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Damage caused by a combination of Nectria neomacrospora and Dreyfusia piceae in an Abies alba stand in Allgau, Germany, in 2001 is reported. The symptoms are similar to beech bark necrosis..
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The Committee of Plant Protection is the statuary body of the Polish Academy of Sciences which periodically evaluates the situation in the area of plant protection sciences in Poland compared to the situation and the developmental...
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The Committee of Plant Protection is the statuary body of the Polish Academy of Sciences which periodically evaluates the situation in the area of plant protection sciences in Poland compared to the situation and the developmental trends in this field in the world. Since previous evaluation in 1993 and in 1996, a distinct progress has been noticed in research and practical achievements in the field of applied entomology and zoology, phytopathology, weed sciences and in plant protection technologies. A selected example of important achievements in the above disciplines are presented. The Polish community of plant protection specialists during the period 1994-2004 has published over 5000 regular research papers, books, reviews and technical articles concerning all aspects of plant protection. Polish specialists continue in their active participation in various international research projects and programmes such as HRAC, EUCABLIGHT, PHARE, UE CRAFT, COST 819, COST 850 and many others. The number of plant protection specialists employed in agricultural universities (175 persons including 51 professors) and in research institutes (131 persons including 35 professors) changed very slightly during 1994-2003. More detailed analysis of positions and age of scientists is provided for a groups of phytopathologists employed in agricultural universities and in research institutes. The analysis prepared by the Committee provides conclusions and indicates research priorities in entomology, phytopathology, herbology and plant protection technologies for 2005-2013 in Poland..
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The Alaskan swallowtail butterfly, Papilio machaon aliaska (Lepidoptera: Papilionidae), uses three plant species as host plants. Cnidium cnidiifolium (Turcz.) Schischk. belongs to the family Apiaceae, the ancestral host-plant fami...
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The Alaskan swallowtail butterfly, Papilio machaon aliaska (Lepidoptera: Papilionidae), uses three plant species as host plants. Cnidium cnidiifolium (Turcz.) Schischk. belongs to the family Apiaceae, the ancestral host-plant family of the P. machaon group. Artemisia arctica Less. and Petasites frigidus (L.) Franch, in contrast, belong to the distantly related Asteraceae family and were colonized relatively recently by this group of butterflies. Previous work has shown that larval survival is highest on the novel host plants when natural enemies are present in the field. Here I examine whether P. m. aliaska fitness varied when individuals were reared on the three host plants in a common environment, free of environmental and ecological complications such as predation. I collected 12 P. m. aliaska females and measured their reproductive success when their progeny were reared on each of the three host plants. I assessed larval fitness on each of the hosts by recording the percentage pupation and percentage emergence as well as by measuring pupal mass. I found that larvae reared on the ancestral host plant, C. cnidiifolium, had higher fitness than did larvae reared on either of the novel host plants, A. arctica or P. frigidus. Larvae reared on C. cnidiifolium were more likely to pupate, achieved a greater pupal mass, and had higher emergence rates than larvae reared on the novel hosts. I interpret these results to mean that, in the absence of predation, the ancestral host plant is a better host for P. m. aliaska larvae than either novel host and I contend that this result does not appear to support the hypothesis that P. m. aliaska populations in central Alaska are divided into host races..
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Associational resistance occurs when host plants experience reduced attack when in the presence of other plant species. The issue is most studied in agriculture and forestry because of the potential benefits to pest control, but r...
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Associational resistance occurs when host plants experience reduced attack when in the presence of other plant species. The issue is most studied in agriculture and forestry because of the potential benefits to pest control, but recent research indicates that associational resistance may be relatively common in natural systems as well, especially against specialist herbivores. Research on associational resistance to a tropical leaf miner is presented.
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The effects of O. humeralis on the number and size structure of its host plants were studied from August 2000 to March 2003 in Serra do Japi, Sao Paulo, Brazil. Several native Miconia (M. sellowiana, M. jucunda and M. latecrenata)...
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The effects of O. humeralis on the number and size structure of its host plants were studied from August 2000 to March 2003 in Serra do Japi, Sao Paulo, Brazil. Several native Miconia (M. sellowiana, M. jucunda and M. latecrenata) and Leandra (L. scabra and Leandra sp.) species were abundant in the study area. Of the 296 M. sellowiana individuals sampled during 1999-2000, 67 (23%) had the trunk girdled by O. humeralis and had lost their crown. Of the 126 individuals sampled in 2002-03, 11 (9%) had their canopy cut down by the beetle. Only 3 individuals died for a reason other than beetle attack. Of the 35 individuals cut by O. humeralis that were monitored in 2001, 15 (43%) died and the remaining individuals produced 2-5 new shoots near the point of the cut in the following year. The host species M. sellowiana and L. scabra decreased by approximately 60 and 40%, respectively, during the study, whereas M. jucunda and M. latecrenata did not significantly change in abundance. M. sellowiana was the most abundant plant species in the first period of the study, but became less dominant after 2 years of infestation. Larger individuals of M. sellowiana decreased in proportion from 1999-2000 to 2002-03. Despite the decrease in the number of smaller individuals and increase in larger individuals of L. scabra, there was no significant difference in size structure of the populations between sampling. Because of the change in size structure, O. humeralis gradually attacked smaller plants of M. sellowiana in successive years..
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EPPO Standards on national regulatory control systems describe procedures for official control of individual regulated pests, for the purpose of their eradication or containment, or demonstration or maintenance of pest-free areas,...
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EPPO Standards on national regulatory control systems describe procedures for official control of individual regulated pests, for the purpose of their eradication or containment, or demonstration or maintenance of pest-free areas, pest-free places of production or areas of low pest prevalence. These standards conforms to supplement No. 1 of ISPM no. 5 Glossary of phytosanitary terms: Guidelines on the interpretation and application of the concept of official control for regulated pests.
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Host defenses can generate Allee effects in pathogen populations when the ability of the pathogen to overwhelm the defense system is density-dependent. The host-pathogen interaction between conifer hosts and bark beetles is a good...
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Host defenses can generate Allee effects in pathogen populations when the ability of the pathogen to overwhelm the defense system is density-dependent. The host-pathogen interaction between conifer hosts and bark beetles is a good example of such a system. If the density of attacking beetles on a host tree is lower than a critical threshold, the host repels the attack and kills the beetles. If attack densities are above the threshold, then beetles kill the host tree and successfully reproduce. While the threshold has been found to correlate strongly with host growth, an explicit link between host physiology and host defense has not been established. In this article, we revisit published models for conifer-bark beetle interactions and demonstrate that the stability of the steady states is not consistent with empirical observations. Based on these results, we develop a new model that explicitly describes host damage caused by the pathogen and use the physiological characteristics of the host to relate host growth to defense. We parameterize the model for mountain pine beetles and compare model predictions with independent data on the threshold for successful attack. The agreement between model prediction and the observed threshold suggests the new model is an effective description of the host-pathogen interaction. As a result of the link between the host-pathogen interaction and the emergent Allee effect, our model can be used to better understand how the characteristics of different bark beetle and host species influence host-pathogen dynamics in this system.
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摘要 :
Host defenses can generate Allee effects in pathogen populations when the ability of the pathogen to overwhelm the defense system is density-dependent. The host-pathogen interaction between conifer hosts and bark beetles is a good...
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Host defenses can generate Allee effects in pathogen populations when the ability of the pathogen to overwhelm the defense system is density-dependent. The host-pathogen interaction between conifer hosts and bark beetles is a good example of such a system. If the density of attacking beetles on a host tree is lower than a critical threshold, the host repels the attack and kills the beetles. If attack densities are above the threshold, then beetles kill the host tree and successfully reproduce. While the threshold has been found to correlate strongly with host growth, an explicit link between host physiology and host defense has not been established. In this article, we revisit published models for conifer-bark beetle interactions and demonstrate that the stability of the steady states is not consistent with empirical observations. Based on these results, we develop a new model that explicitly describes host damage caused by the pathogen and use the physiological characteristics of the host to relate host growth to defense. We parameterize the model for mountain pine beetles and compare model predictions with independent data on the threshold for successful attack. The agreement between model prediction and the observed threshold suggests the new model is an effective description of the host-pathogen interaction. As a result of the link between the host-pathogen interaction and the emergent Allee effect, our model can be used to better understand how the characteristics of different bark beetle and host species influence host-pathogen dynamics in this system.
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The aphid Astegopteryx sp. forms a banana-bunch shaped gall consisting of several subgalls on Styrax benzoides in northern Thailand, and completes its life cycle on the tree, without migrating to secondary hostplants. We found tha...
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The aphid Astegopteryx sp. forms a banana-bunch shaped gall consisting of several subgalls on Styrax benzoides in northern Thailand, and completes its life cycle on the tree, without migrating to secondary hostplants. We found that its soldiers had sclerotic, protruded heads with many spine-like setae, and that several soldiers cooperate to plug the ostiole of the subgall with these heads. Of 173 ostioles examined in the field, 90.8% were plugged with no space among the guarding soldiers. Many eggs and sexuals were found within subgalls guarded by soldiers, and a number of males were found trying to intrude into these subgalls. However, they were blocked by guarding soldiers, and it was no easy task for them to intrude into subgalls. The same was true for some soldiers that had rushed out of the subgall. Guarding soldiers often prevented outside soldiers from coming back into the subgall. These findings suggest an interesting possibility that guarding soldiers might consequently select still active, reusable soldiers and strong males for sexual females in their subgall..
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