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PCR analysis was used to detect Fusarium species generically, as well as the mycotoxin-producing species F.␣subglutinans, F. proliferatum, and F. verticillioides in leaf axil and other maize tissues during ear fill in a multiyear study in central Illinois. The frequency of Fusarium detected varied from site to site and year to year. Fusarium was generically detected more frequently in leaf axil material than in leaf/husk lesions. In two growing seasons, the leaf axil samples were also tested for the presence of the mycotoxin producing species F. proliferatum, F. subglutinans, and F. verticillioides. Overall, F. proliferatum and F. verticillioides were detected less often than F. subglutinans. Fusarium was generically and specifically detected most commonly where visible fungal growth was present in leaf axil material. Disclaimer: The mention of firm names or trade products in this article does not imply that they are endorsed or recommended by the United States Department of Agriculture over other firms or similar products not mentioned.  相似文献
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Absract Nitidulid beetles (Coleoptera) are considered serious pests of date palms throughout the world. They attack the ripe fruit, causing it to rot, and damage is reflected in both reduced yield and lower fruit quality. Previous studies demonstrated the susceptibility of larvae of this pest to entomopathogenic nematodes from the genus Heterorhabditidis. In the present study nematode efficacy was evaluated in greenhouse and field. In containers filled with soil, moderate reduction in insect emergence was achieved when the nematodes were applied at concentrations of 25 and 50 IJs/cm2. However, the highest concentration (100 IJs/cm2) treatment resulted in a drastic reduction (by 70–90%) in emergence of the beetles. The lowest emergence was achieved by the IS-19 and IS-21 strains (>10%). Efficacy of the IS-19 strain was retained up to 7 days after application at a rate of 100 IJs/cm2. When the insect larvae were introduced to the soil 2 weeks after nematode application, the percentage emergence of insects increased by 2–2.5 fold as compared to previous introductions but was still lower than in the control. Insect density per container did not have an effect on efficacy of the nematodes when the strains IS-19 and IS-12 were used. Two field trials were conducted in different sites in Israel. In the first trail, conducted in date palm orchard, four strains of Heterorhabditis sp. were tested. No significant difference in insect emergence was recorded among the various treatments or the control. Whereas in the second trial conducted in a fig orchard, substantial reduction (by 50–70%) in insect emergence was recorded following nematode treatment. Further studies, under natural conditions, are needed to optimize application efficiency and evaluate the commercial utilization of these biological control agents.  相似文献
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Omositoidea gigantea Schaufuss, 1892 is redescribed; O. pubescens sp. nov. from the Baltic amber, Palaeometopia dominicana gen. et sp. nov. and P. colorata gen. et sp. nov. from the Dominican amber are described. The taxonomic position of the two genera and their probable bionomy are discussed.  相似文献
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Abstract.  1. Scaling relations between weapons and body size depart from linearity in many male beetles. In many previous studies, these males have been divided into major and minor males with a switch point, that is male dimorphism. Major and minor males adopt strikingly different reproductive tactics.
2. We found three size-dependent behaviours, i.e. fighting, dispersing, and sneaking, however, among Librodor japonicus males with dimorphic mandibles. We statistically classified males into large, medium, and small (L-, M-, and S-males) sizes and then compared the dispersal of males from a foraging site, behaviours to gain access to females, and sizes of mandibles, wings, and testes.
3. M-males dispersed earlier than L- and S-males from a territory in a field, but no difference in the frequency of dispersal was observed between L- and S-males. Observations of male–male interactions in the laboratory showed that L-males frequently fought with other males in a fighting arena, while S-males often showed sneaking behaviour without fighting.
4. On the basis of the morphological analysis, we concluded that S-males invested their available resources more in sperm (= testes), M-males more in wings, and L-males more in mandibles in L. japonicus .
5. Even though a morphological male dimorphism was detected, it might be possible to classify the males of the armed beetles into more than two behavioural tactics if we examine their behaviours.  相似文献
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