Abundance of insect pests and their effects on biomass yields of single vs. multi-species planted fallows

Indigenous and exotic leguminous shrubs that are promising for planted fallow for soil fertility replenishment in east and southern Africa have been found to harbour many herbivorous insects, giving suspicion that widespread adoption of fallow systems may aggravate insect pests. Studies were conducted on farms in western Kenya from 1999 to 2001 to monitor the abundance of herbivorous insects and assess their effects on biomass yields of pure and mixed fallows. The treatments tested were single and two-species mixtures of Tephrosia vogelii, Sesbania sesban and Crotalaria grahamiana and a natural fallow in a split plot design, with the fallow systems in the main plots and protection vs. no protection against insects in sub-plots spread over six farms. Eighteen insect species belonging to seven orders and 14 families were identified as pests of␣the fallows with varied abundance and infestation level across the sites. While Hilda patruelis and Amphicallia pactolicus were most damaging to C. grahamiana, Mesoplatys ochroptera was detrimental to S.␣sesban. T. vogelii hosted fewer insects than others. Nevertheless the pest infestation did not cause significant biomass yield reduction during the study period. Pest attack was generally greater in villages that had been testing the planted fallows for some years compared with villages that took up the fallows recently. This indicates the potential for increased pest infestation with increased adoption of the system by farmers. Multi-species fallows did not indicate any advantage over single species fallows in terms of either reduced pest incidence or increased biomass production.     

Post-fire attractiveness of maritime pines (<Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait.) to xylophagous insects

The spectrum and dynamics of xylophagous insects infesting Pinus pinaster after a fire event were studied from November 2007 to December 2008 at Sierra de Outes (Galicia, NW Spain). Insects were collected within and outside the fire area. Relationships among species status, species abundance, tree parameters and tree injury were assessed. Mortality of injured trees was also recorded. Insect colonization built up consistently during the first year after the fire, although the pests did not colonize unburned trees in nearby areas. Thirteen insect species from six xylophagous families were collected. Tomicus spp., Buprestis novenmaculata, Anobium punctatum and Pissodes castaneus were the first species detected. Tomicus spp. (29%) and Ips sexdentatus (23%) were the dominant taxa. Bole char height and soil burn severity were positively correlated with insect presence. Trees with short stem diameter and thinner bark were also preferred. B. novenmaculata presence was positively correlated with crown scorch. Loss of cambium hydration was negatively related to the occurrence of pests, likely because sapwood desiccation and loss of nutrient impede brood development. About 33.3% of the fire-scorched pines died. The results recommend the removal of injured and dying pines after fire, to avoid the rise of pest population threatening recovering trees in the burned areas.     

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.     

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.     

综合治理与常规防治枣园天敌昆虫的群落结构及其多样性

1999— 2 0 0 1年对山西太谷地区综合防治枣园与常规防治枣园天敌昆虫的群落结构及其多样性的研究结果表明 :在综合防治枣园中发现有 8个目、2 5个科、5 8个种和 5 0 0 9个天敌的个体数 ,而在常规防治枣园中发现有 8个目、18个科、2 7个种和 1911个天敌的个体数。方差分析结果表明综合防治枣园天敌的科、种及个体数显著大于常规防治枣园 (P <0 0 5 )。枣园中天敌的优势种是枣盲蛇蛉、七星瓢虫、晋草蛉、桃小甲腹茧蜂和蚧金小蜂。在综合防治枣园中 ,主要天敌昆虫的优势度显著大于常规防治枣园 (P <0 0 5 )。天敌昆虫各群落的生态优势集中性在两区不同生育期基本上趋于一致 ,综合治理区主要类群的优势集中性几乎总是大于常规防治区 ;综合治理区天敌昆虫群落和捕食性亚群落的多样性与均匀度较常规防治区有明显 (P <0 0 5 )的提高 ;在综合治理区 ,影响群落多样性的主要成分是种类丰富度 ,在常规防治区 ,影响群落多样性的主要成分既有种类丰富度 ,又有均匀度和个体数。     

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.     

Using flower strips to promote green lacewings to control cabbage insect pests

Habitat management improves biological control by increasing the abundance and fitness of natural enemies through the provision of floral resources along field edges or between crops. Among the natural enemies reliant on flower resources, green lacewings often stand out due to their abundance, predation capacity and polyphagy. We evaluated the impact of tailored flower strips on the enhancement of natural enemies, especially green lacewings, in three organic cabbage (Brassica oleracea) farms in Southern Sweden. Insects were sampled from the flower strips, and cabbage pests and predators were visually recorded in the crop. In a laboratory assay, the pollen feeding preferences of Chrysoperla carnea (Stephens, 1836) were evaluated in a dual-choice test. The pollen consumed by the Chrysopidae was extracted from laboratory and field specimens, then quantified and identified. Flower strips were found to attract predators and parasitoids, whose abundance increased as flowers bloomed. Cabbage plants next to the flower strips showed lower pest infestation as compared to cabbage plant control, although no significant differences were observed in the number of predators. Chrysopidae used flower strips as feeding, reproduction and shelter sites and mainly consumed pollen from Phacelia tanacetifolia Benth. Under laboratory conditions, C. carnea showed a preference for P. tanacetifolia and Coriandrum sativum L. pollen over Borago officinalis L. and Fagopyrum esculentum Moench. We show that tailored flower strips could be an efficient tool for enhancing beneficial arthropods and should be considered in integrated pest management for cabbage crops.

     

The distribution of Phratora vulgatissima (Coleoptera: Chrysomelidae) on cultivated willows in Britain and Ireland

Insect samples were collected from the canopy of 24 willow short rotation coppice (SRC) sites on farmland in Britain and Ireland in 1995. The blue willow beetle Phratora (= Phyllodecta) vulgatissima (L.) (Coleoptera: Chrysomelidae), previously identified as the main defoliating pest of this crop, was recorded from 13 of these at varying levels of abundance. Data describing aspects of the environment at each site were also collected. These data were used to create potential explanatory variables for a regression analysis of beetle abundance. This analysis indicated that P. vulgatissima were most likely to occur and were more abundant at older willow sites on clay soils and at sites that bad certain free-living willow species growing nearby. Within sites, most willow clones sampled contained P. vulgatissima, although two, Salix burjatica‘Germany’ (‘Aquatica Gigantea’) and Salix mollissima‘Q83’ (Salix triandra × Salix viminalis), were avoided. Chrysomelid pest avoidance and clonal resistance could form part of an integrated pest management strategy for SRC crops.     

世界针叶树球果种实害虫研究进展

系统地介绍了当今世界对针叶树球果种实害虫研究方面所取得的新进展,包括害虫种类、生物学、种团结构、与球果及树木结实量的相互关系对寄主视觉与嗅觉的识别机制、生物防治、化学防治及种子园内对球果种实害虫的综合管理。还介绍了一些球果种实害虫的新名词和新理论,以及我国林业界在这一领域所取得的成果。     

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.     

The threat of the ambrosia beetle Megaplatypus mutatus (Chapuis) (=Platypus mutatus Chapuis) to world poplar resources

We describe the life cycle of Megaplatypus mutatus (Chapuis)(=Platypus mutatus) and the damage it causes to poplar resourcesin Argentina. This insect, native to the subtropical and tropicalareas of South America, has extended its range into temperateregions, reaching as far south as Neuquén in ArgentineanPatagonia. The damage is caused by the adult insects, whichbore large gallery systems into living poplars (Populus spp.),willows (Salix spp.) and many other broadleaf species, includingimportant fruit trees species such as apples (Malus spp.), walnuts(Juglans spp.) and avocados (Persea spp.). The galleries degradethe lumber and weaken the tree stems, which often then breakduring windstorms. A recent introduction of M. mutatus to Italydemonstrates that this insect can be transported long distancesbetween countries, and therefore presents a threat worldwide—particularlyto poplar cultivation. We review the taxonomic nomenclaturefor this pest, provide a summary of the life cycle, hosts anddamage and summarize actions taken to reduce the risk of introductionof M. mutatus to Canada.     

松毛虫应用价值研究在综合管理中的作用初探

探讨了松毛虫应用价值研究与松毛虫综合管理的关系。介绍了云南民间利用松毛虫的概况,简述了松毛虫利用价值研究所取得的进展和成果。从昆虫资源的角度来看,松毛虫的种资源是相当丰富的。从森林有害生物综合管理的观点出发,松毛虫也是森林生态系统中的重要成员。如果人对松毛虫资源进行开发利用,也可以把人视为森林生态系统中抑制松毛虫种群数量增长的天敌。人类的天敌作用与对松毛虫的需求量有密切的关系。松毛虫的应用价值越大,需要量越多,松毛虫种群数量的抑制作用也就越大。因此,人类开发利用松毛虫可以视为综合管理的技术之一。     

Zur Kenntnis der Schädlinge und Krankheiten der Kulturpflanzen in Südsomalia

Summary Most of the crops in Southern Somalia suffer from a heavy attack of insect pests. Contrary, the importance of diseases is in general less at least during the dry seasons. This was stated during a survey of the author in 1963. Bananas are infested by scale insects, especiallyAspidiotus destructor and white grubs (Schizonycha spp.) which damage the roots. The so-called sigatoka disease shows some importance on certain varieties. The stainer bugDysdercus cardinalis and the bollwormsPlatyedra gossypiella andDiparopsis watersi are major pests of cotton. Numerous other cotton pests were not very harmful during the time of the survey. Maize proved to be badly attacked by stemborers mainly the pyralid mothChilo zonellus. The same species plays an important part as a pest of sorghum where it is frequently associated withSesamia cretica. The weaver birdQuelea quelea aethiopica causes damage in certain areas during the wet seasons. Among the sorghum diseases,Sphacelotheca spp. andTolyposporium spp. are important. Sugarcane is attacked by the mealy bugSaccharicoccus sacchari. The pyralid mothAntigastra catalaunalis is a very common pest of sesame. Major diseases of the same crop are caused by a leafcurl virus and the bacteriumXanthomonas sesami. Roots and pods of groundnuts are infested by the mealy bugDysmicoccus brevipes. Coconut palms suffer from the damage of rhino beetles (Oryctes monoceros) and scale insects (Aspidiotus destructor). Citrus shows mostly a heavy infestation by scale insects (Parlatoria spp.,Lepidosaphes spp.) and aphids (Toxoptera aurantii). The same applias to guava and sweet sop. Mealy bugs and other scale insects suck in considerable numbers on the fruits and other parts of these plants. Spider mites are important pests of papaya leaves which are also infested on many localites by a mildew disease. Among the vegetables, tomatoes show frequently an infestation by a very harmful leafcurl virus.      

Use of modified water sources by bats in a managed pine landscape

In eastern North Carolina, USA, intensively managed pine (Pinus spp.) forests, a primary forest type in the Southeastern United States, often are established where water levels are maintained via ditching. In these landscapes, water occurs in numerous linear ditches and several small ponds (heliponds), used by helicopters for the suppression of forest fires. Changes to the physical structure of water sources may be important to bats that use these sources for drinking and foraging. Therefore, we examined bat activity in a managed pine landscape and an adjacent natural wetland in relation to water source type (heliponds, ditches, and natural wetland) and insect abundance. We sampled bat activity using remote acoustic detectors; we sampled insects using passive traps. Insect abundance did not differ among water source types. Bat activity was most concentrated at modified water sources within the managed pine landscape (heliponds and ditches). Feeding activity was highest at heliponds. Heliponds and ditches were important sources of open water and insect prey for bats in the managed pine forest landscape. We suggest management for bats in similar forest landscapes should include maintenance of open and accessible water sources such as heliponds.     

Insect pests and beneficial arthropods population under different hedgerow intercropping systems in semiarid Kenya

Exploiting the principles of biological control of crop pests is an important management strategy for the resource-poor smallholder farmers of the tropics. The effects of nine hedgerow species on the abundance of major insect pests of beans and maize, and predatory/parasitic-arthropods were monitored over two cropping seasons and the intervening dry period. The tree/shrub species evaluated were Gliricidia sepium, Grevillea robusta, Senna siamea, Senna spectabilis, Flemingea congesta, Croton megalocarpus, Morus alba, Calliandra calothyrsus and Lantana camara. Arthropod abundance was monitored through counts of infested plants and using yellow pan and pitfall traps. Beanfly (Ophiomyia spp.) infestation was significantly higher in the presence of hedgerows (35%) than in their absence (25%). Hedgerows did not influence aphid (Aphis fabae) infestation of beans. In contrast, maize associated with hedgerows experienced significantly lower stalk borer (Busseola fusca and Chilo spp.) and aphid (Rhophalosiphum maidis) infestations than pure maize, the margin of difference being 13% and 11% respectively for the two pests. Ladybird beetles closely followed their prey, aphids, with significantly higher catches in sole cropped-plots than in hedgerow-plots and away from hedgerows. Activity of wasps was significantly greater close to hedgerows than away from them. Spider catches during maize season were 77% greater in the presence of hedgerows than in their absence, but catches during other seasons were similar between the two cropping systems. Differences among hedgerow species were not significant for most of the arthropods monitored, except that beanfly infestation was greater with Gliricidia hedgerows. The study indicates that the effect of hedgerows on pest infestations of crops and their role as refugia for predators cannot be generalized but depends on the specific arthropods.This revised version was published online in November 2005 with corrections to the Cover Date.     

泡核桃林昆虫群落结构及其摄食功能研究

采用灯诱法,于2021年4月上旬至6月中旬对泡核桃林昆虫群落结构及其摄食功能进行研究。共诱捕到昆虫2 968头,隶属13目63科172属187种,其中74种取食植物叶片,29种刺吸植物汁液,22种捕食其他昆虫,17种取食植物花、芽、果,10种取食腐烂物,12种钻蛀植物茎干,8种为地下昆虫,5种寄生其他昆虫,4种取食植物花蜜,3种取食苔藓,3种传授植物花粉,3种取食腐木,2种取食粪,隶属13个营养生态位集团。对泡核桃造成严重危害的昆虫有核桃星尺蛾、漫绿刺蛾、星天牛、梗天牛、绿凹缘花金龟、暗异花金龟。个体数量以鳞翅目最多,鞘翅目次之,螳螂目最少;物种数以鞘翅目最多,鳞翅目次之,螳螂目最少。核桃星尺蛾、粗狭肋鳃金龟、华锐紅蝽、黑翅土白蚁为优势物种。昆虫群落组成与泡核桃林物候关系密切,在泡核桃开花、结果的高峰期,昆虫群落呈较高的多样性、均匀度分布格局。在一定程度上,捕食与寄生昆虫控制了林内害虫;食粪与腐烂物、食腐木与苔藓昆虫分解了林内有机物,促进了生态系统的物质循环。     

Insect herbivores and pathogens of Alnus species in Uganda

Published documentation of insect pests and pathogens associated with Alnus species in Africa is very scarce. We surveyed damaging insects and pathogens, and arthropod natural enemies on Alnus acuminata and A. nepalensis in Kabale and Mbale districts, Uganda between March 1999 and August 2000 in order to identify the range and relative abundance of arthropods and pathogens associated with the Alnus species. Frequently encountered damaging insects on the Alnus species included Apis mellifera, Apion globulipenne, a Systates sp. (Coleoptera: Curculionidae), Phymateus viridipes, a Lobotrachelus sp. (Coleoptera: Curculionidae), Coloborrtics corticina and some Chrysomelidae. Some species such as Aphis fabae, Parastictococcus multispinosus and a Cacopsylla sp. (Homoptera: Psyllidae) were observed feeding on other agroforestry tree species and/or crops although they generally occurred at low population intensities. Spiders and parasitic Hymenoptera were the most common natural enemies. Diseases were more severe in nurseries than in the field. Damping-off caused by Fusarium oxysporum, Septoria brown leaf spot and stem canker were the most serious diseases of Alnus. The array of damaging insects and pathogens indicates a potential danger to the cultivation of Alnus species in Uganda as adoption of the species for agroforestry continues to expand in the country. In view of the increasing demand for Alnus species for agroforestry in Uganda, regular pest monitoring and appropriate control strategies are necessary.This revised version was published online in November 2005 with corrections to the Cover Date.     

Assessing repellency,movement, and mortality of three species of stored product insects after exposure to deltamethrin-incorporated long-lasting polyethylene netting

Long-lasting insecticide-treated netting (LLIN) has begun to be used in agricultural product protection. We investigated the effect of a deltamethrin-incorporated LLIN on three stored product insects, red flour beetle, Tribolium castaneum (Herbst), lesser grain borer, Rhyzopertha dominica (F.), and rice weevil, Sitophilus oryzae (L.). Long-distance repellency was assessed in a wind tunnel for adults of each species, but no repellency was observed. Insect movement and behavior was assessed by observing the movement of adult beetles on treated and untreated netting during a 5 min period for distance traveled, velocity, mobility, and time on each netting type. Among all netting combinations, T. castaneum spent the most time highly mobile, higher velocity, and traveled a greater distance. Sitophilus oryzae and R. dominica spent significantly more time immobile and lower velocity. Efficacy of LLIN was tested by exposing adults for 60 min, removing, and holding with or without food, and monitoring for mortality up to 7 d. All S. oryzae and R. dominica were either affected or dead at all post-exposure times. The number of affected and dead adult T. castaneum combined 7 d after exposure was 42% and 95%, with or without food, respectively, and 52% of affected adults were able to recover when food was present. Overall, LLIN had no repellency or negative effect on insect movement, which increases the probability of lethal exposures of adults from walking on the netting. LLIN can be adopted in existing integrated pest management (IPM) programs for food processing facilities to prevent stored product insect infestations.

     

Effect of interspecific competition on <Emphasis Type="Italic">Mus musculus</Emphasis> in an urban area

In this study, we examined the role of interspecific competition between native species and Mus musculus by a removal experiment conducted in vacant areas of the city of Río Cuarto. Abundance, demographic parameters, and habitat occupancy of M. musculus were recorded in grids where native species were removed (experimental grids) and in grids without removal (control grids) from November 2004 to April 2005. During the study period, we observed an increasing trend in the abundance and habitat occupancy by M. musculus in experimental grids, suggesting that interspecific competition could be determining the numbers and habitat use of M. musculus in vacant areas of the city of Río Cuarto. Understanding the population ecology of M. musculus in an urban area is crucial to the development of ecologically based pest management to provide effective management of a pest species.     

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.