Responding to Economic Crisis in Sub-Saharan Africa: New Farmer-Developed Pest Management Strategies in Cocoa-Based Plantations in Southern Cameroon

Cocoa is a key or source of income and poverty reduction in the humid forest of Southern Cameroon. Cameroon like other African countries went through a major economic crisis in the early 1980s with a decline in international commodity prices and significant changes in macroeconomic policies. Structural adjustment reforms following the economic crisis led to removal of fertilizers and pesticides subsidies, cocoa price liberalization and the overall withdraw of Government interventions from the cocoa sub-sector. Cocoa input price increases have been compounded by the devaluation of the CFA Franc, which doubled the prices of the imported pesticides which were considered key to the control of cocoa pests. This overall economic shock led to changes in cocoa producer's production decisions as a response to minimize cost. Among the changes the use of alternatives to imported chemicals for cocoa pest control. Farmers responded to the high prices of pesticides by developing, from local botanical knowledge and pest management strategies, which include plant extracts and plant extracts mixed with pesticides at different proportions. This is a major decision given the importance of imported chemical in the cost of production of cocoa. Valuable indigenous knowledge from farmers could be used also as an effective support system for communicating and diffusing modern knowledge and technologies to farmers. The paper describes the farmer knowledge-based alternatives to chemical pesticides for pest control in cocoa fields as a response to high pest control costs. Pest management specialists are urged to take advantage of this shift in practice and assess their effectiveness for further use. Two sets of questions are posed: (1) were the conventional insecticides, with all their problems, really necessary? and (2) are the materials derived from locally grown plants effective pest management agents or are they, in some way, placebos?     

温度与取食对越冬后马铃薯甲虫飞行能力的影响

［目的］ 探明马铃薯甲虫的迁飞规律,为防止马铃薯甲虫的扩散提供依据。［方法］ 通过昆虫飞行磨系统测定温度和营养条件对越冬后马铃薯甲虫飞行能力的影响。［结果 ］马铃薯甲虫雄虫飞行能力稍大于雌虫,但无显著性差异。温度≤25 ℃时,越冬后饥饿3 d马铃薯甲虫的飞行能力大于越冬后补充营养3 d的成虫,在30 ℃和33 ℃时饥饿状态与补充营养的马铃薯甲虫飞行能力无明显差别,35 ℃和38 ℃越冬后补充营养的马铃薯甲虫飞行能力大于饥饿3 d的马铃薯甲虫。饥饿3 d的马铃薯甲虫在常温下更容易迁飞。［结论］ 温度对越冬后马铃薯甲虫的飞行能力影响较大,越冬后马铃薯甲虫起飞温度为23 ℃,25～33 ℃是越冬后马铃薯甲虫的最适飞行温度。     

Insecticide resistance in field populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in West Africa

BACKGROUND: The tobacco whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), has developed a high degree of resistance to several chemical classes of insecticides throughout the world. To evaluate the resistance status in West Africa, eight insecticides from different chemical families were tested using the leaf‐dip method on four field populations collected from cotton in Benin, Togo and Burkina Faso. RESULTS: Some field populations showed a significant loss of susceptibility to pyrethroids such as deltamethrin [resistance ratio (RR) 3–5] and bifenthrin (RR 4–36), to organophosphates (OPs) such as dimethoate (RR 8–15) and chlorpyrifos (RR 5–7) and to neonicotinoids such as acetamiprid (RR 7–8) and thiamethoxam (RR 3–7). Bemisia tabaci was also resistant to pymetrozine (RR 3–18) and to endosulfan (RR 14–30). CONCLUSION: The resistance of B. tabaci to pyrethroids and OPs is certainly due to their systematic use in cotton treatments for more than 30 years. Acetamiprid has been recently introduced for the control of whiteflies. Unfortunately, B. tabaci populations from Burkina Faso seem to be already resistant. Because cross‐resistance between these compounds has never been observed elsewhere, resistance to neonicotinoids could be due to the presence of an invasive B. tabaci biotype recently detected in the region. Copyright © 2010 Society of Chemical Industry     

马铃薯甲虫入侵贵州的风险分析

马铃薯甲虫是马铃薯等茄科作物上毁灭性的检疫性害虫。本文利用定性分析和定量分析相结合对马铃薯甲虫入侵贵州的风险进行了分析。结果表明,马铃薯甲虫在贵州具有大面积种植的寄主,入侵、定殖可能性大,风险管理难度大;其风险评估R值为2.23,在贵州为高度危险的有害生物。因此应加强检疫管理,以防止其传入和扩散蔓延。     

Pyrethroid resistance in the cotton bollworm,Helicoverpa armigera (Hübner), in West Africa

The susceptibility of Helicoverpa armigera to pyrethroids has been investigated in West Africa by means of laboratory bioassays since 1985, the first year of widespread pyrethroid use. For some years, this survey has shown a tendency for the pest to become more tolerant to pyrethroids. During the 1996 growing season, farmers using calendar‐based spraying programmes reported control failures in various countries. The strong efficacy of cypermethrin on small larvae was confirmed in experimental plots, but the effect decreased quickly in successive instars. Bioassays performed on resistant strains revealed an increase in LD₅₀ that was related to different resistance mechanisms. Metabolic resistance (MFO) appears to be a possible primary mechanism of resistance to pyrethroids. Target modification (kdr) is involved to a small degree and esterases seem to appear only after additional selection pressure. © 2000 Society of Chemical Industry     

绿肥害虫发生与防控研究现状与发展趋势

绿肥作物不仅能够提供地肥、改善土壤结构,而且还可以提供优质饲料,对我国农牧业生产安全具有重要意义,也是我国实现化肥减量、保持农业绿色发展的重要途径之一。我国绿肥种质资源丰富,绿肥害虫种类较多,但有关绿肥害虫研究的基础目前还较为薄弱,一些主要绿肥作物以及绿肥与主栽作物不同配置模式下害虫的发生种类与发生规律尚不清楚,相应的监测与防控技术缺乏。本文在系统分析国内外文献的基础上,结合国家绿肥现代农业产业技术体系的研究进展,综述了目前国内外主要绿肥作物上害虫发生的种类与规律、绿肥害虫的风险评估、不同绿肥-主作物种植模式下害虫发生规律与防控研究的现状。针对国内外绿肥害虫防控研究的现状及存在的问题,结合我国农业产业结构的调整,提出了今后绿肥害虫防控研究的主要方向。     

新西兰出口苹果的有害生物监控及检疫监管体系

新西兰苹果出口到欧盟、亚洲、美洲和中东等65个国家和地区,其国内水果生产建立了较完善的出口苹果有害生物监控及检疫监管体系,通过介绍新西兰苹果出口的监管体系、有害生物监控防治、出口检验检疫等,供国内检验检疫部门和农业生产部门借鉴和参考。     

Tackling fall armyworm (Spodoptera frugiperda) outbreak in Africa: an analysis of farmers’ control actions

Abstract

Since its emergence in Africa in 2016, fall armyworm (FAW) has spread rapidly and poses a severe threat to the food security and livelihood of millions of smallholder farmers in the continent. Using survey data from Ghana and Zambia, we examined FAW prevention and control methods implemented by farm households and their impacts on maize output and household consumption of self-produced maize. The main control methods used included pesticide application and handpicking of larvae, while access to information on FAW was a key driver behind the implementation of the control methods. Results from an endogenous switching regression showed that the implementation of a FAW management strategy significantly enhanced maize yield and households’ own maize consumption. When disentangling the impacts of the main control methods, we found that the combination of pesticide application and handpicking of larvae produced the highest yield gain of 125%. We concluded that the current interventions put in place by farmers to tackle FAW infestations are providing positive outcomes, but successful management of the pest will require more actions, including raising awareness to enhance the adoption of control interventions and exploring other control options.     

Utilization of Fodder Trees and Shrubs in the Arid and Semiarid Zones of West Asia and North Africa

Utilization of fodder trees and shrubs (FTS) in the Mediterranean arid and semi-arid zones was initiated after World War I and expanded between 1950 and 1970. A similarly slow expansion has taken place in other arid zones in the USA, South Africa, South America, and Australia. Currently in West Asian and North African (WANA) countries, the area planted with native or exotic species is about 10 6 ha. Mainly they include three categories of plant species: cacti, saltbushes, and wattles. At this time there is an expansion of hectareage and a diversi-cation of genetic material. The relative success of FTS has a number of reasons. They are tolerant to drought and have the ability to accumulate green fodder over several seasons, providing fodder reserves for times of dearth and thus permitting a switch from transhumance to sedentary husbandry. Deep rooting enables them to reach water resources unavailable to herbaceous species. Their Rain Use Efficiency (RUE) and Water Use Efficiency (WUE) rates provide productivities three to five times higher than rangelands. FTS have a positive impact on soil fertility due to their organic matter production, hence they increase microbial activity, rates of geobiogenic element cycling, and soil structure stabilization. Their above ground biomass, canopy ground cover, provides a microclimatic buffer role for wind, temperature and evapotranspiration, and their landscape roughness factor makes them efficient for erosion and desertification control. Other positive aspects include: the use on non farming land; general suitability for runo farming systems; production of valuable goods, such as food, shade, and firewood; providing wildlife shelter; and other benefits. FTS plantations are subjected, however, to constraints that limit their expansion. Their main shortcomings include the cost of establishment, often not affordable by a small farmer; required long-term planning may not be feasible, as a secure land tenure system often is nonexistent. Appropriate methods of cultivation are not being applied, management, and utilization are lacking, and availability of plant material is limited. Discipline of utilization, allowing regeneration of stands after defoliation is a problem. Identification of constraints indicates needs for research and extension activities. These include reduced-cost of establishment and improved management methods, such as ensuring availability of low-cost seeds and selection of high grade cultivars, and introduction of new high quality exotic species. Additionally, integration into economically feasible and socially acceptable production systems, including joint cultivation with cereal farming and combination with runo farming techniques, should be developed. Legal, regulatory, and administrative incentives are also needed.     

黄曲条跳甲药剂敏感性监测方法的比较

应用浸叶法、点滴法和滤纸药膜法对黄曲条跳甲药剂敏感性测定结果的重复间变异系数比较表明,用点滴法测定黄曲条跳甲成虫药剂敏感性的重复性最好,变异系数为6.42%;其次为浸叶法和滤纸药膜法。利用点滴法和浸叶法测定了4个菜区黄曲条跳甲成虫对毒死蜱、丁硫克百威、氯氰菊酯的敏感性,结果表明点滴法和浸叶法测定结果均能一致反映出黄曲条跳甲田间种群的药剂敏感性水平。     

Arthropod populations and rice yields in direct-seeded and transplanted lowland rice in West Africa

Studies were conducted on the effect of pruning time, host age, urediniospore release and weather parameters on the incidence and intensity of mulberry leaf rust (Peridiopsora mori). Rust severity significantly increased with increasing shoot age, irrespective of pruning time. Maximum disease severity was observed in plants pruned during the third week of October, and minimum severity in plants pruned during last week of November. Apparent infection rate was higher in younger shoots. Infection rate was higher in plants pruned during the last week of November. Urediniospore release was influenced by prevailing climatic conditions. A higher rate of spore release was noticed during sunny days. Maximum spore release was found between 12.00 h and 14.00 h. Spore release was positively correlated with temperature and negatively correlated with relative humidity. Rust severity (34.97%) was higher in January and least (1.03%) during May. Rust severity was negatively correlated with both temperature and rainfall. An exponential model was developed for the prediction of rust severity which was accurate up to 96.60%.     

我国鼠害学科发展现状与展望

鼠害作为一种重要的农业生物灾害, 造成的危害不仅涉及国家粮食安全、生态安全, 还严重威胁人民健康。随着鼠害防控理念的转变, 对鼠害治理工作提出了新的要求和目标。本文简要介绍了我国近5年来在鼠害治理研究及相关领域取得的成绩和不足之处, 提出了在生态文明建设为目标的要求下, 研究不同生态区域害鼠群落结构和危害特征、种群数量暴发机理等生物学特性, 建立害鼠物联网智能监测系统, 构建不同生态系统的鼠害防控生态阈值。研发生态环境友好型的鼠害绿色防控技术是鼠害治理的基本发展方向。     

纳米载导RNAi技术在害虫防治中的研究和应用

每年重大病虫害的流行和暴发都会对农业产生重大的影响,进而造成严重的经济损失,随着化学试剂的施用其抗药性也逐渐增强,因此探索新的绿色、安全、高效的害虫防治技术具有十分重要的意义。RNAi作为一种研究基因功能的工具,在开发新的害虫防治策略方面显示出巨大的潜力,但RNAi的效率受限于核酸酶的降解作用,为了改善dsRNA的有效递送,研发了纳米载导技术且被广泛应用于害虫防治。同时,基于工程菌高效合成靶向昆虫dsRNA的技术为田间推广提供了可行性及技术支撑。本文主要对RNAi技术及纳米载导RNAi技术在害虫防治中的研究和应用进行了总结和归纳。     

The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. IV. Evaluation of Insecticides Applied as Aerosols

Abstract

The effects of aerosol dosages of different categories of insecticide were tested against Glossina tachinoides when applied by helicopter to riverine forest habitats of the River Komoe, Upper Volta, West Africa. The method of application, droplet characteristics of the aerosols and meteorological conditions are described in accompanying papers. Comparative trials based on field dosages calculated initially from dosage mortality curves obtained from topical application studies in the laboratory were carried out. Endosulfan applied at 5.4 g a.i./ha and 9.0 g a.i./ha reduced G. tachinoides populations (determined by Challier/Laveissière traps) by more than 90% in all age and sex categories and evidence is presented which indicates a residual effect at the higher of these dosages. Good results were also obtained with the synthetic pyrethroid decamethrin at a dosage of 0.36 g a.i./ha; another synthetic pyrethroid, permethrin, gave promising results at a dosage of 1.9 g a.i./ha. At the higher dosage of 4.3 g a.i./ha disappointing results were obtained, which were considered to be more attributable to a weakness in the application technique under challenging field conditions, than to a limitation of the insecticide. The organophosphate compounds tested, fenthion, azamethiphos and tetrachlorvinphos although known from laboratory tests to be appreciably toxic to G. tachinoides, performed poorly under field conditions. This was thought to be due to the formulations employed and the authors feel that further small-scale field testing of different formulations of these compounds is warranted. The compounds considered most worthy of larger scale field evaluation were endosulfan and permethrin. Although decamethrin was also very toxic to G. tachinoides it was considered inadvisable to field test this compound on a larger scale, until more information was available on its impact on aquatic food chains. The trials demonstrated that it is not always possible to extrapolate from laboratory-obtained comparative dosage/mortality data (in ng/fly) the field dosages of insecticides (in g a.i./ha) required to produce a certain level of mortality in target populations of G. tachinoides.     

The Development and Status of Biologically Based Integrated Pest Management in Cuba

This paper describes the evolution of IPM in Cuba during three pre- and post-revolutionary periods. The state of the art of IPM after the collapse of Cuba's relations with the soviet block is analyzed in detail. During this 'special period' Cuba is undergoing a major conversion from conventional agriculture dependent on external inputs to a semi-organic agriculture dependent on local resources and low external inputs. The massive production and use of microbial pesticides complemented by cultural and habitat management techniques are at the heart of this new quest of agricultural sustainability in the midst of the economic crisis. About 982,000ha of various crops are under biological control, with savings of about US$ 30 million in pesticide imports.     

中国大豆病虫害发生现状及全程绿色防控技术研究进展

病虫害频发是制约大豆高产稳产的重要因素之一。中国大豆生产中已知病虫害近500种,产生重大危害的有50余种,造成的大豆产量损失一般为15%～30%,严重时甚至大面积绝收。该文综述了中国大豆生产中主要病虫害的种类、大豆主要产区病虫害的发生现状和全程绿色防控技术的相关研究进展,探讨了当前大豆病虫害防控中存在的问题,并对未来发展方向进行展望,以期为后续开展大豆病虫害监测与绿色防控关键技术的研究与应用提供借鉴。     

Cereal leaf beetles (Oulema spp., Coleoptera: Chrysomelidae) control following various dates of wheat sowing and insecticidal treatments

In this paper, we report the sowing date and intensity of chemical control on presence of the cereal leaf beetles (CLB) on spring wheat. The CLB monitoring (Oulema melanopus L. and Oulema gallaeciana Voet.) was conducted in May–June of each year, following the announcement of the IOR-PiB in Poznań (Institute of Plant Protection, National Research Institute), that economic threshold levels in Poland of this pest is observed. For the spring sowing dates between (20 March–20 April) and late autumn sowings (21 November–7 December) larger amounts of CLB adults (1.6–1.1) in comparison to early autumn sowings (25 October–02 November) were noticed (0.4). Following the insecticidal seed treatment with imidacloprid, the occurrence of adults was 0.2–0.7 individual per stem, while the use of fungicidal treatment with triadimenol–imazalil–fuberidazol resulted in average 1.1–2.2 individual per stem. The reduction in the number of larvae per stem was 7–10 fold larger following the foliar application (pirimicarb + dimethoate + cypermethrin) compared to the seed treatment with imidacloprid. The lowest grain yield (3.83 t ha^?1) from the spring crop without any insecticide was obtained. Foliar application with blend of pirimicarb + dimethoate + cypermethrin increased the yield crop by 0.41 t ha^?1 (10.7%) and additionally by 0.78 t ha^?1 (20.4%) to compare to the fungicidal control when imidacloprid was used. Wheat seed treatment with imidacloprid and sowing date in autumn showed to be suitable and economically efficient preventive strategies for controlling the pest population.     

Pest Management in Traditional Tropical Agroecosystems: Lessons for Pest Prevention Research and Extension

Based on current agroecological theory and IPM practices, this review explores the role of traditional practices, involving site selection, soil management, timing of planting and harvesting, crop resistance, intercropping, weed management, harvest residue management, post-harvest management, natural enemies management, mechanical control, repellents and traps in the natural regulation of potential pests. In synthesis, the literature suggests that although pest management professionals focus their efforts on pest control, the preventative approach taken by traditional farmers is more effective. Potential constraints to the implementation of this preventive pest management approach include:(1) lack of integration of ecological theory and pest management, (2) lack of cooperation among social and biological scientists, and (3) lack of real efforts to work with farmers as equals and support mechanisms that protect their knowledge. This revised version was published online in July 2006 with corrections to the Cover Date.     

南昌高尔夫草坪虫害调查与防治初探

调查了保利（南昌）高尔夫球场草坪害虫种类和密度,其中以蝼蛄、蛴螬等地下害虫和水稻切叶野螟、斜纹夜蛾、淡剑袭夜蛾等地面害虫对草坪造成严重危害。果岭草坪上的主要虫害是氮甲和蛴螬;发球台草坪的主要虫害有蝼蛄、蛴螬以及地上害虫;球道和高草区草坪上的主要虫害有蛴螬、蝼蛄、水稻切叶野螟、淡剑袭夜蛾、斜纹夜蛾等。掌握各功能区主要害虫的数量消长情况,可对高尔夫球场各功能区虫害提出更有针对性的防治方法,从而减少害虫对高尔夫球场的危害。