Multicentre studies of insecticide-treated durable wall lining in Africa and South-East Asia: entomological efficacy and household acceptability during one year of field use.

BACKGROUND: Indoor residual spraying (IRS) is a primary method of malaria vector control, but its potential impact is constrained by several inherent limitations: spraying must be repeated when insecticide residues decay, householders can tire of the annual imposition and campaign costs are recurrent. Durable lining (DL) can be considered an advanced form of long-lasting IRS where insecticide is gradually released from an aesthetically attractive wall lining material to provide vector control for several years. A multicentre trial was carried out in Equatorial Guinea, Ghana, Mali, South Africa and Vietnam to assess the feasibility, durability, bioefficacy and household acceptability of DL, compared to conventional IRS or insecticide-treated curtains (LLITCs), in a variety of operational settings. METHODS: This study was conducted in 220 households in traditional rural villages over 12-15 months. In all sites, rolls of DL were cut to fit house dimensions and fixed to interior wall surfaces (usually with nails and caps) by trained teams. Acceptability was assessed using a standardized questionnaire covering such topics as installation, exposure reactions, entomology, indoor environment, aesthetics and durability. Bioefficacy of interventions was evaluated using WHO cone bioassay tests at regular intervals throughout the year. RESULTS: The deltamethrin DL demonstrated little to no decline in bioefficacy over 12-15 months, supported by minimal loss of insecticide content. By contrast, IRS displayed a significant decrease in bioactivity by 6 months and full loss after 12 months. The majority of participants in DL households perceived reductions in mosquito density (93%) and biting (82%), but no changes in indoor temperature (83%). Among those households that wanted to retain the DL, 73% cited protective reasons, 20% expressed a desire to keep theirs for decoration and 7% valued both qualities equally. In Equatorial Guinea, when offered a choice of vector control product at the end of the trial (DL, IRS or LLITCs), DL consistently emerged as the most popular intervention regardless of the earlier household allocation. CONCLUSIONS: Just as long-lasting insecticidal nets overcame several of the technical and logistical constraints associated with conventionally treated nets and then went to scale, this study demonstrates the potential of DL to sustain user compliance and overcome the operational challenges associated with IRS.

Groundwater monitoring for 1,3-dichloropropene in high fumigant use areas of North America and Europe.

BACKGROUND: 1,3-Dichloropropene (1,3-D) is a soil fumigant used for the control of nematodes in high-value fruit, nut and vegetable crops globally. Extensive water monitoring efforts have been undertaken over the past four decades by public and private institutions, given the widespread agricultural use of 1,3-D, and environmental fate and metabolism data suggesting the potential for 1,3-D to leach into groundwater. The aim of this study is to review the results of groundwater monitoring studies for 1,3-D conducted in North America and the European Union (EU) since 1980. RESULTS: Analysis of > 50 000 water samples by state and federal agencies in the USA resulted in 151 detections of 1,3-D. An additional 4000 samples analyzed in groundwater studies specifically targeting high 1,3-D use areas in Europe and the USA resulted in 74 detections of 1,3-D or its primary metabolites. The combined detection rate of 1,3-D and its primary metabolites in high-use areas of the EU and North America was 0.7%. CONCLUSIONS: The availability of extensive groundwater monitoring information developed through decades of study supports the conclusion that soil fumigation with 1,3-D poses an inconsequential risk for drinking water exposure. The lack of significant detections of 1,3-D from targeted monitoring studies is due to the high volatility of 1,3-D, the rapid degradation of 1,3-D in most agricultural soils, the rapid degradation of 1,3-D and its metabolites in aerobic aquatic systems, and the rapid hydrolysis of 1,3-D in water. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Integrating ecosystem services into crop protection and pest management: Case study with the soil fumigant 1,3-dichloropropene and its use in tomato production in Italy.

Ecosystems provide the conditions for producing food, regulating water, and providing wildlife habitats; these, among others, are known as ecosystem services (ESs). Food production is both economically and culturally important to southern European farmers, particularly in Italy where farmers grow flavorsome tomatoes with passion and pride. Growers rely on pesticides for crop protection, the potential environmental impact of which is often questioned by regulators and other stakeholders. The European regulatory system for the approval of pesticides includes a thorough evaluation of risks to the environment and is designed to be protective of ecosystems. The consideration of ESs in environmental decision making is a growing trend, and the present case study provides an example of how ESs evaluation could be used to enhance agricultural practices and regulatory policy for crop protection. By attacking plant roots, nematodes may affect the growth and yield of fruit and vegetable crops, and the income earned by farmers at harvest time. Available solutions include chemical treatments such as 1,3-dichloropropene (1,3-D), physical treatments (solarization), and biological treatments (biofumigation). In order to characterize the risks and benefits associated with the use of 1,3-D in crop protection, ESs and socioeconomic analyses were applied to its use in the control of nematodes in tomato cultivation in southern Italy. The present study confirmed the benefits of 1,3-D to tomato production in Italy, with significant positive effects on production yields and farm income when compared to limited and transient potential impacts on services such as soil function. It was confirmed that 1,3-D allows farm income to be maintained and secures tomato production in these regions for the future. Integr Environ Assess Manag 2016;12:801-810. © 2016 SETAC.

Insecticide resistance in malaria vector mosquitoes at four localities in Ghana, West Africa.

BACKGROUND: Malaria vector control programmes that rely on insecticide-based interventions such as indoor house spraying with residual insecticides or insecticide treated bed nets, need to base their decision-making process on sound baseline data. More and more commercial entities in Africa, such as mining companies, are realising the value to staff productivity of controlling malaria transmission in their areas of operation.This paper presents baseline entomological data obtained during surveys conducted for four mining operations in Ghana, West Africa. RESULTS: The vast majority of the samples were identified as Anopheles gambiae S form with only a few M form specimens being identified from Tarkwa. Plasmodium falciparum infection rates ranged from 4.5 to 8.6% in An. gambiae and 1.81 to 8.06% in An. funestus. High survival rates on standard WHO bioassay tests were recorded for all insecticide classes except the organophosphates that showed reasonable mortality at all locations (i.e. >90%). The West African kdr mutation was detected and showed high frequencies in all populations. CONCLUSIONS: The data highlight the complexity of the situation prevailing in southern Ghana and the challenges facing the malaria vector control programmes in this region. Vector control programmes in Ghana need to carefully consider the resistance profiles of the local mosquito populations in order to base their resistance management strategies on sound scientific data.