Fourth Conference of West African Cocoa Entomologists,Legon, December 1974

Abstract

Hollow‐fibre, laminate‐flake and microencapsulated formulations of the synthetic sex pheromone (Z,Z) and (Z,E)‐7–11‐hexadecadienyl acetate of Pectinophora gossypiella (Saunders) were applied aerially in large scale trials in the Delta region of Egypt in 1985. 100 ha blocks of cotton were treated at regular intervals throughout the season as the only means of controlling the pest and compared with a 100 ha block of cotton sited in the same locality which was treated aerially with conventional insecticide spray applications. Comparisons of numbers of infested bolls, open boll counts and yields of seed cotton showed that adequate levels of control were achieved with all three pheromone formulations which were at least as effective as the insecticide sprays. The costs of the pheromone formulations and their aerial application also compared favourably with the insecticide programme. Greater numbers of beneficial insects were recorded in the pheromone‐treated areas than in the insecticide treated area.     

A review of progress toward field application of transgenic mosquitocidal entomopathogenic fungi

In Africa, adult mosquito populations are primarily controlled with insecticide‐impregnated bed nets and residual insecticide sprays. This coupled with widespread applications of pesticides in agriculture has led to increasing insecticide resistance in mosquito populations. We have developed multiple alternative strategies for exploiting transgenic Metarhizium spp. directed at: (i) shortening the lifespan of adult mosquitoes; (ii) reducing transmission potential of Plasmodium spp.; (iii) reducing vector competence via pre‐lethal effects. The present challenge is to convert this promising strategy into a validated public health intervention by resolving outstanding issues related to the release of genetically modified organisms. © 2019 Society of Chemical Industry     

Effects of lambda-cyhalothrin on mosquito larvae and predatory aquatic insects

Agricultural insecticides can affect mosquito production in rice fields by controlling mosquitoes, disrupting biological control or contributing to selection of insecticide resistance. The duration of insecticidal activity of the pyrethroid lambda-cyhalothrin was quantified on predatory insects in rice fields and on three kinds of mosquito larva: a pyrethroid-susceptible strain of Culex tarsalis Coquillet, a pyrethroid-resistant strain of Cx pipiens L. (sensu lato) and non-resistant Cx pipiens s.l. Lambda-cyhalothrin killed most caged, susceptible mosquitoes for up to 21 days. It killed fewer resistant Cx pipiens s.l., but suppressed their survival for over a week. Lambda-cyhalothrin suppressed field populations of predatory insects through day 29. Agricultural use of lambda-cyhalothrin can provide incidental mosquito control. However, the pyrethroid persisted in sediment and gradually decreased in activity, which could contribute to selection of pyrethroid-resistant mosquitoes. Because caged mosquitoes showed good survival before predators recovered, disruption of biological control is possible. It is therefore advisable for growers and mosquito control agencies to communicate about pesticide use.     

Diversity and Selectivity of Flower-visiting Insects in Xipu Forest Park

[Objective]This study was conducted to understand the species and quantity of flowervisiting insects in Xipu Forest Park,supplement the data of local flowervisiting insects,and fill the research gap of flowervisiting insects in the Lesser Hinggan Mountain.[Method]The methods of route survey and sample plot survey were used to investigate the community of flowervisiting insects,and the method of net catching was used to collect flowervisiting insects and record relevant data.[Results]A total of 1526 flowervisiting insects belonging to 79 species,27 families and 9 orders were found.Among them,Lepidoptera was the most,accounting for 40.51%,while Odonata,Mantodea,Hemiptera and Thysanoptera are the least.The results showed that the insect diversity index and insect dominance index were higher in the flower cultivation area,the insect evenness index was highest in the lawn area,and the flowervisiting insects in arbor area and flower shrub area were more similar.Rosaceae had the most flowervisiting insects,followed by Compositae,Cruciferae and Leguminosae.[Significance]The study provides scientific basis and data support for the rational development and utilization,biodiversity protection and sustainable development of forest parks.     

The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. VI. Observations on Side-Effects

Abstract

The experimental application by helicopter of six insecticides to riverine forest galleries of the Komoe River in Upper Volta against Glossina tachinoides Westw. was monitored for its effects upon non-target organisms, in particular birds, fish, insects and crustaceans inhabiting the experimental area. There was no recognisable mortality associated with applications of these insecticides on birds or fish. Aerosol applications of permethrin and decamethrin produced mortalities in two species of crustacea and very high mortalities occurred from a residual treatment of decamethrin at 12.5 g a.i./ha.     

Area-wide management of Aedes albopictus: choice of study sites based on geospatial characteristics, socioeconomic factors and mosquito populations

BACKGROUND: Aedes (Stegomyia) albopictus (Skuse), the Asian tiger mosquito, is an introduced invasive species in the United States that is responsible for a significant proportion of service requests to local mosquito control programs. This container‐utilizing mosquito is refractory to standard mosquito abatement measures in the United States. This study is part of a USDA‐ARS project to develop an area‐wide management strategy for Ae. albopictus. The goal was to identify three study sites, similar in socioeconomic parameters, geography and Ae. albopictus abundance, in urban and suburban areas in Mercer and Monmouth counties in New Jersey. Prior service requests and light trap counts and also detailed county maps were used to chose nine preliminary sites (four in Mercer and five in Monmouth) where weekly surveillance for Ae. albopictus was performed throughout the 2008 active season. RESULTS: Although outliers were detected, socioeconomic variables in the study sites within each county were fairly consistent. Ae. albopictus abundance was associated with poverty levels and had the highest maxima in Mercer, although average mosquito abundance was similar in urban Mercer and suburban Monmouth. CONCLUSION: Three study sites in each county were identified for future studies. The summer‐long surveillance also revealed socioeconomic variables critical for the development of integrated mosquito management. Copyright © 2011 Society of Chemical Industry     

Diversity of insecticide resistance mechanisms and spectrum in European populations of the codling moth, Cydia pomonella

Only a few of the registered insecticides against Cydia pomonella L. are still effective in areas where insecticide resistance has emerged in this pest. Resistance mechanisms are multiple, and their lone or cumulative effects in a single population are not completely understood. A detailed estimation of resistance spectrum is still required to define the suitable insecticides to use against a given population. The efficacy of ten insecticides was therefore investigated together with the resistance mechanisms expressed in four laboratory strains and 47 field populations of C. pomonella from five countries. Bioassays were performed using topical applications of diagnostic concentrations on diapausing larvae, and resistance mechanisms were analysed on adults emerging from control insects. All populations exhibited a reduced susceptibility to at least one insecticide when compared with the susceptible laboratory strain. Cross-resistances were observed between azinphos-methyl or phosalone and more recent compounds such as spinosad and thiacloprid. Resistances to azinphos-methyl, diflubenzuron, spinosad, tebufenozide and thiacloprid were significantly correlated with mixed-function oxidase activity, while increased glutathione-S-transferase and reduced non-specific esterase activities were correlated with resistance to azinphos-methyl and emamectin, respectively. Conversely, resistances to azinphos-methyl, tebufenozide and thiacloprid were negatively correlated with increased esterase activity. None of the observed mechanisms explained the loss of susceptibility of populations to chlorpyrifos-ethyl, and no significant correlation was detected between resistance to deltamethrin and the presence of the kdr mutation. The suitability of such non-target instars to monitor insecticide resistance in field populations is discussed.     

昆虫病毒生物杀虫剂产业化及其展望

昆虫病毒杀虫剂是环境友好、对非靶标生物安全、无毒无害绿色农用品,本文从昆虫病毒杀虫剂发展历史、现状、产业化研发和生产、市场和应用的多个方面,结合笔者从事此方面工作的经验和体会,进行总结和评述,希望以此为同行提供借鉴和参考,以促进我国病毒杀虫剂产业化及其应用的进程。     

Addition of alarm pheromone to insecticides and the possible improvement of the control of the western flower thrips,Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)

This study represents the first attempt to improve insecticide contact using the dodecyl acetate component of the alarm pheromone of the western flower thrips ( Frankliniella occidentalis Pergande ). Dodecyl acetate dissolved in ethanol was added to both fipronil and maldison and used in three spray applications (7 days apart) against field infestations of F. occidentalis on strawberries in two separate trials. Fipronil alone was highly effective against larvae and to a lesser extent against adults; however, the addition of dodecyl acetate did not significantly enhance thrips mortality. Although maldison was significantly less effective against adults and larvae, the larval mortality rate was significantly increased with the addition of dodecyl acetate. In one trial, dodecyl acetate applied on its own caused a significant reduction in larval numbers. Frequent insecticide applications are recommended for control of F. occidentalis in Australia because of the short-term effectiveness of most insecticides. This may hasten the development of insecticide resistance, which is already evident in F. occidentalis populations across the continent. Hence, either cultural methods, biological control agents or more effective chemicals need to be identified. This study has shown that there is potential for dodecyl acetate to enhance insecticide control of F. occidentalis .     

The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. I. Objectives,Experimental Area and Insecticides Evaluated

Abstract

The rationale is presented for the development of techniques for applying insecticides by helicopter in small-scale field trials against Glossina tachinoides, an important vector of human sleeping sickness. This approach has been adopted in view of the difficulty of applying non-residual insecticides to the riverine forest habitat by fixed-wing aircraft and the need to test the efficacy of new insecticides to ascertain effective dosages. Six insecticides were tested; endosulfan, decamethrin, permethrin, azamethiphos tetrachlorvinphos and fenthion. The trials were carried out in the River Komoe valley, a typical humid savanna area with savanna woodland, woodland/floodplain ecotones, moist riverine forest and dry forest as the main vegetation types. Glossina tachinoides was the only tsetse fly present in sufficient numbers for it to be used for evaluation in the trials, it feeds on bushbuck and carries Trypanosoma grayi, a parasite of crocodiles and Varanus spp. The area was divided into an untreated control zone, droplet penetration study area and experimental airspray blocks. Prior to the trials themselves it was necessary to undertake equipment tests and droplet size and spray penetration studies in selected typical riverine forest habitats; to determine the most effective method of aerosol application in the riverine forest and to ascertain, through meteorological studies, the most appropriate time of day to apply the pesticide. It was also necessary to monitor the effects of the insecticide applications on the non-target organisms inhabitating or associated with the gallery forest. Detailed reports of these activities are given in accompanying papers.     

Parasitoid control of the tomato fruitworm,Helicoverpa armigera,in smallholder farmer fields in Senegal

In Africa, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) is a key pest of cotton and vegetable crops, particularly tomato. Alternatives to insecticides to control this pest are needed such as conservation biological control. However, knowledge on the diversity and ecology of naturally occurring enemies of H. armigera is limited. A two-year field survey was conducted in a set of tomato farmer fields in the main vegetable-growing area in Senegal (Niayes) to assess the spatial and seasonal occurrence of indigenous parasitoids of H. armigera, and to evaluate the effect of insecticide use on biological control efficiency. No parasitoid emerged from H. armigera eggs. Incidence of larval parasitoids was generally moderate (20%) but highly variable (0%–100%) among fields, independently of host abundance, and negatively affected by the number of insecticide applications. Larval parasitism was largely dominated by the larval parasitoid Meteorus laphygmarum Brues (Hymenoptera, Braconidae), but a positive correlation was found between specific richness or Shannon diversity index of the parasitoid community and parasitism rate. This study is a first step toward development of research and extension programs for conservation of natural enemies in the framework of integrated management of the tomato fruitworm in Senegal.     

Biochemical and physiological changes on Bacillus thuringiensis cotton after imidacloprid foliar spray

Bacillus thuringiensis cotton is a variety of cotton genetically modified to contain a gene derived from B. thuringiensis bacteria; which results in expression of toxin protein that confers resistance to bollworm complex (the most destructive pest of cotton). Introduction of Bt cotton lowered the need of insecticides, but still a number of insecticides are used for other insects like jassids, whitefly, aphids and tobacco caterpillar to which Bt gene does not provide effective control. Imidacloprid (tradename Imidacel 17.8 SL) is an insecticide designed for control of these major sucking/piercing insects that affect cotton. So in the present work we studied the post effect of imidacloprid insecticide on plant health of three Bt cotton hybrids (RCH-134, JKCH-1947, NCEH-6R) as there are reports of this insecticide causing growth and yield enhancements in absence of insect pests. Imidacloprid was first sprayed at recommended concentration (40 ml/acre) on 3 months old plants sown in randomly designed plots with three replications of each hybrid. The spray was repeated three times at 10 days interval. The level of B. thuringiensis gene expression, peroxidase activity and total phenols was measured on third day after every spray in leaves along with growth and yield of plants. The insecticide has shown to increase the level of B. thuringiensis protein, peroxidase enzyme activity, total phenols, height, number of bolls retained on plants and yield. These observations suggested that the imidacloprid treated plants showed better growth and development, thereby imidacloprid has growth enhancing effect on Bt cotton plants in addition to its insecticidal properties.     

Second International Symposium of the European Weed Research Society,Uppsala, August 1977

Abstract

The results of a discriminative spray application of decamethrin from a helicopter to fringing forest habitats of Glossina tachinoides in the Komoe valley, Upper Volta, are described. The insecticide formulated as a 2.5% emulsion concentrate was diluted with river water and applied from a Bell 47G-4A helicopter to the fringing forests of a 14 km long stretch of the River Komoe at a dosage of 12.5 g a.i./ha. The insecticide application equipment was so adjusted that when the helicopter was flown at 30 km/h, the effective swath width was about 30 m and the vmd of emitted spray was c.150 μm. Insecticide swaths were applied to the inner edges of fringing forests that were up to 100 m wide. Forests wider than 100 m received an additional insecticide swath.

The experimental area was protected from reinvasion by the establishment of dieldrin barriers at its extremities and along some tributaries and woodland/floodplain ecotones. The dieldrin was applied by the same method as was used to apply the decamethrin. The single discriminative application of decamethrin was extremely effective in controlling G. tachinoides for a period of at least 38 days, at the end of which time the wet season had commenced and there was evidence that flies were entering the experimental area from nearby unsprayed areas. The authors discuss the possible practical applications of the technique and make suggestions on how it might possibly be refined in order to reduce undesirable river water contamination and operational costs. The authors draw attention to the need for field trials, such as that reported upon, to be conducted on a sufficiently large scale and for the experimental areas to be well protected against reinvasion, if meaningful evaluation data are to be obtained.     

Insecticidal and repellent activities of insecticide-sucrose solutions to Culex pipiens molestus (Diptera: Culicidae) under laboratory and field conditions

BACKGROUND: Culex pipiens molestus Forskal has been reported as a dominant species in underground structures of urban areas in the Republic of Korea (ROK) during all seasons and becomes bothersome to humans in late autumn and winter. Most Cx. pipiens molestus in septic tanks are controlled in the ROK using larvicides such as Bt and IGR. However, there are a number of problems associated with larvicides, such as high cost and requirement for frequent use. In the present work, a new control method for Cx. pipiens molestus in septic tanks by using mixtures of sucrose solution with insecticides was investigated. RESULTS: The insecticidal and repellent activities of ten insecticides were evaluated for best control of Cx. pipiens molestus in septic tanks. Firstly, differences in susceptibilities to insecticides were evaluated in topical assays by forced direct contact bioassay and in a screened wire cage by free direct contact bioassay. The difference in insecticide susceptibility in the mosquitoes was the result of repellency by the insecticides. In three septic tanks, the density of Culex mosquitoes was sharply reduced by a deltamethrin–sucrose solution kit. CONCLUSIONS: The results demonstrated the potential for mosquito control by deltamethrin–sucrose solution, and the study offers basic information related to mosquito control in septic tanks. Copyright © 2011 Society of Chemical Industry     

Changing rice farmers' pest management practices through participation in a small-scale experiment

Asian rice farmers commonly spray insecticides in the early stages of the crop to control leaf-feeding insects. The most common leaf feeder during this period is the leaf folder. Research shows that these sprays are usually unnecessary as the damaged crops mostly recover. It appears that farmers spray to control leaf folder because of misperceptions. We explored the use of farmer participation to change these misperceptions by inviting farmers to test a simple rule-of-thumb or 'heuristic': 'Do not spray against leaf folders for the first 30 days after transplanting (or 40 days after sowing)'. About 77% of the 101 participating farmers reported that yields of rice in their test plots were not significantly different from yields in their control plots. Before participating in the evaluation exercise, about 70% of the farmers applied their first insecticide sprays during the first 30 days after transplanting. In the first year after participation, 20% applied insecticides in the first 30 days and this was further reduced to 11% in the second year. The mean number of insecticide sprays was reduced from 3.2 to 2.0. Farmers' attitudes towards leaf-feeding insects has also changed. Before participation, farmers believed these insects cause yield loss (87%), severe damage (77%) and had to be sprayed early in the season (62%). After participation, these were reduced to 9%, 28% and 10%, respectively. Through information from research distilled into a 'high science-low tech' decision rule, farmers can readily derive a test hypothesis from it, evaluate itusing a simple experiment, learn its results and change perceptions and practices.     

Climate change and the genetics of insecticide resistance

Changes in global temperature and humidity as a result of climate change are producing rapid evolutionary changes in many animal species, including agricultural pests and disease vectors, leading to changes in allele frequencies of genes involved in thermotolerance and desiccation resistance. As some of these genes have pleiotropic effects on insecticide resistance, climate change is likely to affect insecticide resistance in the field. In this review, we discuss how the interactions between adaptation to climate change and resistance to insecticides can affect insecticide resistance in the field using examples in phytophagous and hematophagous pest insects, focusing on the effects of increased temperature and increased aridity. We then use detailed genetic and mechanistic studies in the model insect, Drosophila melanogaster, to explain the mechanisms underlying this phenomenon. We suggest that tradeoffs or facilitation between adaptation to climate change and resistance to insecticides can alter insecticide resistance allele frequencies in the field. The dynamics of these interactions will need to be considered when managing agricultural pests and disease vectors in a changing climate. © 2019 Society of Chemical Industry     

Cross-resistance to dicyclanil in cyromazine-resistant mutants of Drosophila melanogaster and Lucilia cuprina

Cyromazine is an insect growth regulator insecticide with a novel mode of action, mainly used to control dipteran insects. Previously, cyromazine-resistant mutants of the Australian sheep blowfly Lucilia cuprina and the vinegar fly Drosophila melanogaster have been isolated following ethyl methanesulfonate mutagenesis and selection for resistance. Here, we show that these cyromazime-resistant mutants are cross-resistant to dicyclanil, an insect growth regulator compound with a similar chemical structure to cyromazine. Dicyclanil was recently introduced as a control agent of L. cuprina. Cross-resistance to the benzylphenylurea insecticide lufenuron was also assessed. Only one D. melanogaster cyromazine-resistant mutant is cross-resistant to lufenuron.     

Green peach aphid,Myzus persicae (Hemiptera: Aphididae), reproduction during exposure to sublethal concentrations of imidacloprid and azadirachtin

BACKGROUND: Resurgence of insect pests following insecticide applications is often attributed to natural enemy disturbance, but hormesis could be an alternative or additional mechanism. Green peach aphid, Myzus persicae (Sulzer), is an important insect pest of many crops worldwide that may be exposed to sublethal insecticide concentrations over time. Here, the hypothesis that exposure to low concentrations of imidacloprid and azadirachtin can induce hormetic responses in M. persicae is tested in the laboratory. RESULTS: When insects were exposed to potato leaf discs dipped in sublethal concentrations of insecticide, almost all measured endpoints—adult longevity, F1 production, F1 survival and F2 production—were affected, and a statistically significant (P < 0.05) stimulatory response was recorded for F2 production following exposure to imidacloprid. No other measures for hormesis were statistically significant, but other trends of hormetic response were consistently observed. CONCLUSIONS: Given that variable distribution and degradation of insecticides in the field would result in a wide range of concentrations over time and space, these laboratory experiments suggest that exposure to sublethal concentrations of imidacloprid and azadirachtin could stimulate reproduction in M. persicae. Copyright © 2008 Society of Chemical Industry     

A note on the carpenter moth Salagena sp., a new pest of cashew in Zambia

Abstract

Salagena sp. (Lepidoptera: Metarbelidae) is reported for the first time as a pest of cashew. The larva feeds on the bark and bores galleries in the wood, covering the point of attack with a typical mass of frass and silk. The attack is widespread on most adult cashew trees In the western province of Zambia, severely reducing their vigour and opening the way to secondary invaders leading to progressive decline of the trees. Seasonal cycle and preliminary control measures including removal of the grubs, pruning, spraying and swabbing with insecticide, are briefly described.     

Insect Pests and Mites

Abstract

Weeds are major components of agro-ecosystems and they affect the biology of pests and beneficial insects in several ways; provision of flowers, presence of neutral insects, modification of crop microclimate, production of chemical stimulus, alteration of colonisation background, etc. The more relevant beneficial crop–weed–insect interactions are discussed. The role of weeds in regulating pest populations is illustrated by studies on bean (Phaseolus vulgaris L.) cropping systems, in which chemical interactions between Empoasca kraemeri Ross &; Moore and two grass weeds were identified. It is proposed to continue and develop this kind of research in order to incorporate weeds into pest control strategies.