scholarly journals A cascade of destabilizations: combining Wolbachia and Allee effects to eradicate insect pests

2016 ◽  
Author(s):  
Julie C. Blackwood ◽  
Roger Vargas ◽  
Xavier Fauvergue
Keyword(s):  
Pest Management ◽  
Allee Effect ◽  
Mating Disruption ◽  
Insect Pests ◽  
Control Strategies ◽  
Insect Pest ◽  
Host Population ◽  
Marginal Effect ◽  
List Type ◽  
Allee Effects

SummaryThe management of insect pests has long been dominated by the use of chemical insecticides, with the aim of instantaneously killing enough individuals to limit their damage. To minimize unwanted consequences, environmentally-friendly approaches have been proposed that utilize biological control and take advantage of intrinsic demographic processes to reduce pest populations.We address the feasibility of a novel pest management strategy based on the release of insects infected with Wolbachia, which causes cytoplasmic incompatibilities in its host population, into a population with a pre-existing Allee effect. We hypothesize that the transient decline in population size caused by a successful invasion of Wolbachia can bring the population below its Allee threshold and, consequently, trigger extinction.We develop a stochastic population model that accounts for Wolbachia-induced cytoplasmic incompatibilities in addition to an Allee effect arising from mating failures at low population densities. Using our model, we identify conditions under which cytoplasmic incompatibilities and Allee effects successfully interact to drive insect pest populations toward extinction. Based on our results, we delineate control strategies based on introductions of Wolbachia-infected insects.We extend this analysis to evaluate control strategies that implement successive introductions of two incompatible Wolbachia strains. Additionally, we consider methods that combine Wolbachia invasion with mating disruption tactics to enhance the pre-existing Allee effect.We demonstrate that Wolbachia-induced cytoplasmic incompatibility and the Allee effect act independently from one another: the Allee effect does not modify the Wolbachia-invasion threshold, and cytoplasmic incompatibilities only have a marginal effect on the Allee threshold. However, the interaction of these two processes can drive even large populations to extinction. The success of this method can be amplified by the introduction of multiple Wolbachia cytotypes as well as the addition of mating disruption.Our study extends the existing literature by proposing the use of Wolbachia introductions to capitalize on pre-existing Allee effects and consequently eradicate insect pests. More generally, it highlights the importance of transient dynamics, and the relevance of manipulating a cascade of destabilizatons for pest management.

scholarly journals Modern Stored-Product Insect Pest Management

2014 ◽  
Vol 54 (3) ◽  
pp. 205-210 ◽  
Author(s):  
David William Hagstrum ◽  
Paul Whitney Flinn
Keyword(s):  
Pest Management ◽  
Insect Pests ◽  
Control Strategies ◽  
Insect Pest ◽  
Pest Species ◽  
Management Tools ◽  
Processing Plants ◽  
Insect Infestations ◽  
Food Residues ◽  
And Control

Abstract Stored-product entomologists have a variety of new monitoring, decision-making, biological, chemical, and physical pest management tools available to them. Two types of stored-product insect populations are of interest: insects of immediate economic importance infesting commodities, and insects that live in food residues in equipment and facilities. The sampling and control methods change as grain and grain products move from field to consumer. There are also some changes in the major insect pest species to take into consideration. In this review, we list the primary insect pests at each point of the marketing system, and indicate which sampling methods and control strategies are most appropriate. Economic thresholds for insect infestation levels developed for raw commodity storage, processing plants, and retail business allow sampling-based pest management to be done before insect infestations cause economic injury. Taking enough samples to have a representative sample (20-30 samples) will generally provide enough information to classify a population as above or below an economic threshold.

Insect Pest Management in Stored Products

2020 ◽  
Vol 31 (1) ◽  
pp. 24-35 ◽  
Author(s):  
Somiahnadar Rajendran
Keyword(s):  
Pest Management ◽  
Insect Pests ◽  
Insect Pest ◽  
Control Measures ◽  
Stored Products ◽  
Insect Pest Management ◽  
Insect Infestation ◽  
Combination Treatments ◽  
Agricultural Produce ◽  
Food Commodities

Insects are a common problem in stored produce. The author describes the extent of the problem and approaches to countering it. Stored products of agricultural and animal origin, whether edible or non-edible, are favourite food for insect pests. Durable agricultural produce comprising dry raw and processed commodities and perishables (fresh produce) are vulnerable to insect pests at various stages from production till end-use. Similarly, different animal products and museum objects are infested mainly by dermestids. Insect pests proliferate due to favourable storage conditions, temperature and humidity and availability of food in abundance. In addition to their presence in food commodities, insects occur in storages (warehouses, silos) and processing facilities (flour mills, feed mills). Insect infestation is also a serious issue in processed products and packed commodities. The extent of loss in stored products due to insects varies between countries depending on favourable climatic conditions, and pest control measures adopted. In stored food commodities, insect infestation causes loss in quantity, changes in nutritional quality, altered chemical composition, off-odours, changes in end-use products, dissemination of toxigenic microorganisms and associated health implications. The insects contribute to contaminants such as silk threads, body fragments, hastisetae, excreta and chemical secretions. Insect activity in stored products increases the moisture content favouring the growth of moulds that produce mycotoxins (e.g., aflatoxin in stored peanuts). Hide beetle, Dermestes maculatus infesting silkworm cocoons has been reported to act as a carrier of microsporidian parasite Nosema bombycis that causes pebrine disease in silkworms. In dried fish, insect infestation leads to higher bacterial count and uric acid levels. Insects cause damage in hides and skins affecting their subsequent use for making leather products. The trend in stored product insect pest management is skewing in favour of pest prevention, monitoring, housekeeping and finally control. Hermetic storage system can be supplemented with CO2 or phosphine application to achieve quicker results. Pest detection and monitoring has gained significance as an important tool in insect pest management. Pheromone traps originally intended for detection of infestations have been advanced as a mating disruption device ensuing pest suppression in storage premises and processing facilities; pheromones also have to undergo registration protocols similar to conventional insecticides in some countries. Control measures involve reduced chemical pesticide use and more non-chemical inputs such as heat, cold/freezing and desiccants. Furthermore, there is an expanding organic market where physical and biological agents play a key role. The management options for insect control depend on the necessity or severity of pest incidence. Generally, nonchemical treatments, except heat, require more treatment time or investment in expensive equipment or fail to achieve 100% insect mortality. Despite insect resistance, environmental issues and residue problems, chemical control is inevitable and continues to be the most effective and rapid control method. There are limited options with respect to alternative fumigants and the alternatives have constraints as regards environmental and health concerns, cost, and other logistics. For fumigation of fresh agricultural produce, new formulations of ethyl formate and phosphine are commercially applied replacing methyl bromide. Resistance management is now another component of stored product pest management. In recent times, fumigation techniques have improved taking into consideration possible insect resistance. Insect control deploying nanoparticles, alone or as carriers for other control agents, is an emerging area with promising results. As there is no single compound with all the desired qualities, a necessity has arisen to adopt multiple approaches. Cocktail applications or combination treatments (IGRs plus organophosphorus insecticides, diatomaceous earth plus contact insecticides, nanoparticles plus insecticides/pathogens/phytocompounds and conventional fumigants plus CO2; vacuum plus fumigant) have been proved to be more effective. The future of store product insect pest management is deployment of multiple approaches and/or combination treatments to achieve the goal quickly and effectively.

scholarly journals Application of Trap Cropping as Companion Plants for the Management of Agricultural Pests: A Review

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 128 ◽  
Author(s):  
Shovon Chandra Sarkar ◽  
Endong Wang ◽  
Shengyong Wu ◽  
Zhongren Lei
Keyword(s):  
Pest Management ◽  
Natural Enemies ◽  
Natural Enemy ◽  
Insect Pests ◽  
Cropping Systems ◽  
Insect Pest ◽  
Critical Time ◽  
Trap Crops ◽  
Companion Plant ◽  
Trap Cropping

Companion planting is a well-known strategy to manage insect pests and support a natural enemy population through vegetative diversification. Trap cropping is one such type of special companion planting strategy that is traditionally used for insect pest management through vegetative diversification used to attract insect pests away from the main crops during a critical time period by providing them an alternative preferred choice. Trap crops not only attract the insects for feeding and oviposition, but also act as a sink for any pathogen that may be a vector. Considerable research has been conducted on different trap crops as companion plant species to develop improved pest management strategies. Despite this, little consensus exists regarding optimal trap cropping systems for diverse pest management situations. An advantage of trap cropping over an artificially released natural enemy-based biological control could be an attractive remedy for natural enemies in cropping systems. Besides, many trap crop species can conserve natural enemies. This secondary effect of attracting natural enemies may be an advantage compared to the conventional means of pest control. However, this additional consideration requires a more knowledge-intensive background to designing an effective trap cropping system. We have provided information based on different trap crops as companion plant, their functions and an updated list of trap cropping applications to attract insect pests and natural enemies that should be proven as helpful in future trap cropping endeavors.

scholarly journals Effects of Different Water Regimes and Spacing on Insect Pest Infestation and Efficacy of Control Measures in Cucumber (Cucumis sativus)

2019 ◽  
pp. 1-8
Author(s):  
A. A. Oso ◽  
G. O. Awe
Keyword(s):  
Integrated Pest Management ◽  
Pest Management ◽  
Pest Control ◽  
Control Strategies ◽  
Insect Pest ◽  
Cultural Control ◽  
Irrigated Agriculture ◽  
Yield Attributes ◽  
Pest Infestation ◽  
And Control

Aim: Information on the influence of water availability during different seasons of rainfed or irrigated agriculture as it relates to insect pest population build-up in crops could assist in the development of integrated pest management. A study was therefore conducted to investigate effects of spacing, pest infestation and control on cucumber under rainfed and irrigated conditions. Place and Duration of Study: At the Teaching and Research Farm, Ekiti State University, Ado Ekiti, Nigeria during the 2016/2017 rainy and dry seasons. Methodology: The experiment was laid out using randomized complete block design (RCBD) in a split-plot arrangement in five replications, with spacing (60 x 60 cm, 60 x 90 cm and 60 x 120 cm) as the main plot treatments and the sub-plot treatments were different pest control strategies. The pest control strategies include synthetic insecticide (Lambda-cyhalothrin), botanical insecticide (Anogeissus leiocarpus) and control. Growth parameters and yield attributes were recorded. Insect pest occurrence, their build-up and percentage infestation on cucumber and the efficacy of the management strategies were monitored. Results: The results showed that yield was enhanced in irrigated system with the widest spacing of 60 x 120 cm botanical treatment interaction. Bemisia tabaci was the most prominent insect pest attacking cucumber under irrigated system. Conclusion: Other cultural control practices such as the use of trap crops with little or no financial implication should also be added to botanical pesticides as an integrated pest management tactic for effective management and control of the pest.

scholarly journals Hydrogels: From Controlled Release to a New Bait Delivery for Insect Pest Management

2020 ◽  
Vol 113 (5) ◽  
pp. 2061-2068
Author(s):  
Jia-Wei Tay ◽  
Dong-Hwan Choe ◽  
Ashok Mulchandani ◽  
Michael K Rust
Keyword(s):  
Controlled Release ◽  
Pest Management ◽  
Insect Pests ◽  
Insect Pest ◽  
Management Strategies ◽  
Future Research ◽  
Insect Pest Management ◽  
Release Formulation ◽  
The Past ◽  
Minimal Environmental Impact

Abstract Here, we review the literature on the development and application of hydrogel compounds for insect pest management. Researchers have used hydrogel compounds for the past few decades to achieve the controlled release of various contact insecticides, but in recent years, hydrogel compounds have also been used to absorb and deliver targeted concentrations of toxicants within a liquid bait to manage insect pests. The highly absorbent hydrogel acts as a controlled-release formulation that keeps the liquid bait available and palatable to the target pests. This review discusses the use of various types of hydrogel compounds in pest management based on different environmental settings (e.g., agricultural, urban, and natural areas), pest systems (e.g., different taxa), and modes of insecticide delivery (e.g., spray vs bait). Due to their unique physicochemical properties, hydrogel compounds have great potential to be developed into new and efficacious pest management strategies with minimal environmental impact. We will also discuss the future research and development of hydrogels in this review.

The first account of the mating disruption technique for the control of California red scale, Aonidiella aurantii Maskell (Homoptera: Diaspididae) using new biodegradable dispensers

2009 ◽  
Vol 99 (4) ◽  
pp. 415-423 ◽  
Author(s):  
S. Vacas ◽  
C. Alfaro ◽  
V. Navarro-Llopis ◽  
J. Primo
Keyword(s):  
Sex Pheromone ◽  
Pest Management ◽  
Chemical Communication ◽  
Field Trial ◽  
Mating Disruption ◽  
Control Method ◽  
Insect Pests ◽  
Environmentally Friendly ◽  
Untreated Plot ◽  
Aonidiella Aurantii

AbstractSemiochemical-based pest management programs have been increasingly used to provide environmentally friendly methods for the control of major insect pests. The efficacy of the mating disruption technique has been demonstrated for several moth pests. Unfortunately, not many experiments on mating disruption to control diaspididae species have been documented. In this work, biodegradable dispensers for mating disruption with increasing pheromone loads were used in order to study the potential of this technique for the control of Aonidiella aurantii Maskell. Field trial results demonstrated that dispensers loaded with 50 mg (a.i.) (20 g ha−1) and 100 mg (a.i.) (40 g ha−1) of sex pheromone were the most suitable, achieving significant reductions in male catches, compared to an untreated plot. In treated plots, virtually a 70% reduction in damage to fruit was recorded. Pheromone release profiles of all the dispensers were also studied under field conditions. We found that emission values >250 μg day−1 were the most suitable. This study suggests a new biodegradable dispenser capable of interfering with normal A. aurantii chemical communication. The use of mating disruption as a control method against A. aurantii is discussed.

scholarly journals Entomopathogens : role of insect pest management in crops

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
AMAR BAHADUR BAHADUR
Keyword(s):  
Pest Management ◽  
Crop Yields ◽  
Insect Pests ◽  
Insect Pest ◽  
Food Resource ◽  
Alternative Methods ◽  
Natural Environments ◽  
Insect Pest Management ◽  
Natural Ecosystems ◽  
Chemical Pesticides

Entomopathogens are microorganisms that pathogenic to insect pest. Several species of naturally occurring viz; fungi, bacteria, viruses and nematodes, infect a variety of insect pests and play an important role in agricultural crops controlling insect pest management.  This kind of biopesticide has many advantages and alternative to chemical insecticides, highly specific, safe, and environmentally sustainable. Pest problems are an almost inevitable part of agriculture. They occur largely because agricultural systems are simplified and modifications of natural ecosystems. Viruses, bacteria are host specific and fungi generally have broader host range and can infect both underground and aboveground pests, soil-dwelling nature nematodes are more suitable for managing soil pests. Growing crops in monoculture provides concentrated food resource that allows pest populations to achieve higher densities in natural environments. Some of the most important problems occur when pests develop resistance to chemical pesticides. These cause highly significant damage to crops, there are also threats from emerging new strains of pests. Crops cultivation can make the physico-chemical environment more favourable for pest activity. Agricultural pests are reducing the yield and quality of produce by feeding on crops, transmitting diseases. Agricultural production significantly loss crop yields, suggest that improvements in pest management are significant forward for improving yields. Crop growers are under immense pressure to reduce the use of chemical pesticides without sacrificing yields, but at the same time manage of pests is becoming difficult due to pesticide resistance and the decreasing availability of products. Alternative methods are needed urgently. These need to be used as part of Integrated Pest Management safety and environmental impact.  

scholarly journals Rural Farmers’ Perceptions, Knowledge and Management of Insect Pests of Fruit Vegetables in Ogbomoso Agricultural Zone of Nigeria

2014 ◽  
Vol 25 ◽  
pp. 18-28 ◽  
Author(s):  
Oladele Abiodun Olaniran ◽  
Samuel Adelani Babarinde ◽  
Adeola Foluke Odewole ◽  
Peter Ademola Aremu ◽  
Kehinde Popoola
Keyword(s):  
Management Practices ◽  
Insect Pests ◽  
Control Strategies ◽  
Insect Pest ◽  
Cultural Control ◽  
Control Methods ◽  
Rural Farmers ◽  
Planting Season ◽  
Age Category ◽  
Structured Questionnaire

Surveys were carried out in five local government areas of Ogbomoso Agricultural Zone Nigeria during planting season in 2010 to investigate rural farmers perceptions and management practices of insect pests of fruit vegetables. The survey involved 150 randomly selected farmers who were interviewed using structured questionnaire. Fruit vegetables planted by the farmers were okra, tomatoes, pepper and garden egg. Reasons given by farmers for cultivating fruit vegetables were significantly favored by age category, educational qualification, and secondary occupation of farmers (x2 = 4.757, P = 0.029). Field insect pests were perceived as the major production constraint to fruit vegetables in this zone. Majority of the farmer estimated 78.4 % rated insect pest as the most serious pest infesting fruit vegetables, the insect pests were grasshopper (Orthoptera), beetles (Coleoptera) and caterpillar (Lepidoptera). Integrated pest management module consisted basically of chemical and cultural control strategies, with weeding, shifting cultivation and crop rotation as main cultural control methods. More than 76.7 % of the farmers make use of cultural control because of unavailability and cost of chemical insecticides. Only 23.3 % had access to chemical insecticides in controlling insect pest of fruit vegetables.

scholarly journals Barriers to IPM adoption for insect pests in New Zealand pastures

2019 ◽  
pp. 139-148 ◽  
Author(s):  
Sarah Mansfield ◽  
Colin M. Ferguson ◽  
Toni White ◽  
Scott Hardwick ◽  
Sean D.G. Marshall ◽  
...  
Keyword(s):  
New Zealand ◽  
Pest Management ◽  
Management Practices ◽  
Insect Pests ◽  
Control Strategies ◽  
Economic Losses ◽  
Control Methods ◽  
Current Management ◽  
Share Information

New Zealand’s pastoral sector faces significant challenges to pest management as long-standing insecticides are deregistered. To protect their pastures, farmers need to shift from reactive responses that lead to poor economic outcomes to pre-emptive responses that are viable in the long term. Current management practices (insecticides, endophytes, biological control) for New Zealand’s pasture insect pests were assessed from the perspective of Integrated Pest Management (IPM). Potential impacts from novel control strategies and emerging digital technologies were evaluated to determine how these could improve pest management. Cryptic IPM is present within the New Zealand pastoral sector: that is, farmers practise various elements of IPM but these elements are not integrated into a cohesive system, so farmers often fail to recognise pest impacts until significant economic losses have occurred. We identified important networks by which farmers, industry and researchers communicate and share information, and can develop strategies to raise awareness of IPM. To encourage adoption, farmers need to feel ownership of pasture IPM. Investment in IPM training for farmers through industry extension networks is essential to prepare farmers for the shift away from chemical insecticides to new biologically based control methods. Adoption of IPM will help pastoralists respond to current and new pest challenges.

scholarly journals Genetic Allee effects and their interaction with ecological Allee effects

2016 ◽  
Author(s):  
Meike J. Wittmann ◽  
Hanna Stuis ◽  
Dirk Metzler
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Survival Probability ◽  
Allee Effect ◽  
Extinction Risk ◽  
List Type ◽  
Small Populations ◽  
Allee Effects ◽  
Deleterious Mutations ◽  
Lethal Equivalents

SummaryIt is now widely accepted that genetic processes such as inbreeding depression and loss of genetic variation can increase the extinction risk of small populations. However, it is generally unclear whether extinction risk from genetic causes gradually increases with decreasing population size or whether there is a sharp transition around a specific threshold population size. In the ecological literature, such threshold phenomena are called “strong Allee effects” and they can arise for example from mate limitation in small populations.In this study, we aim to a) develop a meaningful notion of a “strong genetic Allee effect”, b) explore whether and under what conditions such an effect can arise from inbreeding depression due to recessive deleterious mutations, and c) quantify the interaction of potential genetic Allee effects with the well-known mate-finding Allee effect.We define a strong genetic Allee effect as a genetic process that causes a population’s survival probability to be a sigmoid function of its initial size. The inflection point of this function defines the critical population size. To characterize survival-probability curves, we develop and analyze simple stochastic models for the ecology and genetics of small populations.Our results indicate that inbreeding depression can indeed cause a strong genetic Allee effect, but only if individuals carry sufficiently many deleterious mutations (lethal equivalents) on average and if these mutations are spread across sufficiently many loci. Populations suffering from a genetic Allee effect often first grow, then decline as inbreeding depression sets in, and then potentially recover as deleterious mutations are purged. Critical population sizes of ecological and genetic Allee effects appear to be often additive, but even superadditive interactions are possible.Many published estimates for the number of lethal equivalents in birds and mammals fall in the parameter range where strong genetic Allee effects are expected. Unfortunately, extinction risk due to genetic Allee effects can easily be underestimated as populations with genetic problems often grow initially, but then crash later. Also interactions between ecological and genetic Allee effects can be strong and should not be neglected when assessing the viability of endangered or introduced populations.

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