Agricultural Intensification Causes Decline in Insect Biodiversity

The world’s population exceeded 7 billion in late 2011 and it is expected to reach 9.3 billion by 2050. Meanwhile, demand for food is predicted to increase between 50 and 100% by 2050. To meet the food demands of the increasing population, agricultural intensification practices including growing monocultures of high-yielding crop varieties and increased applications of fertilizers and pesticides have been used to increase productivity. These practices, however, impact negatively on biodiversity of existing flora and fauna, particularly causing huge declines in insect biodiversity. This chapter reviews present state of knowledge about agricultural intensification practices and global decline of insect biodiversity (i.e., pest and beneficial insect species) in intensive agricultural system and point out the likely drivers of these declines. It concludes the review by examining sustainable agricultural intensification practices that could be used to mitigate these biodiversity declines while maintaining productivity in intensive agricultural systems

Examples of Risk Tools for Pests in Peanut (Arachis hypogaea) Developed for Five Countries Using Microsoft Excel

Suppressing pest populations below economically-damaging levels is an important element of sustainable peanut (Arachis hypogaea L.) production. Peanut farmers and their advisors often approach pest management with similar goals regardless of where they are located. Anticipating pest outbreaks using field history and monitoring pest populations are fundamental to protecting yield and financial investment. Microsoft Excel was used to develop individual risk indices for pests, a composite assessment of risk, and costs of risk mitigation practices for peanut in Argentina, Ghana, India, Malawi, and North Carolina (NC) in the United States (US). Depending on pests and resources available to manage pests, risk tools vary considerably, especially in the context of other crops that are grown in sequence with peanut, cultivars, and chemical inputs. In Argentina, India, and the US where more tools (e.g., mechanization and pesticides) are available, risk indices for a wide array of economically important pests were developed with the assumption that reducing risk to those pests likely will impact peanut yield in a positive manner. In Ghana and Malawi where fewer management tools are available, risks to yield and aflatoxin contamination are presented without risk indices for individual pests. The Microsoft Excel platform can be updated as new and additional information on effectiveness of management practices becomes apparent. Tools can be developed using this platform that are appropriate for their geography, environment, cropping systems, and pest complexes and management inputs that are available. In this article we present examples for the risk tool for each country.Instituto de Patología VegetalFil: Jordan, David L. North Carolina State University. Department of Crop and Soil Sciences; Estados UnidosFil: Buol, Greg S. North Carolina State University. Department of Crop and Soil Sciences; Estados UnidosFil: Brandenburg, Rick L. North Carolina State University. Department of Entomology and Plant Pathology; Estados UnidosFil: Reisig, Dominic. North Carolina State University. Department of Entomology and Plant Pathology; Estados UnidosFil: Nboyine, Jerry. Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; GhanaFil: Abudulai, Mumuni. Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; GhanaFil: Oteng-Frimpong, Richard.Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; GhanaFil: Brandford Mochiah, Moses.Council for Scientific and Industrial Research. Crops Research Institute; GhanaFil: Asibuo, James Y. Council for Scientific and Industrial Research. Crops Research Institute; GhanaFil: Arthur, Stephen. Council for Scientific and Industrial Research. Crops Research Institute; GhanaFil: Paredes, Juan Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Paredes, Juan Andrés. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Monguillot, Joaquín Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); ArgentinaFil: Monguillot, Joaquín Humberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; ArgentinaFil: Rhoads, James. University of Georgia. Feed the Future Innovation Lab for Peanut; Estados Unido

Understanding the pathways from biodiversity to agro-ecological outcomes: A new, interactive approach

The adoption of agro-ecological practices in agricultural systems worldwide can contribute to increased food production without compromising future food security, especially under the current biodiversity loss and climate change scenarios. Despite the increase in publications on agro-ecological research and practices during the last 35 years, a weak link between that knowledge and changed farmer practices has led to few examples of agro-ecological protocols and effective delivery systems to agriculturalists. In an attempt to reduce this gap, we synthesised the main concepts related to biodiversity and its functions by creating a web-based interactive spiral (www.biodiversityfunction.com). This tool explains and describes a pathway for achieving agro-ecological outcomes, starting from the basic principle of biodiversity and its functions to enhanced biodiversity on farms. Within this pathway, 11 key steps are identified and sequentially presented on a web platform through which key players (farmers, farmer networks, policy makers, scientists and other stakeholders) can navigate and learn. Because in many areas of the world the necessary knowledge needed for achieving the adoption of particular agro-ecological techniques is not available, the spiral approach can provide the necessary conceptual steps needed for obtaining and understanding such knowledge by navigating through the interactive pathway. This novel approach aims to improve our understanding of the sequence from the concept of biodiversity to harnessing its power to improve prospects for ‘sustainable intensification’ of agricultural systems worldwide

Examples of risk tools for pests in Peanut (Arachis hypogaea) developed for five countries using Microsoft Excel

Suppressing pest populations below economically-damaging levels is an important element of sustainable peanut (Arachis hypogaea L.) production. Peanut farmers and their advisors often approach pest management with similar goals regardless of where they are located. Anticipating pest outbreaks using field history and monitoring pest populations are fundamental to protecting yield and financial investment. Microsoft Excel was used to develop individual risk indices for pests, a composite assessment of risk, and costs of risk mitigation practices for peanut in Argentina, Ghana, India, Malawi, and North Carolina (NC) in the United States (US). Depending on pests and resources available to manage pests, risk tools vary considerably, especially in the context of other crops that are grown in sequence with peanut, cultivars, and chemical inputs. In Argentina, India, and the US where more tools (e.g., mechanization and pesticides) are available, risk indices for a wide array of economically important pests were developed with the assumption that reducing risk to those pests likely will impact peanut yield in a positive manner. In Ghana and Malawi where fewer management tools are available, risks to yield and aflatoxin contamination are presented without risk indices for individual pests. The Microsoft Excel platform can be updated as new and additional information on effectiveness of management practices becomes apparent. Tools can be developed using this platform that are appropriate for their geography, environment, cropping systems, and pest complexes and management inputs that are available. In this article we present examples for the risk tool for each country.Fil: Jordan, David L.. University of Georgia; Estados Unidos. North Carolina State University; Estados UnidosFil: Buol, Greg S.. North Carolina State University; Estados UnidosFil: Brandenburg, Rick L.. North Carolina State University; Estados UnidosFil: Reisig, Dominic. North Carolina State University; Estados UnidosFil: Nboyine, Jerry. Council for Scientific and Industrial Research Savanna Agricultural Research Institute; GhanaFil: Abudulai, Mumuni. Council for Scientific and Industrial Research Savanna Agricultural Research Institute; GhanaFil: Oteng Frimpong, Richard. Council for Scientific and Industrial Research Savanna Agricultural Research Institute; GhanaFil: Mochiah, Moses Brandford. Council for Scientific and Industrial Research Crops Research Institute; GhanaFil: Asibuo, James Y.. Council for Scientific and Industrial Research Crops Research Institute; GhanaFil: Arthur, Stephen. Council for Scientific and Industrial Research Crops Research Institute; GhanaFil: Akromah, Richard. Kwame Nkrumah University Of Science And Technology; GhanaFil: Mhango, Wezi. Lilongwe University Of Agriculture And Natural Resources; MalauiFil: Chintu, Justus. Chitedze Agricultural Research Service, Lilongwe; MalauiFil: Morichetti, Sergio. Aceitera General Deheza; ArgentinaFil: Paredes, Juan Andres. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; ArgentinaFil: Monguillot, Joaquín Humberto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Singh Jadon, Kuldeep. Central Arid Zone Research Institute, Jodhpur; IndiaFil: Shew, Barbara B.. North Carolina State University; Estados UnidosFil: Jasrotia, Poonam. Indian Institute Of Wheat And Barley Research, Karnal; IndiaFil: Thirumalaisamy, P. P.. India Council of Agricultural Research, National Bureau of Plant Genetic Resources; IndiaFil: Harish, G.. Directorate Of Groundnut Research, Junagadh; IndiaFil: Holajjer, Prasanna. National Bureau Of Plant Genetic Resources, New Delhi; IndiaFil: Maheshala, Nataraja. Directorate Of Groundnut Research, Junagadh; IndiaFil: MacDonald, Greg. University of Florida; Estados UnidosFil: Hoisington, David. University of Georgia; Estados UnidosFil: Rhoads, James. University of Georgia; Estados Unido

Integrated management of ground wētā (Orthoptera: Anostostomatidae) in Marlborough vineyards

The intensification of agriculture has led to monocultures of high-yielding plant species/cultivars over large areas of land. This provides abundant resources for insects which feed on those monocultural species, elevating them to the status of econmic pests. In the Marlborough region, New Zealand, the conversion of native vegetation in the Awatere Valley to pastures, and in the last 30 years to vineyards, has elevated an endemic orthopteran insect, referred to as wētā (Anostostomatidae) in Maori language, to occasional pest status. This wētā damages vine buds at budburst, consequently reducing yields. Damage is currently managed by tying plastic sleeves around the trunks of vines (Vitis vinifera L.); the sleeves are slippery and deny wētā access to buds. This management approach was adopted, instead of using pesticides, because of the significance of wētā in Maori culture and threats to populations of some wētā species. However, this management technique is labour intensive and costly, and sleeves often need to be repaired/replaced, leading to further costs. They also litter the environment when they become detached from the vines. Hence, this PhD work aimed at developing an ecologically-based integrated management strategy for wētā based on an understanding of the biology and ecology of the species associated with vine damage. A range of laboratory and field experiments were conducted to 1) confirm the identities and number of wētā species damaging vines, 2) wētā biology, densities and distribution in vine and non-vine habitats, 3) the range of plant species in wētā diet, 4) habitat manipulation strategies to mitigate wētā damage and 5) strategies to deter this insect from vineyards. A phylogenetic analysis of sequences obtained from wētā collected from vineyards confirmed that a single species was associated with bud damage. It was identified as Hemiandrus sp. ‘promontorius’ (Johns 2001) using morphological keys. This species is not threatened but has a restricted habitat range. It laid a mean of 55 eggs between March and May, and these hatched after five months. The sex ratio of this wētā was unity. Of three habitats searched, higher numbers of this insect per square meter were found in vines than in either pastures or shrublands. Within vineyards, they were mostly found inhabiting burrows in the bare, moist and less compact soil under vines, with few wētā occupying burrows in the inter-row. A high throughput analysis of DNA sequences from faecal pellets of wētā collected from vineyards showed that this insect feeds on plants from 30 families and 44 genera. Although vines and grasses were the dominant plants in the viticultural landscape studied, dicotyledonous weeds were found to be important components of wētā diet. In terms of management, three under-vine treatments [pea straw mulch (Pisum sativum L.), mussel shells (Perna canaliculus Gmelin, 1791), tick beans (Vicia faba Linn. var. minor (Fab.))] and two inter-row treatments [exisitng ryegrass-dominant vegetation, tick beans] were tested for their efficacy to mitigate wētā damage. Controls comprised vines with plastic sleeves (treated) or no sleeves (untreated), with the existing ryegrass-dominant inter-row vegetation. In this experiment, damage reduction resulted in a 28 and 39% significant yield increase in the under-vine bean and shell treatments respectively, compared to the untreated control. These yield increments were not significantly different from a 30% increment recorded in the sleeve treatment over the untreated control. Apart from mitigating wētā damage, some advantages of the under-vine bean and shell treatments over sleeve treatments include the ability of the beans to habour natural enemies for the control of other vine insect pests; shells conserve moisture and suppresses weed growth under the vines. Endophyte-infected grasses were also tested for their potential to deter wētā from vineyards. Laboratory choice and no-choice experiments demontrated that the loline alkaloids produced by the endophytes in the grasses prevented further feeding by wētā after the initial bite which occurred at the base of their stems. However, this initial bites severed the tillers from the stem and resulted in reduced biomass of endophyte-infected grasses in the no-choice experiment. Results of field experiments from one site also corroborated the potential of these grasses to be used to deter wētā from vineyards. In conclusion, this work proposes a suite of non-pesticidal and sustainable alternatives (shells, under-vine tick beans, endophyte-infected grasses) to mitigate wētā damage in vineyards. These alternatives could either be used alone or together with the current sleeve management approach. Future works could examine combining these strategies into a kind of ‘push-pull’ wētā management strategy, with ‘push’ factors comprising endophyte-infected grasses and shells. ‘Pull’ could comprise strips of non-crop habitats established at the boundaries of vine blocks. Plants in this habitat could consist of tick beans, as well as the shrubs and dicotyledous weeds identified in the insect’s diet

Identifying plant DNA in the faeces of a generalist insect pest to inform trap cropping strategy

International audienceMonocropping elevates many insects to the status of economic pests. In these agroecosystems, non-crop habitats are sometimes deployed as trap crops to reduce pest damage. This environmentally friendly alternative to pesticides can be particularly fitting when dealing with native invaders that may be afforded legal protection or enjoy public sympathy as is the case for the ground wētā Hemiandrus sp. 'promontorius' (Orthoptera) in New Zealand. However, this approach requires knowledge of the insects' diet to select the most appropriate plant species for trap cropping. Here, ingested plant DNA in the faeces of wētā was analysed to help develop strategies for mitigating its damage in New Zealand vineyards. DNA was extracted from faeces of wētā collected from six different vineyards over four seasons. Using a DNA metabarcoding approach, we amplified the rbcL gene region and sequenced the amplicons on an Illumina MiSeq platform. The identity of plants in the diet of this insect was determined by comparing the sequences generated with those available in the GenBank database and cross-checking the results with a database of plants known to be present in New Zealand. A total of 47 plant families and 79 genera were detected. Of the genera identified, Vitis, Poa, Festuca, Anthoxanthum, Anagallis, Camelina, Epilobium, Menyanthes, Pedicularis, Urtica, Garrya, Pinus and Tilia were the major ones (i.e. they were present in more than 50% of the faecal samples). The composition of the above plant taxa in faecal materials was significantly different between collection sites or dates, except for Menyanthes. The occurrence of the latter was significantly different between collection sites. These results indicate that effectively mitigating wētā damage to vines requires the use of a diverse mix of plant species for trap cropping as wētā seem to be highly generalist in their feeding behaviour even when plant diversity is relatively low

Agroecological management of a soil-dwelling orthopteran pest in vineyards

International audienc

Ecological and pest-management implications of sex differences in scarab landing patterns on grape vines

Background Melolonthinae beetles, comprising different white grub species, are a globally-distributed pest group. Their larvae feed on roots of several crop and forestry species, and adults can cause severe defoliation. In New Zealand, the endemic scarab pest Costelytra zealandica (White) causes severe defoliation on different horticultural crops, including grape vines (Vitis vinifera). Understanding flight and landing behaviours of this pest can help inform pest management decisions. Methods Adult beetles were counted and then removed from 96 grape vine plants from 21:30 until 23:00 h, every day from October 26 until December 2, during 2014 and 2015. Also, adults were removed from the grape vine foliage at dusk 5, 10, 15, 20 and 25 min after flight started on 2015. Statistical analyses were performed using generalised linear models with a beta-binomial distribution to analyse proportions and with a negative binomial distribution for beetle abundance. Results By analysing C. zealandica sex ratios during its entire flight season, it is clear that the proportion of males is higher at the beginning of the season, gradually declining towards its end. When adults were successively removed from the grape vines at 5-min intervals after flight activity begun, the mean proportion of males ranged from 6–28%. The male proportion suggests males were attracted to females that had already landed on grape vines, probably through pheromone release. Discussion The seasonal and daily changes in adult C. zealandica sex ratio throughout its flight season are presented for the first time. Although seasonal changes in sex ratio have been reported for other melolonthines, changes during their daily flight activity have not been analysed so far. Sex-ratio changes can have important consequences for the management of this pest species, and possibly for other melolonthines, as it has been previously suggested that C. zealandica females land on plants that produce a silhouette against the sky. Therefore, long-term management might evaluate the effect of different plant heights and architecture on female melolonthine landing patterns, with consequences for male distribution, and subsequently overall damage within horticultural areas

Interdependence of Extension and Improved Variety Adoption

This paper, seeks to empirically establish the complementarity or otherwise between the decision to adopt improved soybean variety and the decision to participate in extension service training. The paper departs from the traditional binary dependent regression model (probit and logit) with extension treated as one of several covariates and instead model the binary outcomes of the decisions to adopt improved varieties, and access to extension services simultaneously using bivariate probit model. Data for the study is from 1432 farmers across the three regions of northern Ghana to jointly model the determinants of access to agricultural extension services and adoption of improved soybean variety (Jenguma). We found a positive correlation between the decisions to adopt improved soybean variety (Jenguma) and access to agricultural extension services. The implication is that, the decision to adopt the variety is interrelated with access to agricultural extension services. Hence, access to agricultural extension services is complementary to the decision to adopt new soybean varieties. Findings also indicate that, the decision to adopt improved soybean varieties is influenced by younger, less educated farmers with large farms and ownership of parcels. Given that agricultural extension service is a public good, we recommend that the government of Ghana allocates more human, financial, and technical resources to the extension services to enhance the delivery of extension services to farmers so as to improve the adoption of productivity enhancing technologie

Field efficacy of genetically modified FK 95 Bollgard II cotton for control of bollworms, Lepidoptera, in Ghana

Abstract Background Cotton (Gossypium hirsutum L.) cultivation in Ghana is constrained by bollworms that damage squares (flower buds) and developing bolls, resulting in loss in seed cotton yield. Control of these insects is heavily dependent on insecticides that are costly and also pose health and environmental risks to users. Potential alternative control strategies have focused on using cotton genetically modified with the soil-borne bacterium Bacillus thuringiensis Berliner (Bt) that confer resistance against these pests. This study evaluated the field efficacy of the genetically modified FK 95 Bollgard II (FK 95 BG II) cotton for control of bollworms in Ghana. Results Results showed that bollworm densities in the FK 95 BG II cotton were lower compared with those in the FK 37 conventional cotton. However, populations of the natural enemies, ladybird beetles Coccinella undecimpunctata L and lacewings Chrysoperla carnea [Stephens] were higher in the Bt compared with the conventional technology of pest management. On average, seed cotton yields were higher in the FK 95 BG II compared to those in the FK 37. Net profit and cost–benefit ratios also were higher for the Bt technology compared with the conventional practice, indicating that farmers would benefit more if they adopt the Bt technology of cotton pest management. Conclusion The Bt cotton technology of pest management was more effective and economical than the conventional practice of wholly relying on insecticides and was a better management option for bollworm in cotton in the savanna ecology of Ghana