Crop Protection Practices Research Articles

Limiting factors for yields of field tomatoes grown by smallholders in tropical regions

Tomatoes are widely cultivated in developing countries and are a major source of income for small-scale farmers. Yields of field-grown tomatoes vary considerably under tropical conditions but the main factors that limit yields remain to be identified. To this end, we conducted an on-farm survey in 22 fields in 2003 and in 28 fields in 2005 in a range of socio-economic settings typical of smallholder farms on the island of Mayotte (Indian Ocean). Data on crop management, fulfilment of water requirements, weed density, nitrogen absorption by the crop and nutrient availability in the soil, as well as the sanitary status of the crop were recorded at two-week intervals throughout the crop cycle. The data were analysed by principal component analysis, and multiple linear regression. Yields varied between years and sites from 0.7 to 45.3 t ha−1 in 2003 and from 8.1 to 89.1 t ha−1 in 2005. In 2003, the number of fruits per m2, fruit weight, the health status of the crop, and the cation exchange capacity of the soil explained 84.7% of yield variability among fields. In 2005, the number of fruits per m2 and the health status of the crop explained 84% of yield variability. In 2003, 61.8% of the variability of the number of fruits per m2 was explained by health status and the number of plants per m2, whereas in 2005, 65.6% of the variability was explained by health status, the number of pesticide applications, and planting density. The results of this study indicate that tomato yield could be increased by improving the health status of the crop by improving the efficiency of crop protection practices and by increasing planting density.

A dual indicator set to help farms achieve more sustainable crop protection

Farmers are being called to use plant protection products (PPPs) more consciously and adopt more sustainable crop protection strategies. Indicators will help farmers to monitor their progress towards sustainability and will support their learning process. Talking the indicators through in farmers' discussion groups and the resulting peer encouragement will foster knowledge acquirement and can lead to changes in attitudes, norms, perception and behaviour. Using a participatory approach, a conceptual framework for on-farm sustainable crop protection practices was created. The same participatory approach was used to design a dual indicator set, which pairs a pesticide impact assessment system (PIAS) with a farm inquiry. The PIAS measures the risk for human health and the environment exerted by chemical crop protection. The inquiry reveals the farmers' response to this risk, both in terms of the actions they take and their knowledge, awareness and attitude. The dual indicator set allows for implementation in four tiers, each representing increased potential for monitoring and social learning. The indicator set can be adjusted on the basis of new findings, and the participatory approach can be extrapolated to other situations.

Predation of codling moth eggs is affected by pest management practices at orchard and landscape levels

The low sustainability of pesticides calls for alternative pest control practices. Among these, the conservation of pest natural enemies is governed both by the local farming practices and by the presence of resources in the surrounding landscape. We investigated the effect of landscape composition on predation of sentinel eggs of the codling moth (Cydia pomonella), a key pest in apple orchards. Thirty egg cards of approximately 15 eggs were exposed twice in each of 12 orchards. Orchards were characterized by their area, their crop protection practices, the abundance of their codling moth population and the abundance of predatory earwigs. The landscape was characterized by the area and management of orchards host to the pest and by the characteristics of the hedgerow network in 50m and 100m wide buffers. On average, 12.4% and 48.3% of the egg cards were attacked by predators in June and August, respectively. Predation depended mostly on the toxicity of the crop protection programs. Predation rates were also lower in orchards surrounded by large areas of conventional orchards. No other landscape variable was significant. This indicates that the spatial distribution of pesticides around orchards impacted the within orchards natural enemies.

Response of animal physiology to organic versus conventional food production methods

A dietary intervention study was conducted to analyse the effects of compound feeds based on crops produced in two consecutive growing seasons under four agronomic regimes that differed in crop protection (organic versus conventional) and fertilization (organic versus conventional) practices, on the growth, body chemical composition, haematological parameters, plasma antioxidant capacity, hormonal balance and immune status of male Wistar rats. The nutritional composition of the compound feeds complied with the nutritional recommendations for rats. In the first season only one generation of rats (F1) was examined whereas in the second season two rat generations (F1 and F2) were studied. The agronomic variables affected markedly the nutritional composition of feeds and there were statistically significant differences in physiological parameters between dietary groups of rats. There were however statistically significant differences in feed composition and in the physiological response of the rats between the two seasons. There were also differences in physiological response between the F1 and F2 generation of rats in the second season, although these animals were fed the same compound feeds. More detailed studies are required to quantify the effect of agronomic factors on the composition of crops and the physiology of rats fed on compound feeds prepared from these crops.

Crop protection in European maize-based cropping systems: Current practices and recommendations for innovative Integrated Pest Management

Maize-based cropping systems (MBCSs), with different frequency of maize in the crop sequence, are common in European arable systems. Pesticide use differs according to the type of active ingredients and target organisms in different regions. Within the EU Network of Excellence ENDURE, two expert-based surveys were conducted focusing on four European study regions where experts were asked to identify MBCSs in their region, determine the current crop protection practices, propose advanced practices against major pests, weeds and diseases, and evaluate the potential agronomic, environmental, economic and social impact of innovative Integrated Pest Management (IPM) tools on the sustainability of MBCSs. In the northern region (Denmark and The Netherlands), maize is mostly cultivated as non-irrigated continuous silage maize or rotated with grass, while in the central-eastern region the major systems are non-irrigated continuous grain maize (Tolna county, Hungary) or grain maize grown in rotation with winter wheat, oilseed rape and sunflower (Békés county, Hungary). In the south-western (Ebro Valley, Spain) and southern (Po Valley, Italy) regions, continuous and irrigated grain maize, as well as irrigated grain and silage maize/winter wheat rotations are prevalent. Differences in current and proposed advanced crop protection practices for MBCSs were identified between regions due to specific pest, weed and disease problems. The tolerant/resistant non-GM maize cultivars, early detection methods, pest and disease forecasting models, precision/patch spraying using GPS spray maps and the community-based decisions through information sharing were commonly recommended for innovative IPM implementation in all regions. Deviations in the recommendations between regions were mainly caused by differences in the evaluation of economic or social impact of some tools (i.e. innovative mechanical weeding). Applied multi-disciplinary research and farmer incentives to encourage the adoption of innovative IPM strategies are essential for sustainable MBCSs development in Europe. The introduction of innovative tools into IPM strategies can contribute significantly to addressing the EU’s strategic commitment to the sustainable use of pesticides and, consequently, more environmentally sustainable MBCSs.

Effect of Organic and Conventional Crop Rotation, Fertilization, and Crop Protection Practices on Metal Contents in Wheat (Triticum aestivum)

The effects of organic versus conventional crop management practices (crop rotation, crop protection, and fertility management strategies) on wheat yields and grain metal (Al, Cd, Cu, Ni, Pb, and Zn) concentrations were investigated in a long-term field trial. The interactions between crop management practices and the season that the crop was grown were investigated using univariate and redundancy analysis approaches. Grain yields were highest where conventional fertility management and crop protection practices were used, but growing wheat after a previous crop of grass/clover was shown to partially compensate for yield reductions due to the use of organic fertility management. All metals except for Pb were significantly affected by crop management practices and the year that the wheat was grown. Grain Cd and Cu levels were higher on average when conventional fertility management practices were used. Al and Cu were higher on average when conventional crop protection practices were used. The results demonstrate that there is potential to manage metal concentrations in the diet by adopting specific crop management practices shown to affect crop uptake of metals.

Volumetric Collection Efficiency and Droplet Sizing Accuracy of Rotary Impactors

Measurements of spray volume and droplet size are critical to evaluating the movement and transport of applied sprays associated with both crop production and protection practices and vector control applications for public health. Any sampling device used for this purpose will have an efficiency of collection that is a function of the sampling device itself, the droplet size of the spray being sampled, and the airspeeds under which the sampling is conducted. This study focuses on two rotary impaction devices, the Hock and the FLB samplers, that were evaluated under two droplet sized sprays and four airspeeds. The collected spray concentrations were compared to standard passive samplers whose theoretical collection efficiency was calculated and used to estimate the actual spray volume sampled. Additionally, droplet sizing information derived from image analysis of droplet deposits on the rotary impactor collection surfaces was compared to actual measurements of droplet size of the sampled spray cloud. Generally, overall collection efficiencies ranged from 2.5% to 20%, with the FLB being more efficient than the Hock and with lower efficiencies at higher airspeeds for both samplers. Comparison of the droplet sizing data showed that the FLB sampler tended to underpredict the DV10 and DV50 data, while the Hock tended to overpredict the DV50 and DV90 data.

A Review of Recent Patents on Macroorganisms as Biological Control Agents

The indiscriminate use of synthetic pesticides has brought undesired problems to human health, agriculture, and the environment. Integrated Pest Management (IPM) and Biological Control (BC) programs, which are based on minimum use of pesticides, are seen as alternative, more ecological solutions to the unintended problems associated with pesticide use. These programs combine the introduction, augmentation, and/or conservation of pest natural enemies, with other protection tools. Although patents and the process of commercialization of microorganisms has been the subject of various reviews, macroorganisms used for pest and disease control have stimulated less comprehensive analyses. From our review of patents, there has been an enormous increase in the number of macroorganism-related patents registered in the last two decades. Private companies own 65% of all these patents. Rearing methods and crop protection strategies are the main intellectual property patented, with parasitoid wasps and predatory mites being the primary Biological Control Agent (BCA) focus of patents. Among countries, Japan was the first country with these types of patents, followed by the United States, Canada and China. Increasing concern for pesticide risks by governments and the public is seen as the main impetus for change in "traditional" crop protection practices and for investment in other more ecological products like BCAs.

Can summer and fall vegetative growth regulate the incidence of Tetranychus urticae Koch on clementine fruit?

Fruit scarring caused by Tetranychus urticae is one of the main pest problems faced by Spanish clementine growers as it can downgrade the quality of the fruit completely. T. urticae infestations concentrate on fruit at the end of summer. This study assessed the influence of vegetative growth of clementine trees during summer and fall on the damage caused by T. urticae. Damage significantly increased in trees in which summer and fall flushes were mechanically removed. This indicates that summer and fall leaf growth is a key factor limiting mite damage on fruit. Cultural and crop protection practices which promote abundant normal summer and fall vegetative growth seem to be critical for minimizing the impact of T. urticae populations on fruit quality.

Effects of agricultural production systems and their components on protein profiles of potato tubers

A range of studies have compared the level of nutritionally relevant compounds in crops from organic and nonorganic farming systems, but there is very limited information on the effect of farming systems and their key components on the protein composition of plants. We addressed this gap by quantifying the effects of different farming systems and key components of such systems on the protein profiles of potato tubers. Tuber samples were produced in the Nafferton factorial systems study, a group of long-term, replicated factorial field experiments designed to identify and quantify the effect of fertility management methods, crop protection practices and rotational designs used in organic, low input and conventional production systems. Protein profiles were determined by 2-DE and subsequent protein identification by HPLC-ESI-MS/MS. Principal component analysis of 2-DE data showed that only fertility management practices (organic matter vs. mineral fertiliser based) had a significant effect on protein composition. Quantitative differences were detected in 160 of the 1100 tuber proteins separated by 2-DE. Proteins identified by MS are involved in protein synthesis and turnover, carbon and energy metabolism and defence responses, suggesting that organic fertilisation leads to an increased stress response in potato tubers.

Farmer Participatory Evaluation of the Potential for Organic Vegetable Production in the Wetlands of Zambia

Although wetlands (locally called dambos) are considered extremely vulnerable to poor agricultural practices, rising population pressures have caused their agricultural use to become increasingly important. Intensification of dambo use by way of chemical fertilizer and pesticide applications poses serious challenges to their ecological sustainability. This study evaluated gliricidia (Gliricidia sepium) leafy biomass as a possible alternative to commercial fertilizer, and Tephrosia (Tephrosia vogelii) leaf extract, commercial formulations of neem seed extract (Achook) and Bacillus thuringiensis (Thuricide) as alternatives to chemical pesticides in the production of cabbage in dambos. The study showed that soil fertility management practices can significantly influence the time to harvest the cabbage crop and its yield. Vegetables grown using gliricidia biomass produced significantly higher yields compared with the no-input option. The population density of diamondback moth (Plutella xylostella) larvae, the percentage of plants infested by cabbage webworm (Hellula undalis) and cabbage aphid (Brevocoryne brassicae) was significantly lower in cabbage treated with sprays of Tephrosia leaf extract and Achook. It is concluded that gliricidia leafy biomass as a soil fertility management practice combined with Tephrosia leaf extract and neem seed extract as a crop protection practice could increase the productivity of cabbage and ensure sustainable utilization of dambos.

Crop losses to pests

Productivity of crops grown for human consumption is at risk due to the incidence of pests, especially weeds, pathogens and animal pests. Crop losses due to these harmful organisms can be substantial and may be prevented, or reduced, by crop protection measures. An overview is given on different types of crop losses as well as on various methods of pest control developed during the last century.Estimates on potential and actual losses despite the current crop protection practices are given for wheat, rice, maize, potatoes, soybeans, and cotton for the period 2001–03 on a regional basis (19 regions) as well as for the global total. Among crops, the total global potential loss due to pests varied from about 50% in wheat to more than 80% in cotton production. The responses are estimated as losses of 26–29% for soybean, wheat and cotton, and 31, 37 and 40% for maize, rice and potatoes, respectively. Overall, weeds produced the highest potential loss (34%), with animal pests and pathogens being less important (losses of 18 and 16%). The efficacy of crop protection was higher in cash crops than in food crops. Weed control can be managed mechanically or chemically, therefore worldwide efficacy was considerably higher than for the control of animal pests or diseases, which rely heavily on synthetic chemicals. Regional differences in efficacy are outlined. Despite a clear increase in pesticide use, crop losses have not significantly decreased during the last 40 years. However, pesticide use has enabled farmers to modify production systems and to increase crop productivity without sustaining the higher losses likely to occur from an increased susceptibility to the damaging effect of pests.The concept of integrated pest/crop management includes a threshold concept for the application of pest control measures and reduction in the amount/frequency of pesticides applied to an economically and ecologically acceptable level. Often minor crop losses are economically acceptable; however, an increase in crop productivity without adequate crop protection does not make sense, because an increase in attainable yields is often associated with an increased vulnerability to damage inflicted by pests.

Safeguarding production—losses in major crops and the role of crop protection

It is well accepted that agricultural production must be increased considerably in the foreseeable future to meet the food and feed demands of a rising human population and increasing livestock production. Crop protection plays a key role in safeguarding crop productivity against competition from weeds, animal pests, pathogens and viruses. The loss potential of these pest groups and the actual losses—i.e. losses despite the present crop protection practices—have been estimated for wheat, rice, maize, barley, potatoes, soybeans, sugar beet and cotton for the period 1996–1998 on a regional basis for 17 regions. Among crops the loss potential of pests worldwide varied from less than 50% (on barley) to more than 80% (on sugar beet and cotton). Actual losses are estimated at 26–30% for sugar beet, barley, soybean, wheat and cotton, and 35%, 39% and 40% for maize, potatoes and rice, respectively. Overall, weeds had the highest loss potential (32%) with animal pests and pathogens being less important (18% and 15%, respectively). Although viruses cause serious problems in potatoes and sugar beets in some areas, worldwide losses due to viruses averaged 6–7% on these crops and <1–3% in other crops. The efficacy of crop protection was highest in cash crops (53–68%) and lower (43–50%) in food crops. The variation coefficient of efficacy among regions was low in cash crops (12–18%) and highest in wheat (28%). As weed control can be achieved through mechanical or chemical means, worldwide efficacy in weed control (68%) was considerably higher than the control of animal pests or diseases (39% and 32%, respectively), which relies heavily on pesticides. The intensification of crop production necessary to meet the increasing demand through enhanced productivity per unit area might be impossible without a concomitant intensification of pest control. The perspectives of integrated pest management in safeguarding crop production and preventing negative effects on the environment are discussed for developing and developed countries.

PESTS, ENDANGERED PESTICIDES AND PROCESSING TOMATOES

Processing tomatoes are attacked by a number of important arthropods, plant diseases and nematodes which significantly reduce fruit yield and quality. Weeds compete with tomato plants, further reducing attainable yield. Worldwide, losses due to these pests are estimated to be about 34.4% of attainable tomato yield under current production practices. Without crop protection, losses would increase to 77.7% of attainable yield. Crop protection practices employed in the EEC and North America reduce yield losses from pests to about 15.4% and 22.8% of attainable yield, respectively. In some areas of the world, tomato production losses due to all categories of pests continue to exceed 50% of attainable production. Weeds are estimated to present the greatest potential for tomato yield loss, about 32.5% of attainable yield. Employing current crop protection practices, worldwide yield losses are only about 6.5% and are as low as 2.5% in the EEC. Similar though less dramatic reductions in actual yield loss are observed for pathogens (excluding viruses) at 40% of potential losses without crop protection, and insects and nematodes at 49% of potential losses. The level of pest control achieved largely results from cultural practices, currently registered pesticides, pest and crop monitoring and host plant resistance. Many pesticides used on tomatoes are of concern due to biological, regulatory and social issues. In the US, and California in particular, the Food Quality Protection, Clean Water, Toxic Air Contaminants, and Safe Drinking Water and Toxic Enforcement Acts represent regulations potentially affecting pesticides registered on processing tomatoes. Internationally, residue tolerance inconsistencies between nations limit pesticide choice. Social standards, which are not independent of regulatory issues, have brought about various types of certification proposals. Effective and economical pest management in the future will require research on the pest complex attacking processing tomatoes in an IPM context. Such research must address both biological needs and societal demands.

IPM for control of cashew powdery mildew in Tanzania. I: Farmers' crop protection practices, perceptions and sources of information

A survey of 218, mainly male, cashew farmers conducted in three Tanzanian cashew-growing Districts recorded farmers' knowledge of cashew powdery mildew disease caused by Oidium anacardii Noack and its control. The survey complemented a wider study of cashew powdery mildew disease management knowledge and information systems. The overall objective was to identify difficulties in, and solutions to, implementing IPM to minimise costly and environmentally harmful use of sulphur fungicide. Over 90% of farmers in Newala and Nachingwea Districts, and 70% of respondents in Mkuranga District, used sulphur dust. Most farmers believed that sulphur was essential for protecting cashew flowers from damage by mist - 'mist disease', and for increased production, and knew no ways of reducing use of sulphur. A minority of farmers had some knowledge of the life-cycle of O. anacardii and of the possibility of linking cultural practices to remove infection sources with reduced need for sulphur later. This farmers' knowledge was related directly or indirectly to official research and extension sources, and to their own observations and experiments. Their efforts to implement these IPM strategies reflected interest in reducing costs but were also limited by gaps in biological understanding and by difficulties in sharing IPM concepts and field tasks in the villages. Many farmers (44%) in Newala reported using more than recommended sulphur rates, whilst a majority (66%) of farmers in Nachingwea reported using well below recommended rates. These results suggest farmers' independent adaptation of standard recommendations according to perceived needs and opportunities. Sulphur-based control of cashew powdery mildew, particularly at the higher rates reported used in Newala, appeared to be highly vulnerable to low cashew prices. The diverse information sources used by farmers afforded little or no access to details of cashew powdery mildew disease nor alternative ideas about its control. The implications for future IPM-related research and for communication of research results are highlighted.

BCPC - Then and Now!

John Fisher, General Secretary of BCPC, describes the history, evolution and future direction of a major organisation in the science and practice of crop protection.

Crop protection in organic farming

David Younie and Audrey Litterick from the Scottish Agricultural College (SAC) discuss the principles and practice of crop protection in organic systems

The agrochemical industry: its contribution to crop protection and environmental policy

The agrochemical industry: its contribution to crop protection and environmental policy

Sampling for Decision Making in Crop Loss Assessment and Pest Management: Introduction

ABSTRACT Data obtained by sampling are crucial for decision making in crop loss assessment and pest management. Such data improve farmers' perceptions of the threat of pests and can, therefore, improve the quality of decision making in the practice of crop protection. The concept of a threshold, representing the dividing line between two alternative courses of action relating to seed or crop health, is an important aspect of crop protection decision making. Sampling is the means by which the required judgment can be guided. Operating characteristic curves are an important tool in the evaluation and comparison of the performance of sampling schemes. Precision integrated pest management, in which the objective is spatially variable pest management within fields, poses new problems for decision makers and statisticians developing sampling methodology in the context of crop protection.

Review: Resistance as a concomitant of modern crop protection

This paper reviews the impact of resistance to fungicides and insecticides/acaricides on the way crop protection is practised. It is now clear that resistance can develop to virtually any crop-protection product, in any pest, fungal pathogen or even weed. As a limiting factor in crop protection, it is a fact of life. A positive side-effect is the precision with which products are used today, with increasing implementation of Integrated Pest Management (IPM) programmes. This is a vital step towards sustainability. This paper describes: past experiences; current status of resistance; how resistance management influences current crop protection practices; regulatory aspects; and the outlook for the future. It concludes that EU regulations on resistance management must be simple and workable. Chemicals will continue to have a central role in optimising yields from the world's crops, as new tools, including biotechnology, become available for crop protection and resistance management. The crop-protection industry's innovations and product stewardship programmes will contribute to sustainable agriculture. This will provide continued benefits to users, the environment and society.