Population dynamics of herbivorous insects and potential arthropod natural enemies on Alnus species in Kabale district, Uganda

Monitoring populations of pests and their natural enemies under different management situations and seasonal weather parameters provides extremely useful information for taking preventive measures against pest outbreaks. The abundance, spatial and temporal distributions of herbivorous insects and arthropod natural enemies on Alnus species were monitored at four sites in Kabale district, Uganda between June 1999 and August 2000. Chewing insects, dominated by Coleoptera (75%), constituted the majority of insect herbivores sampled. Dominant and potentially serious pests of Alnus included Apion globulipenne, an unidentified Chrysomelidae (Coleopt. 27), Phymateus viridipes, Coloborrtics corticina and a Cacopsylla species (Homoptera: Psyllidae). Spiders were the predominant natural enemies accounting for 64% of the total natural enemies encountered, followed by parasitic Hymenoptera (30%). There were marked spatial and temporal variations in arthropod abundance. Among sites, mean abundance of total insect herbivores and total natural enemies on A. acuminata over 15 months ranged from 3.8–8.5 and 3.3–4.7 individuals per 1-m branch length respectively. Over the same period, mean number of total insect herbivores and total natural enemies on A. nepalensis that was studied at only one site were 11.9 herbivores and 4.2 natural enemies per 1-m branch length. Populations of most insect orders increased in the wet season although the greatest herbivore abundance was evident in the dry season. Further studies are necessary on the impact and management strategies of the potentially important insect pests and natural enemies on Alnus.This revised version was published online in November 2005 with corrections to the Cover Date.     

Insects feeding on Sesbania species in natural stands and agroforestry systems in southern Malawi

Pest and disease interactions in agroforestry systemsis a little studied area.Surveys were conducted in the Mangochi and Zomba districts of southern Malawi between December 1997 and February 1998 to identify insects feeding on Sesbania species in natural stands and in agroforestry systems at the research station and on farms, and the host range of the insects. Out of a total of 30 insect species recorded in natural stands, Brachyplatys testudonigro, Mesoplatys ochroptera, Exosoma sp. and Ootheca sp. were the most commonly found insects feeding on S. sesban. Afrius figuratus, Glypsus conspicuus, Macrorhaphis acuta, Mecosoma mensor, Rhinocoris segmentarius and Cyaneodinodes faciger were recorded for the first time as natural enemies of Mesoplatys ochroptera in Malawi. The defoliating beetles, M. ochroptera, Exosoma sp. and Ootheca sp., were the most frequently found insects infesting S. sesban on farms. M. ochroptera attacked only Sesbania species, and usually higher populations of this beetle were recorded on annual Sesbania species (S. tetraptera, S. bispinosa, S. leptocarpa and S. sericea) than on perennial types. Although the sap-sucking bug, B. testudonigro, was relatively less common on sesbania on farms, it has been found to infest a number of other legumes of the genera Aeschynomene, Crotalaria, Desmodium, Indigofera, Mucuna, Phaseolus, Tephrosia and Vigna. Given the wide variety of plant species it attacks, B. testudonigro may become a potential pest of many agroforestry tree species. The insects Anoplocnemis curvipes, Aphis fabae, Hilda patruelis, Megaleurothrips sjostedti, Mylabris dicincta, Nezara viridula and Ootheca sp. also have the potential to become pests of agroforestry systems, as they can damage many agroforestry trees, including Sesbania, and crops. There is a need to study the biology and ecology of potential insect pests of S. sesban to plan for their integrated management in agroforestry. This revised version was published online in June 2006 with corrections to the Cover Date.     

Arthropod pests and their natural enemies in stored crops in northern Namibia

A survey of stored product pests, their natural enemies, grain storage and pest management approaches in northern Namibia was conducted. The survey revealed five types of crop commodities (pearl millet, sorghum, cowpea, maize, feed mixture) stored in four types of grain stores (baskets, bag stags-flat stores, concrete bin, metal containers). No synthetic pesticides or plastic sheeting was recorded. Wooden-ash natural pesticide is the only protectant used. Ten insect pest species were found affiliated to the orders of Coleoptera (Attagenus fasciatus, Callosobruchus subinnotatus, Cryptolestes ferrugineus, Oryzaephilus surinamensis, Rhyzopertha dominica and Tribolium castaneum), Lepidoptera (Corcyra cephalonica, Sitotroga cerealella), Psocoptera (Liposcelis paeta) and Blattodea (Blattella germanica). Out of these, seven species were recognized as new stored-products pests for Namibia. Although listed for southern Africa region, no storage pest-mites (Acari) and Sitophilus spp., Prostephanus sp. or Trogoderma sp. beetles were traced. We found four new species of natural enemies of storage pests recruiting from insects (Habrobracon hebetor, Cephalonomia wattersoni, Brachymeria sp.) and mites (Blattisocius tarsalis). The occurrence of natural enemies indicates a potential for pest bio-control in Namibian grain stores.     

Pathogens and parasites of adults of the great spruce bark beetle, Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) from Turkey

In this study, the pathogen and parasite spectra of Turkish populations of the great spruce bark beetle Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) are analysed. In addition to the previously studied infective green alga Helicosporidium, three more pathogens and parasites, i.e. the yeast Metschnikowia sp., the neogregarine Mattesia sp. and a nematode, were recorded here for the first time. The pathogens and parasites occur in different quantities and combinations in outbreaks of the beetle at five Turkish localities.     

Insect inhabitants of old larval galleries of<Emphasis Type="Italic"> Saperda populnea</Emphasis> (L.) (Coleoptera: Cerambycidae) in Bulgaria

The complex of insect inhabitants of old larval galleries of Saperda populnea (L.) (Coleoptera: Cerambycidae) was studied during the period 2000–2003 in 18 localities in Bulgaria. As a result, 32 insect species were reared from old S. populnea galls: Metopoplax origani (Kolenati) (Heteroptera: Lygaeidae), Malachius sp. (Coleoptera: Malachiidae), Agrilus pratensis pratensis (Ratzeburg) (Coleoptera: Buprestidae), Xylocleptes bispinus (Duftschmidt) (Coleoptera: Scolytidae), Crossocerus cetratus (Shuckard), Crossocerus megacephalus (Rossi), Crossocerus nigritus (Lepeletier & Brullé), Crossocerus acanthophorus (Kohl), Passaloecus brevilabris Wolf, Passaloecus gracilis (Curtis), Psenulus schencki (Tournier), Solierella compedita compedita (Piccioli), Trypoxylon figulus figulus (Linnaeus), Trypoxylon fronticorne fronticorne Gussakovskij (Hymenoptera: Crabronidae), Cleptes schmidti Linsenmaiser, Trichrysis cyanea (Linnaeus) (Hymenoptera: Chrysididae), Clistopyga incitator (Fabricius), Ctenochira sanguinatoria (Ratzeburg), Liotryphon crassisetus (Thomson), Nemeritis fallax (Gravenhorst), Mesochorus georgievi Schwenke, Campoletis sp. (Hymenoptera: Ichneumonidae), Charmon extensor (Linnaeus) (Hymenoptera: Braconidae), Eupelmus urozonus Dalman (Hymenoptera: Eupelmidae), Perilampus aeneus (Rossius) (Hymenoptera: Perilampidae), Trichiocampus grandis (Lepeletier) (Hymenoptera: Tenthredinidae), Janus luteipes (Lepeletier) (Hymenoptera: Cephidae), Cydia corollana (Hübner) (Lepidoptera: Tortricidae), Fiebrigella brevibucca (Duda) (Diptera: Chloropidae), Eustolomyia hilaris (Fallén) (Diptera: Anthomyiidae), Senotaina sp. (Diptera: Sarcophagidae) and Heringia vitripennis (Meigen) (Diptera: Syrphidae). Amongst them, 27 species were established as new inhabitants of old S. populnea galls. Five species (C. schmidti, N. fallax, M. georgievi, P. aeneus and J. luteipes) were recorded for the first time in Bulgaria. The dwellers of old S. populnea galls belong to the following ecological groups: insects using galls as a place to develop (3 species); insects nidificating in empty galls (10 species); insects using old galls as a pupating place (1 species); insects using empty galls as overwintering shelters (3 species); predators and parasites of primary dwellers of empty galls (13 species); or insects with uncertain ecological status (2 species).     

Dry matter production and nutrient cycling in agroforestry systems of cardamom grown underAlnus and natural forest

A study on dry matter production and nutrient cycling in agroforestry systems of cardamom grown under N₂-fixingAlnus and mixed tree species (non-N₂-fixing) was carried out in the Sikkim Himalaya. The stand total biomass, and tiller number, basal area and biomass of cardamom crop was much higher under the influence ofAlnus. Annual net primary productivity ofAlnus trees was slightly higher than mixed tree species in spite of lower stand density ofAlnus. The agronomic yield of cardamom increased by 2.2 times under the canopy ofAlnus. Litter production and its disappearance rates were also higher in theAlnus-cardamom stand. Nitrogen and phosphorus concentrations of different components ofAlnus were higher than those of mixed tree species, whereas their back translocation from leaf before abscission was lower inAlnus. The cardamom based agroforestry system under the influence ofAlnus was more productive with faster rates of nutrient cycling. The poor nutrient conservation and low nutrient use efficiency ofAlnus, and malleability of nutrient cycling under its influence make it an excellent association which promotes higher availability and faster cycling of nutrients.     

Fungi and insects associated with Euphorbia ingens die-off in South Africa

Euphorbia ingens, landmark succulent trees in savannas of South Africa, have been dying in large numbers over the last 10–15 years. Initial studies conducted in the Limpopo province of South Africa revealed a diverse group of biotic agents including fungi, beetles and moths associated with dying trees, but due to the limited geographic extent of these studies, it was not known if the same agents were associated with dying trees regionally. In this study, diseased and insect-infested trees were sampled for fungal pathogens and insects at six sites in four provinces located across South Africa. Fungi were identified based on morphology and DNA sequencing of the ITS, LSU, β-tubulin and TEF 1-α gene regions, and insects were identified based on morphology. Fungal isolates were identified as Aureovirgo volantis, Fusarium solani, Lasiodiplodia × egyptiacae, Ophiostoma thermarum and a Readeriella species. Five insects were identified, all in the family Curculionidae, including two ambrosia beetles, Cyrtogenius africus and a Stenoscelis species. All fungi and insects collected are known to be opportunistic and occur on stressed trees as secondary agents of mortality or disease. These results suggest that the die-off is not related to attack of the trees by aggressive insects or pathogens, but rather that E. ingens in this region is under stress from environmental factors that supports the ability of opportunistic insects and pathogens to establish.     

The scale Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in Greece

The phenology and natural enemies of Nemolecanium graniformis (Wunn) (Homoptera: Coccidae) in infesting Abies cephalonica, were studied in Greece during 1998?–?1999. This oviparous species develops one generation per year in Central Greece (Attica) and overwinters as 2^nd instar nymph. Young adult females appear by the end of July, and the first instar nymphs by the middle of August. By the middle of October, the whole population of the scale is recorded as 2^nd instar nymphs. The parasitoids Coccophagus lycimnia (Walker), Coccophagus Westwood sp., Aphycoides Mercet sp. and the predator Exochomus quadripustulatus L. (Coleoptera: Coccinellidae), were observed as natural enemies of the scale. The average fecundity of N. graniformis was 188.4 eggs.     

Cardamom, mandarin and nitrogen-fixing trees in agroforestry systems in India's Himalayan region. II. Soil nutrient dynamics

A study on seasonal soil nutrient dynamics was made in large cardamom (Amonum subulatum) and mandarin (Citrus reticulata) agroforestry systems in the Sikkim Himalaya, India. Alnus nepalensis was the N₂-fixing associate in the large cardamom system, and Albizia stipulata in the mandarin agroforestry system. Sites without N₂-fixing species in both agroforestry types comprised native non-symbiotic mixed tree species. Soil was acidic in the cardamom agroforestry and slightly acidic to neutral in the mandarin agroforestry system. Total-N in soils was the highest in the forest-cardamom stand and the lowest in the mandarin-based agroforestry systems. Soil ammonium-N and nitrate-N concentrations were highly seasonal, and the ratio of seasonal maximum and minimum varied up to six times. The C/N ratio was higher in cardamom agroforestry indicating lower N availability than in the mandarin agroforestry. Cardamom stand with Alnus showed a relatively narrower C/N ratio. N₂-fixing species help in maintenance of soil organic matter levels with higher N-mineralization rate as land use change from natural-forest system to agroforestry systems with sparse tree populations. Ratios of inorganic-P/total-P were lower in cardamom agroforestry than the mandarin agroforestry. Seasonal fluctuation in Ca-PO₄, Al-PO₄ and Fe-PO₄ contents regulated the availability of phosphates to some extent for plant uptake.     

Zur Kenntnis der Mikrosporidienarten (Sporozoa,Nosematidae) bei Vorratsschädlingen der Ordnung Coleoptera

On the microsporidian pathogens of Coleoptera living in grain and meal in Yugoslavia In some mills in the Kosova district, Yugoslavia, the species of Nosematidae (Microsporidia) infecting the grain and meal eating larvae of Coleoptera were investigated. A view of all Nosematidae of Coleopterous meal and grain pests found hitherto by the author and by other authors is given. Informations are maded on the different pathogens. Two new species,Nosema albanica n. sp. undPlistophora manningeri n. sp., are described.     

Cardamom, mandarin and nitrogen-fixing trees in agroforestry systems in India's Himalayan region. I. Litterfall and decomposition

Litterfall and decomposition were studied in agroforestry systems involving large cardamom (Amomum subulatum) and mandarin (Citrus reticulata) in the Sikkim Himalaya, India. There were stands with N₂-fixing trees (Alnus nepalensis over large cardamom, and Albizia stipulata over mandarin agroforestry) or without them (native non-symbiotic mixed tree species) in both systems. The total annual litter (litter + crop residue) production was higher in the Alnus-cardamom than in the forest-cardamom stand and in the mandarin than in the Albizia-mandarin stand. The ratio of litter production to floor litter was higher in the N₂-fixing stands than in the non-N₂-fixing stands, indicating a faster litter turnover in the former. Tree litterfall occurred throughout the year, but with marked peaks during November to April. Total soluble polyphenolics of fresh litter were higher in N₂-fixing species than in mixed tree species and crops. Half-life values for ash-free mass were shortest in the leaves of N₂-fixing species. N loss was higher from N₂-fixing Alnus and Albizia leaves, whereas P loss was faster and nearly equal in Alnus leaf litter and cardamom residue in cardamom, and Albizia leaf litter and crop residue in mandarin agroforestry systems. The P turnover in N₂-fixing Alnus and Albizia twigs was faster than in the twigs of mixed tree species. The N₂-fixing tree species increased the N and P cycling through production of more above-ground litter and influenced greater release of these nutrients.     

Important insect pests of poplars in agroforestry and strategies for their management in northwestern India

Today, more than 143 species of insects infest both indigenous as well as exotic species of poplars in northwestern India, with about 65 species infesting Populus deltoides alone. Random sampling surveys (1984-2002) were undertaken in lower hills and plains of six states (Uttar Pradesh, Uttaranchal, Haryana, Punjab, Himachal Pradesh, and Jammu and Kashmir) in this region. The survey included 36 nurseries, 84 large ( ≥ 3 ha) and 255 small (< 3 ha) block and bund plantations and recorded seven species causing outbreaks. However, eight insects having wide spread distribution in this region were identified as posing a threat to agroforestry with P. deltoides and need to be managed. Amongst these, three species (Clostera cupreata, C. fulgurita and Apriona cinerea) were ranked as 'major pests' as they had relatively higher incidence (> 50% of attack) and caused extensive economic loss during outbreaks, coupled with tree mortality which persisted for several years in succession over large areas. Five insects were identified as 'potential pests', as they also caused heavy infestation and economic loss, but only in some years, on a localized scale and with no large scale plant mortality, but need to be checked to improve productivity. The 'potential pests' were: one species in plantations (Ascotis selenaria) and four insects in nurseries [(Eucosma glaciata , Phalantha phalantha, Nodostoma waterhousie and white grubs) with >50% incidence]. Integrated pest management practices, comprising cultural methods, use of bio-pesticides, tolerant poplar varieties/clones, natural enemies, recommended safe insecticides and avoiding alternate host plants of the pest, are discussed for important pests.     

Insect pest problems in tropical agroforestry systems: Contributory factors and strategies for management

Agroforestry trees are attacked by a wide spectrum of insects at all stages of their growth just like other annual and perennial crops. Pest management in agroforestry has not received much attention so far, but recent emphasis on producing high value tree products in agroforestry and using improved germplasm in traditional systems, and emergence of serious pest problems in some promising agroforestry systems have increased awareness on risks posed by pests. Insects may attack one or more species within a system and across systems in the landscape, so pest management strategies should depend on the nature of the insect and magnitude of its damage. Although greater plant diversity in agroforestry is expected to increase beneficial arthropods, diversity by itself may not reduce pests. Introduction of tree germplasm from a narrow genetic base and intensive use of trees may lead to pest outbreaks. In simultaneous agroforestry systems, a number of factors governing tree—crop—environment interactions, such as diversity of plant species, host range of the pests, microclimate, spatial arrangement and tree management modify pest infestations by affecting populations of both herbivores and natural enemies. Trees also affect pest infestations by acting as barriers to movement of insects, masking the odours emitted by other components of the system and sheltering herbivores and natural enemies. In sequential agroforestry systems, it is mostly the soil-borne and diapausing insects that cause and perpetuate damage to the common hosts in tree—crop rotations over seasons or years. An integrated approach combining host-plant resistance to pests, exploiting alternative tree species, measures that prevent pest build up but favour natural enemies and biological control is suggested for managing pests in agroforestry. Species substitution to avoid pests is feasible only if trees are grown for ecological services such as soil conservation and low value products such as fuelwood, but not for trees yielding specific and high value products. For exploiting biological control as a potent, low cost and environmentally safe tool for pest management in agroforestry, research should focus on understanding the influence of ecological and management factors on the dynamics of insect pest-natural enemy populations. Scientists and policy makers in national and international institutions, and donors are urged to pay more attention to pest problems in agroforestry to harness the potential benefits of agroforestry.This revised version was published online in November 2005 with corrections to the Cover Date.     

Limited host range in the idiobiont parasitoid Phymastichus coffea,a prospective biological control agent of the coffee pest Hypothenemus hampei in Hawaii

Phymastichus coffea LaSalle (Hymenoptera:Eulophidae) is an adult endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera:Curculionidae:Scolytinae), which has been introduced in many coffee producing countries as a biological control agent. To determine the effectiveness of P. coffea against H. hampei and environmental safety for release in Hawaii, we investigated the host selection and parasitism response of adult females to 43 different species of Coleoptera, including 23 Scolytinae (six Hypothenemus species and 17 others), and four additional Curculionidae. Non-target testing included Hawaiian endemic, exotic and beneficial coleopteran species. Using a no-choice laboratory bioassay, we demonstrated that P. coffea was only able to parasitize the target host H. hampei and four other adventive species of Hypothenemus: H. obscurus, H. seriatus, H. birmanus and H. crudiae. Hypothenemus hampei had the highest parasitism rate and shortest parasitoid development time of the five parasitized Hypothenemus spp. Parasitism and parasitoid emergence decreased with decreasing phylogenetic relatedness of the Hypothenemus spp. to H. hampei, and the most distantly related species, H. eruditus, was not parasitized. These results suggest that the risk of harmful non-target impacts is low because there are no native species of Hypothenemus in Hawaii, and P. coffea could be safely introduced for classical biological control of H. hampei in Hawaii.

     

Ambrosia beetles (Coleoptera: Curculionidae) can directly transmit the fungal pathogens responsible for Rapid ʻŌhiʻa Death

The ecologically and culturally vital tree species, ʻōhiʻa lehua (Metrosideros polymorpha), is threatened by the fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, the causal agents of the disease complex called Rapid ʻŌhiʻa Death (ROD). Four invasive ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) species in the Xyleborini tribe colonize ROD Ceratocystis-infested ‘ōhiʻa and produce inoculum through their frass; however, the potential for direct transmission of the ROD fungi by these beetles was unknown. We fulfilled Leach's rules to support insect transmission of ROD by documenting the visitation of these ambrosia beetles to healthy ‘ōhiʻa trees, culturing C. lukuohia and C. huliohia from the ROD-associated beetles using three different collection methods at multiple study sites, and challenging healthy ʻōhiʻa seedlings with beetles that were exposed to both C. lukuohia and C. huliohia cultures. We documented all four invasive ROD-associated ambrosia beetle species including Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, and Xyleborus perforans to regularly visit healthy ʻōhiʻa trees on sticky traps. Viable Ceratocystis propagules were isolated from all species, and C. lukuohia was most commonly isolated of the two ROD-causing fungi. Consistently across all collection techniques, ROD Ceratocystis spp. were detected on just under 3% of all assayed beetles, with the highest detection rate from X. affinis. All four beetle species were capable of directly transmitting both pathogens to healthy ʻōhiʻa seedlings with a high rate of transfer. Ceratocystis spp. are highly virulent pathogens in trees, and a single inoculation can result in tree death, therefore any direct transmission is a cause for concern. After meeting the criteria of Leach's rules, we propose that Xi. saxesenii, X. affinis, X. ferrugineus, and X. perforans are vectors of C. lukuohia and C. huliohia, particularly in areas of high ROD pressure and tree stress.     

The role of integrating agroforestry and vegetable planting in structuring communities of herbivorous insects and their natural enemies in the Neotropical region

The integration of agroforestry plots with ephemeral crops such as vegetables on the farm scale can probably serve as a refuge and source of beneficial insects. Therefore, agroforestry systems possibly represent an alternative that favors ecosystem services and help growers in the transition process from conventional to agro-ecological agriculture. This study aimed to understand the role of introducing agroforestry systems in structuring insect communities, with consequences for the abundance of herbivore and natural enemies, contributing to farm management and favoring biological control as an ecosystem service. Field surveys showed that agroforestry systems can harbor more species than horticultural crops, independent of the functional group. They also contain a greater diversity of herbivores and an even greater diversity profile of natural enemy communities. Agroforestry systems served as a source of natural enemies that can colonize horticultural crops when herbivores are present. As a consequence, natural enemies can establish a numerical response to herbivore abundance, but their communities are also affected by stochastic factors related to climatic conditions. Thus, agroforestry systems and agro-ecological practices might favor an agriculture based on the maintenance and conservation of ecosystem services.     

Individual and synergistic toxicity of solanaceous glycoalkaloids against two coleopteran stored-product insects

Toxicity of solanaceous glycoalkaloids against stored-grain insects was investigated under laboratory conditions. The total glycoalkaloids (TGAs), α-chaconine and α-solanine from potatoes, Solanum tuberosum L. and α-tomatine from tomatoes, Lycopersicon esculentum Mill. were isolated and tested in this bioassay. Their acute and residual toxicity were assessed against the rust red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), and the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae). All compounds were tested either individually or as binary mixtures. Results revealed considerable toxicity of the tested glycoalkaloids against the target insects. When adults of S. oryzae were exposed to a dry-film residue of these phytochemicals, the total glycoalkaloids (TGAs) fraction was the most toxic, followed by α-solanine, α-chaconine, and α-tomatine with LC_50s of (38.6 and 22.1), (48.2 and 38.9), (52.00 and 41.6), and (82.3 and 67.00) μg/cm² at 24 and 48 h post-treatment, respectively. The order of toxicity against T. castaneum in a descending order was TGAs > α-chaconine > α-solanine > α-tomatine. All compounds were more toxic when insects were fed grains treated with these phytochemicals (LC_50s of TGAs were 7.4 and 16.2 mg/kg grains at 48 h post-treatment against S. oryzae and T. castaneum, respectively. All compounds, particularly the TGAs, exhibited promising residual toxicity effects. Toxicity of glycoalkaloids was exceeded when tested as binary mixtures indicating their synergistic interaction. The study recommends the use of glycoalkaloids of Solanaceae as biorationals and natural leads to protect stored grains from insect infestation.     

Arthropod diversity of cocoa farms under two management systems in the Eastern and Central regions of Ghana

Diversity of insect communities can be used as bioindicators for change in the environment especially in farms under different management systems. In line with that, we conducted a research on insect species associated with cocoa under organic and conventional management systems in the Eastern and Central regions of Ghana. Insect collection was done using Hand height visual count, Canopy, and “Knock down”, pitfall, coloured bowl and fruit-baited traps. A total of 13,742 individual insects belonging to 138 species from 63 families and 12 orders were recorded in the study. Insect abundance and diversity were generally higher in organic farms compared to conventional farms with Oecophylla longinoda as the most dominant species in both management systems and especially more dominant in organic cocoa farms. Our study revealed that most of the insect species recorded were known cocoa pests although there was high abundance of beneficial insects too. Some of the pest species were Planococoides njalensis, Salhbergella singularis, Helopeltis spp and Pseudococus spp, while some of the beneficial insects recorded were Pheidole spp, Tegenaria spp, Camponotus spp, Crematogaster spp. We can conclude that cocoa farms are potential habitats for insect biodiversity conservation. We recommend that management and/or agronomic practices used in cocoa farms should be geared towards protecting beneficial organisms for instance pollinators and natural enemies by effectively suppressing insect pest populations while enhancing good seed production.

     

洞庭湖区杨树食叶害虫蛹期天敌调查及优势天敌筛选

湖南洞庭湖区杨树食叶害虫蛹期天敌有啮小蜂(Tetrastichus spl.)、白蛾黑基啮小蜂(Tetrastichus nigricoxae)、日本追寄蝇(Exorista japonica)、毛虫追寄蝇(Exorista dmoena)、伞裙追寄蝇(Exorista civilis)、双齿多刺蚁(Polyrhach...     

Adelina tribolii Bhatia und A. mesnili Pérez (Sporozoa,Coccidia) als Krankheitserreger bei vorratsschä dlichen Insekten im Gebiet von Kosova,Jugoslawien

Adelina tribolii Bhatia and A. mesnili Pérez (Sporozoa, Coccidia) infecting insect pests of stores in Kosova region, Yugoslavia Till now little is known about the three species of genusAdelina (Spor., Coccidia) living as pathogens in insects pests of stores. In the course of investigations in old mills in the Kosova region, Yugoslawia, twoAdelina species were found in insects.Adelina mesnili parasitized in two species of Lepidoptera(Ephestia kühniella, E. elutella) and was restricted to four of nine places. Its quota in the total parasitization withAdelina amounted to 15,7%.Adelina tribolii parasitized in six species of Coleoptera.(Attagenus pellio, A. piceus, A. fasciolatus, Laemophloeus ferrugineus, Trogoderma granaria, Gracilia albanica) and was be found in all the nine places which were investigated. Its quota amounted to 84,3%.