Insect Pest Populations Research Articles

Comparative Influence of Green Manure (Trifolium Alexandrinum L.) and Conventional IPM on Population of Sucking Insect Pests of Cotton

Comparative Influence of Green Manure (Trifolium Alexandrinum L.) and Conventional IPM on Population of Sucking Insect Pests of Cotton

Rapid Immobilization of Adult Aedes aegypti Caused By Plant Essential Oils At Sublethal Concentrations.

Many synthetic insecticides cause immobilization in insect pests after they are exposed. This immobilization or knockdown is an important feature of intoxication that contributes to the abatement of pest insect populations, while preventing vectors of disease from biting and spreading pathogenic organisms to susceptible individuals. We have previously demonstrated that certain plant essential oils rapidly immobilize adult female mosquitoes that have been exposed via topical application. To further characterize this effect, adult female Aedes aegypti were exposed to multiple concentrations of 32 commercially available plant essential oils, and immobilization at 1 h after exposure was recorded. The dose required to produce the 1-h knockdown effect in 50% of the test population (KD50) was calculated and compared with concentrations of each plant essential oil that caused mortality at 24 h. In the current study, multiple plant essential oils caused high percentage knockdown at 1 h at lower concentrations than concentrations that caused mortality at 24 h. Moreover, delayed mortality was observed in mosquitoes that were exposed to various concentrations of the 2 plant essential oils that produced significant knockdown at 1 h. These observations demonstrate an important characteristic of many plant essential oils and represent a novel means for which these oils may be incorporated into future insecticidal formulations.

Toxicity and sublethal effects of fluralaner on Spodoptera litura Fabricius (Lepidoptera: Noctuidae)

The increasing occurrence of resistance to chemical insecticides in insect pest populations is a serious threat to the integrity of current pest management strategies, and exploring new alternative chemistries is one important way to overcome this obstacle. Fluralaner, as a novel isoxazoline insecticide, has broad spectrum activity against a variety of insect pests, but little data is available about its effect on Lepidopterans. The effects of fluralaner on Spodoptera litura Fabricius, a widespread and polyphagous pest, were evaluated in the present study. Our results showed younger larvae were more susceptible to fluralaner treatment, but feeding and topical applications were similarly effective in 3rd instar larvae. Synergism assays indicated that piperonyl butoxide (PBO) could increase the toxicity of fluralaner to S. litura to a certain degree and P450 may be involved in the detoxification of fluralaner in vivo. Sublethal developmental effects included reduced larval body weight, decreased pupation and emergence, and notched wings in adults, accompanied by changes in the transcript levels of chitinase 5 (CHT5) and juvenile hormone acid methyltransferase (Jhamt), genes vital for insect development. Above results manifested that fluralaner is highly toxic to S. litura larvae via either topical or oral application and provide an indication of how this insecticide is metabolized in vivo. Further, our results provided a foundation for further development of fluralaner as a new tool in insect pest management.

Evaluation of Insect Pests on Edamame Varieties in Minnesota.

Edamame, Glycine max (L.) Merrill, consumption continues to rise in the United States. Improved understanding of production threats, including insect pests, could facilitate increasing production of edamame in the north-central United States. Two years of complimentary field and laboratory experiments were performed to assess insect pest populations on commercially available edamame varieties. Fourteen varieties of edamame and four grain-type soybean varieties were tested in the laboratory with soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), and subsets of these varieties were tested in the field with naturally occurring insect populations. In the laboratory, mean aphid densities on the edamame varieties Agate and Chiba Green did not differ from the aphid-resistant grain-type soybean. Among edamame, aphid densities on Agate, Chiba Green, and Kuroshinju were significantly lower than on Hokkaido Black. In both years of the field experiment, aphid densities were significantly lower on the aphid-resistant grain-type compared to all others varieties. In 2016, aphid populations on edamame varieties did not differ from the aphid-susceptible grain-types. However, in 2017 with greater aphid exposure, differences were seen among edamame varieties, and between edamame and aphid-susceptible grain-types. In both years, potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae), densities tended to be higher on edamame varieties compared to grain-types, and varied significantly among edamame varieties. In a laboratory study, differences were seen among varieties in mean density of trichomes, with grain-types generally having more trichomes than edamame. Results of this research will provide a foundation for development of production recommendations for edamame in the north-central United States.

A Bayesian classification approach for predicting Gesonia gemma Swinhoe population on soybean crop in relation to abiotic factors based on economic threshold level

Predicting of insect pest population with accuracy and speed when given large data set will make a major contribution to the success of integrated pest management. Naive Bayesian classification has been proposed for predicting the insect pest Gesonia gemma Swinhoe on soybean crop. The Naive Bayesian classifier works based on Bayes’ theorem and can predict class probabilities that a given tuple from the dataset belongs to a particular class. The dataset includes abiotic factors as features along with the class feature (pest incidence) are separated as training data and testing data, then the model was built on the training set by finding the probability for each of its features in relation with the class feature. The Naive Bayesian classification from the trained model, best fits the testing data with 90% accuracy, thus the proposed approach can be very useful in predicting the pest G. gemma on soybean crop.

A novel, easy method for estimating pheromone trap attraction range: application to the pine sawyer beetle Monochamus galloprovincialis

Abstract Pheromone traps are widely used for monitoring or managing insect pest populations. However, it is important to know their range of attraction to optimize the setting of pheromone trap networks. We propose an easy method based on the use of pairs of adjacent traps located at decreasing distance from each other. The range of attraction is deduced from the observation of reduced trap capture when the attraction range of two adjacent traps starts overlapping. The relationship between the relative trap capture and the distance between paired traps is fitted with a logistic curve. To empirically test these predictions, we conducted trapping experiments with the beetle Monochamus galloprovincialis, the insect vector of the pine wood nematode. Fifteen pairs of traps separated by 25 to 300 m, in France, and 18 pairs of traps distant from 25 to 400 m, in Portugal, were installed in maritime pine plantation landscapes. In both countries, the relative percentage of capture per trap per week was best fitted by a logistic model with two parameters. The estimated attraction ranges were 92 m (confidence interval = 62–211 m) in France and 123 m (confidence interval = 64–491 m) in Portugal. The interference between paired traps thus provides a simple and robust method for estimating the attraction range of pheromone traps.

Isolation and characterization of Beauveria and Metarhizium spp. from walnut fields and their pathogenicity against the codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae)

Entomopathogenic fungi (EPFs) play an important role for regulating insect pest populations, as they exist in many different ecosystems. Within these fungi, Beauveria and Metarhizium spp. genera include species that are the most commercially important. The aim of this study was to determine the diversity and distribution of Beauveria and Metarhizium spp. in walnut fields of Kırşehir, Turkey, and to evaluate their pathogenicity against Cydia pomonella (L.) (Lepidoptera: Tortricidae). To perform this, 90 soil samples were collected from walnut fields where Beauveria and Metarhizium spp. were isolated from these soils, using selective media. The isolated 40 fungi were characterized based on their morphological and molecular characteristics including Bloc and β-tubulin gene sequences. Also, eight selected fungi were tested against C. pomonella larvae under laboratory conditions. The fungal isolates were identified as Beauveria pseudobassiana (15), B. bassiana (12), Metarhizium robertsii (11), and M. brunneum (13). M. brunneum ELA-38 caused 83% mortality within 2 weeks after application of 1 × 108 conidia/ml. Consequently, Beauveria and Metarhizium spp. are the common component of the soils collected from walnut fields and some of fungi obtained from this work might be beneficial in the future biological control programs of C. pomonella.

Insecticidal activities of crude extact of Metarhizium anisopliae and conida suspension against Crocidolomia pavonana fabricius

Pest resistance, resurgent and the residual effect of conventional insecticides are the basis to apply Insect Pest Management (IPM) strategies. Metarhizium anisopliae is an entomophatogenic fungus that has considerable promise for usage in IPM. The spores of fungus had great potential as insect pathogen, in addition the mycotoxins products having current interest as bioactive agent. M. anisopliae was exhibited to control pest insect populations of crops especially host plant of Brassica oleracea (Cruciferae), i.e. Plutella xylostella, Spodoptera litura, and Crocidolomia pavonana. The insecticidal activities of conidia suspensions and crude extract product containing mycotoxins were investigated, withthe parametersmortality and lethal time of C. pavonana 3rd instar larvae. The experimental design of crude extract and conidia suspensions of M. anisopliae on mortality effect used Completely Randomized Design (RAL). The bioassay of conidia suspensions mortality test used 6 level spore concentrations (0, 105, 106, 107, 108, and 109 spores/ml). Analysis of variance (ANAVA) at α 95% followed by Duncan multiple test at α 5% was carried out. The result of crude extract mortality test showed that M. anisopliae produced mycotoxins from the third day of fungal growth. The long growth of fungus is directly proportional with the produced mycotoxins. The mycotoxins was optimally produced in 7th days. The extract M. anisopliae at highest mortality effect on larvae was tested for 24 to 120 h. One hundred percent mortality of larvae were achieved at 120 h with an average lethal time were 3.6 days shorter than mortality caused by conidia infections. Thus, conidia infections showed that M. anisopliae at 105 - 109 spores/ml concentrations led to mortalities of 75%, 90%, 80%, 85%, and 95 %, respectively (P<0.05). The larvae lethal time had no different in all concentration levels, but the shorter lethal time (4.66 days) was showed in the infected larvae with 109 spores/ml concentration.

Life history and habitat explain variation among insect pest populations subject to global change

AbstractPopulation dynamic responses to global change have varied widely among taxa. Most studies of population dynamics of insect pests focus on one or a few species, leaving open the question of whether changes in outbreak patterns are species‐specific or reveal predictable responses to global change, and what factors explain differences among populations. We analyzed 64 multi‐decadal time series of agricultural and forest pest insect populations in the United States. We first characterized populations according to long‐term trends, strength of population regulation, and cycle presence and length. We then asked whether these attributes could be predicted by geography, taxonomy, and life‐history traits. Roughly half of time series exhibited a long‐term trend, and agricultural pests were more likely to be declining, while forest pests were more likely to be increasing. Approximately one quarter of records exhibited periodic oscillations, and we used their statistical properties to infer whether the oscillations were environmentally forced or arose from density dependence. Insects hatching in early spring may be more strongly influenced by environmental forcing, for example, early springs or late spring frosts, than species hatching later. Our findings suggest roles of climate change, forest compositional change, and agricultural practices in driving long‐term change in pest populations.

DNA barcoding unravels contrasting evolutionary history of two widespread Asian tiger moth species during the Late Pleistocene.

Populations of widespread pest insects in tropical areas are characterized by a complex evolutionary history, with overlapping natural and human-mediated dispersal events, sudden expansions, and bottlenecks. Here, we provide biogeographic reconstructions for two widespread pest species in the tiger moth genus Creatonotos (Lepidoptera: Erebidae: Arctiinae) based on the mitochondrial cytochrome c oxidase subunit I (COI) gene. The Asian Creatonotos transiens reveals shallow genetic divergence between distant populations that does not support its current intraspecific systematics with several local subspecies. In contrast, the more widespread Creatonotos gangis comprises at least three divergent subclades corresponding to certain geographic areas, i.e. Australia, Arabia + South Asia and Southeast Asia. With respect to our approximate Bayesian computation (ABC) model, the expansion of Creatonotos gangis into Australia is placed in the Late Pleistocene (~65–63 ka). This dating coincide with an approximate time of the earliest human migration into the continent (~65–54 ka) and the period of intervisibility between Timor and Australia (~65–62 ka). Our findings highlight that the drying Sunda and Sahul shelf areas likely support successful migrations of Asian taxa into Australia during the Pleistocene. The phylogeographic patterns discovered in this study can be used to improve the effectiveness of integrated pest control programs that is a task of substantial practical importance to a broad range of agricultural stakeholders.

Organophosphate Pesticide Effects on Neuronal Cytoarchitecture and Morphological Abnormalities in 72 hour Zebrafish Embryos

Organophosphate pesticides (OP) are a class of acetylcholinesterase (AChE) inhibitors, which have effects on the central and peripheral nervous systems. OP's inhibit AChE through phosphorylation of the active site serine, which leads to a toxic and potentially lethal buildup of the neurotransmitter acetylcholine (ACh) causing excess stimulation of cholinergic neurons. OP's are widely used to suppress the activity and growth of insect pest populations in both agriculture and household settings. The objective of this study was to examine both organismal and cellular morphological changes caused by OP exposure. Specifically, zebrafish (Danio Rerio) embryos were exposed to sub‐lethal concentrations of Chlorpyrifos (CPF) and its bioactive form Chlorpyrifos‐oxon (CPO), and compared to vehicle controls (MeOH). Gross morphological changes were observed at 72 hours via light microscopy and morphological changes to cholinergic neurons were observed via confocal microscopy of wholemount immuno‐labeled embryos using anti‐ChAT. Light microscopy observations of the embryos showed varying degrees of cardiac edema in both CPF and CPO exposed embryos. Additionally, mild kyphosis was observed in CPF and strong kyphosis in CPO exposed embryos. Confocal observations of the trunk spinal region showed embryos exposed to CPF lost dorsal neural tube cell staining and dark pockets, possibly indicating cell death, were observed along the ventral neural tube. For CPO exposed embryos, cells bodies in the neural tube were disorganized. Additionally, axon projections across the neural tube showed differences in branching and spacing in both CPF and CPO exposed embryos. Together our results showed that OP exposure causes changes in neuronal cytoarchitecture and embryo morphology. Understanding the developmental effects of these pesticides is particularly important since developmental changes have significant effects on adult systems and children represent a vulnerable population.Support or Funding InformationDepartment of Defense, ARO 66377‐RT‐REP; Keck Foundation Undergraduate Fellowship to T.H.W.; James Irvine Foundation Chair in Biological Sciences to E.A.F.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Post-harvest insect infestation and mycotoxin levels in maize markets in the Middle Belt of Ghana

This study focused on assessing maize post-harvest losses in three maize markets in the Middle Belt of Ghana during the storage periods after the harvest of major and minor cropping seasons, September to December and January to April, respectively. The major and minor cropping seasons in the Middle Belt occur during the periods April to August and September to December, respectively. Storage temperature of bagged maize, grain moisture content (MC), and relative humidity (r.h.) were monitored monthly, along with insect infestations, percentage weight loss of kernels (% WL), the percentage of insect damaged kernels (% IDK), and percentage of discolored grains (% DG). Aflatoxin and fumonisin levels were assessed at the beginning and end of the major and minor crop storage seasons. Cryptolestes ferrugineus (Stephens), Cathartus quadricollis (Guerin-Meneville), Carpophilus dimidiatus (F.), Sitotroga cerealella (Olivier), Tribolium castaneum (Herbst), and Sitophilus zeamais (Motschulsky) were found in all markets. Mean insect infestation levels varied throughout the sampling period and were generally similar in the three markets, but were not correlated with temperature, MC, or r.h. (P ≥ 0.05). Mean % WL, % IDK, and % DG peaked in November and December and were usually correlated with total insect populations (P < 0.05). Aflatoxin levels of 2.9–3.4 ppb were found in all markets in the minor season maize samples, but levels ranging from 38.2 to 64.0 ppb were found in the major season samples. Fumonisin levels for all markets ranged between 0.7 and 2.3 ppm. Environmental conditions favor insect pest population development throughout the year in maize stored in markets in Ghana, thus the maize must be monitored regularly and appropriate interventions implemented to avoid product loss.

Population dynamics of stored maize insect pests in warehouses in two districts of Ghana

Understanding what insect species are present and their temporal and spatial patterns of distribution is important for developing a successful integrated pest management strategy for food storage in warehouses. Maize is stored in bags in warehouses in many countries in sub-Saharan Africa, but little monitoring information is available on insect activity in those warehouses. We monitored the populations of major post-harvest insect pests of maize at three different warehouses (MiDA, Gundaa and Wienco) in two regions in Ghana (Middle Belt and Northern Belt). The study was conducted from September 2015–July 2016, which represents a common maize harvest and storage period in the two regions. The most abundant insect pest found in the warehouses was Plodia interpunctella (Hübner), but other major pest species were recovered during the study. Sitotroga cerealella (Oliver) and Prostephanus truncatus (Horn) which are major pests on farms, were more likely to be captured in traps outside or at nearby farms than inside the warehouses. When recovered inside they tended to be found in the receiving and cleaning areas. Sitophilus spp. were commonly captured in the warehouses, but were more abundant in the Middle Belt warehouse. Our results identified the major species found during warehouse storage of maize in Ghana and suggest that the specific pest species may be different in warehouses compared to on-farm storage.

Frequency and Abundance of Selected Early-Season Insect Pests of Cotton

Abstract The use of insecticides at planting has been a common crop management practice in cotton for several decades. Historically, U.S. cotton growers relied on in-furrow applications of insecticides, such as aldicarb, to control early-season insect pests. In-furrow applications have largely been replaced with insecticide-treated seed. Since 2012, more than 60% of the U.S. cotton crop is planted with seed treated with insecticide, primarily the neonicotinoids imidacloprid or thiamethoxam. Several insects or insect groups are included on the labels of these neonicotinoids for use as seed treatments. An increased understanding of the risks associated with economically injurious populations of insect pests is needed to optimize use of early-season insecticides and reduce over-reliance on them in cotton, especially when initial decisions for insect control before planting have subsequent influence on future pest abundance. Existing literature pertaining to these early-season cotton insect pests was examined to identify factors favoring their distribution and abundance and the importance of insect control tactics used at planting. The relative importance of some of these pests is dependent on the cotton-growing region and impacted by local production practices. Thrips (predominantly Frankliniella spp.) (Thysanoptera: Thripidae) are the most prevalent early-season insect group in cotton across the United States and the primary target of initial insect control. Other targeted insects include the black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), aphids (predominantly Aphis gossypii Glover) (Hemiptera: Aphididae), plant bugs (Hemiptera: Miridae), and wireworms (Coleoptera: Elateridae).

Integrated management of pine wilt disease in Troia

Troia is a sandy peninsula covered mainly by maritime pine, Pinus pinaster, forest which has suffered since 1999 the impact of pine wilt disease caused by the pinewood nematode Bursaphelenchus xylophilus. The nematode is dispersed by the insect vector Monochamus galloprovincialis. Over the years, intensive management of the forests involved annual sanitary felling of dead and wilted pines, the placement of baited traps to capture flying insects, and the preventive inoculation of pines with a nematicide/insecticide by micro-injection. These measures have been effective in the control of pine wilt disease and in the decrease of the insect pest populations.

Comparative assessment of insect pests population densities of three selected cucurbit crops

Comparative assessment of insect pests population densities of three selected cucurbit crops

Agricultural production: assessment of the potential use of Cas9-mediated gene drive systems for agricultural pest control

ABSTRACTTo highlight how gene drives could be useful for control of agricultural insect pests, we selected species that are pests of animals (New World screwworm), plants (spotted wing Drosophila, diamondback moth, Bemisia tabaci whitefly), or stored grains (red flour beetle). With the exception of whitefly, routine methods for delivering DNA to the germline and selecting for genetically modified insects have been developed. The traditional approach in agriculture has been to suppress insect pest populations using insecticides and other farming practices. Similarly, we suggest the main use of gene drives in agriculture will be for population suppression through targeting essential genes. We provide examples of gene drives that target specific genes including female-essential genes. Further, we discuss issues related to containment in the laboratory and eventual field testing of strains harboring a Cas9-mediated gene drive system.

SEASONAL INCIDENCE OF PLUME MOTH, EXELASTIS ATOMOSA (LEPIDOPTERA: PTEROPHORIDAE) ON LONG DURATION PIGEONPEA, CAJANUS CAJAN

The present research was aimed to study the incidence pattern of plume moth, Exelastis atomosa during Kharif 2015-16 and 2016-17 for long duration on pigeonpea cv. Bahar. The results revealed that the incidence of pod bug started from the 5th standard week during 2015-16 and from 6th standard week during 2016-17 and it remained active up to 15thstandard week of both the years. The E. atomosa population attained its peak level during 11th standard week of both the years i.e., 1.73 larvae/ plant and 1.6 larvae/ plant respectively. Correlation studies indicated that population of E. atomosa exhibited a significant positive correlation with maximum and minimum temperatures and wind velocity whereas a significant negative correlation was established with average relative humidity. Other abiotic factors had no significant effect on this insect pest population. The regression equation revealed that variations of different weather variables caused approximately 85.3 and 75.9 per cent variations in E. atomosa population during both years, respectively.

Cis-Jasmone treatments affect pests and beneficial insects of wheat (Triticum aestivum L.): the influence of doses and plant growth stages

cis-Jasmone (CJ) is a natural plant volatile derived from linolenic acid via the octadecanoid pathway, and acts as a semiochemical and plant defense elicitor. In the present study, the effects of three different CJ doses (25 g.ha−1; 50 g.ha−1; 100 g.ha−1), applied at two different wheat growth stages (flag leaf just visible and emergence of inflorescence completed), on wheat insect pests and beneficial insects were investigated using three different sampling methods (direct visual counting, sweep-netting, colored sticky traps) under semi-arid conditions during 2011–2013.Depending on the insect species, CJ dose-effects varied with study years, plant growth stages and/or sampling methods. Among the pest species, cereal aphids (apterous and alate) were the most prominently affected by CJ treatment, irrespective of the dose; fewer aphids were detected on the CJ-treated plants than on untreated control plants by direct visual counting, sweep net and yellow sticky trap samplings. CJ treatment also had deterrent effects on phytophagous thrips species and wheat stem sawflies (Hymenoptera: Cephidae), whereas CJ was an attractant for aphid parasitoids, coccinellid species and the wheat stem sawfly parasitoid Collyria coxator (Hymenoptera: Ichneumonidae). CJ treatment had no effect on syrphid species (Diptera: Syrphidae). There was no significant effect of CJ treatment on wheat yield; however, CJ-treated plants were taller than untreated control plants.Although the behavioral responses of the studied species to CJ treatment varied with the plant growth stage and treatment dose, and were not consistent across all sampling methods, our findings indicate CJ treatment may be used to reduce some insect pest populations and manipulate some natural enemy species under field conditions.

Assessing the feasibility of creating tsetse and trypanosomosis-free zones

Abstract The establishment of the Pan-African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) falling under the African Union Commission, and the initiation of national PATTEC projects in affected African countries stimulated a revival of national and sub-regional efforts and helped to generate donor support for creating sustainable agricultural and livestock development zones that are free of tsetse and trypanosomosis (T&amp;amp;T). Such projects are long-term, complex undertakings, requiring careful planning and consideration of relevant technical and non-technical interdependencies. There is international consensus that T&amp;amp;T interventions should: (a) adopt a phased and conditional approach in their planning, implementation, and monitoring; (b) adhere to the integrated pest management area-wide (AW-IPM) concept, ensuring that the most appropriate combination or sequence of intervention measures is selected; and (c) follow the AW-IPM concept of targeting entire isolated or well-confined insect pest populations. The phases of this process include: (a) policy and strategy development, assurance of long-term commitment, and establishment of effective management structures; (b) baseline data collection; (c) general technical feasibility assessment; (d) consideration of various relevant factors and trends; (e) detailed assessment of the technical feasibility of combinations of intervention tactics that may or may not include a sterile insect technique component; (f) capacity development and pre-operational work; (g) operational implementation of an AW-IPM campaign to create T&amp;amp;T-free zones; and (h) adherence to agreed procedures for the ‘Declaration of Assumption of Freedom from T&amp;amp;T’, and, eventually, the ‘Declaration of Elimination’. This paper provides guidance on the steps to be followed to assess the feasibility of creating T&amp;amp;T-free zones.