Limothrips Denticornis Research Articles

Thrips species biodiversity and dynamic populations in an organic Citrus orchard in northeastern Tunisia

Thrips species diversity in a Citrus organic orchard in the region of Mograne in Northeastern Tunisia based on biodiversity parameters (Shannon index, dominance, and equitability) showed the existence of ten thrips species. Among those species, five are phytophagous: Thrips tabaci, Thrips angusticeps, Frankliniella occidentalis, Limothrips denticornis, and Melanthrips fuscus. The remaining species are predatory: Aeolothrips tenuicornis, Aeolothrips fasciatus, Aeolothrips intermedius, Franklinothrips meaglops, and one genus, Haplothrips sp. The most abundant species are Aeolothrips intermedius (55%) followed by Thrips angusticeps and Haplothrips cottei (the same percentage of 11%), F. occidentalis and T.tabaci (5% and 6%, respectively), Aeolothrips fasciatus and Limothrips denticornis (3% and 4%) then Aeolothrips tennuicornis and Melanthrips fuscus (the same percentage of 2%). The species Franklinothrips megalops is less abundant (1%). The evolution of different thrips species revealed that the emergence reached high levels in March and April. Biodiversity indexes showed a case of lower dominance and higher equitability.

Cereal pests among nest parasites – the story of barley thrips, <i>Limothrips denticornis</i> Haliday (Thysanoptera: Thripidae)

Barley thrips, Limothrips denticornis, Haliday, 1836 (Thysanoptera: Thripidae), a grass-dwelling Holarctic species represents a model example to study transport mechanisms of Thysanoptera into nests. In samples from more than 1,500 nests, barley thrips were recorded in nests of 20 vertebrate species, both birds and mammals. Applying appropriate statistics (nonparametric methods) clear clustering among nest materials and a strong relationship between presence of thrips and grass as the nest material was found. Occurrence of thrips was not associated with nest size, location or height. To validate our statistical analyses 15 wooden boxes were installed and equipped with sticky traps to record the whole year migration dynamics. Barley thrips infiltrate nests by various ways (e. g. dwelling on bark, landing from atmosphere), however most of them (88%) invade passively on nest material (grass) in spring (1st summer nesting) and autumn (winter nest building).

Diversity and sex ratio of thrips (Thysanoptera species) in winter wheat in Lithuania

A study on the variation of species diversity and sex ratio of thrips in winter wheat (Triticum aestivum L.) was conducted at the Lithuanian Institute of Agriculture (currently – Lithuanian Research Centre for Agriculture and Forestry). Assessments of thrips abundance were carried out from the beginning of tillering (growth stage (GS) 21) until complete maturity (Gs 89). Thirteen thrips species belonging to the three families were identified: 10 thrips species belonged to Thripidae, 2 to Phlaeothripidae and 1 to Aeolothripidae families. In terms of the feeding group, one species (Aeolothrips intermedius) belonged to zoophagous, the rest of the species were phytophagous. Frankliniella intonsa, F. tenuicornis, Haplothrips aculeatus and Limothrips denticornis were the earliest thrips species identified on winter wheat in spring. The dominating species were L. denticornis (41.3%), H. aculeatus (25.8%) and F. tenuicornis (20.5%). An average sex ratio of L. denticornis was 84.7%, and of H. aculeatus – 68.2%, and of F. tenuicornis – 71.1% and of F. intonsa – 60.9%.

Commonly Intercepted Thrips at U.S. Ports-of-Entry from Africa, Europe, and the Mediterranean. IV. Miscellaneous Thripine Genera Excluding Frankliniella, Iridothrips, and Thrips (Thysanoptera: Thripidae)

Abstract A total of 130 species of thrips occurring in Africa, Europe, and the Mediterranean region were intercepted by U.S. agricultural quarantine officers from shipments of cut flowers and other plants at various ports-of-entry in the United States from 1983 to 1999. This is Part 4 of a guide to the identification of thrips coming into this country from these regions: it uses keys, line drawings, and scanning electron micrographs to identify 51 species in 36 miscellaneous thripid genera not covered in Parts 2 and 3. Of the 321 records identifiable to species, 70% of the interceptions were attributed to ten species: Odontothrips karnyi Priesner clearly was most commonly intercepted, with substantially smaller percentages attributed to Limothrips cerealium (Haliday), Anaphothrips obscurus (Muller), Neohydatothrips samayunkur (Kudo), Limothrips denticornis (Haliday), Synaptothrips distinctus (Bagnall), Tenothrips discolor (Karny), Ceratothripoides brunneus Bagnall, Ceratothrips ericae (Haliday), and Mycte...

Thysanoptera infestation on skin and periorbital cellulitis in ostriches (Struthio camelus) aged 14 months

AIM: To report the infestation of Thysanoptera (Limothrips denticornis) on ostriches (Struthio camelus) and to determine their relative density. METHODS: A farm in Poland was studied on which ostriches aged 14 months were severely infested with L. denticornis (thrips). Thrips were collected and their density on the neck, torso and legs (10 cm2) of 85 ostriches determined at 0600, 1200 and 1800 h, respectively, over 7 days. At the same times, apparent densities of thrips/m2 were determined in adjacent grassy areas (120 m2) on a muslin cloth impregnated with permethrin. Thrips were mounted onto slides in Hoyer's medium, for identification. RESULTS: The apparent density of thrips was greatest at 1200 h, and was greater on the neck than the torso and legs (p=0.03). In adjacent surroundings, densities were also highest at 1200 h (mean 199 (SE 9.3) thrips/m2) and were similar to the maximum densities recorded on the necks of ostriches at that time (mean 205 (SE 6.4) thrips/m2). Ostriches engaged in excessive preening and attempted to scratch their head/neck with their feet. Numerous small, pale red papules were observed on the skin. Observations of periorbital cellulitis, conjunctivitis, blepharitis, watery discharge, inflammation, and sclerotic discolouration were noted in 65 ostriches. CONCLUSION: Observations were commensurate with L. denticornis infestation. CLINICAL RELEVANCE: Infestation may exacerbate stress levels and subsequently lead to a reduction in feed intake and performance. The infestation and subsequent irritation from thrips impacts negatively on the general health of ostriches by damaging skin and irritating eyes.

Economic damage by Limothrips denticornis in rye, triticale and winter barley

Abstract: Limothrips denticornis is a common thrips infesting rye, triticale and winter barley in Sweden. Field experiments with insecticides were carried out 1983–1996 in farmers’ fields to investigate the damage to the plant and to evaluate the relationship between thrips density and crop yield losses. The total number of experiments was 99 in rye, 41 in triticale and nine in winter barley. The mean number of thrips per leaf sheath was around 8 in all three crops. The highest number found was 27 thrips per leaf sheath. The population density in the leaf sheath was correlated with the damage observed on the leaf sheath as percentage damaged surface. The effect on the leaf sheath alone contributed to a significant proportion of the yield loss. Thrips in the ear and aphids also contributed to the damage but with multiple regression methods it was possible to estimate the damage done solely by L. denticornis. The yield loss caused by L. denticornis was about the same in all three crops, with a variation between 21 and 26 kg per thrips per leaf sheath and hectare. Compared with the yield loss for aphids, which is about 40 kg per aphid per tiller and hectare, this is considerably lower. The economic injury level was found to be about 14 thrips per straw. The economic threshold for L. denticornis has to be decided when the females are flying into the crop and it was found to be 0.5 females per straw at earing. Economic damage by L. denticornis alone was estimated to be 20% of the total number of experiments for all three crops but economic damage for the three pests together was estimated at 40% of the total number of experiments.

Species composition of Thysanoptera in white cabbage heads

In 2000-2002 thrips species were collected from mature white cabbage head leaves in Hungary. The total number of the sampled specimens was 4226. Out of the 3374 identified adults Thrips tabaci was predominant (91.3%). Frankliniella tenuicornis was found in significant number (6.9%) with rather extraordinary appearance in 2000 (15.1%) but in the other years its frequency was lower (0.5%, 1.9% respectively). The rest of the adults (1.8%) were: Frankliniella intonsa, Aeolothrips intermedius, Thrips angusticeps, Thrips atratus, Haplothrips aculeatus, Limothrips denticornis, Anaphothrips obscurus, Chirothrips manicatus and Scolothrips longicornis. The 852 second instar larvae were also identified. 96.4% was Thrips tabaci, 2.7% Thrips angusticeps and 0.8% Anaphothrips obscurus. In spite of the fact that in 2000 15.1% of the adults on cabbage was Frankliniella tenuicornis, not a single larva was found. Therefore we concluded that in Hungary it is only the thelytokous populations of Thrips tabaci that are of high importance as thrips pest of white cabbage.

The occurrence of Thrips (Thysanoptera, Insecta) on winter and spring wheat in chosen regions of Poland

The work has determined the species composition as well as the number of thrips gathered on winter and spring wheat in milk-waxy ripe stage in six soil-climatic regions of Poland. The occurrence of 15 thrips species has been noted, nine of which were associated with cereals. They occurred most amply in south-western Poland. In all regions under study the following species were noted to exist in greater numbers: Frankliniella tenuicornis (Uzel), Limothrips denticornis Haliday and Haplothrips aculeatus (Fabricius). Limothrips cerealium Haliday was dominant in all western regions of Poland whereas Haplothrips tritici (Kurdjumov) in the south-eastern region.

Sequential Sampling Plan for Limothrips denticornis (Thysanoptera: Thripidae) on Spring Barley

Sequential sampling programs were developed for insecticide treatment decisions for adult Limothrips denticornis Haliday on spring barley (Hordeum vulgare L.). To develop models of sample count distributions, adult thrips were sampled at five locations over 2 yr. Decision lines were derived using Iwao’s patchiness regression and Wald’s sequential probability ratio test for a negative binomial distribution. Accuracy of field visual counts of adult thrips was compared with samples processed in the laboratory. Visual estimates corresponded favorably when compared with laboratory estimates of less than three adult thrips per stem. Visual estimates were 53-92% of the laboratory estimates when the laboratory estimate exceeded three adult thrips per stem. There was a significant quadratic relationship between visual field estimates and more accurate laboratory estimates of mean density.

Overwintering of the Onion Thrips, Thrips tabaci (Thysanoptera: Thripidae), in New York

A survey of overwintering thrips and the potential for Thrips tabaci Lindeman to overwinter in upstate New York were investigated during the winters of 1982–83 and 1983–84. Six species— T. tabaci, Anaphothrips obscurus (Muller), Chirothrips manicatus Haliday, Limothrips denticornis (Haliday), Frankltniella tenuicornis (Uzel), and Aptinothrips rufus (Gmelin)—were able to survive as adults in the vegetation sampled, but only Anaphothripini survived as larvae. T. tabaci adults overwinter within winter wheat, alfalfa, and weedy vegetation, and these overwintering females are capable of ovipositing on these plants during the spring. Winter wheat, oats, and alfalfa were the best oviposition and reproduction hosts we examined.

The Genus Limothrips (Thysanoptera) in America.

In J. R. Watson*s recent Synopsis and Catalog of the Thysanoptera of North America (1923), two species of the genus Limothrips are listed, namely, L. angulicornis Jablon and L. cerealium Haliday, both European species with representatives in this country. The first species, angulicornis, was discovered by P. R. Jones in California on Fox-tail grass and described (1912) as L. setariæ. The second species was recorded by Hinds from Massachusetts and Pennsylvania on oats and Festuca pratensis and described (1902) as a new species, L. avenæ. We now have a third species of the genus, Limothrips denticornis Haliday (1836), in America, taken from wheat and from the nests of robins and sparrows.