey present, competition favored T. Pyri , and M. occidentalis eventually disappeared from mixed-, but not from single-species plots. M. occidentalis was more affected by Zetzellia mali (Ewing) than was T. Pyri , but T. Pyri had more impact on populations of this stigmaeid mite. Competition by Z. mali with the phytoseiids may cause negative and pOSitiveeffects on biological control. The two phytoseiids have complementary traits that allow them to control pest mites together, but their management may be complicated by interspecific competition.
Philip J. Lester - One of the best experts on this subject based on the ideXlab platform.
-
Release, establishment, and movement of the predator Typhlodromus Pyri (Acari : Phytoseiidae) on apple
Canadian Entomologist, 2001Co-Authors: Howard M. A. Thistlewood, Philip J. LesterAbstract:Dans les vergers de pommiers [Malus × domestica Mill (Rosaceae)] d'Ontario, l'utilisation de certains pesticides tue les acariens phytoseiides predateurs, ce qui declenche des infestations d'acariens phytophages. Nous avons relâche des acariens predateurs Typhlodromus Pyri Scheuten (Acari: Phytoseiidae) provenant d'une souche de Nouvelle-Ecosse resistante aux pyrethroides et aux oganophosphates dans des vergers adjacents de McIntosh' et de Rouges delicieuses et les avons observes pendant quatre saisons. Les acariens T. Pyri de la souche se sont etablis dans les vergers ou ils sont devenus les predateurs principaux et ils etaient associes a de faibles densites des acariens phytophages Panonychus ulmi Koch et Tetranychus urticae Koch (Acari: Tetranychidae) et Aculus schlechtendali (Nalepa) (Acari: Eriophyidae). Les acariens se deplacaient avec lenteur et ils ont mis 4 ans a atteindre le 28 e arbre (84 m) depuis leurs points de relâchement dans les deux vergers. La direction predominante du vent ne semble pas avoir influence les deplacements. Chaque ete, apres le relâchement, les acariens etaient presents en grands nombres sur les arbres de relâchement et les arbres voisins, contrairement a d'autres especes predatrices, notamment Typhlodromus caudiglans (Schuster) (Acari Phytoseiidae), Amblyseius fallacis (Garman) (Acari: Phytoseiidae) et Zetzellia mali (Ewing) (Acari: Stigmaeidae). Cette espece semble particulierement utile dans la lutte biologique contre les acariens phytophages en Ontario et il vaut la peine de la tester davantage pour la conservation et en prevision de relâchements plus importants.
-
the transfer of Typhlodromus Pyri on grape leaves for biological control of panonychus ulmi acari phytoseiidae tetranychidae in vineyards in ontario canada
Biological Control, 2001Co-Authors: D B Marshall, Philip J. LesterAbstract:The phytophagous mite Panonychus ulmi Koch has become a significant problem in Ontario vineyards. We attempted to introduce and establish populations of the predatory mite Typhlodromus Pyri Scheuten for P. ulmi biological control. Grape leaves were transferred from a vineyard containing T. Pyri in early summer 1998, by picking leaves from a donor vineyard and attaching them onto leaves in the release vineyard where T. Pyri were extremely rare. Two release treatments were used with rates of 8.5 (13) and 25.5 (33) mobiles per vine. In the first season, T. Pyri established in similar densities in both release treatments, which were significantly higher than controls. However, there were no differences among treatments in P. ulmi densities in 1998 as a result of predator release. During summer 1999, significantly fewer P. ulmi mite-days were observed in release plots compared to the control. Amblyseius fallacis (Garman) was common throughout the release vineyard in 1998 and in 1999, but appeared on the vines too late in the season to maintain low P. ulmi densities. T. Pyri appeared to out-compete A. fallacis in 1999 because A. fallacis densities were significantly lower in plots where T. Pyri had been released than in control plots. We conclude that T. Pyri can be effective for P. ulmi biological control in Ontario vineyards and may be introduced by transferring leaves. In Europe, transferring prunings has been the standard method of inoculating T. Pyri into new vineyards. Here we show that transferring leaves is another practical method. © 2001 Academic Press
I A Khan - One of the best experts on this subject based on the ideXlab platform.
-
Seasonal population dynamics of Typhlodromus Pyri Scheuten (Acari, Phytoseiidae) in apple orchards in the region Meckenheim
Journal of Pest Science, 2005Co-Authors: I A Khan, M. FentAbstract:Typhlodromus Pyri Scheuten (Acari, Phytoseiidae) has been reported as the most important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture. However, biological data on T. Pyri was insufficient on important parameters like seasonal population dynamics and within-tree and on-leaf distribution in apple orchards in the region of Meckenheim, Germany. The purpose of the present work was, therefore, to obtain experimental data on these parameters of T. Pyri from 2000 to 2002 in the apple orchards in this region. The results showed that overwintered females of T. Pyri reactivate and start laying eggs between late March and early April. The mean daily number of the different stages of T. Pyri per leaf peaked in July each year, where it ranged between 0.92–1.68 eggs, 0.81–1.41 nymphs, 0.64–1.32 females and 0.37–0.52 males. A significantly higher number of T. Pyri individuals congregated in the bottom layer of trees (0.34–0.64 individuals/leaf) than in the middle and top layers (0.23–0.38 and 0.12–0.23 individuals/leaf, respectively). We found that 91.4–94.1% of the total eggs, 89.6–91.7% larvae, 73.0–76.5% nymphs, 60.5–64.6% adult females and 52.6–55.9% adult males concentrated their activities in the inner area of the leaf surface. More than 50% of the predatory mites congregated in the bottom layer in winter. Mean total density of the overwintering females in December of 2000,2001 and 2002 ranged between 10.6–14.2 females/5 cm twig in the bottom, 7.3–10.4 in the middle and 4.1–6.9 in the top layers of the apple trees. Mean total fecundity recorded over the 3 years was lowest in the overwintering generation with 31.8–37.6 eggs/female, highest in the June generation with 45.9–53.7 eggs/female, and intermediate in the August generation with 41.5–46.1 eggs/female. The overwintering generation was composed entirely of females, while the female to male ratio in the June generation was 2:1, and in the August generation 3:1. T. Pyri overwinters as adult females in rough structures, cracks and crevices of twigs.
-
the predatory mite Typhlodromus Pyri acari phytoseiidae causes feeding scars on leaves and fruits of apple
Experimental and Applied Acarology, 2004Co-Authors: C Sengonca, I A Khan, P BlaeserAbstract:Typhlodromus Pyri Scheuten (Acari: Phytoseiidae) is the most important predator of Panonychus ulmi (Koch) (Acari: Tetranychidae) in orchards and vineyards. It was recently found that adult T. Pyri females cause microscopic scars on apple leaves. The present laboratory experiments were carried out to confirm the production of scars on apple leaves and to assess if females cause scars on fruits as well. Scar production on apple leaves and/or fruits was investigated under various nutritional conditions: no food, pollen of Scots pine (Pinus sylvestris L.) only, nymphs of P. ulmi only, and pollen + prey. Both on leaves and fruits, either offered alone or in combination, feeding scars were produced under all nutritional conditions, but mostly in the ‘no food’ treatment. The predators consumed significantly more P. ulmi nymphs when offered alone than when offered in combination with pollen. T. Pyri laid eggs under all nutritional conditions, but mostly in the ‘pollen + prey’ treatment and least when no food was offered. T. Pyri females caused scars on both leaves and fruits when offered simultaneously, but more on leaves than on fruits. The scars were also bigger on leaves than on fruits in all experiments. T. Pyri survived and reproduced on plant material in the absence of other food sources. Whether the scars produced on leaves and fruits harm the quality of fruits or the yield of apple cannot be concluded from the present experiments.
-
prey consumption during development as well as longevity and reproduction of Typhlodromus Pyri scheuten acari phytoseiidae at higher temperatures in the laboratory
Anzeiger Fur Schadlingskunde-journal of Pest Science, 2003Co-Authors: C Sengonca, I A Khan, P BlaeserAbstract:The predatory mite Typhlodromus Pyri Scheuten (Acari, Phytoseiidae) has been reported as an important predator of the European red mite, Panonychus ulmi (Koch) (Acari, Tetranychidae) in apple culture and vineyards at below 25 °C. However, sufficient biological data was lacking on its efficiency at temperatures above 25 °C. Therefore, the purpose of the present laboratory work was to obtain experimental data on prey consumption during development as well as longevity and reproduction of T. Pyri on apple leaf discs and in Plexiglas cells at constant temperatures of 25 ± 2 °C and 30 ± 2 °C with P. ulmi as prey.
