Diversity and abundance of thrips species on bananas from different ecological zones in Embu County, Kenya

Lemongrass (Cymbopogon flexuosus) agronomic traits, oil yield and oil quality under different agro-ecological zones

Flower thrips are among the most damaging insect pests limiting cowpea yields. Despite their economic importance, the species composition and abundance of thrips associated with cowpea and alternative host plants are little knowing. This study aimed to identify the thrips species associated with various host plants during the main cropping season and to assess their abundance. Thrips samples were collected over two consecutive years across three climatic zones by carefully cutting off flowering structures of the different plants and placing them in vials containing 70% ethanol. Five thrips species were identified on cowpea: Megalurothrips sjostedti, Frankliniella schultzei, Hydatothrips adolfifriderici, Florithrips traegardhi and Arorathrips mexicanus. Arorathrips mexicanus was identified on only cowpea. Among them three species: Megalurothrips sjostedti, Frankliniella schultzei and Hydatothrips adolfifriderici were consistently recorded on cowpea across all three climatic zones. Megalurothrips sjostedti and Frankliniella schultzei were found only on wild host plants and common to all zones. Megalurothrips sjostedti (89.87%) and Frankliniella schultzei (6.91%) were the main thrips species in terms of abundance, occurring on both wild host plants and cultivated cowpea. Florithrips traegardhi (0.39%) was relatively rare, while Arorathrips mexicanus (0.006%) appeared to be an accidental species. Several plants species were identified as alternative thrips hosts. Among them, Piliostigma thonningii and Piliostigma reticulatum were recorded as the main alternative host plants in Burkina Faso.

Sampling was done by a purposive sampling technique based on the results of the location survey of habitat varied in vegetable plantations in South Jambi. The sample collection was carried out in three ways, namely manual sampling (hand picking), using a sticky color trap (sticky trap) and sampling using a tool. Environmental parameters measured included ambient temperature, air humidity and altitude. The results revealed 4 species of thrips namely Thrips parvispinus, Thrips palmi, Megalurothrips usitatus from suborder of the Terebrantia and Haplothrips sp. from sub-order of the Tubulifera. The abundance of the thrips was found in Thrips parvispinus in various host plants with an abundance of 0.623, then Megalurothrips usitatus with an abundance of 0.354, followed by Thrips palmi 0.019 and the lowest was Haplothrips sp., 0.001. The plants that existed at the time of the study were surveyed included long beans, eggplant, bitter melon, mustard greens, peanuts, and sweet potatoes. The abundance of Thrips parvispinus was most common in bitter melon plants, Thrips palmi in eggplant plants, Megalurothrips usitatus in peanut plants, and Haplothrips sp. in mustard plants. The highest abundance of thrips was found in bitter melon, long bean and peanut plants.

The analysis of the high resolution gridded data (1° x 1°) of daily maximum, minimum and mean temperature for the 23 grids covering the Narmada basin has detected varying trends in the upper, middle and lower zones of the basin, based on the 40 years data from 1961-2008.The annual 1-day maximum temperature has been steadily increasing at the rate of 1.10°C/100 yr, but the annual 1-day minimum temperature depicted a much higher rate in increase of 3.20°C/100 yr with significant rising trend at 95% significance level (test statistic: Z = +1.989)based on the non-parametric Mann-Kendall test for detection of trend in time series.The zone-wise temperature variation has been studied for two distinct time periods, each of 20 years viz.1969-88 and 1989-08.A divergent pattern is observed in minimum daily temperature trends in the various zones of the basin with significant rising trends in the lower zone and no significant trend in the upper zone during both time periods.Also a significant rising trend has been detected in the diurnal temperature range (DTR) in the lower zone during August (Z = +2.21),with no significant trends in other months.Significant rising trends have been detected in the mean monthly temperatures in the upper and middle zones, with no significant trend in lower zone.Similar pattern of significant rising trend have been detected in mean monthly temperatures during the principal winter (December and January) and summer months (April and May) in upper and middle zones of the basin.However, no significant trend has been detected during the principal monsoon months (July and August) for all the zones.As the basin is located in a semi-arid region and the perennial flows result from the contribution from the soil moisture and groundwater storages, any increase in the maximum and minimum temperatures will change the water availability scenario due to increased water demands from higher consumptive use requirements.To study the water demand scenario in the various zones in the basin, the potential evapotranspiration (PET) has been computed.Significant rising trends in PET were detected in all the zones, during the 1989-08 time slot, which indicates higher crop water requirement from the agriculture sector due to the increased temperatures.The comparison of the zonal annual rainfall (AR) with the actual evapotranspiration (AET) which gives an indication of the supplydemand scenario, has found that the annual AET has been greater than AR in the middle zone on 5 occasions during 1969-88 and subsequently increased to 10 occasions during 1989-08, whereas in the lower zone the AET was greater than AR during most of the years in both time periods.This indicates increased water demands and lower rainwater availability under the changing climate scenario, in the middle and lower zones of Narmada basin, which calls for effective water resources development and management strategies.

Effects of estradiol and progesterone on the reproductive tract and on uterine sex steroid receptors in female lambs

The Hongge magmatic Fe-Ti-V oxide deposit in the Panxi region, SW China, is hosted in a layered mafic–ultramafic intrusion. This 2.7-km-thick, lopolith-like intrusion consists of the lower, middle, and upper zones, which are composed of olivine clinopyroxenite, clinopyroxenite, and gabbro, respectively. Abundant Fe-Ti oxide layers mainly occur in the middle zone and the lower part of the upper zone. Fe-Ti oxides include Cr-rich and Cr-poor titanomagnetite and granular ilmenite. Cr-rich titanomagnetite is commonly disseminated in the olivine clinopyroxenite of the lower parts of the lower and middle zones and contains 1.89 to 14.9 wt% Cr2O3 and 3.20 to 16.2 wt% TiO2, whereas Cr-poor titanomagnetite typically occurs as net-textured and massive ores in the upper middle and upper zones and contains much lower Cr2O3 (<0.4 wt%) but more variable TiO2 (0.11 to 18.2 wt%). Disseminated Cr-rich titanomagnetite in the ultramafic rocks is commonly enclosed in either olivine or clinopyroxene, whereas Cr-poor titanomangetite of the net-textured and massive ores is mainly interstitial to clinopyroxene and plagioclase. The lithology of the Hongge intrusion is consistent with multiple injections of magmas, the lower zone being derived from a single pulse of less differentiated ferrobasaltic magma and the middle and upper zones from multiple pulses of more differentiated magmas. Cr-rich titanomagnetite in the disseminated ores of the lower and middle zones is interpreted to represent an early crystallization phase whereas clusters of Cr-poor titanomagnetite, granular ilmenite, and apatite in the net-textured ores of the middle and upper zones are thought to have formed from an Fe-Ti-(P)-rich melt segregated from a differentiated ferrobasaltic magma as a result of liquid immiscibility. The dense Fe-Ti-(P)-rich melt percolated downward through the underlying silicate crystal mush to form net-textured and massive Fe-Ti oxide ores, whereas the coexisting Si-rich melt formed the overlying plagioclase-rich rocks in the intrusion.

Evechinus chloroticus (Val.) is known to be an important grazer of subtidal barren habitats in northern New Zealand but its role in structuring rocky reef communities at colder southern localities is poorly understood. The present study was prompted by a proposal for the establishment of an E. chloroticus fishery in Dusky Sound, Fiordland, New Zealand. To determine the ecological importance of E. chloroticus in Dusky Sound, sea urchins were experimentally removed from shallow fucoid fringe (upper zone), mid‐depth barrens (middle zone), and deeper algal meadow (lower zone), at eight sites and compared with a paired set of eight control sites. Two years of continuous removal of E. chloroticus resulted in conspicuous changes to the algal community at all depth zones examined. The density of fucoid algae (Carpophyllum spp., Sargassum spp., Cystophora spp., and Landsburgia quercifolia) increased mostly in the upper and middle zones, although smaller increases were also observed in the lower zone. Changes in cover of herbaceous, turfing and crustose algae observed in the middle and lower zones were larger than in the upper zone. Density increases of the kelp Ecklonia radiata were observed mainly in the lower zone, although still important in the middle zone. These results show that E. chloroticus can have a strong influence on the structure of algal assemblages in Dusky Sound hence the development of an E. chloroticus fishery in this area should be treated with caution.

Abstract. Wairimu WJ, Kimenjul JW, Muiru WM, Wachira PM. 2022. Interactions between soil additives and a variety of naturally occurring nematode-demolishing fungi in banana fields of Meru and Embu Counties, Kenya. Cell Biol Dev 6: 82-93. Plant-parasitic nematodes pose a significant danger to banana production, as they reduce the productivity, quality, and lifetime of banana orchards. This study aimed to evaluate the diversity, quantity, and occurrence of nematode-demolishing fungi in banana production farms to use them to manage plant-parasitic nematodes. Also examined was the impact of organic and inorganic soil additives on nematode-demolishing fungi. The study region was divided into three agroecological zones: UM3 (Low), UM2 (Middle), and UM 1 (Upper). Ten farms were chosen randomly for a soil sample in each zone to determine the diversity and abundance of nematode-demolishing fungi. One farm was chosen randomly for soil additive treatments in each zone. The gathered soil samples were used to isolate and identify nematode-demolishing fungi at the species level. The diversity of nematode-demolishing fungi varied significantly between zones, with the highest variety and number of fungi found in the highest zone. Arthrobotrys, Monacrosporium, Nematoctonus, Harposporium, and Paecilomyces were the identified genera. Arthrobotrys was the most often isolated genus, with a frequency of 45%, followed by Harposporium, with a frequency of 18%. The remaining three genera each had a frequency of 9%. The A. dactyloides, A. oligospora, A. robusta, A. longispora, A. superba, H. anguillulae, H. crassum, Meria coniospora, Monacrosporium cionopagum, N. leiosporus, and P. lilacinus were among the species identified. The A. oligospora had captured and destroyed 98 plant parasite nematodes, whereas M. cionopagum and Dactyllela phymatopaga had eliminated 88 and 76 plant parasitic nematodes, respectively, within the same time frame. The amount of nematode-demolishing fungi was significantly different between the various soil additives, with chicken dung having the greatest number of 74 isolates, followed by cow manure, goat manure, the control treatment, and inorganic additive with 71, 69, 54, and 39 isolates, respectively. The amount of isolated nematode-demolishing fungi fluctuated throughout time, from 89 pre-treatment isolates to 122 after three months and 96 after six months. The variation of nematode-demolishing fungi over time was significantly different, demonstrating the impact of diverse soil additives on their existence. Arthrobotrys spp. is a suitable option for field efficacy studies since it was the most diversified, had the highest demolishing rate, and the organic additives facilitated its dispersion in banana plantations.

Cotton Gossypium hirsutum L. (Malvales: Malvaceae) crops are attacked by a variety of invertebrate pests that include the larvae of Lepidoptera, spider mites, aphids, locust, beetles and thrips. In Australia three species of thrips are regarded as cotton pests, Thrips tabaci Lindeman, Frankliniella schultzei Trybom and F. occidentalis Pergrande (Thysanoptera: Thripidae). Thrips damage can result in delayed development, the early production of fruiting bodies and increased susceptibility to disease. Despite this, the ecology of thrips in cotton producing regions is poorly understood; in particular host-plant relationships and the sources of thrips populations that invade cotton crops require further investigation. The physical presence of other arthropods or the presence of herbivory can influence the attractiveness of plants to colonizing arthropods. The chemical changes that occur in plants following arthropod herbivory are referred to as herbivore-induced plant responses and they can affect host plant attractiveness and acceptance and hence colonization patterns. Laboratory olfactometer experiments determined how the three species of thrips responded to pairwise combinations of cotton seedlings damaged by different arthropod herbivores. Responses of thrips to herbivore induced cotton plants varied dramatically. Frankliniella schultzei was more attracted to cotton seedlings damaged by foliar-feeding arthropods (cotton bollworm (Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)) and root-feeding mealworms (Tenebrio molitor L. (Coleoptera: Tenebrionidae)) than to intact seedlings. Conversely, F. occidentalis was more attracted to intact seedlings than herbivore damaged seedlings. The responses of T. tabaci were different to those of both F. occidentalis and F. schultzei; T. tabaci did not discriminate between intact plants and those damaged by foliar or root feeding arthropods. Thus the responses of T. tabaci to herbivore damaged cotton plants were intermediate to those of F. schultzei and F. occidentalis. However, all three species of thrips were more attracted to plants damaged by two-spotted spider mites (Tetranychus urticae (Koch) (Trombidiforms: Tetranychidae)) than to intact plants. These results highlight the complexity and variability of the responses of thrips to herbivore induced cotton host plants. In the field, herbivore complexes can simultaneously attack cotton seedlings. Laboratory olfactometer experiments investigated the responses of different thrips species to cotton seedlings simultaneously damaged by more than one species of herbivore. The responses of F. occidentalis, F. schultzei and T. tabaci to plants dually infested by different combinations of herbivores were predictable based on their responses to plants damaged by single species alone. Investigation of temporal changes in the responses of thrips to herbivore damaged cotton seedlings showed that cotton seedling responses to herbivore damage were not instantaneous and that the period over which thrips behaviour modifying changes in the plants persisted was determined by both the type and extent of feeding damage. Both F. schultzei and F. occidentalis were attracted to plants damaged by two-spotted spider mites for much longer than they were to plants damaged by cotton bollworm larvae or bean spider mites. Similarly, F. schultzei was attracted to seedlings for much longer when higher densities of two-spotted spider mites damaged plants. The population sources of thrips that invade cotton crops and the abundance and species composition of thrips on cotton were investigated in field studies in the Namoi valley, New South Wales. Host plant utilization by thrips was quantified through a structured sampling program that estimated the presence and abundance of adult and larval thrips across various cultivated and uncultivated plant species. The floral and vegetative parts of different plant species were sampled regularly over two years, during which 65 different plant species were sampled. The seasonal composition of thrips on cotton changed from predominately T. tabaci on seedling cotton to F. schultzei and F. occidentalis on mature flowering cotton later in the season. High T. tabaci abundance on early season cotton was attributed to the high numbers of T. tabaci on the surrounding weed species, as hosts on which it was recorded were plentiful. In contrast, the patterns of F. occidentalis and F. schultzei abundance on cotton were not correlated with their abundances on the weeds but rather the emergence of cotton flowers. The genetic relationships of thrips on cotton relative to those on the other host plant species sampled was investigated by analysis of mitochondrial CO1 gene sequences. No evidence was found for cryptic species of T. tabaci or F. occidentalis in the populations sampled from weeds and cotton, indicating that they were not from different breeding populations. It is inferred that T. tabaci or F. occidentalis were moving from the weeds and other crops onto cotton. Weeds clearly play an important role in the population biology of thrips and thus they must be considered in in the potential pest management strategies. Results of this study indicate that it could be possible to predict large out breaks of thrips (particularly T. tabaci) on cotton based on the relative abundance of different weed species and weather conditions that favour their growth.

This paper deals with biomass accumulation and net primary productivity pattern in a fallow period of a lake margin agroecosystem. The slight slopping margin of present study site was characterized into two ecological zones, i.e. upper and lower from top up-land to lower region near water margin. Maximum biomass of dominant weed Cynodon dactylon (Linn) Pers. and ‘rest (other) weeds’ were 190.55 and 265.22 g m-2 in upper zone in September. In contrast, in the lower zone of study site, peakvalue of biomass of dominant plant C. dactylon and ‘rest weeds’ were 67.91 and 178.84 g m-2, respectively in June as lower zone was inundated from first fortnight of July to September, 2008. Maximum percentage contribution of the weed (C. dactylon) was 54.00 and 59.15% in March and‘rest weeds’ was 74.49 and 75.15% in April, 2008 in the respective upper and lower zones. Maximum productivity values of respective dominant weed (C. dactylon) and ‘rest weeds’ in upper zone were 2.07 and 2.51 g m-2 day-1 in July. In contrast, in the lower zone of the study site peak productivity values of respective dominant weed (C. dactylon) and ‘rest weeds’ were observed 1.36 in June and 1.23 g m-2 day-1 in October. Total productivity values in two respective zones upper and lower zones varied between 330.59 and 140.17 g m-2 per eight month. Analysis of variance in standing biomass of plant species was found significant p&lt;0.05 in upper zone and p&lt;0.01 in lower zone.DOI: http://dx.doi.org/10.3126/eco.v18i0.9412Ecoprint: An International Journal of EcologyVol. 18, 2011 Page: 63-70 Uploaded date: 12/22/2013

This research was conducted to evaluate the gastropods diversity in mangrove forests located in Iranian part of the Govater Gulf in southern border of Iran and Pakistan. Three transects were selected at the water interface vertically to the end of forest stand. In each transect, samples of sediments containing gastropods were taken at the beginning (lower zones), the middle, and the end (upper zone) points during four continued seasons. Biodiversity (Shannon–Wiener index), dominance (Simpson’s dominance index), species evenness (Smith and Wilson evenness index), richness (number of species), and density (number in m3) were calculated for each season in sampling points. Data analysis results showed that biodiversity and richness indices changed significantly among different transects. Shannon–Wiener diversity index in transect one (1.90 ± 0.69) was significantly higher than transect two (1.26 ± 0.67) and three (1.19 ± 0.68). Similarly, richness index was the highest in transect one (7.58 ± 1.53) rather than transect two (4.42 ± 1.15) and three (3.92 ± 0.94). Density index changed differently between lower zone (2318.02 ± 987.76), middle zone (2318.01 ± 605.75) and upper zone (13,420.71 ± 176.50). Species evenness showed significant differences between lower (0.65 ± 0.15) to middle (0.46 ± 0.20) and upper (0.30 ± 0.32) zones. Different seasons had no significant effect on richness, density, diversity, and evenness of gastropod species. Consequently, among the natural factors, it is the intertidal zones which increases the environmental stresses such as salinity and humidity was considered, and surprisingly, weak anthropogenic factors, for example, the effect of the transect was positive due to providing nutrient.

Altitudinal and seasonal variation in herbage composition and energy and protein content of grasslands on Mt Varnoudas, NW Greece

The Fontan procedure [total cavopulmonary connection (TCPC)] is the final palliation for patients with univentricular physiology. We studied differential perfusion ratio and percentage uptake of a radiotracer in different zones of each lung following TCPC. Between July 2015 and June 2017, 45 patients underwent 99mTc macroaggregated albumin lung perfusion scan at a mean follow-up period of 49.3 ± SD 26.1 days following TCPC. Differential perfusion ratio and percentage uptake of the radiotracer in the upper, middle and lower zones of each lung were calculated. Post-foot injection [inferior vena cava (IVC) injection], preferential flow to the lungs was as follows: left lung (n = 13, 30.2%), right lung (n = 13, 30.2%) and uniformly to both lungs (n= 17, 39.6%). Post-arm injection [superior vena cava (SVC) injection], preferential flow to the lungs was as follows: left lung (n = 13, 30.2%), right lung (n = 22, 51.2%) and uniformly to both lungs (n= 8, 18.6%). The middle zone was perfused the most in both lungs. Total lower zone mean perfusion was higher than the upper zone following both SVC injection and IVC injection (34.1 ± SD 5.3% vs 17. ± SD 4.1% and 33 ± SD 5.0% vs 17.5 ± SD 4.1%, respectively). In patients with bilateral SVC, post-IVC injection, 6 (75%) patients had preferential flow to the right lung, whereas post-SVC injection, preferential flow to the left lung was visualized in 7 (87.5%) patients. Following TCPC, IVC blood was distributed uniformly in both lungs. SVC blood preferentially perfused the right lung. The middle zone was perfused the most in both lungs.

Species relative dominance by basal area was assessed along an agro ecological gradient in the Mau Forest Complex (MFC). Trees were recorded per species and diameter at breast height (D1.3) for size class D1.3 ≥ 10 cm in 60 quarter hectare plots distributed in 7 agro ecological zones (AEZ) namely LH1, LH2, LH3, LH4, UH0, UH1 and UH2. Basal area per species was used to calculate species relative dominance i.e. the proportion of basal area by a species to the total basal area of the AEZ. Species associations were analysed as the group of highly ranked species in each AEZ. Sorensons similarity index was used to calculate the proportion of similar species among AEZ. Analysis of variance compared basal area among AEZ and Tukey’s multiple comparison test used to identify specific AEZ with differences. Tabernaemontana stapfiana (Britten) was ranked first in LH1, UH1 and UH0 with relative dominance values of 22.66%, 22.89% and 30.73% respectively. It was however not recorded in any other AEZs. Dombeya goetzenii (K. Schum) occurred in 6 of the 7 AEZs but had moderate dominance values in each of the 6 AEZs. The sum of dominance values per species in all AEZs indicated no species mono-dominance and different species dominated at different AEZs. Co-dominance resulted in species associations like Tabernaemontana-Allophylus-Eke-bergia-Albizia in LH1, Juniperus-Dombeya-Casearia-Prunus in LH2, Acokanthera-Cussonia-Olea-Teclea in LH4 and Tabernaemontana-Syzygium-Podocarpus-Neoboutonia in UH1. Species richness was highest in UH1 and had the highest similarity indices with those of other AEZs. The UH1 had a species similarity of 67% with LH1, 63% with LH2 and 56% with LH4. However, species in the very humid zone UH0 differed with those of the drier lower highland zones (UH0 vs LH3 and vs LH4 = 31% and 37% respectively). Basal area differed significantly among AEZ ( = 3.76) showing that they differ in stocking levels. Tukeys test showed that high potential zones of LH1, LH2, UH0, UH1 did not differ and similarly the lower potential zones; LH3 and LH4. The results show that the variation of species and forest stocking in the MFC is strongly influenced by AEZ and proposes future biomass mapping to be done along AEZ.

The study aimed at determining thrips species composition and thrips population density on French bean planted as a sole crop and as an intercrop with either sunflower, Irish potato, or baby corn, in various combinations. Field experiments were conducted in two seasons to examine: (1) thrips population development and thrips species composition over time, (2) effect of intercrops on thrips population density and natural enemies, and (3) effect of intercrops on French bean yield. The experiments were conducted at the Kenya Agricultural Research Institute, Embu, Kenya in a randomized complete block design with four replicates. The thrips population on French beans increased with time. It showed a peak at the flowering stage then started declining when the crops were nearing senescence. French beans hosted four thrips species, Megalurothrips sjostedti (Trybom), Frankliniella schultzei (Trybom), Frankliniella occidentalis (Pergande), and Hydatothrips aldolfifriderici (Karny) (all Thysanoptera: Thripidae) in order of decreasing abundance. The main thrips species on Irish potato and sunflower was F. schultzei. Baby corn hosted only Frankliniella williamsi (Hood) and Thrips pusillus (Bagnall). A monocrop of French bean hosted more thrips than a French bean intercrop mix. Thrips natural enemies such as Orius spp. and Ceranisus spp. were recorded in all crop plants but in especially high numbers on French bean and baby corn, respectively. Plots with French bean alone had about 1.4 times higher yields compared to intercropped plots of French bean with sunflower and French bean with baby corn. However, the percentage of pods that could get rejected on the market due to thrips damage was highest on plots with French bean alone (68 and 63%) and lowest on plots with French bean and baby corn (35 and 37%) in the first and second seasons, respectively. This study showed that a complex of thrips is found in the field and its composition varies with crop stage and species. Intercropping French bean with other crops compromises on French bean yield but reduces damage to the French bean pods, thereby enhancing marketable yield.