Recovery and germination of Prosopis juliflora (Sw.) DC seeds after ingestion by goats and cattle

Prosopis juliflora is a perennial shrub introduced in the 1980s to the Baringo District in central Kenya, and became highly invasive starting around the late 1990s. This period coincides with a shift of the composition of ruminant herds from formerly cattle to goats in this area. To assess the possible role of this shift in herd structure on P. juliflora spread, we conducted feeding trials and germination tests to determine the capacity of seeds to survive the passage through the intestinal tract of goats and cattle, comparing germination with chemically scarified and untreated seeds. Recovery of seeds eight days after ingestion was lower from goats (7%) than from cattle (15%) dung. Germination dynamics were similar for seeds that had been manually extracted from pods with those recovered after intestinal passage. Chemically scarified seeds germinated fastest and reached a germination rate of 100% within five days. While no apparent scarification effect was observed, the main contribution of endozoochorous dispersal of Prosopis seeds is their release from the enclosing pod segments, their dispersal away from the mother plant and possibly the provision of nutrients by the dung for their establishment and initial growth.     

Determination of Festuca filiformis seedbank characteristics,seedling emergence and herbicide susceptibility to aid management in lowbush blueberry (Vaccinium angustifolium)

Festuca filiformis is a common perennial grass in lowbush blueberry fields, but little is known about the general biology, seedbank characteristics, seedling recruitment or susceptibility of seedlings to currently registered herbicides. The objectives of this research were to determine (i) the presence of F. filiformis seedbanks in lowbush blueberry fields, (ii) whether F. filiformis seedbanks accumulate near the soil surface in lowbush blueberry fields, (iii) the dormancy status of fresh F. filiformis seeds, (iv) the temporal patterns of seedling recruitment in established F. filiformis populations, (v) whether F. filiformis has a vernalisation requirement for flowering in lowbush blueberry and (vi) susceptibility of F. filiformis seedlings to various herbicides currently registered in lowbush blueberry. Festuca filiformis formed a seedbank in lowbush blueberry fields, with an average of 1660 ± 272–5680 ± 1409 seedlings m^?2 emerging from soil cores collected from two infested fields. Most seeds were located at the soil surface, providing opportunities for seedbank management through predation or burning. Fresh seeds lacked dormancy and readily germinated, although germination was reduced by dark conditions. New seedlings emerged in spring and autumn and required vernalisation to flower. Seedlings were susceptible to several currently registered herbicides in lowbush blueberry, although mortality rates were highest in plants treated with glufosinate, flumioxazin, glufosinate + flumioxazin and terbacil. Growers should avoid movement of seeds on machinery, and additional research should be conducted to determine the effects of registered herbicides on F. filiformis seedling recruitment under field conditions in lowbush blueberry.     

Distribution of Megastigmus aculeatus (Hymenoptera: Torymidae) and the levels of seed predation of Rosa multiflora (Rosaceae)

Rosa multiflora Thunb. (Rosaceae), an invasive plant that currently infests millions of hectares in the eastern half of the USA, was planted initially in the 1940s as a “living fence”, cover for game animals and for erosion control. The larvae of Megastigmus aculeatus var. nigroflavus Hoffmeyer (Hymenoptera: Torymidae) feed on the developing R. multiflora seeds and have the potential to reduce the seed output of R. multiflora. Rosehips were collected from 49 sites across eastern and southern Iowa, USA, to determine the presence and distribution of M. aculeatus, the larvae of which were found in 266 of the 979 (27%) rosehips that were dissected and at 31 of the 49 sites (63%) that were sampled. The levels of M. aculeatus infestation over 2–3 years were determined at three selected sites and it was documented that more seeds were aborted than were viable or contained wasp larvae. A negative relationship was observed between the numbers of both the aborted and the viable seeds and the probability of a rosehip being attacked by M. aculeatus, indicating that M. aculeatus females are not preferentially selecting rosehips with higher numbers of viable or aborted seeds for oviposition. There is a significant reduction in both the viable seeds and the aborted seeds in hips that have been attacked by M. aculeatus. Detailed knowledge of R. multiflora demography is necessary to determine the level of seed predation that is required to reduce the recruitment of new individuals into the population.     

Old and new association of Cotesia icipe (Hymenoptera: Braconidae) with alien invasive and native Spodoptera species and key stemborer species: implication for their management

BACKGROUND

Maize production in Africa is hindered by a myriad of biotic challenges, key among them being invasive and native lepidopteran stemborers. Recent invasion of the continent by fall armyworm, Spodoptera frugiperda, has further exacerbated the situation. Fortunately, Cotesia icipe was found to be very promising against S. frugiperda. However, the co-occurrence and interaction between S. frugiperda and the stemborers (Busseola fusca, Sesamia calamistis, and Chilo partellus) in maize agroecosystem may jeopardize the efficiency of C. icipe as a biocontrol agent of S. frugiperda. This study investigated the performance of C. icipe on S. frugiperda, Spodoptera littoralis and the stemborers. Specifically, the preference and acceptability of C. icipe to the host insects, the physiological suitability of the hosts for its development, and the effect of these hosts on the fitness parameters of the offspring were assessed.

RESULTS

Cotesia icipe accepted all the tested hosts, albeit with higher preference for Spodoptera species than for stemborers under multiple-choice tests. Also, the highest parasitism of up to 97% was recorded on S. frugiperda compared with parasitism on the stemborers of 43% in B. fusca. Moreover, physiological suitability and fitness traits (except for per cent female offspring) varied with host species, again being optimal on Spodoptera species.

CONCLUSION

Cotesia icipe demonstrated strong potential to control S. frugiperda in maize due to its high affinity for parasitization and developmental success in this host; and despite its non-specific parasitization, the presence of other hosts may not prevent its maximum control of S. frugiperda. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Effects of temperature and light on seed germination of ephemeral plants in the Gurbantunggut Desert,China: implications for vegetation restoration

Seed germination is a key transitional stage in plant life cycle and is strongly regulated by temperature and light. Therefore, research on the effects of temperature and light on seed germination is extremely meaningful for vegetation restoration, especially in desert ecosystems. Seeds of 28 ephemeral plants collected from the Gurbantunggut Desert of China were incubated at different temperatures (5°C/1°C, 15°C/5°C, 20°C/5°C, 25°C/10°C and 30°C/15°C) in 12-h light/12-h darkness or continuous darkness regimes, and the responses of seed germination to temperature and light and the germination speed were studied in 2016. Results showed that seed germination percentage of the 28 ephemeral plants significantly differed to temperature and light. We classified the studied plants as the following groups based on their responses to temperature: 1 low temperature responsed plants, 12 moderate temperature responsed plants, 7 high temperature responsed plants, 4 non-responsed plants and 5 plants of no germination. It should be noted that Corispermum lehmannianum Bunge is sensitive to both moderate and high temperatures. There were 4 groups of plant in response to light, i.e., 7 light responsed plants, 10 dark responsed plants, 6 light non-responsed plants and 5 plants of no germination. Based on seed germination speed of the 28 ephemeral plants, we divided them into 4 patterns of germination, i.e., very rapid, moderately rapid, moderate and slow. Combining variations of temperature, precipitation and sand dune types in the study area, we suggested that very rapid and moderately rapid germinated plants could be used to moving sand dunes in early spring during vegetation restoration, moderate germinated plants could be used to semi-fixed sand dunes in late autumn, and slow germinated plants could be used to sand plain in summer. Thus, seedling establishment and vegetation restoration would be improved by considering seed germination characteristics of these ephemeral plants in the Gurbantunggut Desert, China.     

Changes in seed bank size and dormancy characteristics of the glyphosate-resistant biotype of goosegrass (Eleusine indica[L.] Gaertn.)

A study on changes in the seed bank size of a glyphosate ( N -(phosphonomethyl)glycine)-resistant (R) Eleusine indica biotype was carried out on a naturally occurring infestation of a young oil palm plantation. The total number of shed seeds collected was 53% of the predicted potential total number of seeds produced by the plants. Ametryn ( N -ethyl- N' -(methylethyl)-6-(methylthio)-1,3,5-triazine-2, 4-diamine) was found to be able to control the R seed population in the soil. The periodicity of seedling emergence was influenced by rainfall subsequent to the 1 month period of seed shedding. Seed burial at 2, 10 and 20 cm depths showed that 39, 33 and 79%, respectively, of viable seed persisted in the soil after 2 years. Seeds in the state of enforced dormancy played an important role in maintaining the seed population throughout the 2 year period of burial in the soil.     

Predicting weed distribution at the regional scale in the native range: environmental determinants and biocontrol implications of Phyla nodiflora (Verbenaceae)

Alien plants produce severe environmental and economic losses in the territories they invade. Modelling the spatial distribution of alien species as a function of the environment in the native range has therefore become an essential first step in the struggle against invasions. Phyla nodiflora var. minor is a fast‐growing perennial herb native to South America that has spread through three continents, where it poses a major threat to biodiversity and significantly impacts on conservation and grazing systems, mainly in riparian areas. To assess the distribution of native Argentine populations of P. nodiflora as a function of the environment, we conducted long‐term roadside surveys and associated the occurrence of the plant with climatic, geographical, demographical and vegetation cover variables in a generalised linear mixed model. The plant was recorded in 230 of 431 sites, mostly east of 66°W and north of 39°S. According to the best model, which predicted the data 58% better than random assignment, its occurrence was associated with temperature variables (mean annual values and daytime range) and relative humidity. Based on these associations, we generated a presence probability map for the occurrence of P. nodiflora in southern South America. Understanding the environmental determinants of the distribution of weeds in their native range provides valuable baseline data to further manage the spread of alien species.     

Comparative life history characteristics of the mite predator Neoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) on mite and pollen diets

The food diversification strategy that can offer suitable nutrients as a diet for the natural enemies may possibly help to decrease pest populations by boosting the efficiency of predators. Therefore, my objective was to evaluate the effects of plant and animal diets on biological parameters of the phytoseiid mite Neoseiulus cucumeris (Oudemans). This predator that is a natural enemy of mites was reared on plant pollens (maize (Zea mays L.), sweet pepper (Capsicum annuum L.), mungbean (Vigna radiata L.), cucumber (Cucumis sativus L.), tomato (Lycopersicon esculentum Mill.), and rose (Rosa multiflora Thunb.), offered alone, and in combination with the prey mite Tyrophagus putrescentiae (Schrank). Results showed that N. cucumeris fed, developed and reproduced better when it was provided with plant and animal diets together, compared to pollens offered alone. The predator showed the most efficient capability for completion of life parameters (development, survival, fecundity, oviposition, longevity and instantaneous rate of increase) with maize and mungbean ingested pollens in combination with T. putrescentiae. The least competency was observed on cucumber and rose pollens used separately. The lowest developmental time of the predator from neonate larva to adult emergence, the highest immature survivorship, higher fecundity, long oviposition period, and the highest adult female's life span were observed when offered maize pollens along with T. putrescentiae compared to other treatments. Accordingly, the instantaneous rate of population increase (r_i) day^?1 was surpassed by N. cucumeris for the combination of pollen and T. putrescentiae diets than pollens utilized alone. It is determined that N. cucumeris can reproduce and develop more successfully on a food complex consisting of pollen and animal diets than any single diet. These findings reveal that pollen can be used by N. cucumeris as a suitable alternative food in periods when prey in the field is sparse or absent. Moreover, such propensity of predators to feed on food from plant origin increases their survival during periods when prey is locally scarce, but natural enemies might occur at the expense of an ability to utilize food as efficiently as specialized predators to boost the management strategies of pest species in field's ecosystem.     

Annual and herbaceous perennial native Australian plant species are symptomless hosts of Phytophthora cinnamomi in the Eucalyptus marginata (jarrah) forest of Western Australia

Resistant annual and herbaceous perennial plant species were identified as key hosts which allow Phytophthora cinnamomi to persist on severely impacted black gravel sites within the Eucalyptus marginata (jarrah) forest of southwest Western Australia. Of the annual and herbaceous perennial plant species present on black gravel sites, 15 out of 19 species were found to be hosts of P. cinnamomi, and 10 of these were symptomless hosts. In particular, the native annual Trachymene pilosa and the two native herbaceous perennials Stylidium diuroides and Chamaescilla corymbosa were commonly found to be hosts of the pathogen. Species from 12 new genera including three from new families (Crassulaceae, Droseraceae and Primulaceae) are reported for the first time to be hosts of P. cinnamomi. The species from which P. cinnamomi was recovered were the native species: Chamaescilla corymbosa, Crassula closiana, Drosera erythrorhiza, Hydrocotyle callicarpa, Levenhookia pusilla, Paracaleana nigrita, Podotheca angustifolia, Pterochaeta paniculata, Rytidosperma caespitosum, Siloxerus multiflorus, Stylidium diuroides and Trachymene pilosa, and the introduced annual weeds Hypochaeris glabra, Lysimachia arvensis and Pentameris airoides.     

Effects of interactions between host plants and selective insecticides on larvae of Plutella xylostella L. (Lepidoptera: Yponomeutidae) in the laboratory

The residual toxicity of two selective insecticides, teflubenzuron (acylurea) and Bacillus thuringiensis Berliner ssp. aizawai (microbial), to laboratory and field strains of Plutella xylostella L. was shown in the laboratory to be significantly affected by leaf nutritional status, other host-plant resistance factors, cultivation method and plant age. With plants offering some degree of host-plant resistance, the toxicity of the insecticides was either increased or decreased compared with highly susceptible plants, depending on the specific nature of the plant-herbivore interaction. Differences in residual toxicity of the insecticides varied up to nine-fold on different host plants (=host-plant- + insecticide-induced mortality) despite less than four-fold differences in P. xylostella mortality in controls (=host-plant-induced mortality alone). Host-plant nutritional status also had a substantial effect on the damage potential of larvae. Different response times by P. xylostella to the two insecticides tested on host plants of varying nutritional status were related to the contrasting modes of action of the respective active ingredients. The present studies suggest that insecticides applied to Brassica oleracea L. var. capitata with partial plant resistance may contribute to improved control of P. xylostella. A conceptual model is used to describe likely mortality responses by macrophagous larvae to insecticides applied to plants of varying resistance status. The implications of the findings in relation to the integrated management of P. xylostella are considered.     

Assessment of ecological quality in Northwest China (2000-2020) using the Google Earth Engine platform: Climate factors and land use/land cover contribute to ecological quality

The ecological quality of inland areas is an important aspect of the United Nations Sustainable Development Goals (UN SDGs). The ecological environment of Northwest China is vulnerable to changes in climate and land use/land cover, and the changes in ecological quality in this arid region over the last two decades are not well understood. This makes it more difficult to advance the UN SDGs and develop appropriate measures at the regional level. In this study, we used the Moderate Resolution Imaging Spectroradiometer (MODIS) products to generate remote sensing ecological index (RSEI) on the Google Earth Engine (GEE) platform to examine the relationship between ecological quality and environment in Xinjiang during the last two decades (from 2000 to 2020). We analyzed a 21-year time series of the trends and spatial characteristics of ecological quality. We further assessed the importance of different environmental factors affecting ecological quality through the random forest algorithm using data from statistical yearbooks and land use products. Our results show that the RSEI constructed using the GEE platform can accurately reflect the ecological quality information in Xinjiang because the contribution of the first principal component was higher than 90.00%. The ecological quality in Xinjiang has increased significantly over the last two decades, with the northern part of this region having a better ecological quality than the southern part. The areas with slightly improved ecological quality accounted for 31.26% of the total land area of Xinjiang, whereas only 3.55% of the land area was classified as having a slightly worsen (3.16%) or worsen (0.39%) ecological quality. The vast majority of the deterioration in ecological quality mainly occurred in the barren areas Temperature, precipitation, closed shrublands, grasslands and savannas were the top five environmental factors affecting the changes in RSEI. Environmental factors were allocated different weights for different RSEI categories. In general, the recovery of ecological quality in Xinjiang has been controlled by climate and land use/land cover during the last two decades and policy-driven ecological restoration is therefore crucial. Rapid monitoring of inland ecological quality using the GEE platform is projected to aid in the advancement of the comprehensive assessment of the UN SDGs.     

Note: Flight capacity,parasitism and emergence of five<Emphasis Type="Italic">Trichogramma</Emphasis> (Hymenoptera: Trichogrammatidae) species from forest areas in Brazil

The flight and parasitism capacities and emergence rate of fiveTrichogramma species [T. acacioi (Brun),T. bruni (Nagaraja),T. demoraesi (Nagaraja),T. maxacalii (Voegelé & Pointel) andT. soaresi (Nagaraja)] were compared. The flight capacity of these parasitoids was assessed in test units. A tube was placed inside each test unit with a piece of card with 300Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs parasitized by one of theTrichogramma species. The emerged adults inside the test units were classified according to their position as flyers, non-flyers and walkers. Cards withA. kuehniella eggs, parasitized by one of theTrichogramma species, were assessed to determine the parasitism rate and emergence of these natural enemies. The data were submitted to analysis of variance and the means compared by the Scott-Knott test at 5% probability.Trichogramma maxacalii exhibited better flight capacity than the other species, in addition to good parasitism rate and high percentage of emergence. http://www.phytoparasitica.org posting May 10, 2007.     

Seasonal dynamics of the pink root fungus (Setophoma terrestris) in rhizosphere soil: Effect of crop species and rotation

Setophoma terrestris, a ubiquitous inhabitant of soil, causes pink root rot in various crops. In the present study, the density of S. terrestris was estimated by quantitative real-time PCR in onion and non-onion fields of Hokkaido, the northernmost island of Japan. Three-year observations in monoculture and rotation fields demonstrated that the fungus grew significantly from the third year onwards, and declined in fields planted with poor hosts (e.g., sugar beet and soybean) that produced few or no chlamydospores of S. terrestris. Seasonal analysis revealed that the population of S. terrestris consistently increased when the tops of onions fell over in summer, which is when root activity declines. However, the soil inoculum potential estimated by a seedling bioassay showed distinct seasonal patterns, which rose from post-harvest in winter and remained high until the subsequent planting in spring. Detailed surveys on depth distribution in an onion field detected a high population of S. terrestris in the effective layer (10–30 cm deep) but not below the hardpan (40 cm), implying that the fungus is intimately associated with roots. These results indicate that the proliferation of the fungus is closely related to root senescence and that over-wintered propagules play an important role in primary infections, affecting disease severity. The present study shows that the temporal dynamics of S. terrestris depend exclusively on the activity of infecting roots and provides circumstantial evidence on the deleterious impact of monoculture on crop production.     

山西省窖藏薯类块茎中2种短体线虫的种类鉴定

本文采用传统形态学与分子生物学相结合的方法,对采自山西省窖藏马铃薯和薯蓣块茎中的短体线虫进行了种类鉴定.结果 表明,从马铃薯块茎中分离出的短体线虫形态学特征与斯克里布纳短体线虫Pratylenchus scrib-neri一致,其SSU序列与P.scribneri美国群体相似性达99.8％.从薯蓣块茎中分离出的短体线虫...     

Olfactory and visual responses of the longlegged chafer Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae) in Qinghai Province, China

BACKGROUND: Monitoring traps and control methods are needed for the long‐legged chafer, Hoplia spectabilis Medvedev, which has recently reached outbreak numbers in pastureland of Qinghai Province, China. RESULTS: Field trapping experiments, using cross‐pane funnel (barrier) traps, showed that H. spectabilis adults were not significantly attracted to branches of the host plant Dasiphora fructicosa (L.) Rydb. However, beetles were slightly attracted to similar host plant branches infested by conspecific beetles, possibly owing to weakly attractive volatiles, primarily (Z)‐3‐hexenyl acetate, released from beetle‐damaged host leaves. This compound was weakly attractive when released from traps. However, H. spectabilis beetles showed strong visual responses to yellow‐ or white‐painted trap panes, with weaker responses to blue, red or green panes, and least response to black panes. Black traps at 0.2–1.5 m above ground intercepted significantly more beetles than traps at 2.5 m. The mean flight height based on trap catches was 0.88 m (SD = 0.76), yielding an effective flight layer of 1.9 m. Flight response of beetles to colored barrier traps occurred between 10:00 and 18:00, and peaked between 12:00‐14:00, when daily temperatures reached their maximum. CONCLUSION: Unbaited yellow or white cross‐pane funnel traps are recommended for both monitoring and mass‐trapping programs against this economically and ecologically important scarab beetle. Copyright © 2010 Society of Chemical Industry