Search results for "Insects"
showing 10 items of 123 documents
Pētījumu reģistrācijas žurnāls: 1869, 1870, 1871
1871
Entomologa F. Sinteņa pašrocīgi veiktie pieraksti insektu kolekcijas veidošanas un pētījumu reģistrācijas žurnālā laikposmam no 1869. gada 3. augusta līdz 1871. gada 27. novembrim, Tērbatā.
Ein Beitrag zur Kenntnis der Aphidenfauna Lettlands
1928
Izvilkums no: Latvijas Universitātes raksti = Acta Universitatis Latviensis XVIII, 1928.
Festschrift zum 60. Geburtstage von Professor Dr. Embrik Strand [Festschrift zum sechzigsten Geburtstage von Professor Dr. Embrik Strand], Vol.5
1939
Jubilāram veltīti ārvalstu zoologu un paleontologu raksti.
Festschrift zum 60. Geburtstage von Professor Dr. Embrik Strand [Festschrift zum sechzigsten Geburtstage von Professor Dr. Embrik Strand], Vol.4
1938
Jubilāram veltīti ārvalstu zoologu un paleontologu raksti.
Festschrift zum 60. Geburtstage von Professor Dr. Embrik Strand [Festschrift zum sechzigsten Geburtstage von Professor Dr. Embrik Strand], Vol.1
1936
Jubilāram veltīti ārvalstu zoologu un paleontologu raksti vācu, franču, angļu, itāliešu u.c. valodās.
Festschrift zum 60. Geburtstage von Professor Dr. Embrik Strand [Festschrift zum sechzigsten Geburtstage von Professor Dr. Embrik Strand], Vol.3
1937
Jubilāram veltīti ārvalstu zoologu un paleontologu raksti vācu, franču, angļu, itāliešu u.c. valodās.
Festschrift zum 60. Geburtstage von Professor Dr. Embrik Strand [Festschrift zum sechzigsten Geburtstage von Professor Dr. Embrik Strand], Vol.2
1936
Jubilāram veltīti ārvalstu zoologu un paleontologu raksti vācu, franču, angļu, itāliešu u.c. valodās.
Sustainable Weed, Disease and Pest Management in Medicinal and Aromatic Plants
2015
As for all other crops, in MAPs as well, weeds, diseases and pests are important yield-reducing factors, which may severely curtain biomass production and, that is maybe more important, may affect several qualitative aspects of production. Research about this topic is generally lacking, for two main reasons: the first is that MAPs are generally grown on rather limited areas, and the incidence of specific pests and diseases rarely takes a relevance outside rather narrow boundaries. The second reason is that the economical importance of MAPs is much lower than that ascribed to the “major” crops, which the bigger efforts of research are addressed to. In the changing scenario of latter years, h…
IPM-recommended insecticides harm beneficial insects through contaminated honeydew
2020
The use of some systemic insecticides has been banned in Europe because they are toxic to beneficial insects when these feed on nectar. A recent study shows that systemic insecticides can also kill beneficial insects when they feed on honeydew. Honeydew is the sugar-rich excretion of hemipterans and is the most abundant carbohydrate source for beneficial insects such as pollinators and biological control agents in agroecosystems. Here, we investigated whether the toxicity of contaminated honeydew depends on i) the hemipteran species that excretes the honeydew; ii) the active ingredient, and iii) the beneficial insect that feeds on it. HPLC-MS/MS analyses demonstrated that the systemic insec…
Exposing the structure of an Arctic food web
2015
15 pages; International audience; How food webs are structured has major implications for their stability and dynamics. While poorly studied to date, arctic food webs are commonly assumed to be simple in structure, with few links per species. If this is the case, then different parts of the web may be weakly connected to each other, with populations and species united by only a low number of links. We provide the first highly resolved description of trophic link structure for a large part of a high-arctic food web. For this purpose, we apply a combination of recent techniques to describing the links between three predator guilds (insectivorous birds, spiders, and lepidopteran parasitoids) a…