Influence of weedy field margins on abundance patterns of the predatory bugs <Emphasis Type="BoldItalic">Orius</Emphasis> spp. and their prey,the western flower thrips (<Emphasis Type="BoldItalic">Frankliniella occidentalis</Emphasis>), on faba bean

The influence of weedy field strips on the abundance patterns of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and predatory bugs of Orius spp. (Hemiptera: Anthocoridae), on faba bean and on weeds was investigated in Adana province, Turkey, during 2005–2006. There were two treatments: in one treatment, weeds at the margins and inside the plots were regularly controlled by tillage; in the other treatment no weed control was done. Thrips and Orius were sampled by beating faba bean plants and weeds. Orius niger (Wolff) was the most abundant predatory insect species in faba bean and flowering weeds, with numbers of adults and nymphs significantly greater in plots with weedy margins than in weed-free plots. Flowering weeds did not contribute to the abundance of F. occidentalis on faba bean. Abundance of adults of Orius spp. did not coincide with the abundance of F. occidentalis on faba bean or weeds. There were significant negative associations for numbers of Orius spp. among faba bean and the weed species Lamium amplexicaule L. or Sinapis arvensis L. (P < 0.05), indicating movement of Orius individuals from the weeds to faba bean during March–April. Finally, faba bean and weeds may provide some benefits to predators, such as nectar, pollen, shelter and egg-laying sites rather than as sources of insect prey. Cultivation of faba bean could be useful for conservation and augmentation of beneficial insects, including Orius spp. Furthermore, field margins bearing flowering weeds such as S. arvensis and L amplexicaule should be protected against destructive management practices, because they host considerable numbers of the Orius species.     

Conference Reports

Abstract

In an insect pests survey of soybean during 1977–1980, in the rabi and kharif seasons, 14 species were more, and 33 species less abundant, representing 19 families under seven orders. The occurrence of Aphis spp., Atractomorpha spp., Spilosoma obliqua W., Monolepta signata Olv., Nezara viridula L., Myllocerus spp., Riptortus spp., and Jassids were most notable.     

Insect Pests of Rice in Laos

Abstract

The insect species feeding on rice in Laos were investigated during 1973–75. Populations were usually small but the most common species were Patanga succincta (L.), Leptocorisa spp. and Nezara viridula (L.) on the upland rice; Oxya and Euscyrtus spp. in the seedbeds and Chilo polychrysus (Meyr.), C. suppressalis Wlk. and Sesamia inferens (Wlk.) in the transplanted paddy rice of the lowlands. The natural enemies of these species were recorded.     

The phytophagous insects on lantana in brazil and their potential for biological control in Australia

Abstract

A ten‐year survey of phytophagous insects associated with Lantana spp. (chiefly L. tiliaefolia Cham, and L. glutinosa Poepp.) in Brazil, yielded 345 species from eight orders. Half of the total species collected were Coleoptera, with Chrysomelidae being the most important family. Other important families were the Curculionidae and, in the Lepidoptera, Geometridae, Arctiidae and Noctuidae. More than 90% of insect species fed on the vegetative parts of the plant, with almost two‐thirds of these chewing holes in leaves, and fewer than 10% attacking the flowers and fruits. Woody stem borers were rare, constituting only 2% of the total insect species collected. The present status of biological control of lantana in Australia is reviewed together with the prospects of importing further biological control candidates from Brazil.     

Can an integrated management approach provide a basis for long-term prevention of weed dominance in Australian pasture systems?

Broad-leaved weeds in pasture, such as Carduus nutans, Onopordum spp. and Echium plantagineum are a major problem for graziers in southern Australia. Previous attempts to combat these weeds with a single technique have only resulted in short-term success. An approach to long-term control, combining biological control with different grazing and herbicide strategies, was evaluated in an integrated weed management (IWM) programme, in south-eastern Australia. This IWM study was one of the few that has focused on biological control agents. During the field trials, the impacts of grazing and herbicide treatments on the weed and biological control agents, as well as on pasture composition, were monitored. This paper concentrates on the part of the study that focuses on the role and importance of pasture composition as part of weed management. The main pasture components were monitored using botanal , a sampling technique for estimating species composition and pasture yield in the field. IWM is a long-term ecological approach and after 3 years, major trends were just becoming apparent. This study shows that pasture composition can be manipulated to increase productivity and sustainability. It demonstrates that broad-leaved weeds can be reduced when high level pasture background management and chemical control are combined.     

Athesapeuta cyperi in Pakistan and its Potential as a Biocontrol Agent of Cyperus rotundus

Abstract

The distribution, hosts, phenology and abundance of Athesapeuta cyperi, an insect enemy of purple nutgrass, Cyperus rotundus, in Pakistan are given. Its biology and damage to C. rotundus in the laboratory are also reported. Usually one egg was laid in a tuber. When two eggs were present, only one reached maturity. The infested tuber was completely hollowed out and failed to regenerate. Thus, 100% plants infested with A. cyperi were killed. In host specificity tests larval development occurred on Cyperus spp. and Fimbristylis ferruginea but oviposition was restricted to Cyperus spp. However, C. rotundus was preferred to other species of Cyperus both for oviposition and development.     

Transmission of ‘Candidatus Phytoplasma pyri’ by naturally infected Cacopsylla pyri to peach,an approach to the epidemiology of peach yellow leaf roll (PYLR) in Spain

Peach orchards in the northeast of Spain were severely affected in 2012 by a previously unreported disease in this area. The symptoms included early reddening, leaf curling, decline, abnormal fruits, and in some cases death of the peach trees. All the infected peach samples were positive for ‘Candidatus Phytoplasma pyri’, but none were infected by the ‘Ca. Phytoplasma prunorum’. In this work, potential vectors able to transmit ‘Ca. Phytoplasma pyri’ from pear to peach and between peach trees were studied and their infective potential was analysed at different times of the year. Transmission trials of the phytoplasma with potential vectors to an artificial feeding medium for insects and to healthy peach trees were conducted. Additionally, isolated phytoplasmas were genetically characterized to determine which isolates were able to infect peach trees. Results showed that the only insect species captured inside peach plots that was a carrier of the ‘Ca. Phytoplasma pyri’ phytoplasma was Cacopsylla pyri. Other insect species captured and known to be phytoplasma transmitters were present in very low numbers, and were not infected with ‘Ca. Phytoplasma pyri’ phytoplasma. A total of 1928 individuals of C. pyri were captured in the peach orchards, of which around 49% were phytoplasma carriers. All the peach trees exposed to C. pyri in 2014, and 65% in 2015, were infected by ‘Ca. Phytoplasma pyri’ 1 year after exposure, showing that this species is able to transmit the phytoplasma to peach. Molecular characterization showed that some genotypes are preferentially determined in peach.     

A survey of entomopathogenic nematodes of the families Steinernematidae and Heterorhabditidae (Nematoda: Rhabditida) in Damascus countryside of Syria

A survey of entomopathogenic nematodes was conducted in Damascus countryside from January 2011 to December 2013. Soil samples were tested for the presence of steinernematid and heterorhabditid nematodes by baiting with Galleria mellonella larvae. Of the 189 soil samples studied 17 were positive for entomopathogenic nematodes (9%), with 11 of these positive samples (65%) containing Heterorhabditis and 6 (35%) Steinernema isolates. Morphological studies were carried out to characterize eight isolates. The Heterorhabditis isolates collected in Syria were identified as Heterorhabditis zealandica (Poinar, 1990), Heterorhabditis indica (Poinar et al., 1992) and Heterorhabditis bacteriophora (Poinar, 1990). Heterorhabditis zealandica was isolated from 4 sites. Heterorhabditis indica and H. bacteriophora were isolated from two sites each. Entomopathogenic nematodes were mainly found in stone fruit orchards and apple orchards but also in citrus groves, vineyards, and walnut orchards.     

Weed populations in olive groves under non-tillage and conditions of rapid degradation of simazine

In 49 olive tree groves in southern Spain under non-tillage and treated in the autumn with simazine, a total of 315 weed species was identified. However, only eight annual specics reached a moderate mean infestation of infested ficlds. In each field the number of observed species ranged from 4 to 78. The most important annual species that survived simazine treatment were Lolium rigidum, Galium tricornutum and Sherardia arvensis and, locally in a few fields, others such as Amaranthus spp., Conyza spp., Pulicaria paludosa, Sinapis alba. Torilis arvensis and Rumex bucephalophorus. Sedum album, R. bucephalophorus, P. paludosa, Briza maxima and Hypericum perforatum were mainly found in slope soils with high altitude and low carbon content. Cyperus rotundus, Conyza banariensi, Amaranthus blitoides, Galium spurium and Diplotaxis virgata were found at high densities in irrigated fields. Simazine residues recorded 6 months after herbicide application were very low, amounting on average to levels less than 3% of the applied rate. In soil treated with simazine for 7 years. simazine degradation was much faster than in previously untreated soil, particularly at temperatures of 15-25°C.     

Problems of development of resistance to phosphine by insect pests of stored grains1

The FAO global survey of pesticide sensitivity of stored grain pests in 1972–73 showed an overall incidence of phosphine resistance of 9.7% in insect strains from 82 countries, especially in Tribolium spp. and Rhyzopertha dominica. The levels of resistance increased under laboratory selection. Generally, eggs and pupae were found to be more tolerant, and fumigation doses have to be designed with these stages in mind. With increasing worldwide use of phosphine, resistance has become more frequent and occurs at a higher level and in other species (Cryptolestes ferrugineus, Oryzaephilus surinamensis). Studies of fumigation under different conditions in Bangladesh showed that common procedures, without use of sheets, led to chronic underdosing, creating ideal conditions for the selection of resistant strains. Such strains are very likely to be introduced into the EPPO region and established there. While inspection and control procedures in ports could limit this risk, these are costly and impractical. The problem is best tackled at source, by supporting projects aimed at improving the conditions under which grain is stored and fumigated in developing countries.     

The dynamics of introduction of alien scale insects (Hemiptera: Coccoidea) into Croatia

In recent years, several species of alien scale insects have arrived and spread rapidly through European and Mediterranean countries. One hundred and twenty‐nine species of alien scale insects have so far been recorded in Europe. This paper presents a list of alien scale insect species for Croatia, comprising 56 species from 8 different families. Four of them are new records for Croatia: Aonidiella taxus Leonardi, 1906, Ichnaspis longirostris (Signoret, 1882), Phoenicococcus marlatii (Cockerell, 1899) and Spilococcus mammillariae (Bouche, 1844). The majority of species recorded belong to the following families: Diaspididae (28 species), Coccidae (12 species), Pseudococcidae (10 species), Eriococcidae (two species). The scale insect families Dactylopidae, Margarodidae, Ortheziidae and Pheniococcidae comprised only one recorded alien species each. During the time frame covered in the review (from the beginning of the 20th century until 2015), the majority of alien scale insect species (23) were registered in the period from 2000 to 2015. Data on the origin of introduced alien scale insects shows that the majority of the species originate from Asia (22 species), followed by North America (6 species), Africa, Australia and Central America (5 species each) and South America (4 species), with 9 species being of unknown origin.     

Insect pests and their management in yam production and storage: a world review

Yam (Dioscorea spp.) is a tropical tuber crop produced for food and medicinal purposes. Yams are infested by a broad taxonomic diversity of insect pests. We reviewed a total of 73 insect species associated with Dioscorea species in different parts of the world. Yam is infested by 48 species when the crop is in the field, and after harvest (i.e. in storage) the tubers are attacked by 27 species. The majority of these insects belong to the order Coleoptera (35 species) followed by the orders Hemiptera (15), Lepidoptera (13), Isoptera (5), Hymenoptera (2), Diptera (1), and Thysanoptera (1). Yam scales, mealybugs, and a few beetles cause significant losses to tubers both in the field and in storage. We review various methods of management for these insect pests. An integrated approach towards managing these pests, both in the field and in storage, is essential. Post-harvest losses in storage of yam can be reduced, partly, by using biocontrol agents for mealybugs and scales. Alternative strategies for the management of insect pests of tubers in storage are discussed.     

Asymptomatic weeds are frequently colonised by pathogenic species of Fusarium in cereal‐based crop rotations

Several Fusarium species cause harmful cereal diseases, such as fusarium head blight and crown rot, which, during pathogenesis, may result in significant grain yield and quality losses. Several species of agricultural weed are believed to be alternative and reservoir hosts for Fusarium spp.; however, studies have not comprehensively evaluated those weed species in cropping systems that may harbour these fungi. The objective of this study was to determine weed species in cereal‐based crop rotations that are asymptomatically colonised by Fusarium spp. We sampled all species of weed present in fields that were managed under six different crop sequences in 2015 and 2016. The study yielded 2326 single‐spore isolates of Fusarium spp. derived from various organs of asymptomatic weeds. Isolates were identified morphologically and then confirmed using PCR with species‐specific primers and/or sequencing of tef1α gene fragments. Isolates of nine Fusarium spp. were obtained from 689 of the 744 individuals collected that represented 56 weed species. Each weed species harboured at least one species of Fusarium, and >80% were colonised by 3–9 Fusarium spp. In total, we identified 27 dicotyledonous weed species that were previously undocumented as Fusarium hosts and 251 new weed × Fusarium species combinations were revealed. Consequently, there is a greater risk of negative Fusarium impacts on cereal crops than was previously thought. We suggest effective weed management and inversion soil tillage may help mitigate these impacts.     

Effect of ensiling and in sacco digestion on the viability of seeds of selected weed species

The germinability and viability of mature seeds of five grass (Hordeum spp., Bromus diandrus, Vulpia spp., Avena fatua and Lolium rigidum) and seven broad‐leaved weed species (Echium spp., Physalis hederifolia, Solanum elaeagnifolium, Raphanus raphanistrum, Marrubium vulgare and Malva parviflora) that were either untreated, ensiled for a minimum of three months, underwent 48 h in sacco digestion in steers or ensiled prior to digestion were tested for germinability and viability. Ensiling and digestion both reduced seed viability, although the extent varied with species. The effect of ensiling was generally greater compared with digestion and differed between years for some species. Ensiling or ensiling plus digestion rendered all seeds of Hordeum spp., B. diandrus, Vulpia spp., A. fatua, Echium spp., P. hederifolia (in one year only), S. elaeagnifolium, R. raphanistrum and M. vulgare non‐viable; ensiling and ensiling plus digestion reduced viability of L. rigidum by 74.4% and 92.7% respectively. Viability of M. parviflora displayed the greatest tolerance to damage, with seed viability reduced on average by 31.4%, 27.6% and 27.4% for ensiling, digestion and ensiling plus digestion treatments respectively. These results indicate that ensiling can provide an effective non‐chemical weed management option, as a component of an integrated weed management package, for certain weed species responsible for significant crop and pasture production losses in Australian and world temperate and Mediterranean agricultural systems.     

Potential manageable exploitation of social wasps,Vespula spp. (Hymenoptera: Vespidae), as generalist predators of insect pests

A manageable, generalist, predatory insect has to date been considered to be unavailable anywhere for pest insect control. Polistes spp. wasps showed promise, but are limited by small numbers of wasps per nest and short nest life. Social Vespula spp. wasps appear to possess the necessary attributes which will allow their development as manageable, generalist predators of a wide range of pest insects. They have a large number of foragers per nest, a high demand for invertebrate protein, a very wide range of prey, an ability to tolerate low temperatures, a tolerance of nest manipulation, and a colony life cycle that can span at least two summers. High numbers per nest and high nest densities can lead to the consumption of many kilograms of prey per hectare per year. Successful development of characteristics desired of a manageable predator, such as the ability to increase colony numbers by dividing and re-queening, and enhancement of multi-year colony existence, could result in management procedures for Vespula spp. wasps that are similar to those used for honey bees. Farmers could have wasp nests available when and where required and in the numbers desired. Wasps would be especially valuable for growers of some ‘organic’ crops in which conventional pesticides are not permitted.     

黄淮海夏玉米主产区穗腐病病原菌的分离鉴定

为明确我国黄淮海夏玉米主产区玉米穗腐病的病原菌种类、优势种群及虫害、年度、省份对病原菌的影响,以形态学为基础,结合分子生物学方法对2013、2015年随机采自河南、河北、山东3省的155份玉米穗腐病样品进行分离鉴定。结果表明,引起黄淮海夏玉米主产区玉米穗腐病的主要致病菌为镰孢菌Fusarium spp.,包括拟轮枝镰孢F.verticillioides、禾谷镰孢F.graminearum、层出镰孢F.proliferatum、木贼镰孢F.equiseti及藤仓镰孢F.fujikuroi,分离频率分别为49.7%、28.4%、12.3%、3.9%和1.3%;其次为木霉菌Trichoderma spp.,包括哈茨木霉T.harzianum、绿色木霉T.viride和棘孢木霉T.asperellum,分离频率分别为8.4%、3.2%和5.2%;青霉菌Penicillium spp.分离频率较低,为14.2%;曲霉菌Aspergillus spp.包括黑曲霉A.niger和黄曲霉A.flavus,分离频率分别为2.6%和1.9%。研究表明,黄淮海主产区玉米穗腐病优势病原菌为拟轮枝镰孢、禾谷镰孢和木霉菌,不同省份不同年度间病原菌种类及优势病原菌存在差异,虫害能加重玉米穗腐病的发生。     

Melanaspis corticosa: a new insect pest of olive trees in Europe

The presence of the South African Obscure Scale, Melanaspis corticosa (Brain) (Hemiptera, Diaspididae), was detected infesting olive trees, in Portugal. The identity of the scale insect was confirmed based on both morphological and molecular studies. Until now, this species was only known in a few African countries, including Guinea, Mozambique, South Africa and Zimbabwe. This is the first record of this species in Europe and in the Palearctic region. The scale was observed in 15 different locations, in the Algarve, since its first detection at the end of 2016. Samples were collected between 21 December 2016 and 10 March 2022, covering all seasonal periods. Most of the sampling sites resulted from private requests from farmers and proprietaries received by the Plant Protection Division of the Regional Directorate of Agriculture. Although it is considered a polyphagous species, it was not observed in other plant species, besides olive trees. The actual dispersion in the region suggests that M. corticosa became established and has been expanded its distribution since its arrival. This scale insect is a potential injurious pest of olive trees and needs to be studied to clarify its pest status and develop effective pest management strategies.

     

Impact of Parthenium hysterophorus on grazing land communities in north‐eastern Ethiopia

An investigation into the impact of Parthenium hysterophorus infestation was conducted in 2007 in the north‐eastern grazing lands of Ethiopia. Data on the above‐ground and seedbank species diversity were collected from five areas, each having sites with low, medium, or high levels of weed infestation. A total of 72 species was found in all areas. They were categorized into grass species (23), other species (48), or P. hysterophorus for ease of interpretation. A regression analysis showed a highly significant, but negative, relationship between the above‐ground species diversity and evenness with P. hysterophorus abundance. The mean cover abundance for the three infestation levels was 33.4% for P. hysterophorus, 41.0% for the grass species, and 26.5% for the other species. The most dominant grass species under all infestation levels were Cynodon dactylon, Urochloa panicoides, and Chloris gayana, while Andropogon abyssinicus and Eragrostis spp. were dominant under the low and medium infestation levels, respectively, and Hyparrhenia hirta was dominant under the low infestation level. Among the other species, Solanum nigrum was the most dominant under the low infestation level and Datura stramonium and Xanthium spp. were the most dominant under the medium and high infestation levels, respectively. The above‐ground dry biomass of P. hysterophorus increased between the low and high infestation levels, while that of the grass or other species reduced in the high, as compared to the low, infestation level. Although the grass species density decreased significantly with successive increases in the P. hysterophorus infestation level, no such trend could be seen for the other species. Within the soil seed bank, the viable seed density for the grass species, other species, and P. hysterophorus were 25.7, 5.8, and 68.5%, respectively. Similarly, the soil seed bank under the low‐, medium‐, and high‐infestation sites was dominated by P. hysterophorus, which contributed 25.1, 65.4, and 87.4% of the viable seed bank, respectively. Although the overall similarity between the above‐ground vegetation composition and the soil seed bank was low, it was similar at the low‐infested site. Thus, the invasion by P. hysterophorus was found to critically endanger the biodiversity of the grazing lands, particularly for the different grass and forbs species in the area. These changes might adversely affect not only future agriculture, but also food security, unless appropriate practises are developed and implemented for P. hysterophorus management.     

Durability of resistance in lily to basal rot: evaluation of virulence and aggressiveness among isolates ofFusarium oxysporum f. sp.lilii

Prospects of durability of resistance in lily to basal rot have been evaluated by testing the virulence and aggressiveness of 31 isolates ofFusarium oxysporum f. sp.lilii towards a number of different resistance sources inLilium spp. Isolates differed strongly in aggressiveness as did species and cultivars ofLilium spp. in resistance. Significant interactions were observed between isolates of the pathogen and genotypes ofLilium spp., but the magnitude was very small compared to the main effects. The interactions were mainly due to a small group of isolates with low aggressiveness. It is argued that the interactions might be based on minor genes. No major break down of the resistance was found. For practical purposes it will be sufficient to use highly aggressive isolates in screening tests.     

Damage pattern and status of the leaf miner Aphanisticus aeneus Kerremans (Coleoptera: Buprestidae) in Saccharum spp.

Biology, damage pattern, incidence levels and status of the leaf miner Aphanisticus aeneus Kerremans (Coleoptera: Buprestidae) were studied in accessions of Saccharum spp. Egg, grub and pupal periods of the miner lasted 6.0 ± 0.8, 18.5 ± 1.9 and 7.0 ± 1.3 days, respectively; adults lived for 8–10 days. The grub tunneled the leaf on the lower surface just above the epidermis forming a linear channel; infested tissues showed brownish discoloration. The extent of leaf miner attack among the 331 accessions of Saccharum spp. ranged 4.00%–76.47% on cane basis and 7.14%–100.00% on leaf basis; the mined leaf area ranged 3.22–11.00 cm². When the accessions were grouped on the basis of an infestation index developed with the above three parameters, 267 occupied very low category, 51 were in low category, 11 were in moderate category and 2 were placed in high incidence category. All accessions showed miner attack in at least one study year. Within each of the four Saccharum spp., accessions differed significantly among the three study years for all infestation parameters. Among the four species, while S. robustum accessions recorded significantly highest infestation index, the other three species remained on par.