Large Infestations Research Articles

The invasion threat of the emerging alien cactus Cylindropuntia pallida (Rosa), F.M. Knuth in South Africa and the potential for control using herbicides

The emerging alien cactus Cylindropuntia pallida (Rose) F.M. Knuth originates from northern Mexico and introduced into South Africa in 1940s as an ornamental plant. Multiple populations of C. pallida have been detected in various areas of South Africa. C. pallida has effective propagule dispersal and rapid recruitment making it a likely key future invader, and thus, is a target for eradication in South Africa. To eradicate C. pallida populations, a foliar spray (i.e. using a 2% concentration of herbicide with fluroxypyr and triclopyr) has been applied to plants in nine populations, with population sizes ranging between 535 and 2701 plants and populations covering areas of 100 –1000 ha. The aims of the study were to investigate the efficacy of the foliar spray method used to eradicate C. pallida; to investigate the impacts of C. pallida invasions on native vegetation integrity; to apply species distribution models (SDMs) to identify suitable climates for C. pallida in South Africa; and to document the biomes vulnerable to the negative impact of C. pallida in South Africa. Results show that foliar spray killed many C. pallida plants (mean percentage of dead plants ± SE, 83.3 ± 6.4; n = 9; range, 70–96%), with adult plants taking about 2 months to die completely. The efficacy of the herbicide was not affected by plant size or the concentration of the herbicide used. The invaded site had significantly greater vegetation cover which persisted across winter compared to the uninvaded site, but the latter site’s vegetation cover significantly dropped in winter. Also, the invaded site had lower plant species diversity than the uninvaded site and was dominated by species in the Poaceae and Asteraceae plant families. Additionally, a normalised difference vegetation index (NDVI) analysis shows that the uninvaded site has higher vegetation cover and health than the invaded site wherein a notable decline in vegetation health was observed between 2019 and 2022. A large area (> 15 million hectares) was predicted to be suitable for invasion by C. pallida in provinces with arid and warm temperate climates - the fynbos and grassland biomes are the most vulnerable. Because of the observed negative impacts, high environmental compatibility, and high cost of clearing large infestations, we advocate for considering the biocontrol method for effectively managing C. pallida invasion in South Africa.

Repurposing Waste from Aggressive Acacia Invaders to Promote Its Management in Large Invaded Areas in Southwestern Europe.

Several Acacia species are aggressive invaders outside their native range, often occupying extensive areas. Traditional management approaches have proven to be ineffective and economically unfeasible, especially when dealing with large infestations. Here, we explain a different approach to complement traditional management by using the waste from Acacia management activities. This approach can provide stakeholders with tools to potentially reduce management costs and encourage proactive management actions. It also prioritizes potential applications of Acacia waste biomass for agriculture and forestry as a way of sequestering the carbon released during control actions. We advocate the use of compost/vermicompost, green manure and charcoal produced from Acacia waste, as several studies have shown their effectiveness in improving soil fertility and supporting crop growth. The use of waste and derivatives as bioherbicides or biostimulants is pending validation under field conditions. Although invasive Acacia spp. are banned from commercialization and cultivation, the use of their waste remains permissible. In this respect, we recommend the collection of Acacia waste during the vegetative stage and its subsequent use after being dried or when dead, to prevent further propagation. Moreover, it is crucial to establish a legal framework to mitigate potential risks associated with the handling and disposal of Acacia waste.

A New Dataset and Comparative Study for Aphid Cluster Detection and Segmentation in Sorghum Fields.

Aphid infestations are one of the primary causes of extensive damage to wheat and sorghum fields and are one of the most common vectors for plant viruses, resulting in significant agricultural yield losses. To address this problem, farmers often employ the inefficient use of harmful chemical pesticides that have negative health and environmental impacts. As a result, a large amount of pesticide is wasted on areas without significant pest infestation. This brings to attention the urgent need for an intelligent autonomous system that can locate and spray sufficiently large infestations selectively within the complex crop canopies. We have developed a large multi-scale dataset for aphid cluster detection and segmentation, collected from actual sorghum fields and meticulously annotated to include clusters of aphids. Our dataset comprises a total of 54,742 image patches, showcasing a variety of viewpoints, diverse lighting conditions, and multiple scales, highlighting its effectiveness for real-world applications. In this study, we trained and evaluated four real-time semantic segmentation models and three object detection models specifically for aphid cluster segmentation and detection. Considering the balance between accuracy and efficiency, Fast-SCNN delivered the most effective segmentation results, achieving 80.46% mean precision, 81.21% mean recall, and 91.66 frames per second (FPS). For object detection, RT-DETR exhibited the best overall performance with a 61.63% mean average precision (mAP), 92.6% mean recall, and 72.55 on an NVIDIA V100 GPU. Our experiments further indicate that aphid cluster segmentation is more suitable for assessing aphid infestations than using detection models.

First record of Caliothrips phaseoli Hood, 1912 (Thysanoptera: Thripidae) causing damage to forage grasses

This paper reports the first record of Caliothrips phaseoli Hood, 1912 (Thysanoptera: Thripidae) causing damage to forage grasses of the species Panicum maximum in the pasture formation phase. Due to the damage observed, it is assumed that the occurrence of these insects at the beginning of the grass implementation phase can, in large infestations, reduce the photosynthetic area of ​​the plants, delaying their growth and consequently the formation of the pasture.

Drone microrelief analysis to predict the presence of naturally regenerated seedlings

Three-dimensional (3D) mapping and unmanned aerial vehicles (UAVs) are essential components of the future development of forestry technology. Regeneration of forest stands must be ensured according to the law in the required quality and species composition. Forest management focuses on the optimization of economic costs and quality-assured seedlings. Predicting the suitability of the plots’ environment for natural forest regeneration can contribute to better strategic planning and save time and money by reducing manual work. Although the savings may be considered negligible on small forested plots, they are significant for large cleared areas, such as those harvested after large beetle infestations or strong windstorms, which are increasingly common in European forests. We present a methodology based on spatial analysis and 3D mapping to study the microrelief and surrounding of recently cleared areas. We collected data on four plots in the spring and autumn of a single year after the harvest of four Norway spruce [Picea abies (L.) Karst.] stands near Radlice, Czechia using a multirotor Phantom 4 Pro UAV with a red, green, blue (RGB) camera. We used RGB imagery to compute microrelief data at a very high spatial resolution and the surrounding forest stands after harvesting. We used the microrelief data to estimate the amount of water accumulation and incoming solar radiation across the sites. Based on presence data of newly-established seedlings, we used linear mixed effects models to create a suitability map for each site. Model variables included topographic wetness index, solar area radiation, fencing, type of soil preparation, and distance to the nearest mature forest edge. The topographic wetness index and fencing had strong positive influence on seedling establishment, while solar radiation had a negative influence. Our proposed methodology could be used to predict spontaneous regeneration on cleared harvest areas, or it can estimate how much area is suitable for regeneration, which can lead to important investment decisions.

Management of Haemaphysalis longicornis (Acari: Ixodidae) on a cow-calf farm in East Tennessee, USA.

Haemaphysalis longicornis Neumann is an exotic and invasive tick species rapidly expanding across the United States. Large infestations of these ticks on cattle can cause anemia, and in eastern regions of the country, they are transmitting Theileria orientalis Ikeda within herds. Methods for managing H. longicornis in the environment are rarely successful and rely on chemicals. To document population effects from producer management decisions, we investigated the change in H. longicornis populations to different tick management practices chosen by producers at 3 different H. longicornis-infested farms. Farm 1 kept a closed herd, chose to cut brush monthly, used on-animal acaricides, and allowed us to drag weekly. Farm 2 kept an open herd, chose to cut brush yearly, did not use on-animal acaricides, and allowed us to drag for ticks weekly/monthly. Farm 3 kept an open herd, chose to cut brush yearly, used on-animal acaracides, and allowed us to drag for ticks monthly. We assessed H. longicornis populations responding to those methods over time using active surveillance methods at each farm. Management decisions on Farms 1 and 3 significantly reduced H. longicornis on farms. Importantly, Farm 1 management decisions reduced the chance of a tick being present by 90%; the number of questing ticks collected fell from 5,000 to 12 H. longicornis in 2 years. Therefore, combined management strategies such as keeping a closed herd, use of on-animal chemical control, mechanical control, and reducing the amount of vegetation on farms were effective ways for producers to manage Haemaphysalis longicornis Neuman (Ixodidae).

Where have all the grouse ticks gone? Apparent decline in collections of Haemaphysalis chordeilis Packard.

Haemaphysalis chordeilis Packard, also known as the grouse or bird tick, is a three-host tick native to North America. Literature from the early 20th century reported a widespread distribution of this tick across the US and Canada. As its name implies, ground-dwelling birds such as grouse and quail were frequent hosts, and occasionally large infestations were reported in domestic flocks making it a pest of economic importance. However, after the mid-1900's records of this species appear scarce, and a number of more recent studies of ticks on birds (including ostensibly favored host species) did not detect it. To confirm this perception with data, we conducted a literature search for collection records of this species and compared the records across two eras (pre-1965 and post-1965), finding very few records of H. chordeilis in recent years, despite increased attention brought to this genus by the detection of exotic Haemaphysalis longicornis Neumann populations in the eastern US. We also compiled a list of studies after 1965 that examined appropriate hosts for ectoparasites but failed to find H. chordeilis. We interpret the apparent decline of ticks in the context of documented population declines in several major host species over the same time frame and discuss whether ectoparasite populations should be subject to the same conservation consideration as their hosts.

Prolonged phloem feeding by the spotted lanternfly, an invasive planthopper, alters resource allocation and inhibits gas exchange in grapevines.

Spotted lanternfly (Lycorma delicatula White; SLF) is a phloem‐feeding planthopper invasive to the Eastern United States that can feed on a range of wild and cultivated plant species. Since its 2014 introduction in the United States, large infestations and subsequent economic damage have been reported in cultivated grapevines, but no studies have detailed grapevine physiological responses to SLF phloem feeding. This study investigated grapevine‐SLF interactions, detailing how different infestation densities affect leaf gas exchange and end‐season concentrations of nonstructural carbohydrates and nitrogen in vegetative and perennial tissues of two Vitis species. Effects on fruit ripeness parameters and dormant bud freeze tolerance were examined, in addition to other year‐after effects. Phloem feeding by low densities (≤4 SLF shoot−1) had minimal effects, whereas greater densities (5–15 SLF shoot−1) increasingly affected carbohydrate and nitrogen dynamics in both Vitis species. Phloem feeding substantially affected starch and, to a lesser extent, total nitrogen concentrations of woody roots. Prolonged exposure strongly reduced leaf gas exchange. We conclude that intensive late‐season phloem feeding by large adult SLF population densities (≥8 SLF shoot−1) can induce carbon limitation, with the potential for negative year‐after effects in cases of severe belowground carbon depletion. This work presents novel insights into SLF‐grapevine interactions, identifies avenues of future SLF‐plant research, and assists the development of action thresholds for SLF management in vineyards.

Rare presentations of ocular enterobiasis - Case reports.

Enterobius vermicularis, also known as pinworm or threadworm, is a large intestinal nematode which has a high prevalence among children and peripubertal age in our country. Transmission usually occurs by autoinfection like finger contamination of the embryonated eggs deposited by the gravid female worm on the perianal and perineal region. Globally, only a few reports are there regarding the isolation of the parasite from extra-intestinal sites. These are two rare case reports of ocular enterobiasis. The first case was a middle-aged female and the second one was a 14-year-old girl, both of whom were referred from other tertiary care hospitals to Calcutta School of Tropical Medicine and who presented with discharge of live motile worms from their eyes (conjunctiva). In both the cases, identification was done by saline wet mount and direct microscopy of a gravid female worm. Plano-convex embryonated eggs were also observed. The oval embryonated eggs, plano-convex in shape, and the gravid female, with its cervical alae near the anterior end and straight thin pointed tail, were identified under the microscope. Although E. vermicularis is a very common large intestinal parasitic infestation of children and adolescents, it can also rarely be isolated from unusual sites, which should be taken into account for effective diagnosis and treatment.

Determination of some factors leading to the infestation of Ips sexdentatus in crimean pine stands

Large infestations of bark beetles result in the death of many trees in large forest areas.Ecological-based modeling approaches that include the factors causing infestations are important for accurately predicting whether these infestations will occur, suggesting ways to avoid large infestations, and understanding sustainable forest management. In the present study, the effects of some stand characteristics and topographical and climatological factors on the of Ips sexdentatus infestation at pure and mixed Crimean pine stands were evaluated. Ten factors were considered as important for predicting the predisposition of a pine forest to infestation: stand structure, site index, crown closure, stand age, aspect, slope, elevation, maximum temperature, precipitation, and solar radiation. Ten conditioning layers were overlayed separately with a beetle infestation map using geographic information system (GIS) to investigate how the beetle damage changed according to these factors and how much damage it caused. Binary logistic regression analysis was used to determine how combinations of the 10 factors affected beetle infestations and which of the factors were most damaging. It was found that the stand structure, crown closure, site index, stand age, slope, elevation, maximum temperature, precipitation, and solar radiation were definite factors in I. sexdentatus infestation; the aspect was not found to be a strong factor. The crown closure was the most significant factor affecting I. sexdentatus infestation followed by maximum temperature, elevation, slope, precipitation, solar radiation, stand age, site index, and stand structure. The crown closure, stand structure, maximum temperature, solar radiation, and forest stand area variables were significantly included in the logistic regression model.

A novel stem-applied herbicide-capsule methodology for control of the invasive cactus Cereus uruguayanus

Cereus uruguayanus R.Kiesling is a naturalised, non-opuntioid cactus that has formed large and dense infestations at several locations in the northern Australian rangelands. Of the Cactoideae subfamily, it typically grows into a large, spiny, single- or multi-stemmed candelabra-shaped cactus. While not classified as a Weed of National Significance (WONS) in Australia, it is causing increasing concern, with some local governments declaring it under their local laws. Recent research has identified several herbicides that control C. uruguayanus by using a range of techniques, including basal-bark, cut-stump, foliar, and stem injection applications. Of these, stem injection is one of the recommended options where weeds grow among desirable vegetation because the risk of non-target damage is minimised. This study evaluated C. uruguayanus control using a range of encapsulated dry-formulation herbicides from BioHerbicides Australia (BHA Pty Ltd), using their novel stem-implantation system (Injecta®). In May 2018, an experiment was established in central Queensland to compare the efficacy of six encapsulated herbicides (aminopyralid + metsulfuron-methyl, clopyralid, glyphosate, hexazinone, metsulfuron-methyl, triclopyr + picloram) against an untreated control. Glyphosate was the fastest-acting herbicide, followed by aminopyralid + metsulfuron-methyl and metsulfuron-methyl, with triclopyr + picloram much slower to act. Nevertheless, all four herbicides eventually caused high mortality (≥85%). In contrast, clopyralid and hexazinone were ineffective at the applied rates. Future research is recommended to compare the cost effectiveness of this system against other techniques, particularly those used for stem-injection applications.

Analytical Approach of Wave Transmission Coefficient through on Composite Hanging Breakwater

Conventional breakwater like a rubble mount is require large infestation, especially when that structure construct in deep water. Currently, innovations are needed to solve financial problems in building breakwaters. Composite hanging breakwater is proposed as a new solution in marine structure. Composite hanging breakwater made by both of stone and concrete or steel material consist of two-part are structural part and filler. Structural parts are piles, beams, and brackets made of concrete or steel. Filler material using of stone or other material. This structure has the advantage are cheaper than conventional breakwater, precast material, and the diameter of stone filler is relatively small. Until now, the performance of composite hanging breakwater is unknown. Commonly, the key performance indicator of breakwaters is wave transmission and represent by the waves transmission coefficient. Therefore, in this study, an analytical equation of wave transmission coefficient was developed using the conservation of energy concept. Based on this equation shows that the wave transmission coefficient is influenced by both structure and wave parameter. After the equation has been obtained, then it is compared with previous research. Research that has been used as a comparison includes research by Weigel (1960), Abul-Azm (1993), Liu and Abbaspour (1982), Abu-Azm (1993), Heikal (1997), Koraim (2005), Rage and Koraim (2010), and Koraim (2014). Wave parameter represents by waves steepness implicitly, and structure parameter is represented by the permeability of structure, relative length, and relative depth. The greater the value both of relative depth and length, the smaller value of wave transmission coefficient. The greater the value of structure permeability, the smaller the value of wave transmission coefficient. When the D/h is zero, the wave transmission coefficient is equal to one and when the D/h is equal to one, the transmission coefficient is close to or equal to zero. When the D/h value is less than 0.5, the Kt value in this present study is lower than the Kt value in previous studies for the same D/h value, and when the D/h value is greater or equal to 0.5 then the Kt value is close or the same with the previous study.

A global review of the invasive aquatic weed Cabomba caroliniana [A. Gray] (Carolina fanwort): Current and future management challenges, and research gaps

AbstractCabomba caroliniana [A. Gray] (Cabombaceae), also known as Carolina fanwort, is a native of South America which has now become a serious invasive threat to aquatic systems across the world. Its capacity to inundate a water column with active fragments and seeds makes the containment and management of C. caroliniana a challenging task and an ecological and economic necessity. Previous and current management efforts have been largely focussed on biological control, drawdown methods, herbicide application, manual removal, shading and the use of a concentrated urea solution. Although these methods have shown some success in reducing large infestations, they are generally considered to be unreliable when used alone since they are unable to contain or reduce the species in the long term with a single‐use treatment protocol. It is feared that, without effective, improved and integrated management strategies, C. caroliniana will continue to invade aquatic ecosystems beyond its already wide current distribution, thus causing increased global economic and environmental damage. This review will therefore explore the biology and distribution of C. caroliniana and examine the current and previous attempts for its global management. It will also evaluate the most successful current treatments and clarify where research efforts are urgently needed for the improved long‐term extirpation of this aquatic invader.

Herbicide Options to Control Naturalised Infestations of Cereus uruguayanus in Rangeland Environments of Australia.

While there are many high profile Opuntioid cactus species invading rangeland environments in Australia, Cereus uruguayanus Ritt. ex Kiesl. has also naturalised and formed large and dense infestations at several locations. With no herbicides registered for control of C. uruguayanus in Australia, the primary aim of this study was to identify effective herbicides to control it using a range of techniques. This involved a large screening trial of twelve herbicides and four techniques, followed by a rate refinement trial for cut stump applications and another to test residual herbicides. Despite most treatments (except monosodium methylarsonate (MSMA)) taking a long time to kill plants, at least one effective herbicide was identified for basal bark (triclopyr/picloram), cut stump (aminopyralid/metsulfuron-methyl, glyphosate, metsulfuron-methyl, triclopyr/picloram, triclopyr/picloram/aminopyralid), stem injection (glyphosate, MSMA, triclopyr/picloram/aminopyralid) and foliar applications (aminopyralid/metsulfuron-methyl, MSMA, triclopyr, triclopyr/picloram/aminopyralid) due to their ability to kill both small and large plants. Ground application of residual herbicides was less conclusive with neither hexazinone nor tebuthiuron causing adequate mortality at the rates applied. This study has identified effective herbicides for the control of C. uruguayanus using several techniques, but further research is needed to refine herbicide rates and develop integrated management strategies for a range of situations and infestation sizes and densities.

Robotic Spot Spraying of Harrisia Cactus (Harrisia martinii) in Grazing Pastures of the Australian Rangelands.

Harrisia cactus, Harrisia martinii, is a serious weed affecting hundreds of thousands of hectares of native pasture in the Australian rangelands. Despite the landmark success of past biological control agents for the invasive weed and significant investment in its eradication by the Queensland Government (roughly $156M since 1960), it still takes hold in the cooler rangeland environments of northern New South Wales and southern Queensland. In the past decade, landholders with large infestations in these locations have spent approximately $20,000 to $30,000 per annum on herbicide control measures to reduce the impact of the weed on their grazing operations. Current chemical control requires manual hand spot spraying with high quantities of herbicide for foliar application. These methods are labour intensive and costly, and in some cases inhibit landholders from performing control at all. Robotic spot spraying offers a potential solution to these issues, but existing solutions are not suitable for the rangeland environment. This work presents the methods and results of an in situ field trial of a novel robotic spot spraying solution, AutoWeed, for treating harrisia cactus that (1) more than halves the operation time, (2) can reduce herbicide usage by up to 54% and (3) can reduce the cost of herbicide by up to $18.15 per ha compared to the existing hand spraying approach. The AutoWeed spot spraying system used the MobileNetV2 deep learning architecture to perform real time spot spraying of harrisia cactus with 97.2% average recall accuracy and weed knockdown efficacy of up to 96%. Experimental trials showed that the AutoWeed spot sprayer achieved the same level of knockdown of harrisia cactus as traditional hand spraying in low, medium and high density infestations. This work represents a significant step forward for spot spraying of weeds in the Australian rangelands that will reduce labour and herbicide costs for landholders as the technology sees more uptake in the future.

Successful Eradication of the Asian Longhorn Beetle, Anoplophora glabripennis, from North-Eastern Italy: Protocol, Techniques and Results.

Simple SummaryAnoplophora glabripennis (Coleoptera: Cerambycidae) is an extremely polyphagus Asian wood-boring beetle accidentally introduced into North America and Europe. In 2009, an infestation was found in the municipality of Cornuda (Veneto Region, Italy). In order to eradicate the pest, several actions were immediately undertaken in the delimitated infested and buffer zones: tree visual inspections twice a year, felling and chipping of infested and suspected trees, trapping protocols, mitigation plans based on substitution of felled trees with new plants, and citizen alerts. The program lasted 11 years, after which the species was declared eradicated from the region. During the eradication program more than 36,000 trees were surveyed and more than 2000 trees were felled. Trees most affected by the pest were birches, elms, maples, and willows. This paper describes all the actions undertaken during the eradication program, providing a protocol that can also be used for future eradications of the species.The Asian Longhorn Beetle (ALB), Anoplophora glabripennis (Coleoptera: Cerambycidae), is an important and extremely polyphagous wood-boring beetle native to Asia. In the 1990s, ALB was accidentally introduced into North America and Europe. In 2009, a large ALB infestation was found in the Veneto Region (north-eastern Italy), in the municipality of Cornuda (Treviso province). Eradication actions were immediately undertaken, based on delimitation of infested and buffer zones, tree visual inspections, felling and chipping of infested trees, trapping protocols, and citizen alerts. A total of 36,361 trees, belonging to 16 genera, were surveyed twice a year over an area of 7594 hectares. In 2020, after 11 years of eradication measures, the ALB population of Cornuda was declared eradicated. Overall, 2361 trees belonging to 8 genera were felled and destroyed, of which 1157 were found to be infested by ALB. This paper describes all the actions carried out and the procedures applied in order to eradicate ALB from north-eastern Italy, providing a useful example for current and future ALB eradication programs.

Evaluating the biocontrol potential of insects auxiliary and bio- insecti-cide extracted from Citrullus colocynthis against Parlatoria blanchardi in date palm in Saoura Oases, Algeria

Saoura, is an Algerian desert region, characterized by a height density of date palm trees (more than 300000).Despite this high density, the produc-tion of dates has seen a continuous decrease due to multiple reasons includ-ing increasing water salinity, the spread of many fungal diseases and insect pests where the most serious is Parlatoria blanchardi. The random use of Malathion during the invasions of desert locusts caused an ecological imbal-ance, where the majority of the natural enemies of date palm scale (DPS) disappeared, as consequence the population of DPS expanded increasingly. This study aims to find alternative methods to control pests taking into con-sideration the ecological balance. For this purpose, three entomofauna in-ventories were carried out to study the dynamics of insect populations and for introduction and acclimatization of new auxiliary insects to biocontrol the large infestation of DPS. we also looked to find a biodegradable insecticide extracted from Citrullus colocynthis (desert plant pariah by insects due to its toxicity). By comparing the results we noticed that effectiveness of the colo-cynth aquatic extracts on the target insect was as high as 65.99 % however it’s side effects on ecosystem were negligible unlike Malathion which exter-minated over than 301 non-target insects where 68% are useful such as bees, butterflies, some entomophagous insects and even some vertebrate such as Oenanthe leucopyga. Finally, a phytochemical screening and toxico-logical studies are recommended to determine exactly which component in colocynth is more effective on DPS and its undesirable effect on human health.

Influence of plant protection methods on weediness and seed yield of meadow clover varieties in Primorskiy region

In the field of fodder production, in most cases, low-yielding, old-age grass stands are used. One of the reasons for this is the low availability of grass seeds. For example, over the past 20 years, the production of grass-clover seeds has reduced by 3.4 times. Therefore, priority should be given to the seed production of leguminous grasses (including meadow clover). A large infestation of the arable soil layer with seeds and buds of annual and perennial weeds in almost all arable land in the Primorskiy Region is the most critical factor in reducing the yield of cultivated crops. The development of practical techniques for clearing fields of weeds is one of the vital links in the technology of increasing the output of fodder crops. The research aims to establish the effect of agronomic practices of cultivation and means of protection on the seed yield of meadow clover in the natural and climatic conditions of the Primorskiy Region. Clover is a crop sensitive to herbicides, with a limited period of their application. Therefore, inter-row treatments were carried out before the rows were closed, and chemical treatments were applied before the budding phase to preserve wild pollinators and bees. The varieties Ogonek, SibNIIK-10 and regionalised Kommandor were evaluated. Experimental data on the impact of agronomic practices of meadow clover cultivation and plant protection methods on the weediness of its crops and the yield quality of seeds under the conditions of the Primorskiy region were obtained. The use of herbicides against the background of inter-row treatment during the second year of clover planting helped reduce the weed infestation from 58.3 to 70% and increase the seed yield by 1.1-1.3 times depending on the variety.

Life history and population dynamics of Aspidiotus nerii (Bouche, 1833), Homoptera: Diaspididae, Saissetia oleae (Olivier, 1751), Homoptera: Lecanidae and Pollinia pollini (Costa, 1857), Homoptera: Asterolecanidae on olive trees in the Blida Region (Algeria)

The work consists of a study on the level of infestation of the 3 species of olive-infused mealybugs at the two stations (Soumaa and Guerrouaou) in the Blida région, with particular attention to the évolution of Pollinia pollini (Asterolecanidae), Octaspidiotus nerii (Diaspididae) and Saissetia oleae (Lecanidae). Unlike the Soumaa station, there is a large infestation in the Guerrouaou station by the three (most abundant) species with a high rate. The life cycle monitoring and the bio-ecology of these three pests were carried out through periodic population counts on the leaves and twigs of the tree from 08 August 2016 to 29 May 2017 in the wilaya of Blida. It appears that the study of the biology of P.pollini evolves in 2 annual generations (the first is the spring generation; the second is through the summer. The larval stage remains the most abandoned compared to other developmental stages. The South orientation seems the most affectionate by P.pollini. We can conclude that O .nerii has two generations « spring and automne » depending on climatic factors. The East and West exposure represent the places most sought after by this scale where we found a relative abundance between larvae and adult females. S. oleae develops only one generation per year (automnal génération). Females are the most abundant in Soumaa station and larvae in Guerrouaou station. The eastern orientation and the automne season are the most favourable for the development of the mealybug.

The effects of soil tillage techniques on weed flora in high input barley systems in northern Spain

In barley cropping systems of northern Spain, agronomic practices and weather conditions are key components of weed control efficacy. We compared the short-term effects of conventional tillage with minimum tillage (MT) and zero tillage (ZT), in barley monoculture and barley rotation systems. Weed density and weed species number were measured at tillering and flowering barley stages. We found that tillage system can influence weed density and weed species establishment due to, in part, the available light for weed seeds. The results obtained indicate that the MT system facilitates the prevalence of the grass weed Bromus diandrus Roth (50.37%) and the annual dicots Galium aparine (L.) and Buglossoides arvensis (L.) I.M. Johnst. abundant were high in the MT system too, 43.71% and 43.97% respectively. The germination of these species showed a high dependence on light availability. We saw that barley-monoculture plots had a large infestation of Bromus (71.29%) and barley-rotated plots presented more infestation of Galium and Buglossoides (74.36% and 84.4%, respectively). After herbicide application, weed infestation in conservation systems was reduced in barley-rotated plots compared with barley-monoculture. If conservation systems avoided the presence of dominant weeds, the weight of each weed species was balanced within competitive relationships of the cropping systems. Our results confirmed that MT and ZT systems favour different weed species emergences in barley-rotated plots. The combination of MT and barley-rotated cropping system resulted in greater weed diversity and lower total weed density.